6-speed manual swap into e36 m3

[jvit27]

6 speeds have essentially identical in-gear ratios the 5 speeds do. You're just adding an overdrive.

I have a six-speed unit from the E46 M3 paired with a 3.91 diff. But my supercharged E36 is making around 380rwhp or so.

This combo is not as bad as some may think considering that I do equal amount of city/highway driving on my E36 (although it's not driven very often). Despite the lower gear ratio, I actually find myself shifting less driving around in the city, as I can just leave it in the fifth gear without shifting as long as I am not going slower than 20mph. 1st gear is still very useful going up a steep driveway and driving around in the parking lots.

Does anyone know how different ratios would impact the way a supercharged E36 accelerates? I had a hard time keeping up with a stock late model Mustang GT off the line this other day because I had to shift to 3rd even before we broke the speed limit.

Jon

Echoing exactly what Braymond said..
As i've touched on in other posts, S52's just don't take well to short gearing. The concept big turbo guys use applies to you too - by running taller(lower ratio) rear end, you'll stay in boost longer and capitalize on the power band. Short gearing winds the gear out quicker, but in the case of a centri SC your mega power range is even smaller than a turbo to begin with so you are basically shifting yourself *OUT* of peak power. Not to mention creating unnecessary traction issues and negating the value of having a 6 speed. With your power and style of use you should be running a 3.46 max IMO.

Very very rough math: +size wheels will offset your ratio by one gear step give or take. So by running 18's with a 3.46 it would be like running 17's with a 3.38. 3.73 would behave like a 3.64, etc. Vice versa, 17's with a 3.46 would be like 18's with a 3.64, or in your case 3.91+18" is more like 17's with a 3.73.

[Braymond141]

6 speeds have essentially identical in-gear ratios the 5 speeds do. You're just adding an overdrive.



Echoing exactly what Braymond said..
As i've touched on in other posts, S52's just don't take well to short gearing. The concept big turbo guys use applies to you too - by running taller(lower ratio) rear end, you'll stay in boost longer and capitalize on the power band. Short gearing winds the gear out quicker, but in the case of a centri SC your mega power range is even smaller than a turbo to begin with so you are basically shifting yourself *OUT* of peak power. Not to mention creating unnecessary traction issues and negating the value of having a 6 speed. With your power and style of us you should be running a 3.46 max IMO.

Very very rough math: +size wheels will offset your ratio by one gear step give or take. So by running 18's with a 3.46 it would be like running 17's with a 3.38. 3.73 would behave like a 3.64, etc. Vice versa, 17's with a 3.46 would be like 18's with a 3.64, or in your case 3.91+18" is more like 17's with a 3.73.

This!

[Baby ///M3]

Excellent points!

Thank you both for your help. Time to hunt down a 3.46 diff to replace the 3.91.

Jon

[Butters Stoch]

The size difference in the wheels does not always apply.
Ie running a 245/45/17 = 25.7" tall tire. Switch that to a 245/40/18 and your still running a 25.7" tall tire. So, all will be equal.

[jvit27]

The size difference in the wheels does not always apply.
Ie running a 245/45/17 = 25.7" tall tire. Switch that to a 245/40/18 and your still running a 25.7" tall tire. So, all will be equal.

Well stock is 245/40-17 and that is 24.7, so.

[Butters Stoch]

Well stock is 245/40-17 and that is 24.7, so.

And that was an example. Not any correct size.
So. You can't say 17 is X.xx and 18 is X xx. Very few run a stock size. Some stretch onto 18's and they are shorter than the 17".
a 16" size would be 225/50/16 is 24.9" wouldn't change any gear ratio.

[jvit27]

Clearly you missed the part where I said "Very very rough math"

Very few run a stock size.

Ok it's time for bed now, Butters.

[Reprisal]

Bumping this for a pertinent question.

Does anyone know the exact length that a 5-speed driveshaft has to be shortened to facilitate the 6-speed swap?

I was initially looking at picking up a used auto driveshaft, but I've got a six bolt input at the differential and recently replaced my driveshaft (last year).

After contacting a shop that willing to modify the length, it'll be about the same price as getting a used auto shaft. I feel its better in the long run since I'll have something that I know works and was recently re-manufactured.

[jvit27]

Bumping this for a pertinent question.

Does anyone know the exact length that a 5-speed driveshaft has to be shortened to facilitate the 6-speed swap?

I was initially looking at picking up a used auto driveshaft, but I've got a six bolt input at the differential and recently replaced my driveshaft (last year).

After contacting a shop that willing to modify the length, it'll be about the same price as getting a used auto shaft. I feel its better in the long run since I'll have something that I know works and was recently re-manufactured.

