- Porsche 924 (931) Turbocharger Upgrade Service


     This is a bolt-on upgrade for the 931 which will easily support over 200 HP.  The factory compressor wheel is tossed aside for a 944 Turbo compressor wheel and the compressor housing is machined to accommodate the (4 - 5mm) larger wheel.  As with all of our signature turbos it has a fully blueprinted CHRA which lowers internal friction and improves durability.  The pair of journal bearings that support the turbine shaft are modified to increase oil flow to the inner journal surface and the turbine shaft bearing surface is polished to increase surface hardness and lower friction.  Even the thrust plate is upgraded from the standard 270 degree arrange to a full 360 degree heavy-duty plate and collar set. These have modified oil ports feeding the thrust pads which we polish to lower friction and improve durability as well.  We even polish the cast surface of the compressor backplate adjacent to the compressor wheel so that airflow into the compressor housing is unimpeded by friction or turbulence.  These modifications improve rotor group transient response significantly because of the cumulative 25% reduction in friction.  Spool-up is thus a good 250 rpm sooner than without these modifications and techniques.


     We not only replace the compressor wheel with a larger 44 mm wheel for substantially more airflow potential, but the housing is fully ported to boost airflow that much further.  Both the inlet and outlet are worked over to make the air path less restrictive and improve compressor map efficiency.  These 931 castings were full of metal flash that only induced great amounts of turbulence and hurt turbo responsiveness.  After a couple of hours being cut and reshaped by long-reach carbide burrs, the sanding rolls are  used on the passageways to produce a smooth surface for the air to flow through quickly and freely.  What is the result?  This compressor section is capable of supporting 190 to 250+ HP worth of airflow with ease depending on boost settings and fuel enrichment.  Now that's an upgrade that you will thoroughly enjoy.


     Each turbine housing receives special attention to complete the package with porting of its passages and a ceramic coating on its exterior.  The KKK K26 inlet or scroll passage has a very rough cast surface from the factory so after more than an hour with the carbide burr it looses exhaust gas flow restriction and has a greater volume capacity too.  The cartridge rolls are called upon next to make the surface properly smooth for the ultimate in gas-flow velocity potential.  The outlet gets opened up a bit to complete the package.  There is just as much attention paid to the turbine housing as the compressor housing to ensure a balanced performance of the rotor group under load.


     The combined efforts of the CHRA blueprinting, compressor wheel upgrade, and housing modifications result in a turbocharger that responds at least some 500 rpm better than a factory 931 turbo with 30% more airflow at the same boost levels.  Power delivery is more immediate and progressive, with boost pressure building just the way you dreamed it could with a hotter engine tune.  Adding an intercooler will turn your powerplant into a proper Carrera GT level performer at close to stock boost levels and even stronger with the wasegate dialed up.  Porsche 924 owners have begged for this upgrade for years, so Exclusive Turbosystems has answered.  Usually this is a great alternative to trying to source a good used turbocharger when the factory spec original has a catastrophic failure occur.


     The polished compressor housing is optional and since it requires cutting of the housing and TIG-welding back together to perform properly is a premium to the standard upgrade.  We can also upgrade the bearing housing to a water-cooled casting for the ultimate in durability and longevity.  Very popular with these turbos which tend to have heavy carbon deposits inside the bearing housing without being water-cooled.



List price  - $947.67 (core turbocharger is required with order)

Polished compressor option list price - $1127.67

Water-cooler bearing upgrade - $175


     Porsche had a wonderful idea with these cars by combining a very tuneable engine and the well balanced 924 chassis.  When setup well and tuned to much higher boost levels, the 931 is a serious performer on the road or the racetrack. Perfect twisty-road delight with character and poise.

      Having ownership experience of one of the world's best turbocharged supercars gives a wealth of insight into what makes for a great road-going tuned vehicle.  Our Lotus Esprit was a low-mileage V-8 twin turbo model that was located in Missouri and purchased from a multiple Lotus vehicle owner and enthusiast.  It was kept in a pristine garage all by itself, parked on 4 pieces of carpet to keep the tires from developing flat-spots, and flat-bedded to Chicago to have the Lamborghini dealership perform its service work.  To say it was clean is an understatement.  We drove it to our first shop in Raleigh, North Carolina to assess it and get a feel for what track we would pursue in any improvements or modifications.  The overall handling was exactly what would be expected from a Lotus.  These cars are most at home on a twisty patch of asphalt.  Having razor-sharp response both in engine output and in chassis dynamics, the pace over the blacktop was swift indeed, leaving our Hemi-Challenger rental car behind with ease in the mountains.  It didn't have a chance of keeping pace really.  When the road opened up it was more stable than our C5 ZO6 Corvette at speed, especially above 100 mph, and simply a much more refined high-speed traveler. The body actually produced some useful downforce, and the Esprit was very precise in handling the road undulations of the mountain passes of West Virginia.  All of which we expected.  No problems dispatching with slower traffic, which was pretty much every other car on the road.  The road test numbers don't  fully tell the story of how this car accelerates on the road.  There is no lag to speak of, or waiting for even the engine to come on cam.  Has a torque feel similar to that of a domestic V-8 engine with a midrange and top-end power delivery they fall well short of.


