91 318is

[hopkinsM42]

hi. Is there a thing that I can do to improve the speed on my '91 318is? I just replaced my diff (325) so my gears are longer now. I don't want to go turbo since it may kill my engine. Any suggestions?

[jackjroadster]

318is flywheel weighs as much as a 325i flywheel(28.5 pounds). It's dual-mass seems to be a big problem since it kills first and second gear acceleration and this is also one reason why 318iS’s 0-60 is so slow.

Some posts on BMW repair questions says you could try to use a 325i flywheel/clutch or buy an aluminum flywheel for your M42's clutch and an aluminum flywheel for using the 325i clutch.

Buying an aluminum flywheel for the M42 runs about $500-700 but is very light(requires no modification to be fitted).

M42 318is aluminum flywheels(12 pounds), and 325i aluminum fly's(8 pounds).

"The 325i flywheel requires a few other modifications to be fitted in the 318iS. Here’s what you need: 325i flywheel, 325i clutch, 325i pressure plate, 325i drive-pinion for the starter motor, and a ‘78-’83 323 throw-out bearing. Replace all these with the 318iS parts and it bolts right together. After all is said and done, your 318iS will have a LOT better acceleration in the first few gears, and deceleration will take place much quicker, which helps on the street and in the auto-x. Turner motorsport and a few other tuners also sell replacement aluminum flywheels for the 318is, but they also more expensive."

[jackjroadster]

Hello,just to follow up. Try to read on BMW repair questions,you'll see there other things that affects the speed and performance of M42 318iS.

Other parts that you can try to modify:

• Computer chip
• Rear end gear
• cam timing(adjust it)
• muffler
• intake system