SRT8 Dyno question

[Eagle1]

While running an SRT8 on the dyno the other day, I noticed that at about 5600-5700 the A/F dropped from 12.8 to 11, while the timing jumped from 15 degrees to 23. We were in 3rd, and at that point the dash was saying to shift, any one shed some light on this? BTW this was on a Mustang, 343hp, 370tq we were tweaking the 91 CAI tune.

[mikel]

Could have been COT kicking in...

[3517]

While running an SRT8 on the dyno the other day, I noticed that at about 5600-5700 the A/F dropped from 12.8 to 11, while the timing jumped from 15 degrees to 23. We were in 3rd, and at that point the dash was saying to shift, any one shed some light on this? BTW this was on a Mustang, 343hp, 370tq we were tweaking the 91 CAI tune.

+1 me too

[SRT8Tech]

My stock tune went rich in the upper RPMS and all of my DS tunes went more rich in the upper RPMS. Not as much as the stock tune but they did. My CMR tune does the same thing and done on purpose. It seems as the 6.1 likes a little more fuel in th upper RPMS. Proven to me on the dyno. My CMR starts out at 12.5 in the lower RPMS and slowly ends up at 12.2 in the upper RPMS. If it was kept at 12.5 the whole range we lost 5 HP and 5 TQ in the upper range. Anything above 12.7 we lost tons of power. 12.7 seems to be the limit to what these Hemis want. Anymore lean and they crap out. Hell, the stock tune was 12.3 in the lower rpms to 11.5 in the upper. The 93cai tune was 12.2 lower to 11.8 in the upper same with the 91cai tune.

[MagnumSRT8]

My stock tune went rich in the upper RPMS and all of my DS tunes went more rich in the upper RPMS. Not as much as the stock tune but they did. My CMR tune does the same thing and done on purpose. It seems as the 6.1 likes a little more fuel in th upper RPMS. Proven to me on the dyno. My CMR starts out at 12.5 in the lower RPMS and slowly ends up at 12.2 in the upper RPMS. If it was kept at 12.5 the whole range we lost 5 HP and 5 TQ in the upper range. Anything above 12.7 we lost tons of power. 12.7 seems to be the limit to what these Hemis want. Anymore lean and they crap out. Hell, the stock tune was 12.3 in the lower rpms to 11.5 in the upper. The 93cai tune was 12.2 lower to 11.8 in the upper same with the 91cai tune.

What kind of timing were you getting with your CMR tune? Ive just done tuning on mine with the handheld and ive added quite a bit of fuel but havent tried much with timing. The car seems to love the fuel though, pulled my best time at the track running with quite a bit of fuel added in the mid and high rpm range.

[SRT8Tech]

With no KNK i get anywhere between 20-23* in the low rrange, 17-20 in the mid range and 22-23 in the upper range. This was on a very hot and muggy day. Might get a bit more timing out of it on a cold day. But we set the CMR to run a bit less timing in the mid range because it got more knock when we put timing in on the mids. Pulled a little timing out of the mid and for some reason we got better results in the whole rpm range. This was the CMR software we used and not the handheld. So when I say mid range, I mean just a couple of the cells in the mid range RPMs were changed. By the way, I just talked to my CMR tuner (Tony G.) and he says these new 9r08 tunes look pretty damn good as what he has seen so far.

[johan]

Could of been COT kicking in if you where doing multiple runs, we do also add some fuel up top due to knock issues and from our testing we did not see a gain in power when keeping it leaner up top.
Not sure what went on with your timing values, the timing curve will drop at peak torque and then go back up after 5000 rpms, thats how we have it programmed.