Manual A/F manipulation

[gorman]

Originally Posted by KAOS_3.0

this is going to get a lot of hate, but you can use a socket to "squish" the FPR down to get richer. it's a jack leg trick the turbo 2.3 guys use

thanks for the tip... but my FPR has plenty of adjustment on it. What i really need is some discussion on tuning strategies... like, what would a perfect A/F trace look like ? ... G.

[SicSE]

Originally Posted by gorman

like, what would a perfect A/F trace look like?

That is going to depend on your individual setup and goals... and even then you may get differences of opinion as to what is "perfect". Most tuners I've talked to, or heard discussing the issue, like to flatten the A/F curve, and keep it leaner than 13:1 NA, and richer than 13:1 in boosted applications... as a generalization. Spark timing, compression ratio and fuel octane all affect a good tuner's desired A/F ratio for a given platform. If you're looking for max power, the numbers would typically be leaner, but it gets to a point where going leaner yields only a tiny amount of additional power at the expense of greatly increasing the chances of detonation.

[gorman]

Originally Posted by SicSE

That is going to depend on your individual setup and goals... and even then you may get differences of opinion as to what is "perfect". Most tuners I've talked to, or heard discussing the issue, like to flatten the A/F curve, and keep it leaner than 13:1 NA, and richer than 13:1 in boosted applications... as a generalization. Spark timing, compression ratio and fuel octane all affect a good tuner's desired A/F ratio for a given platform. If you're looking for max power, the numbers would typically be leaner, but it gets to a point where going leaner yields only a tiny amount of additional power at the expense of greatly increasing the chances of detonation.

Thanks SicSE; low pressure FI is my goal... so i need sufficient fuel flow to maintain 13:1 A/F all the way to 270fwhp... G.

[striker2]

Originally Posted by gorman

Thanks SicSE; low pressure FI is my goal... so i need sufficient fuel flow to maintain 13:1 A/F all the way to 270fwhp... G.

If your going FI then you want to shoot for 12:1

[biminiLX]

Need to clarify FI as forced induction (boost) or fuel injection.

Originally Posted by gorman

thanks for the tip... but my FPR has plenty of adjustment on it. What i really need is some discussion on tuning strategies... like, what would a perfect A/F trace look like ? ... G.

No real perfect A/F as SicSE mentioned.
Also, reread this:

However, if you look at track results vs. dyno numbers at various A/Fs, I've found alot of Mustang guys go faster at the track (make more power) by adding fuel over what proved best on the dyno.
Use the dyno to get it close and then add/subtract fuel at the track and compare the trap speed.
-J

So, just because it makes the best power on the dyno, doesn't make it the the best A/F.
-J

[gorman]

Originally Posted by biminiLX

Also, reread this:

So, just because it makes the best power on the dyno, doesn't make it the the best A/F.
-J

this i read earlier and thought.. my cold air feeds work better at speed... if i was having a remap done on a dyno, i would not be getting the air i would get at speed, so i understand why the mustang guys get different results when stationary with a fan and running at speed. I haven't seen under a mustang race car hood ... but i bet they have proper cold air intakes like WRC cars do .. G.