Gene K

Bear with me here...

I found with my 2007 that 3.55 was the gear. I was running 13.3@103 (on the limiter in 3rd) with a stock car and 12.9 @ 106 (6500 rpm in 3rd) with cai and tune on stock tires. I added 4.10 and even with ET Streets the car was no faster. It just 60's about 1/10 quicker (1.8 vs 1.9) and then gives it all back by the end of the 1/4 mi.

3.31
Im thinking with the gearing of the new MT82 (3.66, 2.43, 1.69, 1.32) compared to the TR3650 (3.38, 2.00, 1.32, 1.00) that I might like the standard 3.31. Overall gearing should be about the same with the MT82 and 3.31 as running 3.55 (1st), 4.10 (2nd), 4.30 (3rd and 4th) with the old TR3650. 6500 rpm in 4th in the traps (115 mph trap speed means 117 mph at finish line).

3.55
This might be better but its hard to say with the engine already making 20% more power by 4000 rpm. Launch ratio will be closest to 3.90 in the old car. Should turn right at 7000 rpm in 4th in the traps. I always thought 3.73 might be ideal on my old car but never tried them.

3.73
This is going to be like launching 4.10's with the old trans plus 20% more power by 4000 rpm and turning around 7350 rpm in the traps (Most likely I will bang off the limiter first which I assume its 7150 rpm). According to the Ford Powertrain Engineers the new engine is safe to 8000 rpm but they had to set the redline at 7000 rpm due to the formula used to figure the rpm for the 150,000 mile Durability Test.

2011 is going to be roughly 115 lb heavier than my 2007. Shipping Weight of 3467 lb (Spoiler Delete) vs 3352 lb. Im trying to take some of that back out of the driver (-35 lb and counting).

Thoughts?

PS If anybody wonders where Ive been. The recession appears to be over in my business and Im back up to 60-80 hours a week (from 20-40).

Mishri

I got considerably better ET and mph switching to 4.10s in my auto.. and the funny thing is people were telling me to get 3.73s.. I went from a 14.6@98mph down to 13.5@102mph.. with DA correction my cai/tuen only 14.6@98mph was a 13.3@105mph i believe? and the 13.5@102 is 12.7@108mph so picked up .6 and 3 mph , got .2 taken off my 60ft

ofcourse I also added UDPs and CMDPs between those runs, those times were on stock tires. 2.2 60ft first time out, 2.0 60ft the other time.. elevation here is around 3500ft. I believe the DAs were 6600 and 4600 respectively.

not going to get in a discussion of if my car will run those times or not.. thats just to take weather out of the equation to see what my mods did for me.

Sam I am

I'm no drag race wizard, but I ordered the 3.55's in my 2011, as I figured it would be a good compromise in off the line accelleration and overall driveability.

Riptide

GeneK's experience would seem to suggest that the addition of the gears helps most early on in your attempt. Since GeneK is also one of those around here who have managed to get exceptional 60' times on the stock setup the gears didn't appear to do that much for him.

For those of us who are not quite as talented they made a bigger impact. I know they made a huge difference for me in the 60' range.

Gene K

For a street car I would say its going to be really nice. Compared to the old TR3650....

1st = 3.90 Gears
2nd = 4.30 Gears
3rd = 4.56 Gears
4th = 4.56 Gears
5th = 3.55 Gears (in old 4th)
6th = 3.31 Gears (in old 5th)

2200 rpm @ 75 mph and accelerate as hard in 1st as the old 4.6 with 4.56 Gears (20% higher torque by 4000 rpm).

I have my suspicion that the 3.73 is really to get the rpm right in 5th (1.0:1) for the Roadracers (Although it will also work for 28" Drag Ties in 4th). I mean after all how many roadcourses do you exceed 147 mph in a stock car on?

Gene K

Just for the record I think the issue with the 4.10 in the 3V was....

With stock tires I cound not really improve the 60'. Ive cut 1.85 on the stock tires and gears. Not being able to take advantage of the harder launch I lost time by shift early in the run right after the 60'. I could see the difference in the split between the 60' and the 330'. It also didnt pull as hard on top in 4th w/ 4.10 as it pulled in 3rd with 3.55 as the rpm was lower.

With ET Streets the car cut a best of 1.79 (Only 0.06 better). The 0.06 is enough to allow me to run the 1/8 0.02 quicker (still slower split form 60' to 330') and now add the additional drag from the tires costing me over a mph in the 1/4 mile and it just didnt help. Maybe I need driving lessons.

Simon1

Interseting topic.

My thoughts on the shifting. I found in my turbo car that short shifting 3rd to 4th would gain about 4 mph in my trap and a few tenths. This is common in turbo cars, but I wonder if it can transfer over to an NA car.

Maybe try shifting 3rd a little early. Also, I have found the best way to shift to 4th is with a powershift. Even at 550 rwhp the trany didnt grown and I never missed it. Striaght back into 4th, don't lift.

Give it a shot.

You should be able to muster more than .06 better with your 60' and the Et Streets.

Simon1

I had 4.10s and 3.55 NA. It's been so long I can't remember what the difference was betweenm the two.

Gene K

I always powershift ever gear at the track (Except when stock which resulted in the PCM shutting the throttle body and a delay in reopening). Anyway the car has been returned to stock, excepting a tune for the stock air box as I cant stand the OEM throttle response, as its soon to be traded for a 2011 5.0...

GTI-Guy

Hey good job whittling away the new car's weight gain with a weight loss of your own. I dropped 30 pounds too (Weight Watchers).