Our custom fabrication is always finished to a show-quality finish. Internal welds are reinforced for strong, seamless tubing forms. We lighten up each component as much as possible to improve power-to-weight ratios.
Here our clients enjoy both faster vehicles and better looking fabrication components
Pictured to the right and below is a Nissan 240SX with a Skyline RB25DET engine, transmission, and brake upgrade done here in Central Florida. Our task was to redo the charge pipes and cleanup the engine bay. Some of the pipes were missing beads to keep the couplers from blowing off. We beaded each of the fabricated pipe assemblies you see below. As you can see, there are no visible weld seams and the pipes take a very direct and clean path from the turbocharger discharge to the intercooler inlet. The BOV was repositioned to be most pleasingly displayed and 90 degrees to the main charge pipe. The valve cover vents were simplified and the breather hose run well away from the hot turbocharger assembly. After our work was done the client said "It sounds amazing". This is how all swaps should be done if you ask us......
Vehicles don't get much cleaner and neater than this Callaway Turbo Rabbit. The engine bay is clean enough to eat out of and the painted metal pieces perfectly match the exterior. Much of the engine ancilliaries were included in the paint scheme for a truly world-class appearance of the late-model 2.0 liter gasoline engine. The famous Corvette tuner Reeves Calloway produced a high-quality turbo kit which this ABA engine features. We were asked to rebuild the turbocharger for the owner before the Rabbit was to be entered in the Waterfest show competition a couple of states away. The turbo performed flawlessly and the Rabbit took home 2nd place! Well deserved.
As if any Acura NSX would be a typical vehicle that a shop would be trusted to work on, this one had a Comptech supercharger kit fitted to the V6 V-Tech engine. Our task was to tune it to run better than it was, which was quite lean. The owner could tell that the previous tuner didn't take into consideration the owner's frequent trips from North Carolina to Florida which required a more robust fuel curve. We dialed in a richer tune to keep it all happy in the Florida heat.
An S4 with an attitude. Sporting a couple of upgraded turbos and a massive front-mounted intercooler, and Porsche 911 Turbo brakes, this Audi was very much well-tuned...just needed some fine tweaks. We TIG-welded a full 3" Stainless Steel DUAL exhaust with ceramic high-flow catalytic converters and v-band clamps. When it shifted through the 6-speed Quattro transaxle you heard a crisp 'POP' which only meant one thing...quick spool-up of the K24's and a nice tune. If you followed behind you probably saw flames! Definitely our kind of car. More than a match for our Lotus Esprit V8. Which says alot. The owner's daily ‘grind’...selling exotics. Sweet.
So where do we begin with this 240SX? The SR20DET swap was done elsewhere but it wasn't anything to write home about. The mild-steel exhaust system was tossed and we custom fabricated a full 3" Stainless Steel system from the turbo back with nothing but v-band clamps at the joints. Even a high-flow catalytic convertor was integrated into the system. It was lighter, meaner, and more powerful than the cheap system it replaced. Then we addressed some wiring issues like the radiator fan leads, and injector loom. Speaking of the radiator, it received a custom-fabricated aluminum shroud around the fan assembly to keep it running cool in summer heat. The pulleys on the motor were upgraded to lighter, billet-machined underdrive pieces to reduce parasitic losses. All of the intercooler and charge pipes were redone to simplify their layout and improve flow characteristics. We installed an air-fuel ratio gauge and pyrometer so that proper tabs could be kept on the SR20DET during 'spirited driving episodes' . The automatic transmission was serviced and new plugs and coils installed atop the cylinder head. To further tune the engine and complement the exhaust system upgrade a performance intake manifold was bolted in place. This we cut open and fully ported the passages along with a similar treatment of the throttle body. One glance will show that we spent much effort prepping the aluminum surfaces in the engine bay before taking each one to the buffer. Valve cover, intake manifold, turbocharger cold-air-inlet piping, radiator fan shroud, intercooler piping, radiator end tank, intercooler end tanks, coolant outlet castings, and the throttle body were all polished. Wow, did we miss anything? Here at Exclusive Turbosystems simple engine swaps don't have to look 'ordinary' or perform without much character.
