Author Topic: Can M42 Handle 2 bar? (Read 9948 times)

futron.sim · « **on:** June 04, 2008, 09:22:41 PM »

Assuming the M42 is rebuilt with forged internals (eg. MM parts), 88mm diesel crank and steel head gasket etc, can it withstand 2bar (~28PSI) of boost for short periods? Will the block itself be able hold the pressure or will the cylinders give way?

This is because i estimate that I will need at least 2 bars of boost in order to outrun 135i on straights. I am hoping to build a M42 that could put those sixes to shame.

Couple of my friends have dumped their M42 infavor of a M50/S50 but I have no intention of doing that. Just wanted to prove that the M42 is just as capable, if not better than the inline 6s.

bar73k · « **Reply #1 on:** June 13, 2008, 04:57:11 AM »

thats exactly what ill be doing at the end of the year

im all ready running 20~22Psi boost
with just forged pistons and cometic steal headgasket the res is bone stock (fully rebuilt/balanced)

i cant see why the motor wont take it

318kid · « **Reply #2 on:** June 13, 2008, 05:22:42 PM »

Someone on Youtube was running 1.5bar on stock internals with ground down pistons. He was putting 333rwhp! I'm pretty sure that that would put you pretty close to 135i territory, but why do you want to beat a 135i?

xwill112x · « **Reply #3 on:** June 13, 2008, 05:55:25 PM »

bahhhhhh

NA>boost

enildeR · « **Reply #4 on:** June 13, 2008, 06:53:48 PM »

sorry. my post is off topic…
people say NA is bettAR than boost because when someone typically builds an engine with a turbo in mind, they make the CR around 8.5 or lower. This results in little or no low-end grunt. that and just so they can brag on the forums that they can drink beer out of their pistons.

(I've seen it more than twice.)

you can build a great engine that has 11.5 CR with a turbo and still produce great power. you just have to have someone that knows a lot about engine mechanics and thermal efficiency to help you accomplish the task. people have done this in the past. it's not an impossible task, and if you do it right, you won't destroy your engine.

You still get the low-end grunt that makes driving a car in the canyons and through traffic fun without having to be near redline.

futron.sim · « **Reply #5 on:** June 13, 2008, 09:50:15 PM »

Quote from: 318kid;51238

Someone on Youtube was running 1.5bar on stock internals with ground down pistons. He was putting 333rwhp! I'm pretty sure that that would put you pretty close to 135i territory, but why do you want to beat a 135i?

I am using the 135i as a benchmark because I saw videos that the 135i is as fast as the new M3 on 1/4 mile test. Thus, if I can make my car as fast as the 135i, I will be as fast as the M3.

rob_e30 · « **Reply #6 on:** June 14, 2008, 09:59:19 PM »

We had a problem with the plumbing on our downpipe and were seeing 27psi. We ran this way for a race day through practice, qualifying, and a race distance without blowing a headgasket or any other problems. The conditions were right for blowing it up too... we were running the injectors at 110% duty cycle at one point so yes, the motor will take it. Once you get detonation however, you will start going through head gaskets.

nuvolarossa · « **Reply #7 on:** June 15, 2008, 03:06:35 AM »

Hope that this thread will help to see more M42 turbo engines in the forum!

If only I had time to fit all that I have in my M44...

futron.sim · « **Reply #8 on:** June 15, 2008, 10:28:20 AM »

Quote from: rob_e30;51323

We had a problem with the plumbing on our downpipe and were seeing 27psi. We ran this way for a race day through practice, qualifying, and a race distance without blowing a headgasket or any other problems. The conditions were right for blowing it up too... we were running the injectors at 110% duty cycle at one point so yes, the motor will take it. Once you get detonation however, you will start going through head gaskets.

Thanks for the info! I am glad to know the motor is able to handle the boost w/o blowing the motor. I think detonation should not be a problem for me because I will be only pumping Shell Ron98 or V-power (supposedly Ron100) gas.

Btw, may I know what are the internals you are using for the motor?

futron.sim · « **Reply #9 on:** June 15, 2008, 10:37:58 AM »

Quote from: enildeR;51246

sorry. my post is off topic�
people say NA is bettAR than boost because when someone typically builds an engine with a turbo in mind, they make the CR around 8.5 or lower. This results in little or no low-end grunt. that and just so they can brag on the forums that they can drink beer out of their pistons. (I've seen it more than twice.)

you can build a great engine that has 11.5 CR with a turbo and still produce great power. you just have to have someone that knows a lot about engine mechanics and thermal efficiency to help you accomplish the task. people have done this in the past. it's not an impossible task, and if you do it right, you won't destroy your engine.

You still get the low-end grunt that makes driving a car in the canyons and through traffic fun without having to be near redline.

Actually, I did thought about it. My originally idea was to install a Euro S50B32 motor. However, after much consideration, I decide to keep my M42 motor and turbo charge it instead.

to overcome the poor low-end grunt, I am thinking of dual charging it. Using an Eaton blower to compensate for the low end.

George77 · « **Reply #10 on:** June 15, 2008, 08:17:06 PM »

That's a good news ,but how many psi a stock head gasket with after market bolts of course can handle??

futron.sim · « **Reply #11 on:** June 15, 2008, 09:17:06 PM »

Quote from: George77;51371

That's a good news ,but how many psi a stock head gasket with after market bolts of course can handle??

I am not sure but I think 7-8psi should be ok for stock gasket since the DASC kit is already running around that boost.

However, I think its best to go for a steel gasket like cometic ones.

George77 · « **Reply #12 on:** June 15, 2008, 09:40:48 PM »

It must hold much more than that if you have a proper tuning and after market head blots.I'm planing to go 10psi veeeeeery soon,like next week.

e30 4cyl · « **Reply #13 on:** June 15, 2008, 09:57:38 PM »

If you do all the modifications you listed above, the m42 should have no problem with 2 bar. There was a guy who turbocharged his m10 with stock internals and ran about 30 psi for I think 2 years before it finally blew. I am not sure if I have all the details correct but I think he was making around 330rwhp with hardly any other mods besides the turbo.

futron.sim · « **Reply #14 on:** June 15, 2008, 10:37:15 PM »

Quote from: e30 4cyl;51377

If you do all the modifications you listed above, the m42 should have no problem with 2 bar. There was a guy who turbocharged his m10 with stock internals and ran about 30 psi for I think 2 years before it finally blew. I am not sure if I have all the details correct but I think he was making around 330rwhp with hardly any other mods besides the turbo.

Wow! 30PSI on stock internals!