BMW M6 Twin Turbo custom DCT gearbox pushing over 1500hp+ is soon to be complete.

[Dr.Tamirlan]

BMW E63 M6 Twin Turbo custom DCT gearbox pushing over 1500hp+ is soon to be complete. Yes you heard that right, a Twin Turbo stroked out S85B50 5.5L V10 with a Dual Clutch Transmission in a BMW E63 M6. "This M6 shown in the video is still undergoing testing and is not a fully finished product"

[Roadrage]

Wow impressive can't wait to see this build complete.

[chask]

Originally Posted by Roadrage

Wow impressive can't wait to see this build complete.

Sounds pretty good to me too.

I've always thought you ought to be able to make a fairly safe and reliable 250-300 hp/liter out of a turbocharged BMW motor. For the 4.4 liter V8 that comes out to around 1100-1300 bhp. But that was without all the fancy stuff BMW has included on these engines (tuned scrolled exhaust headers, double vanos, valvetronic, etc.). I think the figure ought to be closer to the high end of that range, and maybe even above.

The thought of going back to the V-10 and turbocharging it had not occurred to me, but I think it might be a very good idea. First off, a V10 ought to make more power than an identically equipped and equal displacement V8. I forget the numbers but I want to say it should be around a 10-20% gain right there. This has to do with the same BMEP being applied over the much larger piston surface area - more and smaller bore cylinders make for much higher piston area and thus more torque => more bhp. Then secondly the V10 is revving another 1000 RPM (almost 8000 RPM vs. the V8's useful 6700-7000). If you are making the same torque up there as the 8 does at its redline, that alone should be another 14-17% increase in power, not counting the increase from the number of cylinders. Third - on top of that this stroked 5.5 has another 1.1 liters in displacement - that's a 25% gain with just that. Depending on how much they have stroked this maybe it won't rev so high but still that's 25% on displacement. To be honest, if it were mine I would have opted for a larger bore and keep the rev capability, but displacement is displacement and stroke ought to make for even more torque at lower RPM if I remember correctly. However you are doing this it seems very possible, especially if you are going to run some fairly high boost.

What I wonder about is a DCT that will handle this much torque. From my calculations (HP = Torque * RPM / 5252) it'll take about 985 ft-lbs to make 1500 bhp at 8000 RPM; 1125 ft-lbs if you are doing it at 7000 RPM. That's a whole lot of torque. I have read there are a couple of people beefing up the DCT over here. One of them says his mods are good for 900 ft-lbs (don't know about the other one). The nice thing about it is that a car with this much power won't take very long to get to that RPM (acceleration will be unbelievably fast) and you probably won't be there very long at WOT (making all that torque).

I would imagine it will also be kind of hard to put all this power down on the pavement - take some mighty big rubber to get it to not just make a smoke screen. Thinking about it, I am not sure they even make tires wide enough. Keeping them from spinning out of control is hard enough now with less than half that hp and torque. Is there some boost vs. RPM limitation strategy involved to keep the back end stable? It's the stock 560 hp if you make that 985 ft-lbs at 3000 RPM (1125 ft-lbs @ 3000 would be 640 hp). The stock engine has roughly half that torque at 1500 -2000 RPM and all but wastes a set of rear tires as it is. Once the car gets going it's another story, but getting it rolling with all that power without just taking the tread down to the belts will be a trick all on its own. Not to mention the drivability. That's a heck of a lot of torque to suddenly bring on with the mash of the throttle anywhere, and especially coming out of a hard corner.

Have you released any information on what the modifications are to the engine? I would imagine you would have to rebuild the bottom end to lower the compression ratio a bit, but I am also thinking of the turbos (one or two of them?), amount of boost, when it comes in, etc. I'm sorry for asking so many questions but I'm an old gearhead nut that used to do this stuff a lot and really curious what steps you are using to get there.

Frankly I can't wait to see this - not only what you have done to the car but also to see the performance you get out of it. This is going to be really cool! How much longer do you think before you have a working car (with most or all of the bugs worked out and hitting your design goals)?

[Msizzle]

thats an extreme build!! here is a simple question, where the hell did they put them?? Are they rear mounts?