Thread: EFI Tuning

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Jerry,
Tell Corey 'Thanks' for the F/A guidelines. After getting my spark map sorted out with Edelbrock I put my wide band back on and went out for some test runs with laptop in hand. Everything was good up into mid-range, but as I passed 4000 to 4500rpm at WOT I got some pretty severe exhaust 'pop'. With a new confidence level in the spark map I concentrated on the F/A indicator, and what I saw was mid-12's from 1800rpm up past 3500rpm, but then as it got into the peak power area the numbers went into the mid to high 13's, or maybe low 14's - not enough to trigger my "Lean" LED on the Edelbrock Handheld Calibrator (it was not truly Lean with a 14.7 reference point), but it was more lean than desired. I cranked in more fuel at the top end from 3000 to 7000 rpm (6000 rev limiter), and from 26" up to 31"MAP - ended up with 28% more pulse width at the top than it had before! It now pulls strong through the power band, and the torque is scary high I've not had it on an extended highway cruise, but in 4th at 45mph it's at cruise 2000rpm and it homes in on 14.5 to 14.8 F/A which is perfect for closed loop. I appreciate the help

The Handheld Calibrator unit is a pretty powerful tool. Once the base maps are set up to your satisfaction if you're on a trip and cannot get 91octane, no corn fuel it is a very simple matter to do a 'Global Timing' adjustment and back out a couple of degrees across the board, or only at the top. Once you get back into better fuel you can simply back out the over-writing "correction" in the calibrator, returning to your base maps. Pretty sweet!!

Man, this new stuff makes tuning more interesting every day, Roger!!!! I have a new acquaintance at one of the performance companies doing all the new EFI and electronic controls, he's sure got me fired up on all the potential!!!!

Originally Posted by Dave Severson

Man, this new stuff makes tuning more interesting every day, Roger!!!! I have a new acquaintance at one of the performance companies doing all the new EFI and electronic controls, he's sure got me fired up on all the potential!!!!

Yep, when your mind is wrapped around an old two plane mechanical distributor curve it takes a bit of explanation to embrace another dimension with MAP thrown in. Once you get you mind around the concept it is super slick. Same with fuel, rpm vs squirt duration, but add in MAP for a load reference. EFI is a powerful system.

Your welcome Roger and I'll pass it on to Corey--He is off to the dyno place this morning to do some transmission tuning!!!!!The modern day torque management, rpm/speed, etc----shift points that have to be adjusted earlier to allow for the computer to shift the trans with out hitting rev limiter-----------
We (he) has found that the new Camaros fuel lines(even with a big double pump dealie)will only flow enough fuel to supply a little over 700 hp to rear wheels and the injectors will reach 100% duty cycle at about 4700rpm, even going from 80 lb to 90+ lb injectors had the same result---fine curves til about 700hp at 47-5000 and were at 100%-----so now they are working on a new plumbing system---

course it was ME that insisted that they put a mechanical pressure guage between the fuel rails so we could visually watch the pressure---sure enough, went down into 20-30 arae

Learned this week that it pays to open every file in the "Correction Curves", and to see and understand what's there. I found one that was bumping my timing +4 degrees on cold start (Spark vs Coolant Temp). It was said to be "...from the supplier" (FAST to Edelbrock, in this case). Flipped and tweaked the Spark vs Coolant for easier cranking and my cold start issues better. Still trying to find that "ideal" fuel input vs temperature on cold crank.