BMEP!
Turbo Mini Forums

After playing with cam timings boost lca's on various specs I'm ending with bmep from 320 to 380, which seem to be very high.
who now more about bmep ?

how are you measuring this fab ?
regards robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

BMEP is the theoretical average piston pressure based on torque and capacity only. It doesn't consider other factors such as bore stroke cam blah blah.

The only use to the average joe is to compare two engines of similar useage. I don't think the actual number "size" is of significance unless it's far an away much lower than a similar engine, meaning that your engine is not running properly.

Daniel

First 5-port EFI turbo in the world (built 1997, running in 1998)

Robert, I've used an analyser, very interesting stuf!
I was a bit suspiscious before to use it, in fact it does validate some knowed datas (RRs, cams and feelings)), from this I have extrapoled about 50 dif config with boost, cams, cr stroke bore, in ex valves (33/30; 33/32 ; 36/29; 36/32 37/30, 37/29 ; 37/31 ; 37.7 /31), runners, admission lenghts , small a/r big a/r..............
Daniel, so bmep is av pressure based on torque and capacity, thanks (and doesn't consider bore stroke cams....... your point of vue being torque isn't considered by bore stroke cams blah blah is awesome knowledge, I would like to know more)
does someone know a little more about max bmep allowed for minimum reliability regarding an a serie ?

M=Mean and so it would be calculatable. If you wanted a graph of crank angle vs EP, that would be fucking tricky.

Am I on the right track here?

Bugger off, I'm getting there.

M , in BMEP?
(the french term is PME "Pression Moyenne effective" or average effective pressure)
I don't really need crank angle /ep graph, would just have an approximation of what can do an a seri 81.3 crank/rods/cast pistons with this sort of Bmep (350psi , 23bars) knwonig that a good 1600 make about 15 bars at 4000 rpm and a formula one turbo (honda) was 43 bars so we are middle higher of what can survive a ex formula one turbo, and near 150 % of what a good 1600 with five mains ,less stroke. ...take

On diesels at ford I was playing with 150-170 bar :S

Alex

AlexF

Borrowed,

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)

It's basically a reference pressure to compare similar power engines, it indicates a more efficient engine for the same hp output.

If you have the dyno graphs of 3 different size mini turbo engines and compared the graphs by BHP figures alone then capacity should win, however if you compare the BMEP figures you'll probably find the smaller one is the winner.

Daniel

First 5-port EFI turbo in the world (built 1997, running in 1998)