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Compression ratios

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Trd Shane
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Location: Dublin

Compression ratios

Postby Trd Shane » Thu Oct 02, 2014 7:00 pm

What is the best compression ratio to run a turbo setup on ??
All engine is stock .. I've heard stacking two head gaskets will bring it down to 10.5:1 but is that to low or not low enough I don't want to go really low and compromise spool up and low down power is there a fine line ??? Hahaha

What's everyones opinion ??
"If it can't be fixed with a hammer it's an electrical problem"

twiglett-RS200
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Re: Compression ratios

Postby twiglett-RS200 » Thu Oct 02, 2014 9:44 pm

Mine has a very thick gasket to lower the compression. I think it's about 2mm.
My turbo is producing usable boost at about 3000 rpm so there's very little time where you're actually waiting for more power if you're driving properly.
There's always more power than a non turbo altezza where you actually need it.

Soiled
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Joined: Sat Dec 11, 2010 3:35 pm

Re: Compression ratios

Postby Soiled » Thu Oct 02, 2014 9:49 pm

What turbo are you using? If you're using a little TD04 sized turbo, you wont notice a spool difference.

I'm running 8.5:1 compression ratio and it drives perfectly off boost.

The main thing that you should be concerned with compression ratio is being able to get timing while tuning with out detenation. The more advanced your timing the better your car will drive. Having a high compression ratio and turbo you'll have to retard the hell out of your timing making it a pig to drive (depending on boost levels you're wanting to run etc etc).

I wouldn't stress about lowering your compression ratios unless you're getting into a serious engine build.

twiglett-RS200
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Re: Compression ratios

Postby twiglett-RS200 » Fri Oct 03, 2014 11:14 am

The problem I have with mine at 1.2 bar is high egt's
I'm presuming this is due to retarded timing rather than running lean as the afr seems to be a little on the rich side.

ESXTEZZ
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Re: Compression ratios

Postby ESXTEZZ » Fri Oct 03, 2014 6:26 pm

What boost level you looking to run

Trd Shane
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Posts: 232
Joined: Mon Dec 02, 2013 10:44 pm
Location: Dublin

Re: Compression ratios

Postby Trd Shane » Fri Oct 03, 2014 7:40 pm

Boost levels i guess I will be playing it safe ish at the start about 9-10 psi ?? Just want to lower it a bit until I get forged internals .. The turbo I'm using is the td04 19T don't know how much bigger that is compared to the 16T .. I guess I'll just stack two together and see what happens .. Trail and error basis I suppose ??

Also would you use sealant when stacking head gaskets together ?? Or just stack em and the clamping load will seal it up ??
"If it can't be fixed with a hammer it's an electrical problem"

ESXTEZZ
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Re: Compression ratios

Postby ESXTEZZ » Fri Oct 03, 2014 10:13 pm

You will be safe at 9/10 psi with stock compression with a good tune. Just make sure you run 98 or 99 Ron fuel.

Trd Shane
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Posts: 232
Joined: Mon Dec 02, 2013 10:44 pm
Location: Dublin

Re: Compression ratios

Postby Trd Shane » Sat Oct 04, 2014 1:45 pm

ESXTEZZ wrote:You will be safe at 9/10 psi with stock compression with a good tune. Just make sure you run 98 or 99 Ron fuel.



Be safer to lower it though no ??
"If it can't be fixed with a hammer it's an electrical problem"


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