School me on turbo M42s

[Blackangusinc]

I want to know what people have done with boosted M42s. Is there an accepted limit to the PSI a built M42 block and head can contain? Max head flow? Over boring? Sleeves? Dyno pulls? What have some of you seen and done?

[bmwm42]

stock can handle up to 14psi on a fully stock rebuild. im running a stock setup on 7 psi on hx35, im roughly at 170whp. im sure ryan(buttchug) will chime in here as he has a far superior setup aswell many others on here

[Dj Buttchug]

why hello there bitchesssss

[MF DOOM]

85mm cp pistons, aero precision rods, dual valve springs, hardened valve locks and guides, stainless steel valve +1mm oversize, high performance shims, MLS gasket, stock crank, lifters and cams. Shitty master power turbo. .50 cold and .48 hot. tecgt ecu. uhh.. cr is 8.0:1. running 9psi right now. pretty slow honestly. need mo boost. 201whp 198tq. was dynoed at sea level and im about 5200ft above now so whatever difference the elevation makes.

I plan on getting turbo cams in the future and upgrade the turbo. Itll see 2 bar boost. Still lots of work to do.

http://www.youtube.com/watch?v=-r0flMUIy_E&feature=plcp

But the other day i was thinking. What kind of gains would be seen by taking the exhaust cam down a degree or two and intake up four or five? Would be somewhat similar to turbo cams, correct?

[gearheadE30]

I'm running 7.5 psi, soon to be 10 whenever I get around to installing the EBC circuitry in the MS2e. For a moderate, daily-driver setup, I'd stick with stock internals and stock head gasket, just make sure everything is up to snuff, like rings, pistons, bearings, timing case components, etc. Small case diffs won't last long behind much boost at all. The trans will be fine, just don't go too crazy. You'll want to do the M20 flywheel conversion to hold the power; even with my mild setup, a new factory M42 clutch didn't quite cut it. I'm running a custom split-pulse manifold, Garrett TA3107 split-pulse turbo, and a Volvo 740tic intercooler. Haven't had it on a dyno, but the 0-60 time is in the mid 6-second range with a 3.73 rear end. 30k-40k miles or so on the turbo setup so far, on a 260k mile engine that only had a new HG, ARP studs, and a reconditioned head put on, along with new timing case bits. It's a fun combo, and I get about 32 mpg on the highway.

[Blackangusinc]

Wow. Thanks guys! Good info
Does anyone have dyno charts?

[MF DOOM]

But the other day i was thinking. What kind of gains would be seen by taking the exhaust cam down a degree or two and intake up four or five? Would be somewhat similar to turbo cams, correct?

Has anyone experimented with this? buttchug? gearhead? Im trying to get a tune for 15psi before i move to oceanside in february and am debating trying this. I talked with wazzu on m42club about it a little. The car will be my daily for a few months after i move and i really just need reliability. but fast is cool too :.ph34r:

[Dj Buttchug]

the cams in the m42 are fine until you get into really high boost. Theres no need to regrind or change the degree of either cam, especially if you are making under a bar.

Now keep in mind that once you get into the 300 hp range (18-22) psi the cams are the limiting factor. If you got custom cams you could make even more power. Maybe closer to 330 crank...

Also. regrinding cams is kind of a shitty way to change things. To do it right youd have to make some. $$$$

[decay]

i think he was talking about degreeing cams, not changing the grind.

[bmwm42]

As buttchug said no need to change the cam gears either forward or back leave them be

[MF DOOM]

i think he was talking about degreeing cams, not changing the grind.

This^^ But sounds good to me.

[S13_E30]

the cams in the m42 are fine until you get into really high boost. Theres no need to regrind or change the degree of either cam, especially if you are making under a bar.

Now keep in mind that once you get into the 300 hp range (18-22) psi the cams are the limiting factor. If you got custom cams you could make even more power. Maybe closer to 330 crank...

Also. regrinding cams is kind of a shitty way to change things. To do it right youd have to make some. $$$$

What about the head gasket? I've read about OEM replacements holding up fine to low boost. Your opinion on this? and what type of head gasket are you running? Sorry for all this questions! and Thanks in advance! :)

[Dj Buttchug]

What about the head gasket? I've read about OEM replacements holding up fine to low boost. Your opinion on this? and what type of head gasket are you running? Sorry for all this questions! and Thanks in advance! :)

Head gasket is OEM goetz. For low boost stock compression run stock HG. For my built engine I run stock as well. full Arp hardware and 8.5:1 comp ratio...

Also, above there was some confusion about cams. The 6 degrees you get of adjustment on the m42 is pretty useful. Use is to change how you build boost. Advance the exhaust cam a little to give the engine a tad more bottom and build boost a little faster. Adjusting the intake cam is going to give you a tad better up top. With this you are just shifting the power curve ever so slightly. Change is more noticeable on a F/I engine.

[MF DOOM]

Have you played with your cams at all? I doubt ill end up changing it at all.. ive talked with vac about catcams but like you said $$$$ I need to fous more on making the car reliable for the move.. I see youre in san diego/ut? Ill be driving through utah and be living close to san diego. It would be cool to stop by and see the cars on my way. go toy with some mustangs or something.

And what rear ends are you guys running? my open 4.10 makes me sad...

[bmwm42]

Running s3.73