High Compression S52

[MIKe30]

Have you thought about ICS? Are you even close to them? I know they are up in that area.

Never heard of them. I'll google them... I was actually thinking azavedo would be where to go, but then again i haven't always heard/seen good things about them...


oh, and forgot to mention it before, thanks for joining the thread :)

[richard.bratton]

Is there any reason not to go with 11.5 compression? I'm ordering custom JE pistons and can pick whatever CR I would like. It seems that more should be better; well, more should be better to a certain point but I don't know what that point is...

[Deadskittles]

Hmm... Im currently building a high compression S52 and I was wondering why people are talking about running 24# injectors with 270whp. To me that seems low... or maybe the fact that the engine that I am currently rebuilding had burnt up pistons due to being lean, given it was still on stock 21.5#s with cams and a CNC'd head. However I also wanted to let the OP know that JE sells some decently priced pistons at 87.0mm bore (stock is 86.4 i think.)

[klodkrawler05]

My .02, Don't worry about a number, instead do the research and build the best car you can for the money you're willing to dump into the car. Dyno's are for measuring improvement or bragging rights, they Don't really give the whole story.

I say this from personal experience, my buddy has a supercharged focus, all over the forums he's seen dyno sheets ranging from 220-230whp with very similar mods to his, He's been to 2 different dynos with very different weather both times (once hot and humid, once cool and dry) and both times he has dyno'd 205-206hp
His car is just as fast, he's done pulls with cars that have the 220-230whp dyno sheets and they are dead nuts even.

I spent a large portion of this year playing with a miata, absorbing as much info as I could from those guys for building my miata for auto-x use. Because the cars are so light they respond very well to any horsepower increase no matter how small and so those guys take things to a level unheard of around here even to auto-x in stock class means having a built/blueprinted motor to some of those guys.

I've heard the 1 point compression bump leads to 10hp theory as well (on a miata that would be a 10% hp increase!) what no one seems to know or mention is the torque gain.

bumping the compression is good for power across the board as well as torque. How much you can feel the power will depend how much you bump the compression up and how tightly calibrated your butt dyno is.

Boring out the cylinders to the 1st or 2nd overbore while not a huge increase is still some amount of increase in the displacement. For a good baseline of that consider that a stock S52 makes 75hp per litre if the overbore moves you from a 3.2l to a 3.25l you'd gain another 3-4hp and equal amounts of torque.

Other things to consider, Rotating mass, a stock S52 with dual mass flywheel, heavy pulleys, spinning A/C and powersteering with stock valvetrain will feel and rev slower than a S52 with light flywheel, no a/c , no powersteering, an electric fan instead of the clutch fan and a lightweight valve train, revving both back to back I can tell you its noticeable.

Building/creating a maxed out N/A motor is time consuming/expensive compared to just slapping on a cheap used supercharger. But it can be fun, and when you start adding all the little things up, 2-3hp here, 2-3hp there, pretty soon you've picked up 20 or so hp over a non worked over car, which is certainly enough to make a noticeable difference when side by side.

Cliffs: While I agree with everyone else here, boost is a cheaper way to go faster, if your motor already needs work, doing the research you're doing now and choosing the right combination of parts/work will net you a bit more power than the average Joe.

[GunMetalGrey]

I generally agree with the cost of boost vs. the cost of building an NA motor, but skittles stumbled upon an already pretty damn built s52 and is just trying to make it a bit better by fixing it, as stated the pistons had gotten too hot.
The motor was very built (Shrick cams, CNC port/polish, solid lifters, upgraded valvetrain?, and will now go high compression) so it is just the matter of adding a new set of pistons, so why not go crazy?
It will be interesting to see how the motor acts(totally different characteristics than what my m50 turbo will have.)
All a fun game!