Turbo engine build, and parts
 

Just got a set of these new CP pistons in for a customer. They are 9:1 compression and look pretty sweet. I am so used to selling 99.5/100mm STI pistons its weird to see this small 86mm. We also have some Carrillo rods on order for it which will be here soon and I will post pictures. Combined with the slightly thicker HKS gasket compression should be 8.9:1, which should allow the motor to take a fair amount of boost.

https://sphotos-a.xx.fbcdn.net/hphot...57729191_n.jpg
https://sphotos-b.xx.fbcdn.net/hphot...93341057_n.jpg


HKS headgaskets

https://sphotos-a.xx.fbcdn.net/hphot...53271691_n.jpg


HKS spark plugs

https://sphotos-b.xx.fbcdn.net/hphot...45736924_n.jpg

Pauter connecting rods

https://fbcdn-sphotos-e-a.akamaihd.n...24412172_n.jpg

That ringland looks stout.

Can't wait to see how it turns out, what turbo are you putting on there?

with a CR of 8.9:1 you should be able to run like 45lbs of boost lol since stock 20lbs appears to be fine.

Awesome!

kinda where I'm at to. I'm getting the impression that in order to take advantage of such a drop in compression, with these combustion chambers, you'd probably want to be running hardblok aswell.

I can't wait to see the results of where this build is going though, should be stunning.

even with an open deck, if you add aftermarket sleeves you'll increase the rigidity of the block by a big margin. but I'm with you on the fact that dropping 3.5 points in compression is huger, I'm sure going down to 10, 10.5 would've been more than enough.

Wow that's low compression. Definitely in for results. This going to be a drag car mainly?

Saw these at SEMA - they looked great!

Its a street car. It really isn't low compression at all, these cars just come abnormally high. It is perfect turbo engine compression for pump fuel.

Most WRX/STI guys run 8.2-8.5:1 compression.

Ah... I didn't actually know what was normal for STIs. Coming from the K series most of us were dropping from 11:1 or 11.5:1 to around 10:1.

With FI I would go with around 10:1, more response and power. If it wasnt DI I could see why going down so low.

the reason I said it was very low is for DI. will it still be enough for it to work properly or it doesn't matter as it isn't compression ignited like diesels, since you can actually have gas auto ignite(hence detonation)?

DI doesn't mean compression ignition. It's still a gas engine with spark plugs. It'll certainly still work. :happy0180:

That's cuz EJs aren't that great :P

Taking 20psi on stock parts, plenty enough. Gonna take a good few psi just to bring back the power loss from the compression drop, inefficiency creeping in from all directions

Don't forget that took e85. Not everyone wants to or can run e85. Some people can't even run 93.

Personally if I ever change out the engine internals, (probably will happen eventually) I'm looking to hit 10.5:1 or so. However Ill be looking out for more people doing testing before I'd be completely set on a number.

That^^

I believe they make both 9 to 1 and 10 to 1 pistons.

Price?

9:1 is a great number with many builders using this c/r as a norm for building a safe engine.

CP is very good stuff I only use there pistons

wouldnt clearance between piston and head would be close at that CR with boost?

No, because the stock pistons have a taller dome than these, it would be more clearance.

These would be good only IF the total squish area and volume were either improved or remain untouched. If this wasnt taken into consideration they are just shaved down pistons that are nothing special

Beef...

What's the weight on those Pauters?

One thing I can say about Pauter's, having use to special order them in bulk, their tolerances are spot on!!

I see i am gonna have to start saving up for these

591 grams. Yes Pauter makes some top notch items.

I guess I have the first set of 86.50mm on the way :P