Blade_Irl

Id just like a little more information on this please, I have a basic understanding of what its about and the importance of higher octane fuel when running a higher compression ratio.

But how do you go about raising it, and how hard is it to raise it by certain amounts, for e.g from 9.1:1 to 9.6:1.

Skimming the head? i think was mentioned to me, or a thinner head gasket?? I could and probably am talking abosolute crap with the last two sentences so please let me know so If I am?

Bren

dom93hatch

Never heard of "skimming the head."

Using a thinner headgasket works, as well as using some high compression pistons (i.e. CTR).

b19coupe

Milling the head.

dom93hatch

Milling! Oh. duh me. I don't know fancy shmancy jargon

jdmCHEF

u can mill the head to raise the comp without changing the pistons, or u can use a 1 layer headgasket, but that'll only rasie the comp by like .01 u can mill the head till there is no tabs and that would raise ur comp by a good amount. but u need to keep in mind that u will need to run higher octane (i.e. 100) if u raise ur comp above like 12 unless u tune ur car to run on lower octane.

Blade_Irl

I live in Ireland, Standard petrol here is 95 RON.

That said, Our petrol aint cheap -average of 87cent / litre!

98 is available in some places , tho its usually like 1.00-1.10 / litre

But I can get octane boosters at reasonable money.

I only need to bring my engine fromm 9.1:1 to 9.6:1 .
Is that do-able given that 95 is normal petrol for us?

I have a Euro model(cos I live in Ireland) 1.4 Civic. Im planning putting a D15b 1.5sohc Vtec head on it, but the compression ratio on the D15b is 9.6:1, whereas my 1.4 non-vtec is 9.1:1.

Bren

b19coupe

I don't know what 95 RON represents. In the U.S. premium unleaded fuel is available at 91-93 octane (depending on where you live). Stock ITR's have 10.6:1 compression and stock GSR's have 10:1 compression and run fine on premium fuel here, no detonation. If 95 RON is at least equivalent to 90+ octane, you should be o.k. with less than 10:1 compression.

Blade_Irl

RON = Octane
So its 95 Octane.

Im not worried about whether its safe to run the ratio I need, the problem is im not sure of how to go about raising it.

It has to be done cheaply, preferably through machining or sumthing. Expensive Mugen or the like thin head gaskets are out.

Bren

DSeriesBeeKilla

What's the compression ratio for a d16y8?

fukaintmuven

u dont have to get some expensive headgasket to higher your compression.. There is a guy on here that sell them.. They are all custom made to benefit you. i dont know his name but u could find him w/ search. Besides, machine work such as miling the head would probably be more $$

B19CivicHB

First off, you dont have to have the EXACT compression of the engine that the head is from.

Second, I run 12.5:1 compression ratio on 94 octane pump gas and that is 100% UNtuned. Haven't had a ping yet.

-Nick-

13HYBRID20

you can raise the compression ratio a lot more than .1 with a thinner head gasket. use this link you will learn a lot so you don't have to guess and spread disinformation. http://www.c-speedracing.com/howto/c...c/compcalc.php