The V8 Owners Forum -

Bit the bullet this afternoon,
i wired back up my ignition retard and nitrous tps inputs,
then said sod it lets go try it with the new stage 3 heads and cam and the ecu on closed loop. would of been rude not too.

it ran, not as good as i though it may of, it accelerated very well, or maybe its going better than i thought, but felt slower. i only had a bottle pressure of 800 though.
the timing is set to retard 6 degrees at 60%
i was getting a reading of 0.69 lambda while on WOT and on gas,
this sounds a bit rich to me, or would you recomend leaving it as is?

always easier when the numbers are in AFR's lol


0.69 at circa low 10's, is pretty damn rich.


Id normally tune a boosted application into the mid-low 11's, which is also pretty safe.
Low 12's are do-able, but IMO not worth the risk.

Aim for around 0.75-0.79


Im not sure if nitrous engines would be tuned along similar lines as n/a engines, but playing with boosted numbers will be safer.

n/a engines could easily run 0.88 lambda or so ( 13.0:1 ) at WOT.

she runs around 0.88 off gas mate,
looks like i need to drop the fuel jet in the nitrous system a size then
or up the nitrous jet

is there a table anywhere online that shows AFR to lambda??

Tony
I run a 100 shot at only 2 degrees of retard on my low comp V8. 8.2:1 CR and she gobbles up the gas no probs. What CR are you running?
I've just fitted AFR meters to mine. They only show lean, rich and stoic. But they have already pointed out a problem on my fuelling which I have now sorted.
What CR are you running?

hi mate,
im around 9.35-9.40 CR
i run at 8 degrees ignition with 6 degrees retard at 50%

On my 3.5 I just run at 6 degrees BTDC all the time. Retarding the ign on my engine just slows it down.

Trevs sending me a program through to get the right AF ratio when on nitrous,
so then can sort the jet size out for the fuel side.
have asked Trev also regarding my ignition if i can take some back out of the retard side to get her a bit quicker also.

roll on June 10th, i want a 12 so bad now, plus to try and catch Mr Stewart again before he runs off in the distance

Are you gonna go for the 2.0 axle to help with that?

no Gav no time to change it all over before next sunday

Seriously though, how come he can do a 12sec pass with 280 hp and you can only do a 13sec pass with (at the time) 240ish hp and another 100hp gas? I'm guessing the cars weigh about the same? Did you have a trailor?

my problem is traction,
which is why we have the drag radials for this year,
plus his car revs like fook, and he also has soft compound sticky tires now.
if you get chance go in ians tina, its a wild ride which will have you grinning from ear to ear.
plus we now know thanks to the AF gauge she runs very rich at WOT thus losing power

Are you guys gonna be up classic ford?

im hoping to be yeah, not sure if Ians working or not