Possibility for huge HP gain

[SmoothCriminal]

So my friend is rebuilding a bmw 2002 from the ground up, for scca and autocross. While planning out what he was gonna do with the engine, he ran into the problem of meeting emissions standards with his uber-radical cam (304 i believe). Anyway, he came up with the idea of getting a cylinder head from a lower compression model 2002 and putting it on whenever he had to get his car inspected, and then putting the 10.5:1 head when he got it back home. So I got to thinking, our cars weren't exactly meant to be turbo'd, their stock compression ratio is 9.1:1, so what if I went and got the head from my other totalled MSP (r.i.p. - black 2003) and had it machined, bring my compression down to like 8.5:1 in conjunction with a thicker headgasket? With a lowered compression ratio, I'm free to jack up the boost without knocking, then when something goes wrong, swap back on the stock head, and take it in for service. I was wondering if anyone sees any obvious holes in my plan or has some suggestions.

The plan for my car:
Stage 0: getting the ECU reflashed (tuesday)

Stage 1: Injen intake, turbo timer, larger intercooler from a Ford Probe GT (link: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33742&item=2448557874 --lemme know if that wont fit. With the oil cooler on the bracket, it is 17 X 11 X 4. The inlet/outlets also add a little more thickness. ) and a manual boost controller

Stage2: B&B muffler and some custom 2.5" mandrel piping from a guy on campus

Stage3: some really nice boost controller

 

[t3ase]

Other than posting this idea on a public forum that has been proven to be read by employees of Mazda USA, that sounds like a lot of work just to scam your service department for warranty work. I'd just properly lower the compression down on your stock equipment and quit being so scared about saying goodbye to your warranty.

 

[Mike R]

It would make more sense just to swap the cam instead of the whole head. (For the 2002) Compression really doesn't harm emissions, the cam is more to blame.

Machining the head will increase compression. If you were going to do anything, build the other motor up (low comp pistons, rods)and swap the whole motor. Then you'd have a spare for if anything happened. I'd think the dealer would very quickly notice if the head had been removed. Just IMHO

 

[PhreakV]

I would post a question like this in the Performance Forum... but to give you my opinion (sadly this question is beyond my realm of knowledge) I would think that your plan would work but it is kinda shady to do something that radical and then switch back to stock for service. One problem you might run into is that in order to get service you would have to uninstall almost everything connected to your turbo to get something replaced within that system. that seems like a lot of work.

good luck on the pioneering

 

[SmoothCriminal]

well the idea behind the 2002 is to make it an all engine NA beast, so he needs a really radical cam

 

[jred321]

that intercooler looks hideous, look for a starion or even a volvo or ford diesel one if you want to replace the intercooler with something used. swapping the head sounds like more work than it's worth, engine management is really what we need, you should look into that to raise your boost.

 

[CarlM2]

This idea sounds like a LOT of trouble and the wrong way to approach the car. Forget warranty... for the engine anyway.

This idea sounds like either you've never done a head swap or you've done tons of them. Swapping heads is not an easy proposition. Swapping motors would be a little more time consuming but, having a motor built for performance is a great idea.

You have to decide your goals, though. If you want a motor that's so on the edge of its limits that you'd need a backup, you'd want to keep the original motor as a spare. You'll also need a new transmission and other drivetrain parts since you'll probably break them every other month or so.

Why not just get an E-manage or other standalone? For a thousand or less there's other options that won't suck.

 

[03MSP]

The intercooler from the probe(also came on MX-6's) is not going to be as efficient as the stock MSP one. I had it on my MX-6 and it really isn;t that much bigger, just wider than the MSP one.

 

[SmoothCriminal]

I've decided on a spearco 24.5x6x3 intercooler

 

[andersun16]

Mazda Technician (to self): Hmmmm, the entire cylinder area is destroyed - piston top holed, cylinder walls decimated, yet the cylinder head and valve area looks like new?!?! I wonder . . . I think I read about this on that Mazda forum. . .

 

[ThrillRide]

9.1:1 is just fine. leave it alone

 

[SmoothCriminal]

maybe my intentions aren't clear, im not trying to increase the compression ratio, im going to make the combustion chamber larger to bring the compression down, for a more boost-happy engine, shooting for 14psi or so, with a dual stage boost controller i'll be able to flip from econo-mode @ 8psi, to race-mode at 14-16psi

 

[ebsalem]

why not just buy a junkyard motor, there have got to be some MSP's in junkyards by now.

The part swap idea is fraud, and depending in the State you are in, a Felony.

"dude what are ya' in for?"

"I tried to save a few hundred bucks hot-rodding my Protege."

LOL

And yes the MazdaSpeed service writer at my local dealership does follow this board. Really.

 

[1sty]

maybe my intentions aren't clear, im not trying to increase the compression ratio, im going to make the combustion chamber larger to bring the compression down, for a more boost-happy engine, shooting for 14psi or so, with a dual stage boost controller i'll be able to flip from econo-mode @ 8psi, to race-mode at 14-16psi

With out engine management, this is a very bad idea.
There is no need to lower the compression.

 

[ebsalem]

So my friend is rebuilding a bmw 2002 from the ground up, for scca and autocross. While planning out what he was gonna do with the engine, he ran into the problem of meeting emissions standards with his uber-radical cam (304 i believe).

Umm, why if he's building an SCCA Club Racer or an AutoX car would he care about emissions?

 

[ThrillRide]

9.1:1 is boost friendly

 

[Dexter]

1) the MSP engine is the same as all FS DE engines... you dont need to specifically look for an MSP engine.
2) when something "goes wrong", you fess up for it and deal with your actions.

 

[SmoothCriminal]

he cares about emissions because he wants it street legal as well

 

[Wantmoreboost]

BROKEN RECORD..... not worth the time or the hassle. Work on a stand alone fuel management or even a turbo upgrade. The stock compression is fine even for 14 psi.

 

[unwrittenLaw]

I'd be more worried about internals than compression...