      The car already had a 'high-torque ECU' installed to its credit but no other engine modifications were made whatsoever.  So we had a 370-ish HP V-8 Twin Turbo Esprit that was healthy, clean, and true to form.  We found it with a mere 11,297 miles on the clock being originally purchased by the owner of a major bus line and serviced in Springfield, Massachusetts.  It sported a Quaife limited-slip differential installed along with some Stainless Steel brake lines and straight pipes off of the factory converters. It didn't sound bad but it wasn't dreamy.  Off came the 2.5" pipes and thus began our short list of modifications.  We fabricated a custom 3" Stainless Steel exhaust which incorporated the factory catalytic converters and larger resonated 4" exhaust tips.  Now she really had a sweet growling sound that made you take notice.  Added some more ponies for the Michelins to cope with as well.  The boost was tweaked to about 16 psi which was what we deemed safe without intercooling or substantial fuel tuning.  The tank enjoyed a steady filling with 100 octane unleaded race fuel so we had her dialed in to about the 420 - 430 HP level.  Those numbers are enough for a 3000 lb car to be very quick and fast anywhere.  It easily ran neck-and-neck with our C5 ZO6 Corvette which we know is an 11-second quarter-miler.  We saw a drama-free and smooth 160 in her with no sign of slowing, just the fear of the long-arm-of-the-law catching us.  The exhaust gave the Esprit a mean burble at idle that turned to an aggressive ripping tone on heavy throttle input.  It was given much respect on the road.  Enough uumph to get the best of a BPU Supra, run with a 500 +HP M6, and even a well-tuned 335i laying down well over 400 HP at its rear tires.  Yeah, these cars are quick.  None of those cars could keep up in the curves though.  She's just too light on her feet to be held back in the twisties.  We learned that these cars are best modified with respect to the original formula prescribed by the late Colin Chapman himself.  Beyond this requires a racetrack to enjoy fully.  Trust us, she is a real driver's car that deserves respect.


Lotus Esprit V8 Ball-Bearing Turbo Upgrade (Level III)


     For the ultimate Esprit V8 turbocharger upgrade we offer the 660 HP capable 918TT-G66 turbos.  These are based on the Brand New G-Series turbochargers which are the latest turbos to be offered by Honeywell-Garrett.  They are based on a very compact dual ball-bearing CHRA with cutting-edge compressor wheel aerodynamics and outstanding responsiveness that has no pears.  Able to support an astounding 1320 HP at high boost, these turbochargers will unleash new levels of power from the Lotus 918 engine.  If you have a Lotus Esprit that is built to be a GT-1 tribute, these are the best turbos you can bolt onto the Esprit manifolds to deliver the power you crave.  No matter what engine output level you are tuning for 700 HP, 800 HP, 900 HP or higher, these turbochargers will deliver the airflow quickly and efficiently for years to come.


     At the core of the brand new 918TT-G66 is a dual ceramic ball-bearing cartridge. It has a Stainless Steel bearing cage for the the best durability possible.  On the hot side of the CHRA is a newly-designed turbine wheel made from Mar-M, an aerospace alloy of extremely high-temperature stable properties. It can withstand a constant 1050 degree Celsius exhaust stream.  This advanced 84-trim turbine wheel profile delivers outstanding gas turbine dynamic flow rates which even exceed that of the well-respected GTX turbine wheel profiles.  Using Mar-M as the blade material has allowed for a profile which is very thin, not just at the outer edges, but closer towards the shaft centerline as well for a significant reduction in mass and overall inertia.  This aspect is key to the G-Series turbocharger turbine acceleration being so very fast.  The blade profile of course, supports higher exhaust gas flow rates through the wheel, having a distinctively swept trailing edge and large spacing between each blade to allow gas to exit past without restriction.  Countless hours have been invested by the aerodynamicists at Honeywell-Garrett on this turbine wheel design with good reason, the G-Series turbos owe their incredible performance more to it than even the compressor wheel specifications. Speaking of which, the 9-blade compressor wheel is clearly worthy of its own praise.  It features a forged aluminum alloy billet wheel design that is very low in mass, yet it can exibibit next-level airflow capability because of its aerodynamic shaping and profile. These CNC-machined compressor wheels offer very tight dimensional tolerances in the .001“ range which is key to efficiency in high-rpm turbochargers. The forged, billet material is necessary at this level of turbocharger design to achieve such performance and offer the needed durability that is expected. Being able to move about 60 pounds of air each minute with a rather small 54mm compressor wheel inlet diameter is a noteworthy feat so the level of development invested by Honeywell-Garrett has returned excellent results.


     A feature-packed compressor housing surrounds the billet wheel and turns the airflow from the wheel into a mighty stream of pressurized air for your engine to digest.  The inlet has been machined with precision and it has an anti-surge channel surrounding the compressor wheel.  On the discharge scroll a .70 A/R ratio makes the best of the airflow for quick boost-delivery from the turbocharger compressor wheel flow abilities. This new casting has a smoother finish compared to housings of the past and is key to maintaining the G-Series flow efficiency levels.  There is a pre-machined boost reference port and also a port for an optional speed sensor in the compressor housing.  This allows a full-featured ECU the input from the optional speed sensors a to catalog the turbochargers during laps.  Something even the original GT-1 Esprit did not offer.  An o-ring is fitted in between the compressor housing and the backplate surface to keep boost pressure from having the opportunity to escape.  The 918TT-G66 turbocharger has a full-featured compressor housing there is no doubt.  A great match to the compressor wheel itself that is covers.


