i was in hawaii, theres a couple threads with pics and such i posted during the trip


anyways, while hes a little overzealous i dont disagree completely with bailey. 15 psi is too much for a stock ls1 to handle, the GTP is a completely different story, its factory FI so its condition doesnt apply here. but i would change internals before going over 10 psi on an ls1. now, once you drop compression, the pistons, crank, and block are strong enough to support some pretty good boost (although the pistons would already be changed [&:], just saying the stock components are nice and strong). although ur right, 15 psi will not always double hp, although it can usually get close. 4.6 mustang GT (pi) makes 230rwhp stock. guys with prochargers running 10 psi put down 400rwhp pretty regulary even through stock manifolds. i would hope another 5 psi would net at least 60 hp. ur vette is at 8 psi right? what are ur hp numbers? i believe you said you had it dyno tuned, just curious. i bet whatever ur numbers are, we talk about doubling boost its not too far stretched to think you could be around 700hp ish.

 

No, im not at 700... Im at 597WHP right now, When I get my spray ill be in the 700 mark easily... I honestly was hoping to break well into the 600 mark with my setup, but im not...unfortunatly

 

u misheard me (misread? whatever). I knew u wouldnt be at 700rwhp, but 700bhp is 2x what ur car came with. ur at 600rwhp right now essentially. which at 15% driveline loss is right at 700bhp. Now, that is not all due to ur blower bc u have other mods, but you are essentially at 2x ur stock hp (which is 300rwhp for ls1, if u want to stick to the wheels) and thats only 8psi. if u were to do blower only i would hope 15psi would at least double ur output. thats all im saying.

 

I wasnt arguing with you man... I thought you were asking a question... I could run 15 PSI easily with this engine, But the Blower I have is limited to about 8 PSI, its a Vortech, Centrifical blower... Supercharger whatever people prefer to call it.

 

We kinda highjacket this thread to me lol... Wasnt trying to focus on me here, I know that you understand your engine setups, im not debating with you, Im more into fixing problems than making HP... Im a tech, not a performance tech...

 

oh, i thought the discussion had turned to whether or not 15psi could double ur hp, and it is looking like will do at least that with a few solid examples. thats all

 

I think It depends on the setup, Im running 15 + PSI on my GTP, and Im only pushing about 336HP to the ground, stock it was at 240... And I have a custome PCM, no cats, no resignator, full 3 inch exhaust, CAI,autolite 506 plugs, 160* T stat, ported and polished heads. That is where im comming from saying on this guys 3.4 15PSI wont double his power, cause I had a stronger baseline to work from and still cant acheive my desired goals...

 

GTP's dont make 240whp stock, thats crank hp for them. whp is right around 200, i moderate a wbody forum as well, ill ask some of thsoe guys to post up their stock dyno runs. they were rated pretty accurately, however being factory SC its really easy to jack that number up bigtime.

you are also factory supercharged, which means you started out with 8lbs of boost (is that right for a gtp? or is it 6?), ur 336whp now is double that of an NA 3800 GP. to keep this discussion in context we cannot talk about factory SC cars because the guy he is talking about is starting from NA and saying 15psi would double the hp. if you were to add an additional 15psi to your GTP from where it started, so 22-25psi, u would be double hp i would think pretty easily

 

I too am part of a GTP forum... I didnt say that 240 was a whp rating LOL... I know it was a crank HP... I worked on these cars for a living, I understand what stock HP they came with...and yes I was running between 6-8 PSI stock, depended on altitude and such, So far ive doubled the boost of the old blower, and havent doubled the crank HP yet... Plus when I did my supercharger, I had other mods on it also, My blower mods only netted me another 45 HP.... No much for the money it took to do it.

 

i know u werent claiming 240rwhp, i was just tryign to be specific and keep everything equal. to talk about only bhp and factory NA cars, 15 lbs of boost seems to be enough to double hp regardless of what ur driving (thats definitly not a hard fast rule, just an approximation that seems good). 15 additional lbs of boost to a car already boosted at lower boost numbers can also do it, like taking ur GTP from 8 psi to 23 psi, i bet that would give u 400rwhp which is about 2x. this is all too general though, because power is not directly related to PSI, psi is actually a value showing you how much air you are NOT getting into the motor lol. a boosted car with an extensive port job will make more power at lower PSI than it would without the port and higher psi.

lol, i dont think were even really arguing [8D]