RR Results

[Chilliman]

Finally found the print outs from end of March. Would appreciate comments from those in the know, particularly regarding the AFR graph... Standard 500 btw... Many thanks, R.

[blitzracing]

Leaning out a bit at the top end, you need between around to keep it slightly richer than 13:1 make maximum power. Possible slight fuel pressure drop looking at the relatively straight line as the mixture leans off under demand.

[Chilliman]

Thanks Mark... That's pretty much what I thought... What would be the optimum AFR for power ? I'd somewhat assumed it should be fairly level at about 12 to 12.5:1 to get the best out of it ?

[900T-R]

IIRC 12.5 is where it normally makes the most power, but for safety one should aim at 12.2:1 which only loses like 2-3 bhp but gives some leeway so that you don't melt any pistons should anything be slightly off...

Bit of an atypical 500 graph I'd say, they usually max out nearer to 5,000 rpm... Max power is rather good, too (especially on the 1st run) so it looks like cam timing might be a tad more advanced than most. How is low rpm/light load driveability? Does it shunt a lot?

[Chilliman]

Hi Eric... She hardly shunts at all, at least compared to the way that some of the guys have described it previously.. Actually quite driveable. The difference between the two runs was suggested to be the engine running much hotter on the second run. I'm also not sure why the RWBHP appears to be not too different between the two runs compared to the flywheel estimates ??

[lestershaw]

Hi Lester here, showing my graph, any thoughts please would be welcome

[Alexdaredevilz]

Heres mine, a little to rich but i can live with it

[Chilliman]

Hi Lester, I'm no expert, but that looks seriously lean mate... It's nowhere near the mix required for optimum power output...... somebody more qualified to comment will hopefully be along soon though.... R.

Edied to say: Alex, posted at the same time you did pretty much, but that looks like an AFR curve you might expect.... (In my humble opinion..)

Edited by Chilliman on Tuesday 10th May 20:29

[lestershaw]

Chilliman said:

Hi Lester, I'm no expert, but that looks seriously lean mate... It's nowhere near the mix required for optimum power output...... somebody more qualified to comment will hopefully be along soon though.... R.

Edied to say: Alex, posted at the same time you did pretty much, but that looks like an AFR curve you might expect.... (In my humble opinion..)

Edited by Chilliman on Tuesday 10th May 20:29

Hi, Chilliman
yes my son in law who has the rolling road says its really lean, suggests it might be air flow meter, now what do i do about it?
daft question, how do you read the graph to know its lean?

[Alexdaredevilz]

Chilliman said:

Hi Lester, I'm no expert, but that looks seriously lean mate... It's nowhere near the mix required for optimum power output...... somebody more qualified to comment will hopefully be along soon though.... R.

Edied to say: Alex, posted at the same time you did pretty much, but that looks like an AFR curve you might expect.... (In my humble opinion..)

Edited by Chilliman on Tuesday 10th May 20:29

The before and after a/f changes were

45mm trumpets
Ported inlet manifold
Decat
ACT induction
Mark Adams best guess chip
Green tune ress
Lamdba removal