CP Forged Pistons

[Peter Gidden]

They said that's the standard rebuild size...

There isn't a "standard" rebuild size. Use the smallest size of piston the bores will allow. If they meausre up perfectly, then use STD pistons.

There might be a "standard" piston size they buy...

[MR2 Rich]

If it's on a standard bore I would be looking at 86.25mm pistons before going for 86.5mm if I was you.

[gnzyza]

Difficult unless your block isn't in a working car. Makes sense to stay stock if it allows. So are the cp pistons that exact or is there some give? At Honda each piston was matched to each cylinder as far as I know.

[Odin_S]

They said that's the standard rebuild size...

There isn't a "standard" rebuild size. Use the smallest size of piston the bores will allow. If they meausre up perfectly, then use STD pistons.

There might be a "standard" piston size they buy...

Maybe I should be more pacific, it's for my 400bhp build. Doubt you would still use STD pistons

I've bought Wiseco 86.50mm, I'll have a chat with Luke once I get chance. I'd like to stay as close to oem compression ratios because in my limited knowledge it would lessen chances of detonation?

[rev3turbo]

Maybe I should be more pacific

why would you want to be like an ocean?

[ashley]

Maybe I should be more pacific, it's for my 400bhp build. Doubt you would still use STD pistons

I've bought Wiseco 86.50mm, I'll have a chat with Luke once I get chance. I'd like to stay as close to oem compression ratios because in my limited knowledge it would lessen chances of detonation?

Piston size (86.0 vs 86.5mm) will have no real world effect on the power you make.

You would absolutely use standard size (86.0mm) pistons for 400bhp if you can, but they wouldn't be standard pistons because you would used forged replacements.

If you have already bought Wiseco pistons and you want to keep an OEM compression ratio then you already have a problem, the Wiseco's are 9:1 out of the box from memory.

Sounds like you need to talk to an engine builder before you go any further, and don't buy any more pistons until you have the engine apart and have inspected and measured the cylinders

[Odin_S]

Maybe I should be more pacific

why would you want to be like an ocean?

-_- *slow clap*

[Odin_S]

Maybe I should be more pacific

why would you want to be like an ocean?

-_- *slow clap*

[bobhatton]

I'd like to stay as close to oem compression ratios because in my limited knowledge it would lessen chances of detonation?

Yes it will if running stock boost.
If the boost it going up then the compriession ratio has to come down.

You need to design your engine, once you have that all in place the last thing you work out is the compression ratio you need, so the last parts to buy are the pistons.

[Odin_S]

Ok thanks guys

[kev8611]

wossner do low comp (8:1) aswell as high comp (9:1) pistons so check them if you want to change compression ratio. you dont need to go bigger than standard bore size to make 400bhp. only rebore if your block needs it. I dont think it matters as much on a turbo than it does n/a cars. yeah you may gain a small bit power but nothing more.

[MR2 Rich]

Going to be popping to see Simon in the morning and give him the money for the block and confirm everything with him.

[racer_andy]

So are any of the forged piston better than others? JE's, CP's or wossners ?

More specifically can one take higher intake temperatures than another?

Ta

[MR2 Rich]

Don't think so according to my engine builder, only one he said stay away from was JE as they are noisier than the others.

[Adam86]

As a general rule what boost pressure would you switch to a lower crompression over standard?

Would running 1.3 bar on a hybrid CT20 require a lower compression?

[bobhatton]

As a general rule what boost pressure would you switch to a lower crompression over standard?

Would running 1.3 bar on a hybrid CT20 require a lower compression?

The stock JDM engines when running stock boost on our best fuel use the knock sensor quite a lot.
The problems with blown head gaskets, broken ring lands damaged big end bearings all come from detonation.

You would be surprised how much better a stock engine runs with 8.0:1 compression pistons.

So yes if you want the best from the engine please fit lower compression pistons.

[Adam86]

Who sells 8.0:1 pistons?

What's the standard compression? Cheers

[Adam86]

Who sells 8.0:1 pistons?

What's the standard compression? Cheers

[bobhatton]

Who sells 8.0:1 pistons?

What's the standard compression? Cheers

I do.

Standard comp is 8.8:1 for rev 1 and 2, 8.5:1 for rev 3 on its higher boost.

[MR2 Rich]

Does compression directly relate to power? I.e if you have the exact same spec engine one with 8:1 forged pistons and one with 9:1 would there be a power difference?