Hi there, i have a customer that damaged his F20C sleeves runing stock. i will build a turbo kit for his car but we are not sure what's the maximun size for overbore these stock sleeves, ive seen +0.25mm will be good , any input about that please?

Thanks!

Walter R.

 

nobody? :S

 

Depends on his goals.

NASA has regulations depending on class. The honda challenge only allows a 1mm bore or 88mm max.

Ive seen a 90mm bore, but he was doing a NA build.

Since youre turboing the car, I would keep the bore as small as possible. Bore it out enough just to cleanup the sleeves. It all depends on what his ultimate goal with the car is.

 

i assume youre going to be using aftermarket sleeves since the stock ones are FRM and extremely tricky to clean up, right? if that's the case I would do 87.5mm on it and call it a day

 

If you replace the sleeves with something stronger, why not overbore the sucker. No replacement for displacement. That and a turbo would be a good match.

 

Less bore now=more later
If it was all motor then bore it but the turbo will make up for that displacement you want..

 

You wont gain much power from boring it out. You could just add a few extra PSI and that would more than make up for it.

 

Or you can bore it and add a few psi. Or you don't have to add more psi and gain a little more go down low where it is going to be used on the street.

 

Hopefully it will get used at the track. Lets look at it this way, if you're racing the RPMs will most likely be over 6,000. The only time your RPMs will be under 6,000 is if you arnt racing. You wont gain anything remotely noticeable from going a few MM overbore.

 

You guys are all missing the OP point. He has a damaged block and wanted to know how much he should over bore.

Thats why I said to only bore it out enough to clean up the sides, but gave him a range of what he COULD safely bore.

 

If you are not going to sleeve it then 0.25mm is the max overbore on factory sleeves.
If you are going to sleeve it then beware of head gasket problems with larger bores.
Boosted with larger bore requires o-rings to maintain a good head gasket seal.

 

I have a sleeved block 89mm bore message me if interested.
perfect for turbo charging