my car is a 355, comp503 cam, vigilante 3600, ferra valves with a 5 angle valve job, 3.42 gears, AS&M 54mm throttle body, jet hott long tubes, prety much a full built on car. the car made 257rwhp and 255 trq with a 14.6 a/f ratio. the car made power till 5800. this was done on a mustang dyno something doesnt add up as the car went low 12 NA, there is some issues i need to work out like my injector duty cycle hit 94% but i am a little upset, i was atleast expecting 320-330 rwhp.

 

Somethings not right there

 

I would think low 12's would equal the high 3xxrwhp range. I agree that something is amiss.

 

on the way home, it is running alot more clean. i down shifted at 60 hit the gas and the car damn near did a doughnut im running a 275/40/18 out back too and a realy sticky cooper.

 

Check your fuel pressure. Was that converter locked or unlocked? What happened at 5800?

 

was it one of those mustang dyno's or maybe it wasn't S.A.E. corrected.

 

Your A/F is way too lean, should be around 12.5-12.7. Your injectors shouldn't be hitting 94% duty cycle with only 257 rwhp, heck that's stock so I would see what the issue is there. I would say fuel distribution problems are causing the low numbers.

 

2 things: Mustang Dynos supposedly provide much lower numbers.
A/F should be around 12.9-13.1

Is your PCM tuned? If not it should be.
Don't rely on bench racing. The ets and mph tell the story.JMHO

 

they said it wasnt sae corrected. they knocked 10% off for the weather or some crap.

 

As mentioned: do not rely on the dyno, especially if it is not one where the operators don't know what the hell they are doing.

You didn't mention tune. If not tuned you are not maximizing your mods.

 

Go down to hardcore motorsports in Clio if they are still around and use their Dynojet. My numbers were right on from them.

Dan

 

Yeah, you have got to get the tune right especially the wayyyyy lean condition of 14.6:1...Weren't the dyno guys concerned with this? I wouldn't drive it much until you get the fuel issue worked out...What was your fuel pressure at WOT...12.6:1 is good and safe Some use 13:1...I'm at 12.8:1...Is the car tuned for you mods?

...and a Mustang Dyno which has been set up right will read lower than the Dynojets...I agree that numbers alone don't mean squat, you A/F ratio is very concerning...

--Alan

 

i was watching the A/F meter at WOT and it was right around 12.8 i dont know why the sheet said 14. at idle it was between 14 and 15 at idle.

 

Don't worry about your peak numbers. Worry about the curve characteristics. Especially on a Mustang dyno and ESPECIALLY on a Mustang dyno w/ an auto.

 

Bay City, eh? Lansing, origninally.

If the sheet was reading wrong, then what else was it not doing correctly.

12.8 sounds right for WOT. Your tune may be spot on, but would most likely be improved with mail order tune.

If you can, or care, next time use a Dynojet, because it is easier to compare your numbers with others with similar mods using the same measuring devices.
JMHO