View Single Post
      08-23-2011, 01:26 AM   #189
Brigadier General
DLSJ5's Avatar

Drives: 2016 F82 M4 ZCP
Join Date: Dec 2006
Location: CA

iTrader: (1)

Originally Posted by swamp2 View Post
Wow not even sure where to start here. In short this is pretty much all incorrect. It looks like we will probably get way off topic but I can't let this rubbish slide.
  • Assuming good traction, good launch, etc., power to weight is what determines ET and trap speeds. I don't often side with Sticky but he is essentially right here. Everything else is a much smaller factor.
  • Sure if you have a crappy driver in a MT who takes 0.6 seconds to shift, yes this will hurt your ET and trap by quite a lot but a fast shifter can shift a MT in closer to 0.25-0.3 seconds and we should assume this is happening to give a MT a fair shake.
  • I've been a strong and long term proponent of DCT over MT for performance reasons. It does matter but it does not matter nearly as much as you and your referenced info claim. According to both simulations and empirical test results DCT (in a stock M3) is good for about an equivalent of 15-20 hp. That in turn is only good for a few tenths in the 1/4 mi.
  • The advantage of DCT is almost entirely due to shift speed advantages, not gear ratio differences. This also has been proven out with simulation quite well. Where DCT gear ratios shine, that is not related to drag racing, is coming out of a corner at an equal speed to a MT in 2nd or 3rd gear. The overall ratios are quite a bit higher and thus the DCT will come out of corner much harder and pull ahead.
  • The cars that were compared in this "re-enactment" simply DO NOT have anywhere close to the same power. I don't care what the dynos say, different dyno, different conditions, different days, different tunes, different operator, etc. How many differences do you need? The DCT car in this case had substantially more power, period. If the two cars actually had 586 and 594 hp respectively their 1/4 times would be within 0.3 sec ET and 3.5 mph trap, accounting for the DCT advantages and assuming a 0.3 second shift time.
  • It takes about a 75 hp difference and the DCT->MT disadvantage to provide a true 9 mph trap speed difference.
  • Even a really terrible shift time of 0.6 s in the MT would only account for about half of the observed ET differences here. Again... apples to oranges, period.
  • Have a look at some stock M3 quarter mile results differences between DCT and MT. Here we have very high confidence that both cars will be making VERY close to the same power.
  • If you really think this is a true apples to apples comparison of DCT vs. MT then I have some great business ideas centered around selling sand to some Arabs that we should really discuss in detail in person.

You do make some good points, but I think you're just a bit too confident in your assertions.

So far with boosted E9X M3's, when you look at Vbox results, comparo runs, trap speeds, etc, the DCT is superior in straight line acceleration, that's just the way it is, it appears just about everybody, especially those with actual experience, acknowledge this to be the case.

The 6MT and DCT cars in that vid DID make similar WHP on a Dynojet, when comparing different Dynojets it is quite rare that you will get a huge difference in WHP, that's what CF's are for. I do agree that a 6MT with more traction would be a better comparison but for you to overly assert that they aren't making the same whp is rubbish.

You say the DCT is only good for 15-20whp?

Then how do you explain a 366whp DCT trapping 116 and a 500+whp Supercharged 6MT trapping 119, same day, same track?

When you take the traction factor out of it -

How do explain the .7 - 1 second difference between supercharged 6MT's and DCT's 60-130, even when the 6MT's are making more power?

How do you explain the 6MT SC'd Stroker 613whp being .5 -.7s slower than a 570whp and 586whp DCT M3?

How do you explain a DCT making 570whp vs. a 6MT making 590whp, same kit, same dyno on the same day as well produce vastly different results in comparo runs, the DCT was MUCH faster.

How do you explain on the same stretch of road, a Stage 3 6MT @ 640-660whp doing 60-130 in 6.9s vs. a DCT Stage 2 @ 586WHP doing 60-130 in 7 flat and 6.8s, even with 60+whp less the DCT was still faster.

I get what you're trying to say, we're just not seeing that in the results so far.
16 F82 M4 DCT - ZCP - JB4 - 556WHP / 570WTQ
08 E92 M3 DCT - Bolt Ons - 60-130MPH 10.71s - 11.88 @ 118MPH - 377WHP
ESS VT2-625 SC 60-130MPH 6.80s - 11.30 @ 129.3 MPH 586WHP / 379WTQ
ESS VT3-750 - 60-130MPH 6.14s - 10.81 @ 135.13 MPH 690WHP/463WTQ
Shift-S3ctor E92 M3 - 1/2 Mile Trap Speed WR - 174.13 MPH

Last edited by DLSJ5; 08-23-2011 at 01:31 AM.