      Each of the 918TT-G66 turbos has a 3” compressor housing inlet.  Exclusive Turbosystems includes special adaptation pipes for fitment onto the Esprit V8 engine.  For connection to the Esprit V8 these turbos have T25 inlet flanges on the turbine housings.  We have them outfitted this way for a true bolt-on fitment.  These housing feature a .49 A/R ratio which really gets the best response out of the turbochargers.  Exclusive Turbosystems includes turbine housing porting on these turbos for the Esprit V8 just to make the best of the potential of these 918TT-G66 turbos for you.  Both the turbine inlet scroll and the turbine housing outlet area is ported to flow at its ultimate level.  A specially-fabricated 3.5” V-band outlet is TIG-welded onto the turbine housing for the very best exhaust gas flow through the turbine wheel.  Because each of these turbos can support more than 600 HP using a 3.5” exhaust piping diameter is entirely appropriate, even at lower boost and tuning levels.  This allows the lowest backpressure possible on the turbos and the offers the most output from the turbos and the 918 engine at all boost pressure settings.  


     With a pair of these 918TT-G66 turbos bolted in place on the Esprit V8 you have the option of running lower boost settings and enjoying the scintillating responsiveness they offer compared to the factory T25 turbos, or further tuning the engine with fuel delivery and breathing upgrades to really unleash the fury within the Type 918.  With a proper intercooler system and a stronger transaxle handling the power transfer to the axles, there are many different positive aspects of employing these advanced turbochargers on an Esprit V8.  They are far more efficient than even the best T25/T28 hybrid turbos, offer the durability of a full ceramic ball-bearing CHRA, and deliver airflow with much less heat at higher boost settings. 


Cost - $5,685.85  918TT-G66  *1-Year Warranty


Porsche 944 Turbo (951) & 924 Turbo (931)  Turbo Upgrades

     The Esprit was designed just right in our opinion.  From the rigid tubular-steel backbone chassis and well-articulated independent suspension, to the excellent brakes and composite body only weighing in around 3000 lbs, This car was made to take on curves with gusto.  Add to the equation the motivation of a flat-plane V8 with 350 HP and 295 ft-lbs of torque and you have a quick supercar that's iconic in how it looks and drives.

Lotus Esprit Tuning & Turbo Upgrades

     The Porsche 944 Turbo is STILL a force to be reckoned with on the road courses around the world.  The combination of its perfectly balanced chassis boasting  50-50 weight distribution and a tough and simple SOHC 4-cylinder 247 HP engine, make for a great platform to build a fun and competitive track-day pleasure ride.  These cars are very tuneable to much higher performance levels making them a pure delight on a mountain road like the 'Tail of the Dragon'.

- Porsche 944 (951) Turbocharger Upgrade Services/ Turbocharger Upgrades


     For the 951 turbo models we can easily supply a KKK upgrade turbo for a factory-appearance performance upgrade.  We can set you up with either a K-26 with an upgraded compressor section and modified bearing assembly, build a K-26/K-27 hybrid with a larger compressor wheel and turbine wheel for serious top-end pull, or a billet compressor wheel hybrid that can run at higher boost pressures well suited for the track.  Either way, the smiles with will increase the right foot exercise, you can enjoy over 400 HP With the K-26 upgrades and a sobering 500 HP from the K-26/27 billet compressor option we offer.  The KKK turbochargers offer up loads of character in the way they spool-up and deliver the boost.  Matched with a suitable exhaust upgrade, some cylinder head work, larger fuel injectors, and intercooler upgrade, the 944’s low curb weight makes for a very quick car by any standards.  If you don’t need to retain the KKK architecture we can apply some modern turbocharger technology and compressor aerodynamics for incredible boost delivery and res that will have you giving ‘big-brother’ 911’s fits around the track. 



 - Stage I 944 Turbo Upgrade


     Our Stage I upgrade for the Porsche 944 Turbo is a very potent, and 420 HP capable shot in the arm.  We begin with a compressor housing wheel upgrade that is an updated aerodynamic profile for the KKK K-27 turbocharger family.  Our profile of the blades is much larger in blade area with an increase in compressor inducer (inlet) diameter.  Our wheel also features a thicker blade and higher tensile strength cast-aluminum material.  Combined with our blueprinted CHRA and ported housings, this results in a very respponsive turbochrger upgrade that will bolt up to the 951 up-pipe and connects to the 4-bolt downpipe flange as well.  Combined with a good 3" exhaust system you enjoy close to 300 HP engine output with little more than factory boost levels dialed in.  Should make for much better straightaway passing manuevers on-track and thoroughly enjoyable  canyon-carving on your favorite stretch of blacktop.  Need some details to explain what we put into this combination, then read on.

   

     Each of these 944 upgrades begins with a hand-selected bearing housing and turbine shaft.  Our special journal bearings and thrust components are installed after we modify both their oil delivery and journal surfaces for lower friction and higher hardness.  The thrust plate is upgrded to a full 360 degree arrangement for the ultimate in load bearing capacity.  The shaft surfaces where the bearings ride are polished to reduce friction and improve durability as well.  Our tweaks to  the bearings and thrust components improve turbo rotor group acceleration by some 250 rpms over an unmodified CHRA.  The larger diameter (48mm versus 44mm) compressor wheel injests some 50 lbs of air and easily betters the factory 951 wheel by 40% even without the housing enhancements we include with this turbocharger upgrade package. 


   On the working side of the turbocharger we have a housing boasting our porting on both the inlet and discharge of the turbine wheel.  Inlet passage porting takes care of the rough cast finish of the factory K-26 housing which is rough and hurts gas flow and velocity.  The shape of the passage is massaged to form a nicely sloped radius to promote a more effective venturi for the gasses to flow through towards the turbine balade tips.  The finish is smooth to the touch and better gas velocity and ultimate volume capacity is increased as well.  The standard 951-spec turbine wheel will drive the compressor wheel upgrade to the 420 HP level with our combination of housing modifications and improvements and the Turbo-S spec turbine wheel and housing expands this level to the 470 HP with the same compressor section. 


