Real World Transmission Gear Ratio's

[Fit4aking]

There are several good sites for race team specific information.  However they are typically 3-5 years behind.  Trying to get gear ratios for Sebring this time of year would be like trying to walk onto Area 51.  The more production based guys aren't runnig super sophistcates gears, and the privateers all generally use a cheaper production unit than a one-off.

The ratio's in this thread have proven to be quite usefull in at least getting into the ballpark.  It sure beats watching hp and tq numbers on the Ring.

The diesels are a real enigma.  I can find Allison and Ford ratios all day but Peugeot and Audi are locked up tight.  Heck I work for Audi and have access to the corporate website, even an expanded racing section, still nothing.  ZF isn't the kind of company that leaves anything out in the open, they really are strict with information.  If you can ever find the Automatic rebuild kits (not available from the dealer parts network) you'll never get the special tools needed to do the job.  I can get the part numbers but the last time we tried to order a set, Heinz (not the ketsup) called and asked why we needed them.  No go on a rebuild only a straight swap. 

As far as aero testing goes.  I'd bet that 90% of it is done on a scale level.  If a car does get closer to production and a full scale prototype is built its still mostly done in a virtual wind tunnel off of scale measurements.  In a information age, who really needs full scale testing anyhow.  You can't duplicate the ground level air forces in a tunnel anyhow.  The vortex effect of the ground moving under the car make such an effect on the car that only measuring the airflow over the car isn't enough.  Plus from what I've read recently the airflow under the car is increasingly more important in causing negative lift than the spoilers and wings are when it comes to downforce.  Instead of trying to maximize the downforce I believe that creating suction pockets under the car and controlling the airflow using spoilers and strakes is where most of the efforts are now.  The sanctioning bodies have done as much as they can to limit the size and effect of wings as well as front spoilers/overhang to decrease the overall speed of the cars in the name of safety.  If spoilers and splitters are limited by the rule book, I'd be looking elsewhere for an advantage.

[bimmerlovere39]

The diesels are a real enigma.  I can find Allison and Ford ratios all day but Peugeot and Audi are locked up tight.  Heck I work for Audi and have access to the corporate website, even an expanded racing section, still nothing.  ZF isn't the kind of company that leaves anything out in the open, they really are strict with information.  If you can ever find the Automatic rebuild kits (not available from the dealer parts network) you'll never get the special tools needed to do the job.  I can get the part numbers but the last time we tried to order a set, Heinz (not the ketsup) called and asked why we needed them.  No go on a rebuild only a straight swap. 

Hm... interesting.  Not too suprising, sadly.  You can sometimes find street ZF ratios... I haven't gone looking for any modern racing ratios.

[Drift2XL]

That is true about the aero testing. 90% of it is computer simmed.

The problem with the belly trays and diffusers is that they lose effectiveness the further they are from the ground. When dealing with a 2 mil ultracar, ride height adjustable susp. should be on it. But some of the lower (like an F430 or Vanquish is lower to many cars) it a tough call to go, "How low can we get it down and still pass ride height standards?"

If its a race car, and there's no rule banning them. If the cost or performance is worth it, you would be stupid not to take advantage of them. Its almost free DF. Very little drag associated with the undertrays, in fact some cars benefit with less drag than without.

As far as diesels, How about M-B? or BMW. They both make alot of them. Heck with the big trucks, M-B might make more than any other manu.

I would have to figure that the ratios would be, hell I don't know. With the huge torque it should be a wide gap. Hence the almost 50MPG Golf diesels. But the power band falls off rather abruptly on a diesel too. Soooo... 

[bimmerlovere39]

Check for sports diesels (BMW 535d/335d/635d, Alpina D3)... you also might look into the Mercedes ratios for their S/CL/SL65 AMG models - those things have alot of torque, too.

[Ske]

Audi S4 (B7)
3.67 - 2.05 - 1.46 - 1.13 - 0.92 - 0.78
FD 3.89

BMW M3 Evolution II (E30)
3.72 - 2.40 - 1.77 - 1.26 - 1.00 - n/a
FD 3.15

BMW M3 Group A race car (E30) (2027lb, 330hp, 214lbft, 175mph, 4.3sec, 245/18)
2.34 - 1.68 - 1.36 - 1.15 - 1.00 - n/a
FD 3.15 to 5.28
25% LSD

BMW M3 (E36)
4.20 - 2.49 - 1.66 - 1.24 - 1.00 - n/a
FD 3.15

BMW M3 (E46)
4.23 - 2.53 - 1.67 - 1.23 - 1.00 - 0.83
FD 3.62

[Fit4aking]

Ske-you are a machine.

I was in the shop today and we have a Stasis 6-speed on the floor.  I'm pretty tempted to see what the gear ratio's they use are.  Thier website claims that they only change the top end gears but when I drove the car it came out of I'd swear that they change 1st gear as well.

I'm interested in the Group A race trans in the E30.  Bimmer said that the car won't go over 165.  I may have to buy one and try it out.

Thanks for the input.

[Snyder005]

C6 Z06:

Final: 3.42 1st: 2.66 2nd: 1.78 3rd: 1.30 4th: 1.00 5th: 0.74 6th: 0.50

I have read the the ZR1 will have a 2.39 first gear and a 0.67 sixth. It sounds like the rest of the cogs will stay the same.

you sure about that sixth gear?  i made this set-up on the C6 Z06, and it the gear ratio's seemed very strange.  though it did boost the top speed to 226, over my previous 203. 

