Need some help...not happy with Dyno results

[Vette Killer]

Hi All,

Hoping someone who has a good handle on tuning can provide some input on this one....not at all what I expected even considering how stingy a Mustang dyno is compared to a Dynojet.

Looking at it I think the AFR is all over the map and seems close to 100 HP shy based on the combo in my sig file...tell me if you think I am overstating expectations.

Really appreciate any guidance.

Thanks,

Rob

[cheftjpeck]

Originally Posted by Vette Killer

Hi All,

Hoping someone who has a good handle on tuning can provide some input on this one....not at all what I expected even considering how stingy a Mustang dyno is compared to a Dynojet.

Looking at it I think the AFR is all over the map and seems close to 100 HP shy based on the combo in my sig file...tell me if you think I am overstating expectations.

Really appreciate any guidance.

Thanks,

Rob

based everything you have compared to others I have read about I figured you should be around the 650-700rwhp area from what others have made...your A/F is all over the place too. do you have a different tuner to go to? Heck I think even a mail order tune from a good tuner like John Lund or Justin Starkey would result in better numbers...post this in Justin Starkey's VMP section...he could probably give you more tech guidance...

[Birdman]

The first thing I see is that your A/F is too lean for the most part. Should be at the 11.5 mark. Where it is now is very dangerous.IMO

The next thing is this is a Mustang dyno and it is quite possible it is set up to read much lower than a Dynojst or even another Mustang dyno.
I have seen as much as a 25% difference on some Mustang dynos (lower) than a Dynojet .

Did you have your car baselined on this Mustang dyno before installing the 2.9? That is the only way to know what kind of gains you actually made.
However you can and should use this dyno to get the A/F corrected provided you have tuning capability .

[Vette Killer]

Originally Posted by Birdman

The first thing I see is that your A/F is too lean for the most part. Should be at the 11.5 mark. Where it is now is very dangerous.IMO

The next thing is this is a Mustang dyno and it is quite possible it is set up to read much lower than a Dynojst or even another Mustang dyno.
I have seen as much as a 25% difference on some Mustang dynos (lower) than a Dynojet .

Did you have your car baselined on this Mustang dyno before installing the 2.9? That is the only way to know what kind of gains you actually made.
However you can and should use this dyno to get the A/F corrected provided you have tuning capability .

Agree on the AF mess....not at all impressed with this outcome

Never did a baseline dyno as the shop and dyno are about 200 miles apart, do have a Predator tuner but have not messed much with it myself yet but looks like I am going to have to learn quickly....

[Birdman]

Originally Posted by Vette Killer

Agree on the AF mess....not at all impressed with this outcome

Never did a baseline dyno as the shop and dyno are about 200 miles apart, do have a Predator tuner but have not messed much with it myself yet but looks like I am going to have to learn quickly....

Don't be discourged by the numbers from this dyno they simply can't be compared to any other dyno because you don't know what parameters it is calibrated with. They are excellent tools for tuning purposes .

I would be more concerned with correcting the A/f by adding more fuel across the board. That A/F line should be more centered between the 11.0 and 12.0 box going across

Not sure how much you can do with a Predator tuner but the whole EEC needs to be looked at and evaulated. IMO

[Vette Killer]

Originally Posted by Birdman

Don't be discourged by the numbers from this dyno they simply can't be compared to any other dyno because you don't know what parameters it is calibrated with. They are excellent tools for tuning purposes .

I would be more concerned with correcting the A/f by adding more fuel across the board. That A/F line should be more centered between the 11.0 and 12.0 box going across

Not sure how much you can do with a Predator tuner but the whole EEC needs to be looked at and evaulated. IMO

Thanks....I sent an email to John, hoping there is something he can do with a tune....just super disappointed after being without my car for 4 weeks now and seeing these results...

[Birdman]

Originally Posted by Vette Killer

Thanks....I sent an email to John, hoping there is something he can do with a tune....just super disappointed after being without my car for 4 weeks now and seeing these results...