Completed Work/ Client Vehicles
Comptech Supercharged Acura NSX
Volkswagen Rabbit w/ 2.0 8V & Callaway Turbo System
Nissan 240SX W/ (Skyline) RB25DET
Nissan 240SX w/ SR20DET
Dodge Cummins 5.9 24-Valve
We supplied a SNIPER-R 66mm turbocharger and wastegated high-performance exhaust manifold for a 24-Valve Dodge Cummins in Texas. This daily-driven truck needed to be able to tow, haul some loads, and run down the highway at high boost. A Jack-of-All-Trades rig. As you have probably noticed, the exhaust manifold is fully ported for even more flow to support the SNIPER-R and ceramic-coated just like the turbine housing. A cast Stainless elbow TIG-welded onto the manifold allows a Turbosmart 45mm high-pressure wastegate to be clamped into place for accurate boost control. This Borg Warner based turbocharger features a billet compressor wheel and 360 degree thrust component upgrade, with fully ported turbine and compressor housings. We supplied everything you see above for a complete turbocharger upgrade package to replace the stock Holset turbocharger. He already had an upgraded exhaust downpipe so after a couple of oil line connections and the air inlet pipe being bolted on he was off to get a tuned flashed onto the Cummins. The compressor housing polished up nicely as well, so after the mud-slinging is done, he can wash off the grime and show it off to his truck buddies in the Lone Star State. It might have to be ‘truck-tough’ but it doesn’t have to look rough...
1985 BMW E23 745i 'RESTO-MOD'
This is an epic build. The factory BMW 3.5l engine is being fully blueprinted with custom forged pistons, an upgraded camshaft grind, valve springs, retainers, fully ported cylinder head, a modified intake manifold which is ported with the exhaust manifold, balanced rotating assembly, ARP fasteners, and heavy-duty rocker arms. Engine management is a Autronic unit controlling 120lb injectors and individual coils. The turbocharger is a custom 70mm KKK hybrid. Intercooler is a custom-fabricated 4" thick core with 3" piping connecting to a billet 70mm throttle body. The exhaust system is a Stainless Steel 4" into dual 3" with a high-flow cat. A triple-disk clutch and a 6-speed manual transmission conversion transfer power to the rear tires.
The engine of this particular 745i was running when it was parked in 2008 so it was a good platform for a high-output build. The blueprint for the engine was to take the BMW 3.5l block and cylinder head to the limits of what could be achieved with a factory crankshaft, connecting rods, and the factory manifolds with modifications. Essentially, this was to be a ‘hot-rod’ BMW 6-cylinder turbo sedan, not a track car. Or you could call this the ultimate sleeper. Who would expect a 1980’s 7-Series 4-door to lay out the kind of power that Toyota Supras have been known to boast?
The disassembly of the long block revealed a partially blown cylinder head gasket that only manifested itself as a slight miss at idle. Pretty robust engines these M106 turbo 6-cylinders are for sure. All of the bearing surfaces of the conneciting rods and crankshaft were evenly worn and the cylinder head itself was mostly full of carbon and burned oil as to be expected of a mid-80’s turbo sedan. Even with only 2 pistons removed the crankshaft spun very easily within the bearings proving it was perfectly straight and no part of the assembly had seized up. All of the valve faces exhibited normal carbon deposits and valve seat contact wear patterns. Camshaft lobes had only small wear patterns where the rocker pads had made contact. Both the cylinder head casting and the block itself are to be thoroughly cleaned, modified, and upgraded with the appropriate components to better support the output level anticipated with the factory-based 70mm KKK turbocharger upgrade.