Want to say it's 3.5" but I can't remember or find my notes..

Top, shortened for 6spd
Bottom, stock 5spd.

[Reprisal]

Want to say it's 3.5" but I can't remember or find my notes..

Top, shortened for 6spd
Bottom, stock 5spd.

Driveshaft shop I called seems to have done this before. Over the phone said that he thought it was 88mm on the nose (3.5" translates to 88.9), but I wanted some verification.

[jvit27]

Driveshaft shop I called seems to have done this before. Over the phone said that he thought it was 88mm on the nose (3.5" translates to 88.9), but I wanted some verification.

Seems right then. Sorry it's been awhile

Another way to verify is get the measurements from an automatic M3 driveshaft, which works, but is ~1/2" too short of ideal IIRC. (Probably around 3")

[kevinwilly]

Driveshaft shop I called seems to have done this before. Over the phone said that he thought it was 88mm on the nose (3.5" translates to 88.9), but I wanted some verification.

US spec 5 speed CV style driveshaft is 1469mm long

Euro 6 speed driveshaft is 1367mm long. So it needs to be 102mm shorter, or 4.016 inches. And that all has to be in the front section. If you are using a 4 bolt U joint style driveshaft, the flange length on the diff is different. Those are 1492mm long, but the extra 23mm is either the different in flange height from the diff or is taken up with the slide joint. I'm not sure.

So I'm not a driveshaft expert, and those are just the numbers that I've found online. And the euro 6 speed driveshaft I have is in my car at the moment, so I'm not going to be able to measure for you. Sorry. The best bet is to just take your car to the DS shop and have them measure it to be sure.

[Braymond141]

US spec 5 speed CV style driveshaft is 1469mm long

Euro 6 speed driveshaft is 1367mm long. So it needs to be 102mm shorter, or 4.016 inches.

Correct. 6-bolt drive shafts use the same rear section Euro and US. The measured difference is all off the front section.

[RickyN F355]

i hated the way my e46 m3 shifted (gearbox and clutch).
does the zionsville 6 speed feel like the oem e36 m3 tranny?

[tofunin]

i hated the way my e46 m3 shifted (gearbox and clutch).
does the zionsville 6 speed feel like the oem e36 m3 tranny?

It will be similar as it is the 6 speed ZF off the E46 330 ZHP.

[pbonsalb]

Some say the ZF GS6-37 shifts better than the Getrag 420G.

[RickyN F355]

Some say the ZF GS6-37 shifts better than the Getrag 420G.

Which is which? Is the getrag the e46 m3 tranny?

Sent from my BBB100-3 using Tapatalk

[RickyN F355]

It will be similar as it is the 6 speed ZF off the E46 330 ZHP.

Ok so it won't be like the e46 m3 which is the getrag, correct? The 330i is more like the e36 m3?

Sent from my BBB100-3 using Tapatalk

[RRSperry]

By all accounts that I've heard from people that have done both, the ZF is much less notchy and easier to use.

I've got the 420G and a Rogue shifter, it isn't bad, but it's not as nice as the stock 310..

If I were t do it again, I'd go with the ZF...

[RickyN F355]

called zionsville- nice guys. $3500 for their ZF with potential $200 core for trade in

[BimmerBreaker]

Having daily driven a car with a 420G and now daily driving a car with the ZF 6 speed, the ZF gets my vote any day of the week...

Smoother, less notchy, but not at all "vague" - you know where all the gears are and its like the gearbox actually wants you to shift into them. The 420G is almost so notchy that it's like "are you sure neutral isn't ok?" any time you try to put it into a gear.

[MauiM3Mania]

...Smoother, less notchy, but not at all "vague" - you know where all the gears are and its like the gearbox actually wants you to shift into them. The 420G is almost so notchy that it's like "are you sure neutral isn't ok?" any time you try to put it into a gear.

Sounds like a shifter issue or the particular trans in the car you drove. I have the euro six speed (Getrag) and gear selection is a precise. Maybe it's the Auto Solutions shifter I'm using. The only negative of the Getrag is, when cold I get the 'second gear crunch'. Once warm, that disappears.

[BimmerBreaker]

I've driven quite a few 420G's, they were all like that. Its just that it requires more force to get it into gear than the ZF. Have you driven a ZF 6 speed? If you haven't, try to get behind the wheel of one, its silky smooth.

I don't miss the second gear crunch... my ZF syncros are worn, so I get some 2nd gear grindtime funtime in my ZF too. Best of both worlds

[RickyN F355]

yeh and if i remember correctly using the sport mode the e46 m3 made shifting even worse

[MauiM3Mania]

The Getrag in my 99 was not beat and had less than 60K on it... or I just got lucky.