     Since we only use 3 components from the core turbocharger and every other component is brand new, this is a very cost-effective upgrade that boasts easy interchangeability and reliability.  The compressor section uses a later generation wheel and housing combination for improved efficiency and true-to-form KKK appearance and fitment.  The compressor housing inlet is a 2.75" diameter which is the only hint of the turbocharger being a non-original turbocharger.  We even TIG weld the factory 951 turbocharger outlet onto the compressor discharge for a perfect fitment to the turbocharger outlet coupler. The outer diameter of the housing is a mere 1/2" larger than that of the factory 944 turbocharger so it is a tidy fitment.  


 - Included Features:


 - Blueprinted CHRA

 - 360 Thrust component upgrade

 - Fully ported compressor & turbine housings

 - Compressor housing externally polished

 - Ceramic-coated turbine housing exterior


Your Price - $1286.57  (standard turbine wheel & '6cm' housing)   

                   - $1492.76  (Turbo-S turbine wheel & '8cm' housing)

- Turbocharger Upgrades (Bolt-On Level I)


     Exclusive Turbosystems offers a billet compressor wheel T28 Style ball-bearing bolt-on upgrade pair of turbos based on the very latest Honeywell-Garrett turbocharger technology.  The 918TT-860 turbocharger is based on the new GTX2860R turbocharger which features a 46mm billet aluminum 8-blade compressor wheel that is the latest Gen-2 compressor wheel design recently released from Honeywell-Garrett.  It may be small but it boasts a capability of supporting 250 - 450 HP depending on the boost settings that are dialed-in with the wastegate actuators.  This amounts to an output range of between 500 HP to 900 HP potentially.  These can be an excellent upgrade turbocharger for a healthy 918 engine and a good platform for future tuning nice other modifications are performed with the engine and drivetrain.


     A ceramic ball bearing supports each end of the turbine shaft inside of the 918TT-860 CHRA.  Garrett pioneered this technology some years ago and widely accepted to be pretty much perfected it at this point.  The performance and durability of their ball-bearing turbochargers is known wherever turbochargers are used for performance engine builds.  This latest example of that technology is at the center of this turbochargers outstanding responsiveness and high-rpm capability.  You can really lean on these turbochargers with some pretty high boost pressures, well above the 2 BAR level even.  To flow the amount of air this turbocharger can move at the rpms it can achieve, requires a very strong compressor wheel, to this end the ‘860’ has a second generation 8-blade billet wheel. Honeywell-Garrett has fitted a CNC-machined, aluminum alloy wheel with adanced aerodynamic profiling that has a wide range of its peak efficiency flows rates.  This next-level compressor wheel design is why the 860 can achieve such impressive airflow rates with a mere 50mm compressor wheel inlet diameter.  Driving this compressor wheel is a 54mm turbine wheel with a 69% efficiency rating which is as high as the majority of the Honeywell-Garrett GTX lineup of turbine wheels can boast. It obviously delivers enough rotational torque to get the compressor wheel up to the peak rpm levels fast. The 450 HP+ rating of this turbocharger is proof positive to the turbine wheel’s effectiveness. This combination of compressor and turbine wheels is very well suited to deliver high airflow volumes quickly, making it an excellent match to the Esprit V8 engine.


     As a complement to the Gen-2 46mm compressor wheel, Honeywell-Garrett has fitted a redesigned compressor housing to fully exploit its performance capabilities.  The compressor housing has a 3” diameter ported-shroud inlet offering anti-surge properties to the housing.  This particular inlet has a few machining operations applied to improve the incoming airflow efficiency.  The inlet has a smooth bore on both the larger inlet cavity and the inner compressor inlet has been radiused towards the compressor wheel inlet.  A new casting process gives the exterior and interior passageways smoother surfaces for better airflow properties. This housing also features a compact .60 A/R for very fast boost build-up from the compressor wheel.  A fully machined port has been added to the housing for a speed sensor allowing the option of monitoring turbocharger performance directly.  The housing itself has a very small diameter which is key to the 918TT-860’s compact profile allowing placement in the Lotus engine bay with room to spare.


     There are 2 turbine housing choices available for the 918TT-860 turbochargers.  These T25-flanged housings are for an internally-wastegated setup (just like the OEM T25 Esprit turbochargers) and are offered in .64 A/R and .86 A/R sizes.  Both of these housings take full advantage of the turbine wheel thermodynamic flow rates and offer strong turbine acceleration and excellent turbocharger response.  The smaller .64 A/R housing will produce the fastest turbocharger response, while the .86 A/R housing will alloy the 918TT860 turbos to achieve their top airflow potential.  We fit a specially fabricated housing adapter so that a 3” diameter exhaust can be attached to the outlet of each turbocharger.  This is a V-band flanged adapter for superior flow characteristics from the turbine discharge and a gasket-free joint similar to the factory Lotus Esprit V8 exhaust system connection.


     The compressor housing inlet for the 918TT-860 turbocharger is slightly larger than the OEM T25 turbocharger fitted to the Esprit so we have included the correct hose assemblies for connection to the factory air filter boxes.  Also included is a pair of the correct wastegate actuators which are adjustable.  