The cylinder head is responsible for turning the injected fuel and pressurized air into a fast-burning mixture crammed into each combustion chamber in an efficient manner, but since this particular M106 engine has to put out more than twice the factory horsepower, some port and chamber modifications are in order to meet the goal. On the exhaust ports we are most concerned with increasing the gas volume each port can evacuate quickly once the valves open, and improving velocity within the port for providing a stronger exhaust stream for driving the turbine wheel blades. These ports were cast with some flow director humps attached to the valve guide which we have elected to trim away to increase port volume significantly. A small amount of casting material is being shaved away from the port ‘bowl’ area adjacent to the valve seat as well to add volume to the port. These modifications are designated for gas flow that the highly-tuned M106 engine will need to evacuate from each cylinder at high boost and elevated engine RPMs. A horoscope was used to examine each port casting to acertain if these modifications could be performed and to what extent. These ports have a squared-off oval shape and the casting surrounding them does not allow for too much deviation from this overall port shape, however our skilled porting technique adds some serious internal volume for the efforts of close to 20%, with much improved flow dynamics and reduced gas flow restriction. These engines were built to be extremely durable and tough. Some casting material can be removed and the shape modified (carefully mind you this is not kid’s stuff) to open up exhaust flow and tuning potential once done properly. Our porting expert has close to 30 years of experience with porting various cylinder heads, intake manifolds, turbocharger housings, and exhaust manifolds. His patience with a long-reach carbide burr is critical to consistent results with such a delicate procedure. Consider this like open heart surgery on the engine, you want a skilled set of hands with patient attentiveness to subtle details here, not a novice approach to ‘get it done quickly’.
Valves for the cylinder head are stock size which should be well suited to the state of tune this 745i will be used in. The factory exhaust valves are a high-Nickel content Nimonic material and similar to Inconel in durability in a turbocharged combustion chamber envirinment. Simply refacing them to have a fresh surface for contact with the valve seats, and machining the stems (ever so slightly) to remove some weight was deemed ideal for this engine. The intake valves also being refaced to complement the exhaust valves but more material removed from the Stainless Steel stems gets them down to a ‘fighting weight’ more inline with the higher RPM range of this particular M106 engine. Valvesprings are key to controlling valve motion at elevated engine RPMs so a stiffer set are employed to keep the valves from bouncing off of the seats.
Several engine components and drivetrain parts are going to be custom fabricated with this build. The coolant and power steering reservoirs as well as a crankcase breather canister are being fabricated out of aluminum sheet-metal and billet CNC-machined fittings. These fluid containers will keep leakage to a minimum over the years and should be far superior in durability with the turbocharged engine once tuned. It was quickly determined to be wisest to invest in some metal upgrades for the factory plastic coolant reservoir and leak-prone power steering canister. Highly-tuned turbo engines tend to radiate plenty of heat around them and the BMW 6-Cylinder is about has well-tuned as it gets.
Using the OEM coolant reservoir as a template, a sheet-metal replacement was hand-formed to incorporate the same attachment points, hose connections, and a high-pressure cap assembly, all TIG-welded together and fully polished on the exterior. The OEM plastic containers have been known to split and crack which would lead to a coolant loss and possibly an air pocket within the engine coolant passages, this could result in an overheated engine with a blown head gasket if not caught in time. Much better to be safe than sorry with this high-horsepower build.
The power steering reservoir is actually necessary to replace the BMW self-leveling fluid canister originally fitted to this luxury sedan. The self-leveling dampers (which use hydraulic fluid pressurized into a complex tubing duct connected to each damper) in the rear are prone to leak and it is wisest to simply replace the entire system with a conventional hydraulic fluid/gas-charged damper arrangement. Instead of sourcing used (and most-likely very old and probably leaking) replacement parts, a new reservoir was fabricated that only connects to the steering rack and pump. This reservoir has a nice black anodized billet aluminum cap which has been CNC-machined with a scalloped surface for an easy grip when turning to loosen or tighten. The original screen from the OEM reservoir is relocated into this assembly and the entire piece is TIG-welded together with billet aluminum hose fittings for each fluid connection.
A billet fuel rail is being used to replace the stamped steel factory piece on this 745i. The ends of the rail have A/N fittings attached for improved fuel flow to the large 120 LB injectors. Past experience has shown that fuel flow needs to be just right to keep the injectors well supplied on high-output turbochargered engines like this. This presented a clearance issue with the M106 thermostat housing. Our solution is an extension TIG-welded onto the housing which moves the bulk of the casting away from the fuel rail area. New aluminum sheet metal was cut for an angled extension of this housing. Some metalworking of the 2 forms joined together resulted in an elegant solution to the problem which is also polished to complement the other aluminum engine bay components. It doesn’t have to look like it was grafted into place if we have anything to say about it. The thermostat housing itself has AN fittings (TIG) welded into place for the coolant lines to be attached to. No chance of having the thinner rubber hoses collapse or burst with Stainless Steel braided hoses in place.
