dandan
17th June 2004, 11:33 PM
Guys,
Just after some numbers from you regarding desired air/fuel ratios in normally aspirated machines.
I am currently monitoring mixture in a well modified 4 cyl 8 valve A Series engine and modifying carb adjustments for better mixture readings after gas flowing head, intake, adding decent exh and manifold.
Car has 270 and 280 degrees of duration on inlet and exhaust respectively and pulls clean from 2200 to 6500rpm. This is with an HIF44 carburettor and distributor based ingition.
AFR's as follows:
Full throttle:- Ranges from 11.0 to 13.6 as revs climb to 6500rpm.
Part throttle/Cruise:- Hard to quantify but typically 16:1
How do these numbers sound? I've got my Supra TT hitting 11.0 to 11.5 afr under boost but figured we could go a little leaner on an NA engine.
Under full throttle we're aiming for approx 12.8:1 across the engine speed range, is this a comparable figure to anyone else's NA engine tuning?
Thanks for any input chaps...
Dan
Just after some numbers from you regarding desired air/fuel ratios in normally aspirated machines.
I am currently monitoring mixture in a well modified 4 cyl 8 valve A Series engine and modifying carb adjustments for better mixture readings after gas flowing head, intake, adding decent exh and manifold.
Car has 270 and 280 degrees of duration on inlet and exhaust respectively and pulls clean from 2200 to 6500rpm. This is with an HIF44 carburettor and distributor based ingition.
AFR's as follows:
Full throttle:- Ranges from 11.0 to 13.6 as revs climb to 6500rpm.
Part throttle/Cruise:- Hard to quantify but typically 16:1
How do these numbers sound? I've got my Supra TT hitting 11.0 to 11.5 afr under boost but figured we could go a little leaner on an NA engine.
Under full throttle we're aiming for approx 12.8:1 across the engine speed range, is this a comparable figure to anyone else's NA engine tuning?
Thanks for any input chaps...
Dan