     These are the latest generation ball-bearing turbochargers that are far more responsive than any upgraded T25/T28 could possibly be with ALOT more airflow.  These turbos respond as fast as the factory T25 turbos (actually they are faster) but flow twice as well.  They are also far more efficient so that even without intercoolers you can have more airflow delivered into the plenum of the 918 engine at the same boost pressure settings as the factory T25 turbochargers.  The full ball-bearing cartridge means you get reliable performance from day-1 and the boost limits are much higher because of the ceramic ball-bearing‘s higher thrust load capacity.  The 918TT-860 turbos can be great replacements to worn out factory T25 turbos and good upgrades to build a high-output 918 engine from 450 HP up to 800 HP plus.  These turbos are most efficient (73% efficiency) delivering between 180 HP - 325 HP each with the ability to deliver 450 HP+ apiece with 60% efficiency.  No matter how you look at the numbers the 918TT860 turbos offer quite a range of tuning for the Esprit V8.



Costs - $4,687.85  (2) 918TT-860  *1-Year Warranty*


     Arguably one of the best balanced cars ever produced, the 944 chassis is a solid platform to enjoy canyon-carving or club racing alike.  The basic aerodynamics of the body were also quite good when it was designed so with some updating this Porsche can be loads of fun as a fast mover, either on your favorite back roads, or the road courses around the globe.  Look no further for the right shop to keep your classic 944/ 968 in top form or even restoring it if you'd like.  Since we can also provide improvements to both the driveline as well as the chassis, your ideas for a personalized 944 is just a few conversations, suitable base car, and appropriate budget away from your driveway or trailer.


For the road racer in you, we can turn your tired base car into a body-in-white straight unibody with reinforcements for the suspension load points.  Then we'll fit a cage to it that ties the suspension together, stiffens the unibody, and most importantly, protects you if she has a shunt.  Depending on how you want the build to be finished and the class rules to follow, we can use some mild upgrades or we can trick it out with more modern and capable components.  Or we can just set you up with a nice spec car for weekend fun.  No matter what the plan is, the 944/968 chassis lends itself well to driving at high speed over many different roadways and tracks.


     If you don't want a trailer-kept project, no problem, there are numerous options to update the capability of these Porsches in street use.  With our in-house engine department, we can update the four-cylinder powerplant or build something different and unique.  Bring your wildest ideas.  The 944 is a nice canvas to create a masterpiece with if you want to stand out.  Those fender flares beg for lots of rubber to fill them, and the engine compartment seems ripe for a serious engine build, even a transplant.  Why not?  We're always game for 'different'.  A 944-based project with a driveline transplant and customized suspension and super-wide flares won't give the concours crowd any heart attacks over ruining the value of a six figure piece of Porsche history like some early 911's.  These are REAL drivers.  They take very well to being modified far beyond the factory specifications.


Principle Modifications Offered:


 - Turbocharger Upgrades

 - Intake Manifold Upgrade Fabrication

 - Roll Cage Custom Fabrication

 - Unibody Seam-Welding

 - Coilover Installation and Corner Weight Setup

 - Turbo System Custom Fabrication/ Modifications  

 - Race-Prep Modifications (Fuel system, Fluid containers/ reservoirs, Brake setup, Air jack pneumatics, Dry-sump setup)

 - Custom Suspension Modifications 

 - Bespoke Exhaust Fabrication 

 - Engine (SOHC/DOHC) Blueprinting/ Modifications

 - STAGE II Billet Compressor 944 (951) Turbo Upgrade


     At this  level the entire compressor section is updated and upgraded to features a more efficient billet aluminum compressor wheel design.  The forged aluminum alloy billet wheel is a modified K-27 sized upgrade which is stronger, and aerodynamically superior to any K-26 option available.  This upgrade ‘separates the men from the boys’ to quote a phrase.  Each blade has a much larger area and an aggressively swept form allowing spectacular efficiency in airflow.  This compressor wheel will move over 55 lbs of air.  More than enough to support 500 HP.  Surrounding the wheel is a compressor housing that is larger in internal cavity volume and equipped with a larger intake passage and discharge scroll as well.  Special machining of the compressor housing inlet makes certain that critical dimensions and clearances are maintained between the wheel and housing walls.  


     At the center of this upgrade is the bearing housing that we have fitted with several modifications and upgrades to complement the compressor sections capabilities.  All of the thrust components are upgraded to a full 360 degree set and all of the thrust surfaces on the thrust plate and washers are polished to increase hardness and lower internal friction.  The journal bearings are modified to improve oil flow into their inner race surfaces for an improvement in oil flow, cooling, and reduction in shaft rotational friction.  Both journal surfaces on the turbine shaft are polished to reduce frication and increase hardness and durability.  These modifications result in a 500 rpm quicker spool-up time and much better transitional response between various shaft speeds during operation.  Additionally, we modify the oil delivery within the bearings and thrust plate to increase oil flow and improve cooling effectiveness internally.


     The all-important turbine wheel section of the this turbocharger upgrade is based on the larger turbine wheel of the Turbo S 951 so we match it with either a 6cm housing or a 8cm turbine housing depending on your engine modifications and tuning level.  The 6cm housing offers the fastest turbine wheel acceleration with a slight trade-off in top-end compressor airflow, while the 8cm housing is best suited to heavily modified 951 long-blocks with ported heads, aggressive camshafts, and improved intake manifolding, etc.  Essentially, the 8cm option is the better option if fierce midrange and top-end power is paramount.  The housing is extensively ported on the inlet scroll and the discharge so it offers much improved turbine exhaust flow volume and velocity for driving the turbine wheel.  Much of the performance of these KKK upgrades is dependent on the porting of their exhaust housings.  Our feedback shows that customers are surprised to realize better turbocharger response than expected with such performance upgrade turbochargers as these.  The exterior of the housing is treated with a ceramic-based coating to keep the intake manifold heat-soak to a minimum and improve internal thermodynamic energy transfer to the turbine wheel.


