The semi-Comprehensive M60b40 into E30 swap Q&A

[bmwmech1]

Anybody with the 5speed on hand that can weight it? The 6speed is 110lbs dry.

Just weighed the 5 speed... 82 lbs wet. Almost 30lbs lighter than the 6 speed. I would have guessed a little lighter, but the scale don't lie, lol!

Garey

[Wh33lhop]

Well, look at what diff is used on e34 540i cars for example...something like 3.15? is very popular upgrade. I don't think there is any reason to go with some stupid rare/tall gear.... guys with turbo m50/s50 cars still use 3.25 and shorter unless you are trying to go for something with super low cruising rpm?

I plan on giving something like 3.25 a shot...I tried that diff before and it was too long for m30b35 with g260/6, but it may just work with m60 with 5speed.

Will just have to try it and see how it works out.

3.25 with the direct drive 5 speed will be quite a bit shorter than 3.46 with the OD 260/6. I probably wouldn't go that short.

IIRC the stock 540i6 rear end is like a 2.82. They sit at ~2200rpm at 80.

[Jean]

Well, look at what diff is used on e34 540i cars for example...something like 3.15? is very popular upgrade. I don't think there is any reason to go with some stupid rare/tall gear.... guys with turbo m50/s50 cars still use 3.25 and shorter unless you are trying to go for something with super low cruising rpm?

I plan on giving something like 3.25 a shot...I tried that diff before and it was too long for m30b35 with g260/6, but it may just work with m60 with 5speed.

Will just have to try it and see how it works out.

[Mr Two]

I don't think first gear would be useful with this swap, no matter what ratio diff you plop in there. ;)


First gear never really comes into play on a track anyway

e: destroying tires counts as awesome, not useful

[mkcman17]

i really have no intentions of hitting anything resembling 164mph anytime in the near or distant future.

[The Dark Side of Will]

There are lower ratios... down to 2.35, but you have to go to Europe for them.

The V8 can pull a very tall top gear. With the 6 speed and a 2.73, you can have extremely relaxed cruising, while maintaining the same acceleration as the 5 speed. IOW, in order to have the same relaxed cruise, a 5 speed would have to have 2.21 rear, which would cost acceleration significantly.

Even with a 2.73 rear, the 4.23 first gear of the 6 speed will give you an 11.5 overall first. That's a pretty aggressive gear for that much power in a package as light in the rear as an E30.

[Mr Two]

The lowest gear ratio possible (2.73) puts you at 164mph@6500rpm in 5th. If you were interested in a higher top speed you'd need to go with the 6

http://www.fatboyraceworks.com/gears/index.php?MaxRPM=6500&TireDiameter=23.07&GearRatio1=4.32&GearRatio2=2.54&GearRatio3=1.62&GearRatio4=1.23&GearRatio5=1&GearRatio6=.83&FinalDrive=3.25&TireWidth=205&TireAspect=50&RimDiameter=15&MaxRPM_2=6500&TireDiameter_2=23.07&GearRatio1_2=4.32&GearRatio2_2=2.54&GearRatio3_2=1.62&GearRatio4_2=1.23&GearRatio5_2=1&GearRatio6_2=&FinalDrive_2=3.25&TireWidth_2=205&TireAspect_2=50&RimDiameter_2=15&Calculate=Calculate%2FGraph&Compare=1

You can run a 3.25 with the 6 speed trans and still retain the same top speed you'd get with the 5 speed with a 2.73.

The difference in acceleration between a 3.25 rear and a 2.73 would be fairly large, I'd imagine.

Look at this video - the yellow cars are both stock, the red car has intake, exhaust, and 4.30 gears. Stock is 4.10. It has an intake and exhaust as well, but these mods don't really do anything power wise for an s2k. Check out the difference in acceleration. http://youtu.be/NtdOU-yyZ_w?t=2m42s

e: though granted, the S2000 has a much more narrow powerband

[Jean]

lol...but having 6th gear is still pretty pimp on it's own accord.

[mkcman17]

i hate all of you. i searched for a 6spd forever just to be slowly turned against it. fu guys!

[Jean]

Yes, please weight it! I still think there is a chance that m60 swap with 5speed and ligther flywheel has a chance of being lighter than m30b35 swap!

[The Dark Side of Will]

Yeah, the 5 speed doesn't weigh much.

110 is getting into T56 territory...

[bmwmech1]

Anybody with the 5speed on hand that can weight it? The 6speed is 110lbs dry.

Yeah, I'll try to weigh mine by the end of the week... it's pretty light, I'm guessing around 65lbs...

Garey

[Jean]

Anybody with the 5speed on hand that can weight it? The 6speed is 110lbs dry.

[Wh33lhop]

If I'm not mistaken, these two V8 transmissions are geared exactly the same except for the extra over driven 6th...

Garey

You are not mistaken. First five gears are identical, sixth is just an extra overdrive gear on the G420.

[bmwmech1]

It doesn't seem like the 6 speed is THAT much worse.

Assuming they are geared for the same top speed in top gear, a 6 speed car will be WAY faster than a 5 speed around a track. Gearing is awesome, and its one reason why my friends S2k keeps up as well as it does.

If I'm not mistaken, these two V8 transmissions are geared exactly the same except for the extra over driven 6th...

Garey