Gear ratios and boosting

[billyr3d]

Hello fellow boosters.

Just an inquiry regarding gear ratios after adding substantial horsepower. Have you guys experimented with new/taller gears or final drives? And if so whats the consensus recipe?

Thanks.

[Bigmac834]

I think most swap to a 2.93 LSD

Sent from my SM-F900U1 using Tapatalk

[someguy2800]

A lot of people use the rear gear ratio as a way to manage traction. Longer gearing also means less shifting for a given speed range which can be helpful since you are going through each gear faster so less shifting means putting more power down in a given time. 2.93, 3.15, and 3.23 is popular on higher power cars.

[Mklock]

3.15 is a good middle setup. Paired with a 6 speed it's great.

[pbonsalb]

With a supercharger, I went from 3.23 to 3.38 to 3.64. After I changed to a turbo, I dropped to a 3.15 and think it’s a good match to either a 5 speed or a 6 speed—I have run both with the 3.15.

[Colby Colbs]

I have a built 2.79 variable ramp 4 clutch 188mm diff with a polished ring and pinion and a Rogue Finned Diff Cover that's going to be going up for sale. It was awesome on my turbo car. Cost $3k originally, letting it go for less than half price if you are interested in a built 2.79 ratio diff. I also have the Active Diff support to go with it.

[milKt]

Define "substantial" pls

3.15:1 feRatio is the Go To,
unless you have bongloads of money, time and resources.
You can easily upgrade a three (3) clutch LSD, with a small amount of love.
https://www.thayermotorsports.com/co...ade-street-kit

There USED TO BE a video 5mall5nail5 made, but ....dunno where it went.

3:15 spools + gets + goes,
and no one NEEDS to go faster than 168 on the HWY (up for debate)
unless you're in CT and extending the 5Ball Peen

[NOTORIOUS VR]

Love my 2.93 w/ the 5 speed which only has a 1:1 5th.

I couldn't imaging going shorter than that to be honest.

[milKt]

188mm
2.93:1 NON-locker

was stock for 328 + 323 (e36 96-99)

[NOTORIOUS VR]

188mm
2.93:1 NON-locker

was stock for 328 + 323 (e36 96-99)

[milKt]

Whoop WHOOP

[billyr3d]

Thanks for all the responses.

[JOMARO]

would a longer ratio , by any chance help our transmission to survive more ?

[pbonsalb]

If you want to put down big power reliably, you need a transmission that is stronger than a ZF320. There are great options, at varying costs and levels of complexity.

Getrag 420G from a Euro M3 will bolt right in and even has the same clutch splines so you can reuse your clutch. You just need a shorter driveshaft, different transmission bracket, and maybe a different differential input flange or different driveshaft end flange.

420G from E46M3 is the same as the Euro E36M3 but with different clutch splines.

GS6-53 from a rear wheel drive car with N54 motor (2007-2010 plus some later “is” models with a 22RPD kit works - I am using one. Dome say you don’t need to use an adapter plate if you enlarge some of the bell housing holes, but I have not yet read much about people actually trying that. The European diesel version of the GS6-53 does bolt right up but has gear ratios that may not be ideal. People have done that conversion and it works. Like the E46M3 420G, you would need a shorter driveshaft with an end flange to match your diff, a custom trans support bracket, a flywheel and clutch.

Tremec Magnum fits with an aftermarket Quartermaster bell housing, plus custom driveshaft, mounting bracket and flywheel.

Domestic USA automatic trans all require more time and money to make work. Member someguy2800 makes adapters. For the fancier ones, you would need some kind of electronic control. Some would have to be built to handle big power.

DCT has been done. This looks interesting to me if I come across some money to spend and am looking for a project. I have no details on this. There are a couple of companies selling controllers to adapt it to other cars.

[milKt]

Anyone using (successfully) the 6 speed from the E46 330i ?
Advantages?

ZF S6-37

[pbonsalb]

The 37 stands for 370 NM torque rating, which is in between the ZF320 and the Getrag 420G, so no guarantees on durability with high power, but most trans seem to hold way more than their rating.

I think RSperry uses one with a Vortech kit at 9 psi.

[Kevin325i]

would a longer ratio , by any chance help our transmission to survive more ?

Unfortunately no.

The failures I've seen or had are usually third gear sometimes fourth. Rolling on or shifting doesn't seem to have a high prevalence.