, This 745i has the distinction of being fitted with a rather large 70mm KKK hybrid upgrade turbocharger so of course the side-mounted intercooler has to be replaced with a larger core, the charge piping custom-made to connect it to the engine, and a bespoke exhaust system custom-fabricated from Stainless Steel to support the gas outflow properly. All of this means one thing, more horsepower from the BMW engine, and a substantial increase in torque. Enough torque to require a beefy transmission upgrade, doing away with the factory automatic, and necessitating a suitable clutch as well.
For the turbocharger we use a hybrid combination of the factory 745i K26 with a much larger K27 compressor section that features a 70mm inducer compressor wheel and a 4” inlet on the housing itself. This turbocharger should easily support 700 HP and more with this engine and by using the OEM turbine housing and wheel it will respond similar to the factory KKK turbocharger. The turbocharger has a blueprinted CHRA with a 360 degree thrust plate and polished bearing journal surfaces which reduce friction and increase durability. On the compressor housing outlet we find a larger 2.5” discharge that better suits the massive 70mm compressor wheel’s airflow potential. A much needed improvement in compressor housing flow capacity, especially compared to the OEM turbocharger with its 2” discharge. This is the appropriate compressor housing configuration for a 800 HP turbocharger upgrade to be sure. The exhaust housing retains its basic casting profile but has been with significant reworking to allow better gas flow through the turbine wheel for better efficiency with the compressor wheel upgrade. The turbine scroll inlet passage is opened up significantly, and also reshaped to enhance its tapered profile to accommodate a higher volume of exhaust gasses for driving the huge OEM 745i turbine wheel. BMW specified a very small turbine housing area for this turbocharger which means excellent responsiveness but not much top-end airflow delivery from the tiny compressor wheel fitted on the other end. Combining a full complement of compressor and turbine housing portwork to make each passage larger, more efficient, and much smoother, this turbocharger will have very strong response once tuned, even with its huge compressor wheel.
Replacing the factory side-mount intercooler is a 4” thick air-to-air intercooler which has a enough cooling capacity to work efficiently with a 600+HP engine. Both the inlet and outlet of the intercooler are larger than the OEM dimensions at 3” compared to around 2” for the original. Custom end tanks direct airflow through the core and out towards the main charge pipe connected to the throttle body opening. All of the intercooler piping is mandrel-bent aluminum and fully beaded with reinforced silicone couplers. These couplers are secured with high-quality Stainless Steel t-bolt style clamps. Each charge pipe section is carefully fabricated and TIG-welded together for a single pipe section assembly incorporating all of the necessary bends to efficiently direct the airflow with litttle restrictive turbulence. These weld joints are internally finished to be smooth (if needed) for the best flow inside the pipe. We use our tubing bead roller on each end to form the uniform bead for the coupler to be slid over and kept in place with the t-bolt clamps. All of these custom intercooler pipes are metal-finished on the exterior for a smooth finish, sanded smooth as silk, and polished to a high-luster shine of which the owner can be proud any time the hood is raised in public. The factory OEM BMW piping is painted black steel in comparison so this upgraded piping draws attention to the enhanced breathing and level of modifications of this highly-tuned 745i sedan.
The exhaust for this 745i is a bespoke, custom-fabricated assembly of Stainless Steel mandrel-bent tubing, V-band clamps, a high-flow catalytic converter, and a muffler assembly in the rear. For a simple connection to the turbocharger turbine housing outlet, the OEM downpipe flange and clamp are TIG-welded onto the 4” downpipe section directly. This also incorporates a flared cone as a transition from the 2.75” turbine housing outlet diameter to the the 4” downpipe diameter. A mere 1.5” of 2.75” piping is used before the larger cone adapter section is welded in place and it is at a full 4” diameter in another 1.5” so that the smallest portion of the downpipe is a mere 3” long from the turbocharger housing connection. This is a high-flow exhaust system designed to allow the turbocharger to have no restrictions on performance from backpressure. The high-flow catalytic convertor has its opening shaped to connector to the 4” downpipe tubing and its outlet is welded onto a merged pair of 3” Stainless Steel pipes in the rear. All of these welds are metal-finished inside for the best flow characteristics and the tubing welded together for the entire system is mandrel-bent and lacks any kinks or sharp angles for the best gas flow possible. This exhaust could easily support over 1000 HP, but it is an elegant (just the right amount of flow capacity for this aggressive engine build) solution to marrying the turbocharger outlet into a dual exhaust pipe system as originally fitted by BMW. This exhaust system is very much along the resto-mod theme of the 745i.
