Today I got my car dynoed at JBA racing in San Diego. I am a little skeptical about the numbers, they seem a little high.
Temp-60.5
RWHP-291.4 at 5965 RPM, Air/Fuel 11.6
TQ-299 at 4474 RPM

The only mods I have are flowmaster mufflers that are designed for the previous gen. mustangs and steeda udp. I told them that I thought 05-08 Mustangs are putting 255-265 RWP. He told me that is about right.

 

Depends on the dyno and the correction factor applied (SAE vs. STD). Of course, you might have one on the high horsepower side but 292 w/ just mufflers and UDPs does sound high.

 

It appears that JBA does not inflate their numbers. In another forum an 05 Mustang put out these numbers at JBA: HP 257 stock
278 with predtor cai/tune. Not sure if they are STD or SAE numbers.

 

That does seem on the high side but I would know all about that. lol. I'm curious with your car being N/A why they would leave the air/fuel so rich. Do you not have a handheld tuner? You should get one with a tune and cai then go back and get that a/f up around 12.5

 

Once you apply the correction factor to your dyno pull your rwhp goes from 364 to 325 (CF 1.12) but that is still plenty strong based on your mods. I think the correction factor on my pull was 0.98 which puts me at 292 in my case. Assuming SAE correction factor that's how we can compare our two dyno runs equally.... I think.

 

The Air/Fuel ranged from 14.4 to 10.0. It was at 12.5 at 145.6 hp and 274 LBS TQ with a speed of 56 MPH. I should research Air/fuel ratios as I am somewhat clueless.

 

It's pretty simple. The basic rules are if you are N/A you want your a/f to hit NO HIGHER than 12.8.(ie 12.5ish is about where you'd want it all the way through the powerband when the hammer is down ((WOT)) That is about as lean as you'd want it. If you are forced induction you want it a lot richer. Usually around 11.5. And of course the huge boost guys go closer to 10.5.

All I would be really concerned about is that your N/A a/f doesn't go any leaner than 12.8 at wide open throttle. Any more than that and you run the risk of detonation.

 

Yup that's exactly what my dyno guy got for rwhp at my elevation (about 3200 feet) 325/343tq. BUT for my mods that seems high. My guess is that the dyno is out and 325/343 is closer to being my actual SAE #'s.

 

Maybe the dyno used has alot to do with the numbers. It is pulled on a dyno dynamics. My A/F at 6275 RPM was 10.0 That seems rich. I don't have force induction.

 

Did another dynopull at a different place. They used a dynojet and SAE numbers. Here are the results

Max hp 285.91
Max tq 287.36
My airfuel numbers were normal, 12.6.
Maybe my car is a factory freak.

 

I'm thinking you definitely have a good one for sure. I am also sure that being close to or at sealevel helps you also. You seem to have one of those freaks for sure. Can you post your dyno sheet for us to see??
Scott

 

I will try when I get to work on Monday.

 

Did three dyno pulls today. They were free. It was a promotion for a new dynotuning shop that is getting ready to open here in San Diego.

1st pull 280.29 hp 287.71 tq
2nd pull 275.48 hp, 281.91 tq
3rd pull 277.79 hp, 285.16 tq

Mostly mustangs there getting dynoned. A cobra dynoed at 505 hp. Not sure of the TQ.

 

Those numbers are definently possible if your car was on the high side from the factory. I'm kicking myself I didn't get a stock baseline on my car. I'm guessing part of the reason for my numbers is that I started out on the high end with around 275rwhp stock.

 

Those numbers were high. They seem to be even higher than uncorrected numbers. STD correction is .98 and SAE is .95. However, the air fuels you mentioned should be optimized. We tune to 12.8 air fuel even and consistently throughout the whole rpm scale. A straight line. 12.5 is not neccessary on a N/A bolt-on 4.6 motor. Running at 12.8 is still considered quite safe. Either way, with axle-backs and a CAI/Tune, those numbers you posted should be right around what you'd see, maybe a tiny bit lower.

FUNNY SIDE STORY: We have a local competing shop that has supercharged 03-04 Cobras leaving the shop at 14.0 air fuels, and they're supposed to be the "best" in the country. About a week ago they printed out a guy's dyno graph and gave it to him when he came to pick up the car. They NEVER print air fuels. He was told 500hp/570tq ish on a Mustang dyno, which typically reads lower. He drove right to us and we put it on our dyno without touching it and it made 431.60hp/487.13tq SAE. Air fuels at 13.5-13.9. We retuned to 11.7-12.0 and got him 452.27hp/499.13tq SAE with less timing. Even funnier was that he made peak tq/hp at completely different spots than his printout which was OBVIOUSLY from a procharged/vortech car and NOT from a Cobra. It is in our opinion that his car never made it to the dyno, but only got base value files loaded in.

 

When I get home I will double check my A/F ratio. I think the 12.5 was at WOT. The first dyno I did gave me an A/F of 10.0 at WOT.

 

On my sheet is reads SAE .98. On my 1st pull my AF max was 12.75 and min was 12.3. My 2nd pull my A/F was 13.18 max and 10.88 min and my 3rd run my A/F was max 13.08 and min 12.42.
Regarding the CAI/Tune, you are saying that installing one would not help my hp./tq wise, and my actually decrease my hp/tq?

 

No of course not, I'm just saying something isn't right. Get your car dynoed on a Dynojet and have them use SAE numbers and the Dynojet wideband commander.

The 3rd run your air fuels sound great. Every dynojet will read within a percent of each other, and it's the industry standard. Your car should be putting down around 260-265 SAE without a cold air intake / tune and just axle backs. Otherwise, yes... your car is a factory freak @ those numbers.

 

The car was dynoed on a dynojet on Sat and Wed. The first time I went to a dyno, the place used dyno dyamics and the gave me a reading of 291 hp and 299 tq. The dynojet on Sat gave me a reading of 284 hp and 287 tq, it was SAE rated. Wed when I dyoned it on a dynojet and got the 280hp/287tq with as SAE of .98.

 

It was dynoed on a dynojet. The first time I dynoed my car it was on a dyno dymanics and that gave me questionable numbers, 291 hp and 299 tq with a rich A/F of 10.0