What diff ratio are you high hp boys using?

[ANDRÜ]

I have a turbo eta, with a 4.10 lsd. Way too short, 60mph= 3000rpm

[Firestorm]

Yes, and you'll love yours in your e30 And to the OP, what is your trans 5 or 6 speed?

I'm guessing he's running a supra 5 speed.

I'll be using my 3.46lsd with the ls1/t56....until it blows up and i'm stuck with my open 3.15 :p

[PiercedE30]

Firestorm, why not go with the T45? On my friends 00 Mustang, it was the last thing that went. Went through axles, intake manifolds, even a few valves before the tranny decided to bite the dust. We found every week link in that drive train. Went through 3 Strange rear ends before they made him a custom one and refunded his money for the first 2.

[drifty340i]

NA motor = lower final drive (3.25, 3.73) more power and torque in the low end

Turbo motor = higher final drive (4.10) need to get up to boost sooner

CR gearbox - depends on setup

Why not ask BMW why they change out gearbox gearsets & final drive ratios depending on the racetrack they are at.... Long straits need more top speed, twisties need constant RPM.... it depends and no one can answer...

What is your application - maybe we can help

Think your right, 3.25 to 3.43 is what is ideal.
using a supra 5speed .86 final drive. 16/45/215 tires.
4.0l v8

[backtrail69]

I run a 3.73 lsd in my turbo m20. 1st gear is super short but it just rips through it. I might put a 3.25 in it someday.

[Firestorm]

Firestorm, why not go with the T45? On my friends 00 Mustang, it was the last thing that went. Went through axles, intake manifolds, even a few valves before the tranny decided to bite the dust. We found every week link in that drive train. Went through 3 Strange rear ends before they made him a custom one and refunded his money for the first 2.

Why would i want to change from the t56?

[Borat]

NA motor = lower final drive (3.25, 3.73) more power and torque in the low end

Turbo motor = higher final drive (4.10) need to get up to boost sooner

What is your application - maybe we can help

I disagree with you on that, turbos work better under load, a lower final drive allows you to build bost sooner in the rev range for a given gear.

My car would be horrible with a 4.10, it would rev out way to quick between gears, I'm using a 3.64 and it falls straight back into the power band when I change at redline.

Riley, I reckon something like a 3.25 would be the go for your car, I can imagine that 1UZ is pretty grunty down low so should have no worries with that ratio.

Talk to glenn about his final drive, I think he's running a W56 too.

[drifty340i]

I disagree with you on that, turbos work better under load, a lower final drive allows you to build bost sooner in the rev range for a given gear.

My car would be horrible with a 4.10, it would rev out way to quick between gears, I'm using a 3.64 and it falls straight back into the power band when I change at redline.

Riley, I reckon something like a 3.25 would be the go for your car, I can imagine that 1UZ is pretty grunty down low so should have no worries with that ratio.

Talk to glenn about his final drive, I think he's running a W56 too.

I totally argee in the 4.1 ratio on a turbo would be shocking.

Year a 3.25,3.43 would be ideal, ive just got to get off my arse and find a good one. Ill prob do it after the conversion is finished tho

[Garageaholic]

On my M30 Turbo with about 300rwhp, i'm running 3.25 in the rear and running about 74mph at 2750rpm

[JasonC]

since we are on turbo's and gears, my charger has 275+hp and i had this motor in a daytona but with 3.23 gears. Then the trans broke and i replaced it with one that had 3.84 gears. I liked it better with the 3.84's it pulled harder but i had to shift a litte sooner though.

[drifty340i]

On my M30 Turbo with about 300rwhp, i'm running 3.25 in the rear and running about 74mph at 2750rpm

Still get up an boogie well? any chassis mods

[Garageaholic]

Just a stress bar in the front that's all. Why don't you email me your email address at frank.macaluso@lmco.com

Unless you already have similar, I can give you an excel spreadsheet giving an rpm/speed matrix based on tranny and rear end gear ratios, tire size and wheel sizes...

Hell yeah it boogies... anything after 2000 it starts boosting i can feel it. I'm more for highway economy though bc i do alot of highway driving... I found that i get about 25 max mpg on my m30 cruising at about 70mph on hwy, but i dont want to turn this discussion into an economy thread. just thought i'd add it :)

[drifty340i]

Just a stress bar in the front that's all. Why don't you email me your email address at frank.macaluso@lmco.com

Unless you already have similar, I can give you an excel spreadsheet giving an rpm/speed matrix based on tranny and rear end gear ratios, tire size and wheel sizes...

Hell yeah it boogies... anything after 2000 it starts boosting i can feel it. I'm more for highway economy though bc i do alot of highway driving... I found that i get about 25 max mpg on my m30 cruising at about 70mph on hwy, but i dont want to turn this discussion into an economy thread. just thought i'd add it :)

Cheers,Year ive got some software for working it out as well, was just interested in what everyone else was running. I bet your cars a beast! major torque

[MrK]

redundant, but I'll chime in with my setup

Painfully stock m30 (but tuned for spark and fueling by piggyback), 3.25 LSD. Great for cruising. My aim was to match top revs with drag-limited top speed... around 160mph

[BeirBrennerE30]

ok.... S52 with about every bolt on you can muster and cams ... e46 m3 6 speed box and 3.91 rear end. perfect combo....I can pull on new m3's all day and its very streetable