H23 compression-lowering head gaskets... - Honda Prelude Forum

4thGenReady2Go · 06-28-2004, 08:54 PM

anyone make these? For instance, if someone boosted their H23a1 and had to do some engine work that involved removing the head, since they'd be replacing the head gasket anyway, it would make sense to put one in, if one is actually made. Any help would be much appreciated, thanks.

flip1199 · 06-30-2004, 02:50 AM

why would u wanna lower the compression?

trident · 06-30-2004, 07:31 AM

The company I used to work for makes them. Inline performance products. They use them for turbo applications. They are located in Springfield VA. You can find them on the web. I don't remeber their phone # off the top of my head.

4thGenReady2Go · 06-30-2004, 08:07 AM

Quote:

Originally posted by flip1199
why would u wanna lower the compression?

Quote:

Originally posted by 4thGenReady2Go
... if someone boosted their H23a1 ...

to lower compression for an forced induction application.

Thanks trident, I'll check into it. CleanLude told me of Cometic, even though I already knew of them, I hadn't remembered. Anyway, they only make head gaskets for the H22, but since people put h22 heads on H23a1 blocks, wouldn't the head gasket be the same? Thanks for the help so far.

trident · 06-30-2004, 01:49 PM

They should be.. the only difference in displacement between the two motors is that the H23 has a longer stroke (92 mm instead of 88 for the H22) I think those numbers are right. In any case, I don't know of any reason that the H22 gaskets shouldn't work on an H23.

flip1199 · 07-01-2004, 12:35 AM

i still dont see why you would wanna lower the compression in a h23 . i have a turbo h23, and i know quite a few other h23 preludes and none of them lowered compression. it's pointless. the h23 doesnt have high compression. i just put in some 10:1 slugs in my h23 that i will be boostin. just so u know higher compression will make more power per pound of boost then lower compression.

trident · 07-01-2004, 06:15 AM

Well, there are a number of reasons to put a thicker head gasket in. The amount of power created on a stroke is not solely a function of your compression ratio. As a matter of fact, it is really only a fraction of the important components that go into making power. The decrease in compression is linearly proportional to the increase in volume within the cylinder. This means that the cylinder can accomodate more air and fuel. This then means that there is more potential energy in the cylinder. More potential energy means there is a potential for more kinetic energy upon combustion. Another reason (and lesser) reason is that the head gaskets made my Inline Pro are stronger than the stock gaskets. And yet a third reason is the safety of your engine. Yes, Preludes, and nearly every other Honda, will run just fine with a stock head gasket. With such high compression, though, you are that much closer to the limits of detonation. A thicker head gasket allows you to have a larger safety margin, Especially if you have variable boost. One other thing (not that this is a great argument) but nearly all turbo sports cars come out of the factory with relatively low compression ratios. You can't help but wonder why they do this. I would venture to say that they have even better reasons than the ones I just cited. Anyway, I hope this provides some answers.

ExodusFX · 07-01-2004, 12:41 PM

Hmm... how much do these head gaskets lower compression ratio by? I might be in the market for one of these as well.

Preludeian · 07-01-2004, 02:54 PM

In the decimal range and I think a few maybe hit a '1:' but I can't fully recollect. Anyways, like it's been said. The H23 w/H22 VTEC head running stock bottom end components causes a very high compression ratio. This is believed to be a lot of the reasons many ov the H23 VTEC's have went kapoot. However, lately in the H23 VTEC quest a step forward has been taken by changing out rods and/or the crankshaft with other 'H' series pieces. A head gasket is just an easier way of doing so and is also more easily adjustable then pulling the bottom block apart. All this was done just for a 'stock' H23VTEC. One can only imagine how much more would need to be done for one to accept a turbo.

flip1199 · 07-01-2004, 06:54 PM

instead of decreasing the compression i'd rather have a more precise tune and run premium gas. lower compression allows for more error while tuning. it also allows you to run higher boost levels on pump gas. if it is a stock h23 i wouldn't bother lowering the compression. if it's tuned well then you'll blow ringland before u have to worry about detenation. even if the motor is built all u would need to do is add more fuel and up the octane to resist detenation. most people i know that add thicker headgaskets do this on b-series because there bottom ends can handle more then the h-series can stock. you can drop in a thicker headgasket on a b-series and make 400whp on stock internals. try that on a h-series and you blow the ringlands aparts.