Lower Compression via headgasket

[aZn TaK]

Do you think I should lower the C/R on my b18c1? I am going to be running a JRSC 9-10 psi setup. Should I lower the CR via a thicker headgasket? what are the pros and cons?

Also, what brands/types of rings do you guys recommend?

Thanks for the help.
azntak

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[BoostedEX]

You should be fine at 9-10psi on a stock GSR bottom end......take a look at Holden's setup.

I wouldn't worry about your compression at all.

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95 EX w/ SC JDM B16
210WHP/144ft-lbs

[SCedGSR]

I have a question about that! A local shop owner has custom fabricated the vortec on his type R. He is running 8 psi with the aftercooler. He has put on a 2mm head gasket and has explained to me that for each mm it will drop compression 1 so he started at 11.5:1 and is now supposedly at 9.5:1!

I guess I don't know what my question really is, but what do you guys think about this?

Sorry to raid your post!

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[JRCivic]

Thicker head gasket... another bad idea for the street. Adding one of these changes your quench or "Squish" area... which reduces the effectiveness of flame propogation. This in lamens terms means that you have increased your chances of detonation.


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Motorvations Motorsports
(205) 661-3600
'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[marouj_moron]

We use thick head gaskets and they work well. Just make sure to torque the head to 10 more than stock.

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[vactor]

as was said earlier, thicker head gaskets should be a last resort when going for lower compression. do it right or don't do it at all. do soe reading from the guys of the past (check out the various chevy and ford tuning / engine books at the bookstore) and see why it's a bad idea. and where did this magical "torque to 10 over" method come from. use the factory torque settings or whatever is recommended by the stud manufacturer ... overtightening is usually even worse than overtightening.

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More Stop Than Go Power.

[Holden]

Yeah. Stock internals for me. I see 12.5-13psi on the boost gauge. 94 octane only.

I regularly flog my car both autocrossing (which is much harder on the engine due to lots of part throttle boosting and low-rpm WOT) and dragging.

No problems. (knocking on wood...)

Don't boost this much without a J&S Safeguard and as many cooling modifications as you can put up with.

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Greg Holden
96 GSR, JSRC @10psi, All the Goodies!
Best 1/4 ==> 13.356 @ 105.92mph (non-drag street tires!)
My JRSC Install Site

[JRCivic]

Sounds to me like the Vortec "R" gentleman lost some potential ponies !!! There is no reason to drop the compression on that motor... and certainly NOT two full points. There is no substitute for good fuel tuning... look at Mike Marsey's car. His car is running above 8 psi on stock internals and is putting down MAD power. Did I mention his head gasket is STOCK ?!?



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Motorvations Motorsports
(205) 661-3600
'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph