So what do you think

how much hp is gained from 1psi boost. If you do the basic calc with known referance points the cooper to the cooper s. 113 vs 163 thats roughly 50 hp and factory cooper s is running what 11 psi of boost.

that means

50psi / 11psi = 4.54hp/psi

so a 15% pulley gains 5 psi of boost

5psi x 4.54 psi = 22.7hp gain.

And from what I gather from all the post that isnt what the dyno says you gain.

So what do you think, how much hp is gain from 1 psi of boost.

 

maybe Randy from Ross-tech would know....

 

each lb. of boost is not the same. the higher the numbers, the more heat generated, etc....

Plus, boost isn't really needs to be looked at, its airflow. For instance, if one were to unbolt the M45 SC we have now and *just bolt up* an M90, the M90 would out-flow the M45 by quite a bit. ( I don't know the exact rate). What it boils down to is the larger SC will flow more air per each revolution...

hope that helps!!!

-jac

 

well if you ask any toyota supra tuner the answer will be about 10hp per psi... however keep in mind... that the are
1 running a turbo
2 it is a large turbo
3 it is a 2jc I6....

i would think your number might be on the money... maybe a little less... i would say about 3-4 per PSI....

b/c a 15% pulley wont give you 22 hp... unles you add some other mods...

 

remember, it takes HP to turn the supercharger (some people have called this parasitic HP loss). The more your turn it, the more PSI. But also, the more you turn it, the more parasitic HP loss you will see. Also the MCS's Eaton S/C is not that good at compressing the air...it creates a lot of heat in doing so. So the more you spin it the more heat you generate.

What I'm trying to say, is that there probably isn't a nice linear ratio you can apply to the PSI to determine HP gain. As a guess, it's not a straight line, but a wierd curved one.

Get some data points along the way and maybe you can extrapolate an equation from your collected data.

 

The MCS engine isn't the same as the MC engine... The MC has a much higher compression ratio. If you took the supercharger off the MCS and ran it NA it would make far less power than the MC as its compression ratio is 8.3:1 or something like that compared to the MC's 10.5:1 (not sure on the exact numbers). And therefore, if you took the supercharger off the MCS and tried driving it NA it would have alot less HP than the 115 of the MC (also the really low compression ratio would make it really sluggish).

So basically the MCS is built for boost, the MC for NA power, you can't directly compare them.

 

engine stuff... but supporting the post immediately above this, I know there is a carving out of the piston heads on the MCS relative to the MC... this offers 1.6 cc more volume, which lowers the compression ratio.

(Also the MCS has grafual or something close to that word. It is some type of graphite coating silkscreened on to the pistons.)

 

As others mentioned, psi and hp don't have an easily calculated relationship. $ and hp do though:



Ignore the labels on the chart, the x-axis is horsepower and the y-axis is $10's of dollars.