Which 24v to buy?

[BigD]

To get 340 flywheel hp from an S52 you will have to do headwork and move to aftermarket pistons for higher compression. Even then you probably won't hit that target. The head is breathing limited at the top end, and while this can be somewhat mitigated with some headwork, it will certainly cost more than 3K.

Where did I imply natural aspiration? I also don't buy that the S52 head is breathing limited (not saying it isn't for sure but I'd have to see it to believe it type thing). Those ports aren't much smaller than the S38, and I've been up close and personal with both.

Also, the S38 weighs within a few kilograms of the S50 Euro engine.

Which in turn weights a lot more than the S52. I bet the weight figures online are for the bare shortblock too. I mean the E34 535i weights 200 kg less than the M5, and the car and engine block are the same!!! I'm sorry but the slightly larger rotors and wheels only weigh a few pounds. Even if you add the self-levelling shock pump, that's still nothing. That engine is a massive pile of metal. The freaking intake is a huge cast iron box! Even the Euro S50 has a much smaller and neater unit.

[static]

http://forums.bimmerforums.com/forum/showthread.php?t=606139&highlight=ports+size

...anyway, OP you should perhaps state your objectives, otherwise you are open for all sorts of opinionated statements

here is mine: turbo built m42

[dougsic]

That engine is a massive pile of metal. The freaking intake is a huge cast iron box! Even the Euro S50 has a much smaller and neater unit.

FWIW, the intake plenum and throttle bodies are aluminum. The air box is sheet metal. The intake horns are aluminum on the original S38 and plastic on the later two. Maybe it's been a while since you were up close and personal with the s38? ;)

But to the point, everyone is right about the s38. And there is no way you can get the 3.8 for $3k. The crankshaft alone for that engine cost me $2k when I bought one about four years ago.

In three years, I spent well over $30k on my s38 engine. And no, it does not make as much power as a twin screw s52 which would cost you about 1/3rd as much money.

I have another $2.5k into TEC3 6/12 (which I hate) not including labor because I wired it and $3k into tuning it.

Wake up! You were dreaming.

[BigD]

FWIW, the intake plenum and throttle bodies are aluminum. The air box is sheet metal. The intake horns are aluminum on the original S38 and plastic on the later two. Maybe it's been a while since you were up close and personal with the s38? ;)

It's been about 2 years since I sold it. I guess the intake plenum could be aluminum but the finish of it feels like iron. Still a huge chunk of metal. The air box is sheet metal? You mean the air filter housing? Maybe I'm losing my mind but mine was very much plastic.

By the way, here's the head from my ex car, the ports aren't small but they're not that much bigger than the M52 ports, especially considering that these are designed for an engine 13-29% larger in displacement, revving 500+ rpm higher. The S38 is a cool motor but I no longer feel it's anything that special. The Euro S50s are nice, they either hit (b32) or come damn close to hitting (b30) the 100hp/L mark. The S38 never came close, and if you believe the dyno figures of people with S52s gaining 30hp+ with the OBDI upgrades, bigger injectors and maf, it's not that far off.

[FredK]

Hmm, they are indeed not that large.

For 3K I didn't think to factor in FI! I'm sure you can get 300 lbs-ft of torque pretty easily if you get a used supercharger system or something like that.

[winstontj]

Thanks for the thread guys, I'm going to stick with the m20 and build it. For a few G's I can build a sweet m20 that will work fine for a dd that sits in a parking garage all week and gets driven maybe 10 miles a week. I dyno'd my car a few weeks ago and got 168whp with the blown head gasket (or maybe the 3 pulls did it) so all ! really want is a nice clean bone stock car that can put somewhere close to 200 to the pavement. Cars are like boats... 24v swaps are best bought already done, boats are best bought used so the PO can shell out the dollars on the electronics & initial investment, ever notice that racecars that cost $100k to build sell for ~$30k used??