I dont think there is a "magic number" for boost=hp, but good ole Corky gives a formula that uses displacement, compression ratio, psi, compressor/turbine a/r, and a host of other parameters to APPROXIMATE this correlation, so if you want to sit down and be smart, you could actually figure it out. LOL, for all we know it could be 7-10 hp per lb on a 2200 ohv with NO other mods.
Does it go faster?
and engine at 7psi with a 12:1 cr will make more power than an engine with 7psi and a 5:1 cr. PSI means nothing by itself.
<img src="http://www.j-body.org/registry/americanred/deplysig.gif">
c'mon..... (shakes magic 8 ball) 9 HP. there we have it. but at least i know where my answer came from.
Spoolin, U sir are f*ckin retarded. My buddy has a 95 eagle talon tsi awd with a first gen motor swap, all the best internals and some good bolt-on parts. He runs 22 PSI and nets 353.2HP to the wheels Bad thing is he started detonating last week and blew holes in the cylinder walls. Then our other buddy makes 331.6 HP to the wheels with all bolt-ons except for cams. His car is a second gen and that HP was at 26PSI. So how are you makin 450 to the wheels? And dont ever say theres no cav that can hang with you cause you sir are WRONG!!!! And when my cars done, basically I can say you'd be DONE!
"Smoke em till they blow"
"If its to loud, your to old!"
Haha Spoolin thanks for the good laugh, Not only did you type all that in 2 minutes but you improved your grammar 10x.
Way to go SunfighterGT, putting the smack down
Quote:
boost increase is to much a varabile to say everyone gains between this much and that much. (i.e. 7-10)
The only generalization that would apply is that roughly 14.7 psi manifold pressure, at the same temperature as ambient, should roughly double engine horsepower. It would be true in a perfect world, but there's a bunch of factors that will reduce that number in the real world. You can make some reasonable estimates by using the peak power output NA, determining the volumetric efficiency at that power level, determining the new "perfect power" with ratio of 2(actual boost / 14.7) then applying the VE percentage. Sounds screwy, but it does give reasonable numbers.
Once upon a time I'd found a web page that calculated air density and velocity through a pipe based on pressure and temperature. If I remember correctly, a ten degree drop in temperature produced the same numbers as a 1 psi increase in pressure. Good to use as a rule when deciding whether or not to build a bigger intercooler or crank up the boost.
If a rule is correct, such as 7-10 psi per lb of boost, then it should be always correct. 2 quick examples will show this one is not.
1) 1.5 hp briggs + stratton engine will never make 8.5-11.5 hp with 1 psi boost.
2) 455 cubic inch 400hp engine better make a helluva lot more than 407-410 hp with one psi boost.
-->Slow
Guys settle down with the flaming. Yes i copied that stuff from dsmtuners.com. The reason i did so is because i knew that 1psi='s roughly 7-10hp from what I've read before. I could not figure out how to put it into words sot that you guys could understand it. The only reason that i acted like a cock in the first place was because i hate seeing people say newbie and only give a response of search, everyone was not as knowledgeable in the begging don't forget. So who still contests that 1psi is roughly 7-10hp on most street driven cars???
95 Talon Tsi AWD 450whp.....can't do that jbodies
sorry i even asked
<img src=http://registry.gmenthusiast.com/images/notsofast/chevy2.JPG>
There cannot be a formula as there si so muich thatd have to be taken into consideration. I mean reading the old article abou tthe gm drag car they ended up making i think it was 450hp at 8psi at first and ended with 750 at like 18 i think it was, a "normal" eco doesnt make near that so its all in what engine it is, and whats been done to it. It can be approximated, but thats about it, not to mention as you increase boost, you are going to gain less eor each add. lb of boost than you did the one before it as with increased boost there is increased heat will lessen the output as youi increase, so u may make 220whp at say 6psi, but only make270 or so at 10, approx. figuresd but you guys get the idea.
Dreams do come true....
<img src = "http://registry.gmenthusiast.com/images/96sunfireconvt/ModdedFireBlue.jpg">
There is ZERO correlation between boost numbers and HP gains. Every car is different, every application is different. Intercooled cars will have more HP per boost gain. Turbo cars in general will have higher gain per pound boost than supercharged cars, because more of the engine's initial energy is used to turn the supercharger. Then you have a point where more boost will kill power, when the charge air gets too hot to make a difference. To say there is a direct tie between the two is the epitomy of newbidness (if I may make that word up, lol).
<img src=http://ourworld.cs.com/jwithspray/Jbeier_sig3.JPG>
hahahah
You can't say x psi = z hp
Ignoramus.
Spoolin....why won't you just get it that there is NO correlation between a specific boost and horsepower! How many times does it have to be said? Ya know, I thought about getting one of those cars, but I'd rather not deal with a crankwalking motor, differentials that might just lock up at a moments notice, or a host of other problems... To say the least, talons and eclipses are a nuisance. They have an amazing engine (when it works) but they're in the shop more than they're on the road. If you think I'm overexaggerating, look at DSMtuners.com, its riddled with post after post of crap breaking!! Spoolin I know the DSM crowd, its full of either awesome people or knownothing newbs like yourself who think their car is supreme. For the cool people, I apologize!
<IMG SRC="http://j-body.org/registry/paul7878/amsoillogo_iso1.gif">
"Ribbed for her pleasure, but I turned them inside out".
~Dick Solomon 3rd rock from the sun~
spoolhead,
there is no way that you can F*** with SHIFTED.
Arriving...... 3-6-05 ..........
what a power tool and i really love his sig too! my o my what little does he know.
there is just so many thiings that come into a factor, grade fuel, amount of cold air, bore stroke/ port and polish .. a bunch of that. But 6 - 8hp per psi is about right.
dan
actually, to some degree you can predict the power your car can make on boost but not 1 psi, its to iffy, flow dynamics will dictate alot more than pressure going in. Think of it like a section of tubing if you have a 1 inch peice of tubing and put 5 psi on the end, your only flowing so much cfm thru that pipe, step up to a 3 inch pipe and that 5 psi now packs twice as much airflow behind it. So the correct answer to your question would be thats its totally impossible for a general question like that to have a proper answer, factory specs allow a variable on these cars so wide most people would crap a brick, i've seen factory cars that were trully fast and some that should have been recalled. assuming your engine was a magic perfect example, running a perfect fuel setup, with stock internals and conservative timing that 7 to 10 hp theory might hold water but i wouldnt bet any money on it.
Now if you want to have some fun, figure out your standing hp right now, all engines operate under 1 bar of pressure, which is one atmosphere being 14.7 psi as a constant, so lets say you make 120hp at the wheels, if you up to boost to 1 bar adding an addition 14.7 psi to your engine you should in theory double your horespower if i'm remembering my math correctly. now if you do port work and flow bench tuning on your head and can produce 150hp on a stock motor then you would increase your output once boosted just as much.
and leave spoolin alone, yes he proved himself alittle bit of a tard on this post but i've seen talons and eclipses that run high hp numbers, not saying his does, but its been done alot, the talons will take 400+ hp on stock rods and crank at least the 1st gens will and pretty much laugh at you.
Oh and yes awd talons are fast, why else would john sheppard race one? 9 second quarters are very very hard to beat, especially in a front drive street car, so yes an awd can own even a highly modified cavy. that being said i always root for the underdog and theres nothin better than seein a fast car owners face when a cavy blows by them lol.
J~
