Compression Ratio

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KyleCrews

Senior Member
I was wondering if anyone can tell me what the stock compression ratio on a H23 prelude engine. Also what is the easiest way to bump of the compression ratio?
 

BlackJDMdeath

Senior Member
an easy way? replace your head gasket, honda uses a 3 piece head gasket, if you remove a layer it will bump up compression.
 

KyleCrews

Senior Member
How much would this raise my compression ratio and would it be safe to do still running stock internals? I don't want to blow this engine cuz i've only had it for about 4 months.
 

2fastaccord

Senior Member
The other way is just to replace the pistons with higher compression ones. It would cost you a bit more than the head gasket but you would probably want to do that at some point and time anyway.

Peace*
 

BlackJDMdeath

Senior Member
great advice 2fast... although you might want to add in that if you go with anything but OEM pistons you will have to sleeve your block.
 

KyleCrews

Senior Member
will it hurt my engine if i raise the compression ration by removing a layer of the gasket while using stock internals. I'd hate to blow it up since i just go it.
 

tab

Super Moderator
I think the bottom end could handle it. However, I am not sure that you understand how hard it would be for you to replace that head gasket. It would take a long time, and a little money. Would it work, yes. Do you want to, no. The few horses that you would gain could be gained on a dyno, or with some bolt ons. Don't fool with a good thing, experiment on a shitty engine. Just my opinion.
 

KyleCrews

Senior Member
I just planned on tdoing it which I convert my h23 to vtec next month and i figured i could do it then with no trouble. Thanx for the help though guys.
 

KyleCrews

Senior Member
How much would those cost me and where could i get them? Also i plan on putting a head from a '97 up prelude so i can supercharge it. Can my crank and rods hold that compression ratio and boost without blowing up?
 

KyleCrews

Senior Member
My car is an OBD1. Its a '94 prelude Si. Back in november i had to put another engine in it and i found a good deal an an h23 ordered from Japan. I want to put a head from a '97 up prelude so i can add a supercharger because i prefer super over turbo. I'm hoping the vtec head will swap on to my h23 block and i know i'll have to get the ECU for the '97 up and get a wiring harnes to go from OBD1 to OBD2 which is whats in the '97 up. I just dont know how easy this swap will be since i've never seen anyone else do it. Also will the instrument panel in my dash still work cuz i know the dashes in the 2 cars are very different. I know i kinda got of teh whole compreesion ratio topic but any help on these questions would be great. I can get a head from a 92-96 and 9'97 up for about the same price and pretty cheap because my friends dad owns a just yard and said he'd give me everything i needed (IM, Head, EM, ECU) and anything else for like 500 bucks. Just tryin to make a decision so i can get started.
 

BlackJDMdeath

Senior Member
im not sure what all you would have to do to get that head on there, you have to remember that the 4th gen h22a has a different block design than that of the 5th gen, 4th gen being superior of course. if you plan on throwing boost at it, keep the h23 compression. ummm good luck?
 

ludeconduct

Senior Member
^ word, you don't want high compression with boost. Also not only are the blocks different between 4th and 5th gens but since you have a OBD1 setup, I've heard there will be issues when putting on the OBD2 head in a very recent post on hondaswap
 

dohcvtec_accord

WRX Sellout
I think it's a pretty bad idea to try get get an OBD2 head onto an OBD1 block. BlackJDMdeath had a good point about the two different block designs (closed deck vs. open deck), and I think that's just going to give you even more headaches.
 

KyleCrews

Senior Member
Thanx for the advise. I think i'm just going to try to sell my h23 and swap in an H22. I think it will save me alot of time and headaches.
 
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