Dim Sum Posted November 25, 2015 Share Posted November 25, 2015 I am planning to rebuild the head with better parts and I was wondering if anyone could give meopinions on are head gasket thickness. I read OEM is 1.3mm and Im planning to go with the HKS 2.0mm I planning to use the 2.0mm to hopefully lower the compression ratio to help with the spooling. But the questions is will it help that much? Is it worth it, or should I use HKS 1.5mm instead? Also I read somewhere it will likely cause gasket failure (or will that only apply to cheap head gasket)? Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 25, 2015 Share Posted November 25, 2015 I planning to use the 2.0mm to hopefully lower the compression ratio to help with the spooling. How does that work? The lower the compression, the soggier the engine is off-boost so I'd imagine it'll make spool worse, not better? Quote Link to comment Share on other sites More sharing options...
Dim Sum Posted November 25, 2015 Author Share Posted November 25, 2015 (edited) How does that work? The lower the compression, the soggier the engine is off-boost so I'd imagine it'll make spool worse, not better? I read that "Thicker than the factory head gasket, which will slightly reduce compression allowing for even higher boost" So I am assuming that low compression rate will be better for a turbo car Edited November 25, 2015 by Dim Sum (see edit history) Quote Link to comment Share on other sites More sharing options...
Ian C Posted November 25, 2015 Share Posted November 25, 2015 Maximum boost and spool are two different things, and usually affect each other negatively Higher boost = longer spool Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted November 25, 2015 Share Posted November 25, 2015 As above. High compression turbo engines are renowned for responsiveness. Quote Link to comment Share on other sites More sharing options...
Dim Sum Posted November 25, 2015 Author Share Posted November 25, 2015 Okay, maybe I have my facts very wrong I'm reading up from all sorts of pages over the web so maybe got things mixed up. So if I want to achieve faster spooling would I go for a the 2.0mm or 1.6mm gasket? Quote Link to comment Share on other sites More sharing options...
Style Posted November 26, 2015 Share Posted November 26, 2015 1.6mm for faster spooling. I'd just go with a new OEM TT head gasket to be honest. Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted November 26, 2015 Share Posted November 26, 2015 How far are the pistons out of the top of the block? You want to aim for 0.8mm squish band to aid det suppression and mixture control. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 26, 2015 Share Posted November 26, 2015 Get your engine builder to recommend a suitable CR and squish for the fuel you will use. DO NOT just assume things, get him to measure chamber volume on each cylinder, and any piston dish or valve cut out volume (the piston maker should state this for unmodified pistons). Allow for piston protrusion, gasket volume, plug volume, and do the maths. Anything else is guesswork. He should have all the measuring gear. If you are building the engine yourself you can buy a large burette, a depth gauge, and make a perspex plate to seal the head chambers. There are plenty of books and web articles on working out compression ratios. Time consuming but not hard if you work carefully and take proper notes. Quote Link to comment Share on other sites More sharing options...
Dim Sum Posted November 26, 2015 Author Share Posted November 26, 2015 Okay thanks all, I go and doing some more reading to better myself. I want to do this myself but if I have to I will just send it to someone else to do it. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 26, 2015 Share Posted November 26, 2015 Not got time to find an English chap, he'll have to do, forgive me Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 26, 2015 Share Posted November 26, 2015 Actually, glad I found that Yank, I can pull holes in him now Look at the bottom (head chamber) end of the plug thread in the head chamber he's working on. See how there's no radius on it, just sharp edges or flaps of ally athe bottom of the threads? That is a text book classic example of a bad head prep, it WILL cause det or pre-combustion and should be hand finished to a smooth radius. Under duress that sharp edge will glow red hot. Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted November 26, 2015 Share Posted November 26, 2015 Just watched all of them, very intresting set of videos Quote Link to comment Share on other sites More sharing options...
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