3.73s and 4.11s

[EachIt]

If you cruise typically in 5th gear at 70MPH, with 3.27s your turning right around 2000RPM. With 4.10s, you'd be around 2600. To see how comfortable you are with the engine at that speed, shift to 4th and slow to 60MPH and get a sense for engine noise, urgency and all that.

Only you can decide if the 4.10s are too much for you based on this stuff. Certainly, the car can take it...

What would your RPMs be w/ 3.73's? I've done that test to see if I wanted 4.10's before and it was too loud for my taste. When im driving for 5+hrs at 80mph for a good portion of the time, I think the engine noise would start to aggrivate me.

 

[DeadLurker]

What would your RPMs be w/ 3.73's? I've done that test to see if I wanted 4.10's before and it was too loud for my taste. When im driving for 5+hrs at 80mph for a good portion of the time, I think the engine noise would start to aggrivate me.

3.73s...5th gear....2,000rpms is 65mph with a t3650

 

[forpit2000gt]

Er...yeah. Well, my post still helps directly contrast the two...



This is true. But at about 80-some MPH, where 3rd is nearing redline and you've got to shift, you're travelling at 117 feet per second. Even if you could pull off a shift in a quarter of a second, you'd still travel two car lengths (about 30 feet) coasting - no power being put down. Is this countered by the additional acceleration offered in 4th? Hmmm...

The final drive ratio in 3rd with 3.27s is 4.28 (1.31 * 3.27) while a 4.10 gearset in 4th gives a final drive of 4.10 (1.00 * 4.10). The overall ratios are pretty close. Engine RPM in 3rd at 80MPH is about 4620 with 3.27s while in 4th at 80MPH with 4.10s the RPM is 4400. Since the overall ratios are quite close, and both gears find the engine at very close to the same point in the RPM band, I wouldn't expect to get much more (if any) acceleration in 4th with 4.10s than I would in 3rd with 3.27s. Basically, the charge to the traps at the instant of shifting of a 4.10 car with a 3.27 car in 3rd beside him would be a wash.

4 th does pull like 3rd but the car with 4.10s will get better 1/8th with practice and therefore will be ahead of the car with 3.73s at the big end. How many people can run a 1/8 in the 8.8x's with 3.27s?

 

[GinoGT]

Yep. However, you're not making any more power at the wheels. You may be pulling harder in each gear but each gear runs out of steam (speed) sooner too. In the long run, it's a wash. Making up for bogging out of the hole is, I think, where the key lies for improving 1/4-mile performance with gears.

True, gears aren't a power mod, but power is only part of the equation. Just ask Bill.

 

[hognutz]

I am going with 4.10's. I have 245/40-20 though so that would be about the eqivelant of 3.90. if you do what they tell you and drive at higher rpm you will notice your car runs quieter and has power at that rpm that is nice. does anyone know at what cruise rpm you milage starts to drop off?

 

[speed545]

im leanin more and more towards 3.90 every day
u also have to look at ur exhaust ( well i do anyways) cuz some exhausts drone at 2000rpms, i hate drone. had it on my old stang, wouls always drive too fast to get rid of drone

Well i didnt think of that but you have a good point there. Since i put my borla cat-back there s a drone at around 2200 RPM, so l ll make sure i can cruise at 65-70 MPH without that damn drone.

 

[Dark Knight GT]

Also, correct me if I'm wrong 4.10 guys, but with 3.27s, you can run the traps at about 100MPH in 3rd gear with the engine just below redline (around 5780) but with 4.10s, you need that extra shift into 4th (otherwise the 3rd gear RPM at 100MPH, typical trap speed for a well driven, otherwise stock GT is a rod-busting, PCM-angering 7240...) That extra shift can cost time...

Tell Automatic Weapon, Starkie, KenB, and Mustang92 this. They all 4 run 4.30 gears in their 5 speeds and still run fast times without problems. Bill(Mustang92), Starkie, and Automatic weapon have the fastest bolt-on n/a times. KenB, well, he's the fastest n/a 2v 4.6ltr Ive seen yet. Running 11.7's in the 1/4 mile must be nice.

 

[trinity_gt]

Tell Automatic Weapon, Starkie, KenB, and Mustang92 this. They all 4 run 4.30 gears in their 5 speeds and still run fast times without problems. Bill(Mustang92), Starkie, and Automatic weapon have the fastest bolt-on n/a times. KenB, well, he's the fastest n/a 2v 4.6ltr Ive seen yet. Running 11.7's in the 1/4 mile must be nice.

I didn't say they'd be slow. I said that aside from getting around bogging issues at the start, since the gears contribute nothing to getting more power to the ground, that one should not expect miracles from gears. These guys are as fast as they are because they're good drivers and because they're making a ton of power. Their choice of final drive is likely optimized to dig 'em out of the hole and make best use of their engine's powerbands.

And yes, 11.7s would definitely be nice.

 

[DeadLurker]

I didn't say they'd be slow. I said that aside from getting around bogging issues at the start, since the gears contribute nothing to getting more power to the ground, that one should not expect miracles from gears. These guys are as fast as they are because they're good drivers and because they're making a ton of power. Their choice of final drive is likely optimized to dig 'em out of the hole and make best use of their engine's powerbands.

And yes, 11.7s would definitely be nice.

260-270rwhp is tons of power?

 

[Freshpl]

3.73s for 90-150 mph zone

if you like doing the quarter mile go with 4.10s

 

[gt02boy05]

ya i have an 02 gt and i originally started out with the 4.10's until my paps said the gas mileage was suffering and decided to switch to the 3.73's. O MAN! i hate it! noticeable difference with the 4.10's off the line and although the do rev up higher at high speeds, they sure are fun lauching and downshifting! what a blast those 4.10s!

 

[TARZAN]

4.10's!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

That is all

-Will

 

[trinity_gt]

260-270rwhp is tons of power?

Someone is running 11.7s on 260rwHP?

 

['02~'vert~GT]

Thanks for the info boys
Now I have to decide...

 

[Dark Knight GT]

Someone is running 11.7s on 260rwHP?

KenB has 318rwhp. He's the one running 11.7's.

Bill Putnam(Mustang92) is running 12.4X's with 26Xrwhp.
Starkie has like 270rwhp and his best is 12.31
Automatic Weapon has 272rwhp and his best is 12.33

I think all those figures are right. If not, they're very close.

 

[trinity_gt]

KenB has 318rwhp. He's the one running 11.7's.

Bill Putnam(Mustang92) is running 12.4X's with 26Xrwhp.
Starkie has like 270rwhp and his best is 12.31
Automatic Weapon has 272rwhp and his best is 12.33

I think all those figures are right. If not, they're very close.

Wow. Impressive times. I read an editorial in MM&FF (dubiously) where they were discussing the idea of using various techniques to get a 12-second time from a stock-engined 99+ MGT. I didn't really believe it but, well, now I do

See DK...in the presence of evidence, I can be made to believe anything

 

[luther1228]

i have said this a thousand times and i will say it again go with the 4.30 i have it and i get around 22 mpg on the highway. by the way if you are looking to save on gas money you should have gotten a honda civic.

 

[DeadLurker]

Someone is running 11.7s on 260rwHP?

Not 11s but mid to low 12s with 260-270rwhp....

 

[BlackVert]

trinity_gt - great post with the 3.27/4.10 comparisons! Any chance you could add a column for the 3.73s?

 

[Dark Knight GT]

i have said this a thousand times and i will say it again go with the 4.30 i have it and i get around 22 mpg on the highway. by the way if you are looking to save on gas money you should have gotten a honda civic.

I dont think I could have said it any better myself. BTW, you think 4.56 gears would be too much for my car lol. Im definately doing 4.30's at least. Lets just say I dont fear the gear.