Building an M42

[I8UR911]

Build is coming along......just slow. So slow that I'm installing my lightened M20 flywheel this weekend with the M20 clutch. Interested to see how it feels. I'm ordering up my pistons in the next week or so....11:1 CP. I'm up and down on itb's as its a lot of money for not much return from what I've heard. I'm gonna focus on the motor, port and polish the intake manifolds and throttle body first. If I think its worth more than the "cool factor" I'll go for the itb's.

[bmwman91]

Be super careful with the TB. It takes very little to cause the throttle plate to not seal.

ITBs with long enough runners should maintain your mid-range torque and improve power across the board. The stock manifold isn't super efficient since the incoming air needs to do to 90 degree turns to get into the runners. Throttle response with ITBs is also fantastic.

You are going to like the lightened M20 flywheel. Chances are you'll stall the car a few times getting used to it, but damn it spins up fast! I love mine. Please let me know if you get crazy rattle sounds from the tranny at idle with the clutch pedal up, and when engine braking. I have a lot of noise (rocks in a coffee can) coming from my tranny as a result of the flywheel and I am hoping that it is only because of the flywheel.

[decay]

Haha nice. I gotta find one of those shops. Honestly, it is retarded that CA does a visual inspection. Just run the exhaust sniffer, pressure test the gas cap and evap system. Done.

yeah, another way to say that would be "it's none of your fucking business what's under my hood as long as i pass the sniffer", but that's not the state we live in.

I8: i had to go to 25% larger injectors and bump the rail pressure to get the tune right on my ITB setup. also FWIW.

[bmwman91]

OK, I demand pics of people's ITB setups. Nice big ones.

That's right, BIG ones. So I can see...

[wazzu70]

To help solve the getrag rattle, mix some Lucas gear oil in the trans. Also it helps to run standard gear oil and not the synthetic stuff.

ITBs are hottness, but just do the original intake first. Later you can do ITB and document the improvement. Also...you get to drive the car while you are saving for the ITB!

[bmwman91]

Interesting to know about the tranny oil. I switched from RedLine MTL to RedLine MT-90 GL4 and it helped a little. How much Lucas stuff would you recommend in there?

[I8UR911]

To help solve the getrag rattle, mix some Lucas gear oil in the trans. Also it helps to run standard gear oil and not the synthetic stuff.

ITBs are hottness, but just do the original intake first. Later you can do ITB and document the improvement. Also...you get to drive the car while you are saving for the ITB!

I think that's the plan......run the original manifold and see what its like with that first. If I think there's more to gain, then I'll buy the Dbilas kit. I agree that they look badass. I'd really want to run them with no air box, but just 4 ITG filters :)

Check us out at TurnerMotorsport.com. With a 20,000 sq/ft warehouse, we stock everything!

[wazzu70]

Interesting to know about the tranny oil. I switched from RedLine MTL to RedLine MT-90 GL4 and it helped a little. How much Lucas stuff would you recommend in there?

On my DD years back the rattle annoyed me to no end. I did a 50/50 mix with Lucas/regular dino gear oil. Much better.

Hard to get into 1-2 when its cold out though :)

[I8UR911]

Update!

M20 flywheel conversion finished. First impression = disappointment and waste of money. Didn't noticed much of a difference. There is A difference but not a big one. Maybe not enough driving yet? Maybe sky high expectations?.....I don't know, but I wasn't "wowed".

Changed my mind for the last time and ordered my Dbilas kit today with Alpha-N!!! I'll be running "open" itb's. Can't wait to get them.

The head should be out of machine shop in a week or 2. Not going to do the bottom end immediately due to the Dbilas purchase :)

I'll keep updating once I get some parts.

Check us out at TurnerMotorsport.com. With a 20,000 sq/ft warehouse, we stock everything!

[brads2002]

[QUOTE=bmwman91;3843511]Be super careful with the TB. It takes very little to cause the throttle plate to not seal.

ITBs with long enough runners should maintain your mid-range torque and improve power across the board. The stock manifold isn't super efficient since the incoming air needs to do to 90 degree turns to get into the runners. Throttle response with ITBs is also fantastic.

You are going to like the lightened M20 flywheel. Chances are you'll stall the car a few times getting used to it, but damn it spins up fast! I love mine. Please let me know if you get crazy rattle sounds from the tranny at idle with the clutch pedal up, and when engine braking. I have a lot of noise (rocks in a coffee can) coming from my tranny as a result of the flywheel and I am hoping that it is only because of the


I did a JB in mine years back. Rattled like A baby. I ended up putting in a sprung clutch vs the solid finger style. The sprung cutch was stock for a non ac 318. It does a lot for absorbing vibrations. I believe it has to go in backwards so the springs clear the flywheel bolts. It made a huge difference but there is still some rattle under cruzing. I also mixed in heavier oil which helped slightly.

[bmwman91]

If you maintain the same runner length and only switch to ITBs, your power curve should not change much. I was cautioning more about enlarging the stock TB because it is a real pain to get the modified stuff to seal well when closed.

[totheredline]

^the sound and cool factor are enough for one to justify running an ITB setup.

e30 ITBs dyno run

[I8UR911]

Update on M20 lightweight flywheel.

Car does feel better coming out of corners. Last event felt good. Starting to feel a little better about the conversion. Still no rattling coming from clutch area :)

Not engine related, but swapping out H&R springs for GC coilovers next week as well as installing a Z3 1.9 steering rack :)




Check us out at TurnerMotorsport.com. With a 20,000 sq/ft warehouse, we stock everything!

[stanhayward]

I don't know how far along with this you are but Metric Mechanic sells a crate M42 that makes 205 horsepower so more than 200 is definitely doable. It is MM though so it costs a kidney to the black market but that kind of horsepower isn't out of reach. I'm more of an M20 guy but I'm strongly considering a 318 as a DD, way better fuel economy and ~75lbs lighter is always a good thing ;) Very intrigued to see how this turns out!

EDIT: Didn't notice that there were 6 pages to this and that MM has already been discussed, sorry for the repetition

[DER E30]

[QUOTE=brads2002;3858159]

You are going to like the lightened M20 flywheel. Chances are you'll stall the car a few times getting used to it, but damn it spins up fast! I love mine. Please let me know if you get crazy rattle sounds from the tranny at idle with the clutch pedal up, and when engine braking. I have a lot of noise (rocks in a coffee can) coming from my tranny as a result of the flywheel and I am hoping that it is only because of the

I did a JB in mine years back. Rattled like A baby. I ended up putting in a sprung clutch vs the solid finger style. The sprung cutch was stock for a non ac 318. It does a lot for absorbing vibrations. I believe it has to go in backwards so the springs clear the flywheel bolts. It made a huge difference but there is still some rattle under cruzing. I also mixed in heavier oil which helped slightly.

Wait a minute! That freaking rocks in the coffee can noise is my M20 FW?!?!?! I hate that freaking noise! Mine rattles bad when the idle drops significantly as in when I let the clutch out slow without much gas, and CONTINUOUSLY when engine braking... Really loud between 4 and 3k revs.
I bought my car from a guy that did all the work and I thought he screwed something up bad in the drivetrain! I guess thats good then...
I love the way it rips across the tach though...