     Flowing essentially double the airflow of a factory Turbo-S K-26, this is a serious bolt-on upgrade.  It offers essentially factory fitment with improved turbo responsiveness and killer airflow delivery.  This is a modernized turbocharger upgrade for a classic sports car. 


 - Included Features:


 - Billet aircraft alloy aluminum forged compressor wheel

 - Blueprinted CHRA

 - Fully ported compressor &turbine housings

 - Ceramic-coated turbine housing

 - Polished compressor housing exterior


Your Price - $1726.52  (‘6cm’ Turbine housing)

                           - $1843.78  (‘8cm’ Turbine housing)


For those who are truly crazy, we can build a 800 HP 70mm/8cm KKK upgrade.  Call for details

     Most would consider the transaxle fitted to the Esprit to be it’s ‘Achilles heal’.  With good reason.  Many have snapped mainshafts and stripped gears once the engine’s power building potential was explored by tuning.  Our solution involves a 6-speed upgrade which should erase these concerns and establish a new baseline for what you can reliably put to the road in horsepower and most importantly, torque.

 - Lotus Esprit (V8)  6-Speed/ LSD Transaxle Upgrade


     Proudly,  we avail the option of a stronger transaxle with a 6th gear and a tough limited-slip differential for the V8 Esprit.  This is the ‘gateway’ mod for the Esprit that allows you to fully exploit the Type 918 V8 twin-turbo engine.  Say goodbye to the flimsy shafts that can shear, and prepare for a modern transmission design with better ratios overall, more robust internal shafts , bearings, and gears surrounded by a stronger (singular casting for the input shaft, differential, and majority of the gear sets) casing, NOT split down the middle.  The factory UN-1 transaxle is nice enough for pretty much factory-stock Lotus Esprit V8s, but when upgraded turbochargers or other modifications that elevate the 918 V8’s output are brought onboard, it shows its shortcomings in a hurry.


     We secure a suitable (new or low-mileage) transmission core and then perform our cachet of fitment modifications so that it can be installed behind the Lotus V8 engine.  First, we remove the front case and access the inner gears, shafts, bearings, and seals to ascertain which components requiring replacement/ servicing.  During the internal servicing operation the outer case undergoes a precision modification to allow it to mount to the 918 engine bellhousing flange.  Instead of cannibalizing a UN-1 transmission for its front case casting, we have a mounting flange made from billet aerospace (T-6) aluminum alloy precision which is milled to be be fitted to the 6-speed transaxle and TIG-welded onto the front transaxle case.  Dowels are used for alignment of both pieces.  Just before bolting the transmission onto the back of the Esprit engine we finish the internal service with a LSD installation.  Now there are few concerns for putting all of your Esprit’s power to the tarmac whether the road is straight, twisted, or a combination of both.


     The axles attached to the output hubs on the differential are also specially-fitted for the Esprit V8.  We employ a high-torque-capacity CV joint and large axle shaft assembly for this transaxle upgrade.  Mostly we have the idea that if you are having this transaxle installed, you are looking for more engine output/torque to be transferred to the rear wheels.  Stronger axles are a good idea and compliment the transaxle upgrade.  These incorporate a blueprinted CV joint with higher-strength balls in the joint, specially-prepared joint surfaces, and high-temperature bearing grease for the inner and outer joints.

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     We specialize in cylinder head porting for the 918 Lotus engine.  These are great heads as delivered by Lotus, but there is room for some improvement.  The real benefit is the better port tcture after we sand away the casting finish on the inlet ports an make the exhaust ports really smooth.  Throttle response is improved and more power is delivered from the engine.  Excellent for both street-tuned Esprits and purpose-built roadcourse engines alike.

     The Lotus Esprit has plenty of potential to make more power and therefore more heat.  Any modifications need to begin with installation of a proper triple-core aluminum radiator upgrade such as this one to the right with 3 high-performance fans.  Better cooling is a must with these cars to keep temperatures from getting too high.  This radiator and fan package takes away that concern.

     It is commonly known that sitting in traffic for anything more than a couple of minutes will have the temp gauge climbing fast in a Lotus Esprit.  These cars were designed to be driven at high speeds with plenty of air moving across the radiator for keeping temps in line.  That low sloping nose can only fit so much radiator and even though the Esprit’s radiator is angled it is not quite all that it could be to keep the 918 engine temps down under all conditions.  Add to this marginal capacity a highly-tuned turbocharged engine and you hav a recipe for problems, expensive problems.  Simple solution for this is a modern aluminum multi-core radiator and some high-efficiency cooling fans.  Problems solved.  This TIG-welded radiator has better heat dissipation capabilities, higher thermal load capacity, and is much more durable than the radiator fitted by Lotus.  Three pass cooling means the core gets the heat out of the coolant faster and with some reserve capacity for really adverse conditions, like a high boost run up a mountain with a lot of slow speed curves.  Not the place to have a ‘marginal’ radiator in the nose of your Esprit.  A triple set of ultra-efficient high-speed fans keep the air moving across the radiator fins very fast to dissipate the heat out of the coolant in a hurry.  The original triple fan arrangement is light, but pathetic as far as airflow.


Your Price - $872.92

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     Turbocharger upgrades that all feature incredibly swift response and impressively superior levels of airflow that Lotus engineers did not have available when the Esprit V8 was manufactured.  Now the 918 can efficiently reach output levels that modern supercar powerplants produce, with surprising ease.

