AKSSS Posted May 8, 2014 Report Share Posted May 8, 2014 The only catch to that static compression level and boost you will be running meth or higher than 90 octane fuel. Unless you drop the timing way down. The effective compression with the boost is over 17:1. More like 18:1. Unless you drop the dynamic compression with a cam. It definitely would be a screamer! Quote Link to comment Share on other sites More sharing options...
Bigtoyz97 Posted May 9, 2014 Report Share Posted May 9, 2014 My experience its all in the tuning. I started really working on boost is with my 97 LT1. And if I had been advised better by procharger way back then I'd still be on stock motor and 9 psi. After 3 sets of pistons. I know how to keep a motor together now. Procharger kept telling me that it will hold. 3rd time I lowered the CR to 9.5 and it could take full stock tuning at 9psi. But now way full timing at stock CR and full timing now going to happen when you don't know what the fuel is gonna be when your traveling. And there are a few on here with stock internals still and running pretty good boost. So not only having a good tune but RELIABLE fuel source also that is consistent. But with 9.5 cr you can run a good amount of boost and still be reliable. And with the addition of meth on demand..... that's really a lot of safety built into it already. But I think once you get past the 20 psi your probably looking at reducing your CR down to the low 9's high 8's and depending on if your running intercoolers also. And have read that nitrous to help fight detonation also. Cause your getting the cooling effect of the nitrous gas also. Now we are just talking 50 - 75 maybe 100 hp shot now nothing big. Its kind of being the norm for boost recipes for fighting detonation. And running meth instead of intercoolers. Me I would for sure run a intercooler wither A/A or W/A. And it is what your cam specs are also. Quote Link to comment Share on other sites More sharing options...
allballz57 Posted May 9, 2014 Report Share Posted May 9, 2014 Keep the compression close to 10.1,I've had mine both ways and lower compression 8.5-9.0 really sucks outta boost with a heavy truck. Mine is 9.8 with the 408 and it drives like a dream of boost,and then hooly shit on boost! Quote Link to comment Share on other sites More sharing options...
idahoBLKss Posted June 8, 2014 Report Share Posted June 8, 2014 my stock motor held till 26psi and then the rods bent no detonation but I was running e85. If your going to run good fuel run at least 10:1 IMO. I'm going to build a 408 soon and I will be pushing high boost and I'm going to try and keep my compression at least 10:1 or higher. Quote Link to comment Share on other sites More sharing options...
Thickcajun Posted June 8, 2014 Author Report Share Posted June 8, 2014 my stock motor held till 26psi and then the rods bent no detonation but I was running e85. If your going to run good fuel run at least 10:1 IMO. I'm going to build a 408 soon and I will be pushing high boost and I'm going to try and keep my compression at least 10:1 or higher. Since I started this post my dreams where way over budget. Staying NA now. 799 heads cam tbss intake. Bigger injectors, cam and 3400 stall with a built up 4L65. All I want to do is kick my wife's ass in her 550i. Quote Link to comment Share on other sites More sharing options...
zippy Posted June 26, 2014 Report Share Posted June 26, 2014 My question to Blown346. You say you have a Corvette that gets 28mpg city and 35 highway with a Procharger on it. Without a doubt that coudn't be further from a true statement. You also state that it has 11.5:1 compression with stock heads and internals. Unless you have a direct injected LT1 none of them had compression that high. As for compression jumping up one point with a blower, no... Your compression ratio does not change at all with adding boost or not. The cylinder volume is xxx at bottom dead center and xxx at top dead center. That doesn't change and the theory side of it is far from an exact number of where it would be equal to depending on how much boost is added. You have been replying with too many bullshit answers lately and too much of the I read this online type of answers to which you seem to alter depending on how people view what you've said.... Quote Link to comment Share on other sites More sharing options...
2003_SuperSport Posted June 26, 2014 Report Share Posted June 26, 2014 Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 26, 2014 Report Share Posted June 26, 2014 Quote Link to comment Share on other sites More sharing options...
2003_SuperSport Posted July 3, 2014 Report Share Posted July 3, 2014 Quick reply. Forged 408. Static compression at 10.5:1. D1SC pro charged at 12psi... Runs like a raped ape. Another quick reply like above... stock bottom, milled heads 10.5:1, 9.5PSI radix, Meth injection, Comp Cam- See for yourself---- https://www.facebook.com/james.forbord?ref=tn_tnmn#!/photo.php?v=764007193630800&set=vb.100000645801109&type=2&theater Quote Link to comment Share on other sites More sharing options...
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