M52B28 High compression vs turbo.

[jherrer3]

Hello everyone! I need some help. I have two options on my M52B28 engine. Turbo or raising the compressions. I'm currently looking for forged pistons to be able to take the compressions up to 12:1, would anyone know where is the best place for me to find pistons that would match to that engine? for the Turbo I'm looking to do a GT28bb turbo in it. I'm also looking at this in terms of cost. I know they are both going to be up there but I am wanting to see if anyone can throw out some figures for me. Any help or suggestions would be much appreciated.

[Rudolph320i]

Well, what are your goals for this engine?

[jherrer3]

Honestly this is my first big engine project so I wanted to do this to learn how to properly do it. I want an increase in overall power I'm not looking too much into specifics. I want to be able to have it running smoothly and correctly.

[BimmerBreaker]

Raising the compression and turbocharging (which generally requires lowering the compression) are two totally different things. If you just want more power do a header and an intake.

And I am not positive but I would imagine you would need more than just pistons to raise the compression ratio...

[Rudolph320i]

You can do pistons to bump up compression, but your power goals will be pretty important when deciding which route to take. A turbo m52 can go over 500hp if you want it to, all depends on what you want to do with it.

[jherrer3]

Gotcha. This is mainly a street driven car. I want to have a good amount of power. More than stock and the S52 motor. Like I said before this is my first engine project and I just want to do it for the sake of learning. Cost is also an issue.

[Rudolph320i]

I cant recall seeing anyone who bothered doing a high compression N/A build with an m52

[jherrer3]

Ok thanks. I appreciate your help guys.

[auaq]

I say go turbo and you won't look back. Going for a higher compression isn't going to give a whole lot of power to be honest.

[JM35]

^agreed. You have a lot more options if you go with a turbo. Get forged internals and then you can crank that psi like crazy. But of course both these options will take a toll on your engine life.

[auaq]

Turbo + High compression + E85 = Jizz

[jherrer3]

Turbo + High compression + E85 = Jizz

I can't imagine that haha

[pbonsalb]

A GT30R or GT35R sized turbo will make 400+ rwhp on a 328i with a thicker headgasket to lower compression on an otherwise stock motor. Figure on $4-5k if you know what you are doing and buy used or very carefully. $6-7k is a better budget. It is easy to spend much more.

Building a motor is more expensive than most people think. Pistons and rods might be as cheap as $1200, but there are lots of little parts and some work for the machine shop that will double or triple that price. If building, I would go for the S52 crank for a little more displacement. I built a low compression shortblock for turbo use last year and started with an M52 block but used an S52 crank, aftermarket rods and aftermarket low compression S52 overbore pistons for 3.2L displacement. An old saying is "There is no replacement for displacement" and this is true even with turbos.

[BimmerBreaker]

Yeah, most people tend to overlook the supporting mods when they do a build like this. Yeah, you can slap a turbo onto your car, but if you want to make meaningful power, you need an intercooler, larger fuel injectors and a thicker head gasket (or lower compression another way). Then if you want REAL power, youll need internal work, larger fuel pump... this stuff adds up quickly.

For someone who seems to not really know what they want other than "more power" I think a lot more research needs to be done. Raising compression or turbocharging will alter the characteristics of the engine.

Kind of sounds like every 16 year old with an E36... "I WANT MORE POWER!!!"

[jherrer3]

Yeah, most people tend to overlook the supporting mods when they do a build like this. Yeah, you can slap a turbo onto your car, but if you want to make meaningful power, you need an intercooler, larger fuel injectors and a thicker head gasket (or lower compression another way). Then if you want REAL power, youll need internal work, larger fuel pump... this stuff adds up quickly.

For someone who seems to not really know what they want other than "more power" I think a lot more research needs to be done. Raising compression or turbocharging will alter the characteristics of the engine.

Kind of sounds like every 16 year old with an E36... "I WANT MORE POWER!!!"

Haha true. But yea I understand you on the supporting mods. That's why I wanted to ask and find out the important things I was overlooking or things that I didn't find during my research.

[Avec]

Since you are going to open the engine, why not make an S50B30 clone? Lots more power, and naturally aspirated. Plus, you will have less problems than either higher compression or turbo.

http://forums.bimmerforums.com/forum/showthread.php?1715145-Build-yourself-an-S50B30-clone-for-cheap!!!-DIY

[pbonsalb]

High compression and turbos do not go well together, unless perhaps you will be running on E85 fuel.

If you just want more power, you can add bolt on mods to the M52 to raise rwhp from about 160 to about 200. More if you spend more money.

You can swap in an S52 for its added displacement and 200 rwhp stock. Add bolt on mods and 240 rwhp is easy. More if you spend more money.

The only thing I would not do is build a high compression M52 for a street car on pump gas (other than E85). For the money, you get very little gain. If you raised CR from 10.2:1 stock to 12.0:1, you might gain 5% power and torque for your $3k or greater investment.