[Ske]

Holden Monaro (5.7L)
2.66 - 1.78 - 1.30 - 1.00 - 0.74 - 0.50
FD 3.46
Apparently 3.91 and 4.11 FDs are popular for racing.

Edit: Same ratios as the Vette, it seems.

[Fit4aking]

Snyder- I'm sure about 6th.  But I added a note to that little section that the ratio's absolutely suck.  That trans is actually run as a "Skip Shift" and 6th gear is almost only for dropping the RPM's on the highway.  It is by no means a racing trans set up.  I've since not trusted that source anymore.  Sorry for the confusion, I'll change it when I find a suitable replacement.

[Ske]

Most GM ratios can be found here:

http://www.vibratesoftware.com/html_help/html/GM/gm_transmissions.htm


Apparently the Tremec M12 IS the Vette "race" box as well as used with the Monaro, GTO etc... (ratios are in the first post):
FDs used with the M12: 3.46, 3.73, 3.91, 4.11

I guess the LM racers use multiple ratios which we'll never find.


A newer alternative to the Tremecs is the ZF 6HP26 six-speed auto/sequential box:
4.17 - 2.34 - 1.52 - 1.14 - 0.87 - 0.69
Stock FDs: 2.53, 2.73, 3.46

...And the the 6L80E that Holden will be using:
4.02 - 2.36 - 1.53 - 1.15 - 0.85 - 0.67

I also found some kind of Ford race box that I don't know what to make of:
11.38 - 6.39 - 4.15 - 3.11 - 2.37 - 1.88

[Ske]

Quaife QBE15G 5-speed RWD dog sequential
2.20 - 1.67 - 1.24 - 1.09 - 1.00 - n/a

Quaife QBE32G 6-speed FWD sequential
2.62 - 1.94 - 1.61 - 1.35 - 1.16 - 1.04
FD 3.82, 4.13, 4.47, 4.86, 5.31

Quaife QBE33G 6-speed RWD sequential
2.43 - 1.80 - 1.37 - 1.11 - 0.94 - 0.82

Quaife QBE27G 6-speed 4WD uprated sequential
2.62 - 2.00 - 1.68 - 1.41 - 1.24 - 1.14

Quaife QBE42G QTEK 6-speed sequential transaxle MR/RR Race box
2.60, 1.93, 1.53, 1.25, 1.04, 0.88
3.00, 2.00, 1.46, 1.14, 0.92, 0.78
FD 3.70, 4.11

-------------------------------------------------------

Lotus Elise Sequential 6-speed Quaife kit
2.56 - 2.07 - 1.69 - 1.41 - 1.20 - 1.05
FD 3.92

Ford Focus MTX75 5-speed Quaife kit
2.46 or 2.64, 1.82, 1.40, 1.18, 1.040, n/a
FD: 3.625, 3.823, 4.062, 4.250, 4.600 or 4.857

-------------------------------------------------------

Nissan Skyline GT-R 6-speed sequential Quaife box
2.80, 2.00, 1.54, 1.19, 0.92, 0.77

Nissan Skyline GT-R (R34) stock transmission
3.83, 2.36, 1.69, 1.31, 1.00, 0.79
FD 3.55

-------------------------------------------------------

ZF S5-18 (Maserati Biturbo, Ford Escort RS rally car)
2.30 - 1.60 - 1.38 - 1.15 - 1.00 - n/a

[Fit4aking]

WOW, did you see the jump from 1st to 2nd on the ZF unit.  Typical.  1st is pretty useless on their 6 speeds anyway as there is no 2-1 syncro.  You need to be at a crawl or stopped to put it in 1st IRL.  The 6HP19 that is in the S4 is a good box but it takes you out of 1st to quick.  In the Sequential DGS gearbox all of the gears are matched and even decelrating is fun as the trans blips the throttle to rev match.  Much like the in game trans only IRL.  Thanks for the Info Ske, I have been slacking here as I haven't built any more new cars recently.

[fndrbndr]

Don't know the ratios, but my bike is like that, first is really just for leaving at a stoplight.  If I ever downshift from second to first, I hear about it QUICK. hehe.  Then again, since MotoGP races start from a standstill, I guess it would be useful on a track.  Come to think of it, sixth is just a highway gear, too (no track use unless there's a VERY long straight, and why would you race a motorcycle on a track with long straights?).  The gears would only be for comparison, but they're not on the site (Kawasaki ninja 500 if anyone cares).  My car is a nice, boring, automatic 4 speed cruiser, so nothing interesting there.  However, it's amazing to me how useful the four "middle" gears on the bike are.  I've got 48 bhp, and I can make it do pretty much whatever I want.  OK, sorry for the threadjack.  Back to four-wheeled fun.

[Fit4aking]

Found the Trans on the SRT Crossfire.  I hope it works in the PT Cruiser RWD swap.

4.46-2.61-1.72-1.25-1.10-0.84

No final drive listed but I'm sure it can be found.  Unfortunately I never leave that stock but it provides a baseline.

[Tonka Crash]

Mazda Miata

6-speed Manual
3.760-2.269-1.645-1.257-1.000-0.843 FD 3.909

5-speed Manual
3.136-1.888-1.330-1.000-0.814 FD 4.300

4-Speed Auto
2.450-1.450-1.000-0.730 FD 4.100

Quaife Close Ratio 5-speed Gearsets
SET 1    2.564-1.670-1.277-1.000-0.794
SET 2    2.350-1.550-1.240-1.000-0.881