M20 304 degree cams and 87mm piston a good idea?

[mtechni]

Hey guys,
New here, I have a 325i 1989 Mtech sedan.

So far my mechanic has put 86mm pistons, M54 3.0 crankshaft and chipped the ecu, freer flowing headers. I have come across 87mm pistons ( from a m3 i guess ) and i want to purchase 304 Schrick camshafts.
Now I live in a country where dynos are rare and Im not sure as to what hp i have and so forth. Money isn't an issue I just want get the most power out of an M20 without a turbo, and want to leave the e30 engine bay looking classic.

how much hp am I working with? and are the 87mm pistons worth it?

[Kershaw]

All those mods are leaving a lot on the table without actually tuning the car. You can't expect the chip to still be the right tune after changing your current set up. Provided that it was even the right tune for your current set up. That's a really big cam. I would not run it without specific tuning.

What chip is this, where did it come from, was it made for you?

[digger]

i wouldnt use as big as 87mm though it has been done before (by all reports), 86mm is plenty when youve only gaining a couple % engine size but making the cylinder walls thinner than you might actually get less ring seal negating any gains or worse cause premature failure.

without the supporting mods (high enough CR, ITB, headwork, standalone ECU) the 304 will be a bit of a dog for not much gain over a milder cam.

[mtechni]

All those mods are leaving a lot on the table without actually tuning the car. You can't expect the chip to still be the right tune after changing your current set up. Provided that it was even the right tune for your current set up. That's a really big cam. I would not run it without specific tuning.

What chip is this, where did it come from, was it made for you?

Im not technical and dont know much in terms of mechanics. But a technician with a laptop hooked to the car and drove it and I guess put the settings for the engine to run properly. There was a huge difference in torque, but most of the guys here run M50's 24v non vanos on their e30's with cams and cranks are much faster then my set up till this point. My goal is to have a M20 that can keep up with the rest. My mechanic is saying that a 304 would make a huge difference, but I'd like more opinons of people who are experienced

[Kershaw]

Yes, a cam should make a difference. Doing that is a good idea. Maybe not a 304 unless you do what digger said. Maybe 284.

If money is really not an issue, I would just order this engine from these guys and never worry about horsepower from a naturally aspirated m20 again since you'll know you're at the limit. http://racehead.com.au/rhds-293rwhp-2-9l-race-engine/ You're definitely going to need standalone aftermarket engine management and tuning though.

[digger]

first thing i would do is get an ECU, youre not going to get the best potential using the motronic system even if people try and tell you the flappy door isnt a restriction

another thing for sure is it would be nice to know all the specs of the engine. we dont even know what the current cam is, sounds like it might be the stock cam lol

[mtechni]

first thing i would do is get an ECU, youre not going to get the best potential using the motronic system even if people try and tell you the flappy door isnt a restriction

another thing for sure is it would be nice to know all the specs of the engine. we dont even know what the current cam is, sounds like it might be the stock cam lol

Alright, I know the mechanic said he put 86mm pistons and e46 330i crankshaft. Wider exhaust with headers, he is going to install dbilas dynamic throttle body. 3:43 diff, with a different clutch ( supposedly less slipping). As far as camshafts nothing yet, thats why I was asking about the 304. I just dont know the perfect combo.

[LJ851]

Alright, I know the mechanic said he put 86mm pistons and e46 330i crankshaft. Wider exhaust with headers, he is going to install dbliss dynamic throttle body. 3:43 diff, with a different clutch ( supposedly less slipping). As far as camshafts nothing yet, thats why I was asking about the 304. I just dont know the perfect combo.

The perfect combo definitely does not include those throttle bodies, don't waste your money on them.

[mtechni]

The perfect combo definitely does not include those throttle bodies, don't waste your money on them.

:( I already purchased it...whats so bad about them? Whats a better throttle body?

[digger]

:( I already purchased it...whats so bad about them? Whats a better throttle body?

Everything is bad performance loses heaps of torque with barely any gain if any topend , price and fitment all suck. Racehead do a system that works so much better and it's probably less than half price. Seriously cancel the order