     A stronger transaxle to solve the weakness issue that has held back aggressive turbocharger and engine upgrades for the Lotus Esprit.  With this sturdy 6-speed you can handily cope with the torque the flat-plane twin-turbo V8 can produce once the boost is turned way up with modern turbochargers. 

     Engine internal modifications and upgraded components to produce and expanded level of refined power.  Intake and exhaust manifolds ported for unrestricted flow.  Redesigned forged pistons and valvetrain components to handle the 918‘s true output potential when aggressively tuned.

Lotus Esprit V8 Twin Turbo

Transaxle Upgrade Package

Lotus Esprit V8 & 4-Cyl Engine Tuning/ Modifications 

     This compact engine just begs to be tuned beyond the factory 349 HP level.  It has the block construction that other engines are envious of.  Cylinder heads with port angles that flow extremely well.  The manifolds are cast for space considerations and with a bit of portwork (on the exhaust) and modifications (on the intake) this 3.5L engine can approach 1000 HP. Let that sink in...3.5L - 850, 950 HP.

Lotus engineering is THAT good.

     Presently, there are many ways to construct a potent and competitive sports coupe from a Porsche 944, whether turbocharged from the factory or not.  Because of its ‘connected drivetrain’  torque tube design it has a semi-backbone unibody structure lending critically-important rigidity to the coupe.  With a well triangulated and braced roll cage these chassis can easily be setup with accurately-damped (coilover) suspensions for wheel control and consistent traction.  No wonder the 944 is commonly found on tracks today.

     So if you get a hold of a rolling chassis 944 what do you do with it?  Turn it into a nasty expression of all that you can do with a 944, that’s what.  Ours is a humble ‘89 944 originally sprayed in Guards Red and has a sun roof but NOT turbocharged.  No matter, we can fix that small lack of proper specification.  There was no engine, or transaxle, front seats, hood, rear hatch, or even a front bumper.  Like we said, a roller.  Actually a straight chassis, rust-free, lower-mileage, late-model example to be exact.  Pretty much a tailor-made solution to needing a ‘blank canvas’.  Probably should have done this years ago but anyway, its happenening now.


     Our plan is to take it to the max underneath the skin in every way.  The track is being widened and so the fender flares will be expanded.  Our 944 will be an ‘all-steel‘ wide-body for strength, we will shed some weight in other areas.  The larger flares are being fabricated  to allow plenty of room for 9.5” wide front and 12” wide rubber we are using on this chassis.  A full coilover suspension modification is being setup up front, and in the rear the same with a redesign of the geometry.  Don’t even ask, we won’t talk about the details until it is all welded up and she sits on her tires again.  It should generate more than 1.2 lateral G force on DOT-approved radials.  The roll cage will connect both ends of the unibody and suspension pickup points which will be extensively supported and reinforced against chassis twist.   At the rear of the chassis will rest a sturdy 6-speed transaxle and some beefy axle shafts.  Along with a decent size fuel cell, proper surge tank, some Bosch Motorsports pumps and filters, the relocated battery will take up space in the rear compartment of this 944.  For brakes we have decided that a set of 14” rotors front and rear being clamped by a set of lightweight Brembo calipers should cover the stopping duties quite nicely.  A set of adjustable sway bars will allow additional tuning of the roll stiffness and cornering balance.  Should be able to take on most any track we visit with enough adjustability to adapt the chassis for the corners, entries and exits.  All of the hydraulic fluids will be controlled by some Wilwood master and slave cylinders.  The electrical system will be simplified to reduce unnecessary circuitry and wiring weight throughout the body.    


     For weight reduction this 944 will have its unibody structure modified, some components swapped for lighter-weight replacements, and the subframes altered to trim away excess mass.  The body is going to be trimmed away where it does not improve structural rigidity and stiffness like in the rear compartment area and forward of the strut towers.  Since this chassis will have a fully fabricated tubular roll cage that connects both the front and rear suspension load points and drivetrain, many unibody panels can be cut away.  


     As far as the powerplant is concerned, it will be intercooled and turbocharged.  No surprise there.  Output will handily exceed 700 WHP with at least 750 Ft Lbs of torque.   Obviously we are going to fabricate the intake manifold to be most effective in strong midrange air velocity and cylinder filling.  Most likely an Individual-Throttle-Body arrangement.  The redline will be limited to about 8000 - 9000 rpms.  With a broad power-band from 3000 rpm to well over 8000 rpm this will have excellent acceleration out of the corners and down the straights.  It will have a fully-mapped port fuel injection system with a direct ignition of each spark plug.  Engine will be dry-sumped for durability as well as to lower the Center-of-Gravity with a shallow oil pan.  The turbocharger manifolding will be cast Stainless Steel or 321 SS alloy (thin-walled) tubing for durability.  Turbosmart will provide the wastegate and BOV components needed.  The injectors are from ‘The Injector Clinic’ and the engine management will be controlled by an MS3-PRO ECU.  Valves, springs, and Titanium retainers are bespoke pieces to our specifications from Supertech.  A pair of 45mm HyperGate wastegates will be used to regulate exhaust flow into the turbine while a pair of 50mm RacePort BOV’s will vent off the boost once the throttles are closed.  The turbos will be in the 67mm range of compressor size, perhaps larger.  Maybe a pair of the 70mm 944 KKK turbo upgrades we custom build with updated aerodynamics...