Good thing you didn't take the RPM's much higher with it being lean like that.
I'm sure you will get it straightened out . A good mail order tune by someone who has experience with your engine combination should get you much closer .
That said ,ultimately the best way though is to get it tuned on a dyno by someone capable so everything can be monitored and proper setting made specifically for your engine.

[Joe G]

How did you get the AFR #'s? With a bung welded in or just a sensor shoved up the tailpipe?


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[Vette Killer]

Originally Posted by Joe G

How did you get the AFR #'s? With a bung welded in or just a sensor shoved up the tailpipe?


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Pretty sure they used a tailpipe sensor...I could not be there today as I was at work and the car was 8 hours away...

[Joe G]

Originally Posted by Vette Killer

Pretty sure they used a tailpipe sensor...I could not be there today as I was at work and the car was 8 hours away...

That's not the most accurate of methods IMO. May want to have a bung welded on so you can get an accurate reading that you can trust.


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[Vette Killer]

Originally Posted by Joe G

That's not the most accurate of methods IMO. May want to have a bung welded on so you can get an accurate reading that you can trust.


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This may be a stupid question...still getting used to the electronic engine controls...can the AF ratio be monitored through a tuner or is that not broadcast/measured by the PCM?

[SLGT750]

Originally Posted by Vette Killer

Pretty sure they used a tailpipe sensor...I could not be there today as I was at work and the car was 8 hours away...

I have seen tailpipe sensor problems not being accurate, if you could get a wideband or a bung would be more accurate reading. If you get a wideband, get one you can data log with and you don't even need a dyno to tune. I also think this is a better way to tune a car if you can keep the tires stuck to the pavement.

[Vette Killer]

Originally Posted by SLGT750

I have seen tailpipe sensor problems not being accurate, if you could get a wideband or a bung would be more accurate reading. If you get a wideband, get one you can data log with and you don't even need a dyno to tune. I also think this is a better way to tune a car if you can keep the tires stuck to the pavement.

Well on the bottom of the dyno report it does say wideband air fuel ratio...again, not familiar with what this means

[SLGT750]

Originally Posted by Vette Killer

Well on the bottom of the dyno report it does say wideband air fuel ratio...again, not familiar with what this means

Sorry, the wideband is a A/F gauge you add to your car, it has it's own O2 sensor that you install into your exaust rather than relying on the dyno's tail sniffer which I'm pretty sure they did on you car. This way you can data log with your handheld tuner(SCT X3) and send the file to your tuner and have then adjust it accordingly.

Hope that helps, also I have similar mods and will have number next weekend to compare, Lund is my tuner and has done an excellent job helping me tune my car. I was able to send him a data log of my A/F and other parameters and sent me back a tune that will add 30rwhp just like that. My A/F was around 10.5 so he lean it out some.

[Birdman]

Originally Posted by Vette Killer

This may be a stupid question...still getting used to the electronic engine controls...can the AF ratio be monitored through a tuner or is that not broadcast/measured by the PCM?

No you need to use a wide band O2 sensor and A/F monitor.

A Mass Air controlled system actually adjusts the amount of fuel by measuring how much air is entering the engine and adjusting accordingly. Of course I'm over simplifying things here. That's why having the correct meter curve for the mass air meter you are using is so crutial.(which BTW is why I don't like to use a 'mafia')

With regards to the A/F readings....Yes a bung installed in the exhaust prior to the cat is the best location for the O2 sensor ....but with your Exhaust system and hi flow cats there wouldn't be much of a difference in reading at the tailpipe to worry about.
Your A/F ranged from 11.75 to about 12.4 , yes it is too lean but your not that far off.
Your boost level was actually low at only 13.4 lbs of boost @ 6250 rpms ,what pulley are you using? I would say there's room for a smaller pulley and still be conservative at around 14.6 to15 lbs of boost. That would certainly bring the HP#'s up some more and you could still run 93 octane.

[Alloy Dave]

Does that HP line look a bit "flat" to anyone else?

Keep us posted on what you find out. AF definitely needs some work...although it's possible that it's in the measuring equipment rather than the car.

