Power mods for the M42

[harvey2]

don't need to upgrade the fuel pump, because the injectors operate at very nearly the same psi. the injectors are plug and play and do make a difference. nothing earth shattering but it is noticeable. the injectors are from the 5.0 mustang. i got mine for a '90 mustang GT with the 5.0L V8.

I have been absolutely satisfied with the power upgrades on my 91 318is. it is remarkably quick and a lot of fun. Personally i think the M42 is very underrated

i have done the following:
mustang injectors
advanced the intake cam timing by 6 degrees (big improvement in top end)
done a custom high flow cold air intake filter setup
Coil over pug conversion (excellent upgrade)
swapped in a slim electric cooling fan and ditched the heavy factory fan
dinan chip (a bit disappointed. will swap for a markD 93)
custom free flowing exhaust (big improvement, fantastic sound)
cleaned up all the vacuum lines, and made sure no breather lines feed back into the intake. (no more oil and hot air getting sucked back into the intake)
AC delete
Power steering delete
ABS delete
stripped the interior
lightweight front racing seats

One of the most important things you can do is just sort the controls. suspension should be tight and aligned, firm up the brake pedal, make sure the throttle linkage is free, clean the throttle body and manifold. Then your power upgrades will be all the more noticeable

the car's an absolute kick in the pants. i've gone for lightweight and instant response. on windy roads, very, very few cars can hang with it. will still do an aluminum m20 flywheel swap

Nice clean engine bay, good work!  The M20 flywheel swap is a good mod and the upgrade to the M20 clutch is a nice improvement too.  If you go this route, using an M20 steel flywheel, have it lightened as much as you can, like down to 11 or 12 lbs.  Mine is 13 lbs (stock flywheel from older 323i).  I would go lighter if I was doing it over again, perhaps a 9lb aluminum one.  

Are you running a limited slip diff?  That's a good mod if you don't have one.

[woof132]

Nice clean engine bay, good work!  The M20 flywheel swap is a good mod and the upgrade to the M20 clutch is a nice improvement too.  If you go this route, using an M20 steel flywheel, have it lightened as much as you can, like down to 11 or 12 lbs.  Mine is 13 lbs (stock flywheel from older 323i).  I would go lighter if I was doing it over again, perhaps a 9lb aluminum one.  

Are you running a limited slip diff?  That's a good mod if you don't have one.

wow i didn't realize the steel flywheels were so light. i was looking to the 9lb aluminum ones, but at $450, i've been hesitant, and it'd be the most expensive part I've put on the car to date.  think I'll go with a steel one and have it lightened as much as possible. it does have a limited slip diff, and i agree, it's an excellent upgrade. makes a world of difference when you start pushing the car in corners

[harvey2]

wow i didn't realize the steel flywheels were so light. i was looking to the 9lb aluminum ones, but at $450, i've been hesitant, and it'd be the most expensive part I've put on the car to date.  think I'll go with a steel one and have it lightened as much as possible. it does have a limited slip diff, and i agree, it's an excellent upgrade. makes a world of difference when you start pushing the car in corners

Indeed, this is why the conversion to an M20 flywheel and clutch is so popular, because it is relatively cheap.   You have to calculate the total including an M20 starter motor but if you do some research on this conversion on this site, you will find what you need.  

Don't rule out the 9lb aluminum one just yet.  The steel one can't be brought down to that weight as far as I know.  

The stock flywheel is dual mass.  The conversion to M20 changes to a single mass unit.  This means that you lose the flywheels ability to absorb shock and vibration.  With the M20 setup, this is dealt with by a different clutch plate that includes shock absorbing springs.  These springs are not found on the M42 clutch plate because they are not needed.  Changing both flywheel and clutch together to M20 type deals with this problem.  Now, if you were to change to an aluminum flywheel which is single mass, and you don't change the clutch plate then you have no element in the driveline to do that job of absorbing vibration.  I think this is why some that have done a conversion to aluminum flywheel (to flywheels made to fit M42) suffer additional noise, especially during idle, at least that's my theory.

[woof132]

 Now, if you were to change to an aluminum flywheel which is single mass, and you don't change the clutch plate then you have no element in the driveline to do that job of absorbing vibration.  I think this is why some that have done a conversion to aluminum flywheel (to flywheels made to fit M42) suffer additional noise, especially during idle, at least that's my theory.

well said. and i agree. the aluminum one i was considering was one for an m20. so then i can upgrade to that clutch as well. i couldn't agree with you more though. when the right aluminum flywheel is paired with the right clutch, it is a beautiful thing.

[stillmatick]

don't need to upgrade the fuel pump, because the injectors operate at very nearly the same psi. the injectors are plug and play and do make a difference. nothing earth shattering but it is noticeable. the injectors are from the 5.0 mustang. i got mine for a '90 mustang GT with the 5.0L V8.

I have been absolutely satisfied with the power upgrades on my 91 318is. it is remarkably quick and a lot of fun. Personally i think the M42 is very underrated

i have done the following:
mustang injectors
advanced the intake cam timing by 6 degrees (big improvement in top end)
done a custom high flow cold air intake filter setup
Coil over pug conversion (excellent upgrade)
swapped in a slim electric cooling fan and ditched the heavy factory fan
dinan chip (a bit disappointed. will swap for a markD 93)
custom free flowing exhaust (big improvement, fantastic sound)
cleaned up all the vacuum lines, and made sure no breather lines feed back into the intake. (no more oil and hot air getting sucked back into the intake)
AC delete
Power steering delete
ABS delete
stripped the interior
lightweight front racing seats

One of the most important things you can do is just sort the controls. suspension should be tight and aligned, firm up the brake pedal, make sure the throttle linkage is free, clean the throttle body and manifold. Then your power upgrades will be all the more noticeable

the car's an absolute kick in the pants. i've gone for lightweight and instant response. on windy roads, very, very few cars can hang with it. will still do an aluminum m20 flywheel swap

i like this guy setup:D