     Apparently we are not using a 951 engine as our platform to build upon.  The DOHC 944 engine was considered for use but this has been done before.  Our work with this 944 is a showcase operation.  The engine is at the center of the drivetrain buildsheet and has to reliably produce high-horsepower and high-rpm flexibility.  Since we are a turbocharger specialist company with extensive fabrication capabilities we can almost any powerplant that we feel is best for the chassis and how we wish to display our workmanship.  A bolt-in engine upgrade just won’t do.  Neither will an LS engine transplant which is simply archaic.  Pushrods in a Porsche?  Not our idea of a fitting powerplant for a 944.  You hear a Vette, but see a Porsche, scratching your head the whole time.


     Our 944 will be unique all around.  The use of a turbo system that is cutting-edge and not ‘period-correct’.  A lot more power to the rear tires than should be reasonably expected.  Not very much component sharing from the Porsche vehicle lineup.  We are an American company using some New-England style (work indoors in secret all ‘winter’ until the Spring, when you roll out to show what you’ve been up to) ingenuity and workmanship.  This 944 will be our interpretation of what can be done with a great ‘blank-canvas’ chassis.  It’s purpose is for research and development of turbochargers primarily, and a showcase secondarily.

Shop Build - IMSA Wide-body 944

Porsche 944 Turbocharger Upgrades

Lotus Esprit Cooling System Upgrades

Lotus Esprit Turbocharger Upgrades

     Intercoolers for the Esprit V8 are a necessity with higher boost levels and especially with any turbocharger upgrade.  For engine outputs of 400 HP up to 800 HP we offer a single intercooler with dual inlet and outlet connections.  Pictured to the left is a high-output intercooler fitment for 700 HP and above engines.  No matter where you drive your Esprit V8, or how much boost you run, one of these systems will keep the intake charge temperatures cool, allowing you to fully exploit the output potential of the 918 V8 Engine.

     The Lotus Esprit needs intercooling to fully unleash the capability of its Type 918 V8 engine.  We offer a pair of customized systems to retrofit an intercooler into the charge piping of the Esprit.  The first is a more compact system that is a dual inlet Air-to-Water intercooler for engines up to around 600 - 700 HP worth of engine output.  The second system is more ambitious and is built around a pair of Air-to-Water cores which can effectively cool the charge of a 1100 - 1400 HP Esprit V8.  Both of these systems have ample cooling reserve which is a necessity with the tight confines of the engine bay limiting their placement and optimum operational efficiency.  

Lotus Esprit Intercooler Upgrades & V8 Intercooler Packages

Lotus Esprit Cylinder Head Porting

     It must be clearly stated that we are not trying to modify these heads far beyond the original Lotus formula for port volume, velocity and engine efficiency.  We are only trying to get the last few remaining horsepower locked away within the original Type 918 engine blueprint.  These are production cylinder head castings with cast (3-piece) intake manifolds feeding their ports   There is ALWAYS room for improved aerodynamic efficiency when there are so many cast aluminum components involved with flowing the air/fuel mixture.  Having owned and driven the Esprit V8 for a number of years we have a deep appreciation for the original formula and hoe effective it is on the open road.  These engines are responsive and deliver excellent torque.  To simply increase port volumes for more peak horsepower potential is going backwards if done incorrectly.   A small increase of 10% - 15% is ideal for a highly-tuned 918 engine for the street.  These engines have delivered well over 500 HP reliably with the production cylinder head castings in competition so they are not really restrictive.  The intake manifold however, is a limiting factor for output.  But that  we can address separately.  We only need to offer 2 levels of porting for these engines, one for street-tuned outputs in the 400 HP to 600 HP range which are tuned more for responsive boost delivery with upgraded turbochargers and pump fuel, and the high-output engines which are typically tuned beyond 600 HP.  The latter requires higher port volumes and larger intake manifold aiflow delivery for the best results.  



Street-Tuned Cylinder Head Porting


     The first level of porting is ideal for Esprits with upgraded turbos and intercoolers tuned up to about the 600 HP level.  Modern upgraded turbochargers will flow alot more air into the 918 engine so improving its volumetric efficiency will be vital to peak performance.  The intake ports are modified in a different fashion from the exhaust ports.  Primarily we focus on making the intake ports smoother by eliminating the casting part lines and rough finish let behind by the casting process itself.  These are not mirror-smooth finished ports because of the fuel being introduced into them by the injectors which needs to be atomized partially before entering the combustion chambers.  The inlet of each of the (8) ports is opened up slightly to precisely match the gasket profile and promote a more pronounced  venturi-shape for the incoming air column to accelerate through as the valves open up.  This finish is slightly rougher on the port floor for fuel atomization where the injector spray is focused, but smoother everywhere else to increase port flow volume by reducing turbulence and laminar flow efficiency along the port walls.  Overall volume is only marginally increased by a small 10% at this level, but the velocity levels will be improved by 15% which is more important for cylinder filling and volumetric efficiency.  The primary goal is throttle response and more efficient cylinder filling. 


Pricing - $2,440 (Per Pair of Cylinder Heads) 



'Race'-Tuned Cylinder Head Porting


     The goal of this tier of porting is to extend the airflow capability of the 918 engine into the upper echelon of modern Supercar engines.  Since these engines are commonly putting out more than 600 HP, cylinder head flow and engine efficiency is paramount with the smaller 3.5 liter displacement of the Type 918 Lotus V-8 engine.


Pricing - $3,088 (Per Pair of Cylinder Heads)

Esprit V8 918TT-G66 Turbocharger Upgrades

Porsche 944 Tuning/ Turbocharger Upgrades