N3me-350z Posted February 14, 2015 Share Posted February 14, 2015 What forged piston compression ratio are people running with there SC setups? I hear a lot of people run 11:1 but wouldn't that be limiting the amount of fuel you can get in the engine defo detonation occurs? By running a lower compression 9.5:1 you can safely add a lot more fuel without det meaning a lot more power? I understand it would be slower off the go but the top end would be immense. Has anyone tried this or have any thoughts on it? Quote Link to comment Share on other sites More sharing options...
Adrian@TORQEN Posted February 14, 2015 Share Posted February 14, 2015 Very few people in here have forged engines, mostly have OEM engines with SC or TT. I'm having mine built in USA to 9.0:1, about 850rwhp. Quote Link to comment Share on other sites More sharing options...
OllyB Posted February 14, 2015 Share Posted February 14, 2015 (edited) I'm running 10:1 on mine, with the sc your not going to be running as much boost so can afford a little more comp, high boost turbo then you want lower Edited February 14, 2015 by OllyB Quote Link to comment Share on other sites More sharing options...
Keyser Posted February 14, 2015 Share Posted February 14, 2015 I had 11:1 in my built engine with an SC and I got detonation - we added a water meth injection system the cooling effect of this was enough to drop the inlet temps sufficiently to eliminate the det. If you run high boost you may get problems but as said above with an SC the boost is not huge and it is manageable. Quote Link to comment Share on other sites More sharing options...
Mark@Abbey m/s Posted February 14, 2015 Share Posted February 14, 2015 it isnt about how much fuel you can run it is all about cylinder pressure/ignition timing. Running lower compression means you can run more ignition timing so you dont struggle with high Exhaust gas temperatures. We lower the dynamic compression with a DE motor by playing with cam timing and increasing cam overlap. 1 Quote Link to comment Share on other sites More sharing options...
N3me-350z Posted February 14, 2015 Author Share Posted February 14, 2015 Cheers for the response guys, so I have a V2 T trim SC, I'm wondering how much boost/flow I can get out of this thing then? Can I get enough to run low comp or will I just run out of puff. I'm only running it at 43,000 rpm at 8psi and it's rated for 55,000 in its efficiency range. Thanks again guru's Quote Link to comment Share on other sites More sharing options...
evilscorp Posted February 14, 2015 Share Posted February 14, 2015 I would expect a T trim would be able to flow/boost near perfect around 9.5-9.8:1 depends on the rest of your setup? Crank pulley? Headers etc. I am hopeful that when I finally get round to installing my 9.8:1 (I think, need to check my build thread again as they have dust on them, same as my brain.) It should be in the optimum power band with my pulley setup/other mods. Quote Link to comment Share on other sites More sharing options...
evilscorp Posted February 14, 2015 Share Posted February 14, 2015 Don't be fooled into thinking you have to go with the compression ratios shown in the shops, didn't cost much more to get custom ones made to suit your engine. Quote Link to comment Share on other sites More sharing options...
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