data base for expected HP in the making
Turbo Mini Forums

Hi all,

While trying to get a realistic HP figure per advance or at least an achievable target, I crunched numbers today.

For instance, I compared a future 998, Cooper headed, 7 PSI with a standart 240° cam to a Renault phase 2 GT Turbo and I found 82 HP wich i thought was realistic.
But when I added a 1275, small valves head, 7 PSI with a standart 240° cam, it returned 72 !
And a 998, 33mm inlet valves, 15 PSI (8.3 CR) returned more than 150 then I concluded I need to redo my homework

So please quote the figures regarding your engine as stated underneath :
engine size (in liters)
inlet valves per cylinder (1, 2, 3??)
inlet valve size (mm)
boost (PSI)
presence of intercooler (Y, N)
Compression ratio
inlet cam figure (°)

I'll put the calculator on here when OK

Rusty by nature

a 998, 33mm inlet valves, 15 PSI (8.3 CR) returned more than 150 then I concluded I need to redo my homework


well the above spec is similar to wil-hs engine and he pushed out 155 bhp........ so to conclude your not far off the mark ... theres a little more to it that that though

Well, 1275 16 v (28 mm) on 15 psi returned 240, is it correct ?

998 7 PSi cooper head with 260° camshaft was 105, correct too ?
(seems to easy)

Rusty by nature

yes your in the ball park not far off the mark at all

Are you trying to develop an algorythm?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Well, the one really annoying me is the 1275 at 72 with 7 psi ...

In my calculation it is because the inlet area / swept volume is much worse than on the 998 Cooper headed.

Because in the first calculation I didn't take any notice of the engine size wich has to have some importance, at least more than the compression ratio ...


Come on folks, I don't ask for secret tricks, I just want to make sure it is accurate !

well maybe you can mention if the head is modified and if the timing / jetting is correct.

Rusty by nature

I don't know if I am develloping an algorythm (must have been done already), it is just a cross check with a a known engine (Renault 5 GT Turbo) but I want to check the figures I am multiplying have the good influence on the final result

Rusty by nature