Taking into consideration how much torque the BMW 3.5l engine can produce once tuned, a triple-disk clutch was deamed necessary for the vehicle as well as a suitable manual transmission which could also handle the proposed 700+ Ft Lbs of torque. No such clutch exists for this engine fitment so a plan was drawn up to adapt and fit a NASCAR-spec billet triple-disk clutch and Chrome-moly flywheel. Race clutches tend to be harsh in engagement so a newer design was selected which offered a billet aluminum CNC-machined pressure plate with altered geometry and disk engagement dynamics to soften the initial take-up. Our experience with a triple-disk Carbon clutch on our Corvette ZO6 showed that a modern clutch design can hold incredible amounts of torque AND be streetable to actuate. Obviously a V8 pushrod race engine has loads of torque so this would be a good match to the BMW engine once fitted. To affix this clutch assembly onto the rear of the BMW crankshaft requires some precision machining, custom fabrication, and TIG welding. The bolt pattern of the clutch selected was the same as the BMW which was nice, but the hole diameters too small and required precision boring to the correct diameter for fitment. Next step for making this triple-disk clutch work, is the flywheel. The race clutch has a small-diameter flywheel suitable for a race engine application with the starter ring gear being much too small to work in the BMW bellhousing. This requires a removal of the ring gear section of the Chrome-moly flywheel and a similar operation with the OEM BMW automatic transmission steel flex-plate. A custom-machined steel adapter ‘ring’ being machined takes up the distance from the smaller billet clutch flywheel and the OEM ring gear. TIG welding secures the 3 components together so that the starter can engage the flywheel and spin over the engine for the 745i. Of course the clutch disks need to mesh with the transmission input shaft so this necessitated another custom component integration. After the ‘suitable’ transmission was obtained the spline pattern became available for measurement to custom make the hubs for the clutch friction disks. End result should be a reliable transfer of torque to the transmission input shaft, without any slippage mind you.
Choosing a transmission brought up several challenges. The first being torque capacity. The second being simplicity of fitment. And lastly availability. Originally the older Getrag 265 5-speed seemed to fill the bill because it would bolt-up to the block, but none of the 3.5l engines fitted with this have been tuned to this level of torque. Back when BMW raced these engines on road courses, the torque produced once turbocharged would actually shred the transmissions in short order. Rather than take the chance of repeating that outcome looking toward the use of a modern and stronger transmission became the best solution. The E-46 M3 6-speed was considered first but they are just as pricy as a Toyota Supra 6-speed and require a similar (M3) clutch assembly to be used. Moving on to other options revealed that possibly a 335/ 535i gearbox would do quite nicely. This being a turbocharged inline-6 vehicle which makes gobs of torque once tuned and having favorable ratios, it got the nod for this application. The bonus is of course having 6 forward gear ratios to choose from instead of 5. So now this older BMW 7-Series sedan has a modern BMW 6-speed transmission transferring its massive torque to the rear tires. Fitting this transmission would not be very difficult on an E-46 block (we know because of experience with such a task), but an E23 cast iron block has a very different bolt pattern. The ZF transmission is just massive, espossially in the bellhousing area. Back to the machine shop for some more custom fabrication of an adapter plate for affixing the transmission to the rear of the BMW big-6 engine. Some hydraulic slave cylinder line adaptation, lower transmission mount fabrication, and shifter mounting bracket custom fabrication and this is a perfect solution to multiple design challenges with this build. At least these transmissions are easily sourced nowadays, unlike the older Getrag 265 5-speed.
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