Basically this just means that you're over the input torque the gear set can handle.

The failures would occur in lower gears but tractive force limits what the gear set transmits and in turn there is a lower force and stress on the 1-2 gear sets.

The syncros on the zf seem surprisingly robust. The getrag 420g seems a little bit clunkier and had more problems but also came in a car with shorter final drive and higher rpm ceiling so it's subject to higher speed differentials. Usually that's the real killer of syncros.

Just need a wider, taller, higher tooth count gear.

[Bromaguire]

If you want to put down big power reliably, you need a transmission that is stronger than a ZF320. There are great options, at varying costs and levels of complexity.

Getrag 420G from a Euro M3 will bolt right in and even has the same clutch splines so you can reuse your clutch. You just need a shorter driveshaft, different transmission bracket, and maybe a different differential input flange or different driveshaft end flange.

420G from E46M3 is the same as the Euro E36M3 but with different clutch splines.

GS6-53 from a rear wheel drive car with N54 motor (2007-2010 plus some later “is” models with a 22RPD kit works - I am using one. Dome say you don’t need to use an adapter plate if you enlarge some of the bell housing holes, but I have not yet read much about people actually trying that. The European diesel version of the GS6-53 does bolt right up but has gear ratios that may not be ideal. People have done that conversion and it works. Like the E46M3 420G, you would need a shorter driveshaft with an end flange to match your diff, a custom trans support bracket, a flywheel and clutch.

Tremec Magnum fits with an aftermarket Quartermaster bell housing, plus custom driveshaft, mounting bracket and flywheel.

Domestic USA automatic trans all require more time and money to make work. Member someguy2800 makes adapters. For the fancier ones, you would need some kind of electronic control. Some would have to be built to handle big power.

DCT has been done. This looks interesting to me if I come across some money to spend and am looking for a project. I have no details on this. There are a couple of companies selling controllers to adapt it to other cars.

What companies sell a DCT for the E36? What power limits do they have?

[ba114]

Anyone using (successfully) the 6 speed from the E46 330i ?
Advantages?

ZF S6-37

Nutzy on this board is using the BZ behind his M50, I'm using the DZ behind mine. both in e30s though.
I have a 2.93LSD paired with mine.

[Nugs]

What companies sell a DCT for the E36? What power limits do they have?

People retrofit them from F8x or E9x M3s.
With the right clutches they are supposed to hold 900+ft/lbs.
Control can either be done with a standalone, like syvecs or Maxxecu, or a seperate controller like this https://htg-tuning.com/gcu/

[Mklock]

I'm also using a gs6-37bz. It's a good transmission and shiftd better than the zf320, and g420. So far I've thrown 20lbs of boost at it in 3rd gear. Hasn't skipped a beat yet.

It's nice, and only thing custom you need is a crossmember. The rest can be all OEM parts. I also found a neat trick for the driveshafts at least for my combo.

[JOMARO]

Nutzy on this board is using the BZ behind his M50, I'm using the DZ behind mine. both in e30s though.
I have a 2.93LSD paired with mine.

I ve found a GS6-45 Dz
And was thinking to use it in my e30
What cross member did u use ?
What Flywheel ?
What selector

[E30s50dude]

I ve found a GS6-45 Dz
And was thinking to use it in my e30
What cross member did u use ?
What Flywheel ?
What selector

Intreased in this also. Would you need to also need to go to a 210mm diff instead of the 188mm?

[ba114]

the 45 and 53 are similar, both are different to the 37bz/dz.

I'm fitting a 53bz to the new setup. Requires enlarging one hole in the transmission and buying a custom clutch setup.
i bought this one:
https://adamat.com.pl/n54-n55-turbo-...2x-kevlar.html
but had the flywheel customised with an M50 starter ring gear placement so i wouldnt have to use an N54 starter.

Picked up a manual driveshaft from a 135i to go with it. Havent yet assessed whether it will need to be shortened or not. Havent got measurements in gearbox length between the 37dz and 53bz yet.

[Bromaguire]

People retrofit them from F8x or E9x M3s.
With the right clutches they are supposed to hold 900+ft/lbs.
Control can either be done with a standalone, like syvecs or Maxxecu, or a seperate controller like this https://htg-tuning.com/gcu/

Is there anyone running one on an E36 M3 w/ a Turbo. What shop did the retrofit?