[Birdman]

Originally Posted by Alloy Dave

Does that HP line look a bit "flat" to anyone else?

Keep us posted on what you find out. AF definitely needs some work...although it's possible that it's in the measuring equipment rather than the car.

Correction...that is that torque cruve which is normal for these cars.

[Vette Killer]

Thanks for the input everyone, really appreciate it.

A couple of things I should have shared in advance...the boost is reading 2 PSI lower than actual; this was verified and he has replacement parts enroute for the dyno setup so add 2 across the range.

I am running the 3.25" pully and expected it would be about 1 PSI lower than a car without headers.

I pretty much have to stay with a 91 octane tune....where I live it is difficult to get anything other than 91 (92 if I run an ethanol blend but not a good idea I don't think).

[Blackshelby]

can be many factors what's going on. Don't want to point to one area without really seeing what's going on with the car.
Meter curve, Injector curve , fuel pressure curves, fuel pump tables etc.

The best, is to have someone tune it when its on the dyno.(Sniper delta force tuning or SCT tuning is what software I would suggest to use)

But a few things from looking at your dyno graphs.
Your A/F really is not as choppy as you think or that bad its the scale they are using to display it, its 11.8-12.2 Yes a little lean but not really that bad. Would like to see it 11.5-11.7 across the board

Do you know how much timing was in the car?

Mustang dyno's don't get caught up on the hp number because unless they are tweaked they usually will read about 15percent lower then a dynojet.
Pretty obvious this one is not tweaked.
For the magazine tvs testing I did with my car for muscle mustangs my car recorded 605 on dynojet drove it over to do TB test for magazine we used a mustang dyno this time, the car dyno 520hp(just example using a mustang dyno when its not tweaked ver a dynojet number)
Another good option without welding a bung in is to remove your rear o2 sensor and put the dyno's o2 in there. Most all tunes have the rear o2 shut off anyway. If its behind the cat it will read .1 leaner (tops)then in front of cat
so behind the cat a good a/f would be 11.6-11.8

[Vette Killer]

Originally Posted by Blackshelby

can be many factors what's going on. Don't want to point to one area without really seeing what's going on with the car.
Meter curve, Injector curve , fuel pressure curves, fuel pump tables etc.

The best, is to have someone tune it when its on the dyno.(Sniper delta force tuning or SCT tuning is what software I would suggest to use)

But a few things from looking at your dyno graphs.
Your A/F really is not as choppy as you think or that bad its the scale they are using to display it, its 11.8-12.2 Yes a little lean but not really that bad. Would like to see it 11.5-11.7 across the board

Do you know how much timing was in the car?

Mustang dyno's don't get caught up on the hp number because unless they are tweaked they usually will read about 15percent lower then a dynojet.
Pretty obvious this one is not tweaked.
For the magazine tvs testing I did with my car for muscle mustangs my car recorded 605 on dynojet drove it over to do TB test for magazine we used a mustang dyno this time, the car dyno 520hp(just example using a mustang dyno when its not tweaked ver a dynojet number)
Another good option without welding a bung in is to remove your rear o2 sensor and put the dyno's o2 in there. Most all tunes have the rear o2 shut off anyway. If its behind the cat it will read .1 leaner (tops)then in front of cat
so behind the cat a good a/f would be 11.6-11.8

Thanks for the comments; I have been talking with the tuner this AM and what you are saying is very close to what he is saying as well...I never asked about what the timing was at but I know he would have set it on the conservative side given my concerns with fuel quality available to me. The more I read about this and look at other comparisons it looks like 15% is a rough correction % which would peak this in around the 660 range. Again, just based on comparisons that still seems a little shy but again with 91 octane and conservative tuning maybe that is about where it should be.

The two other factors I am starting to understand is the impact of rear end ratio and the RPM limit; I only waived to 6500 and he felt if he had free reign he could have brought it over 600 easily. On the rear end piece I realized a lot of what I was looking at for results were cars with the 3.31 which also can make a significant impact...probably just a tad (lol) of an emotional response here too

Again, thanks for all the input