I have 4.11's and an M6...see sig

I was wondering...what gear would I be in crossing the finish?

Would I still be at the top of 4th? or would I now need to shift into 5th?

5th gear comes up awefully fast so I was just wondering....

thanks

 

You should still be in 4th gear, but it'll be screaming!

Check out this gear calculator to see for yourself, but as long as you aren't afraid to rev the engine a little over ~6000 rpm, then you're good to at least 110 mph, or higher if you hold it longer.

I know with my car, it's still in 3rd gear crossing the line, and it's at about ~5800 rpm (remember, 3rd gear in an A4 and 4th gear in an M6 are both 1:1 ratio).

 

As mentioned above, whatever gear 1:1 is. The overdrive gears are small and weak and are designed for highway cruising. 1:1 doesn't really use any gears but allows the path of power to go straight through the transmission.

If the tire height and gear ratio are matched to the engine's shift point, you should be crossing the 1/4 mile mark at or just before the shift point at the end of 1:1. The shift point isn't the engine's red line so going a few hundred rpm over it isn't going to hurt since you're only going over it for about a second. If you shift just before the finish line to get into 5th, you're going to slow down. You shouldn't have to do any shifts in the last 1/8 mile.

 

naw i was just wondering if i would hit my rev limiter in 4th before finishing...if i do ill just let it bounce for that second or so...but it seems i wont have to...i should be at 5100 +/- according to drag 2000. I dont know how accurate that is but it sounds good to me.

 

Unless you're running taller tires, you're going to be higher.....5800 - 6000 rpm IMO. That's what mine's doing w/4.10's, and 4.11's are just that much deeper. You may need to have your rev-limiter raised upto ~6500 so you aren't hitting it at ~6200 like it's set at.

 

5100 in 4th gear with stock tire diameter is 95mph. Even with 28" slicks, it would only be running 103mph. I'm sure your car is faster than that .

Check the gear calculator link posted above. It is accurate.

 

I just punched in the numbers for my car into that calculator. Althought the calculations are correct, it doesn't account for torque converter slippage in an automatic transmission. If I take out roughly 8% for my converter slippage (estimate), the resulting number is very close to my 1/4 mile mph.

 

yeah that calculator is insanely accuracate on my M6

Darn...I didnt think of running that calculator and look for the MPH/RPM at the end of the run..

at 6000 rpm its 113 mph in 4th

So I should be good.....for now

I would get it tuned, but Im waiting till after the cam swap so I can raise the limiter, eliminate the rear 02s, etc and tune it all at once. Dont want to pay twice...i can hold out for now

Oh yeah....what do you guys think I should run? i know, i know..variables, variables

but just for arguments sake....gimme some #s please

With sticky tires what should I run?

The car feels really strong, so I would assume its gonna run pretty good, especially since we have little to no elevation here

mods in sig. also, I WILL have a lid by the time I go and run it lol, and ill run in good weather too.

thanks guys...a real big help

 

And it also doesn't account for tire growth.... but he had an M6, not running all that fast, so its fine for his use.

 

12.8 - 12.9 @ 108 - 109 mph with traction and good air. Just guessing!

 

hey im fine with 12.8-12.9...we'll see.....

I just want to be in the 12's consistently...not just once or twice...but reliably a 12 sec car..

That would hold me off till I get my cam and suspension tied up

I think I'll do the susp first since I wont be able to hold all that power after the cam (prob 224/224 563 563 112)

Im still not sure if I want to go all motor after the cam, or just spray it with the cam and be done as far as power goes.(its never DONE though..lol)

I might not spray...but I may. (lol new bumper sticker)

 

I have my limiter set at 6500 and I am no where near it. I don't even think I am above 5800 crossing the line and I trap 114. I use 275/40/17 nitto's and 26/11.50/16 ET streets. Also remember trap speed is the average MPH of the last 66 feet of the track. So say 6000rpm=113 and you trap 110 you may be on the limiter crossing the line.

 

The difference between the "average" MPH you get on your timeslip and the actual speed at the true finish line is actually not that large. It can be shown that for the typical 4th Gen perfromance, it is only about 1 MPH. But you need to allow for it. Probably offset by tire growth.

 

I need to hurry up and swap in that cam and have it tuned so I can raise the rev limiter.

Anyways we will see once I make a few runs down the track...

If I tach out hen Im just going to have to wait on the cam and tuning to make any more passes cuz Im not going to have someone raise my limiter just to run a smidgen faster(cost extra $)

I would know that it has more thats all I need

 

i was bouncin off the stock limiter in 3rd gear barley before the finish line..only trapped 101.5.