Another "dissapointing dyno day" post.

AMD[H]unter

Registered User
Well, it wasn't all that bad, considering the state and condition of my motor and tranny. This was done on a Mustang Dyno, with the weight set to 4250, as per the book he had. Here's my specs:

  • Stockish 1991 SC motor (CAI)
  • Dying AOD

I made:

  • 169HP @ 3772RPM
  • 235 ft/lbs @ 3772RPM

I will try to get the dyno sheets photo'd, and posted tonight. Also, my A/F is all over the place. It jumped from 11.6-11.4 the whole pull. it actually looks like a heart monitor, but even more pronounced. Any ideas on that?

I have already talked many times to Dave D about performance upgrades, and i have an upgrade path laid out that involves the top half of the engine. What do I need to do to the bottom end to get it ready to accept all the other goodies? I am talking stuff like bearings, and honing cylinders.

Hopefully I can get all this straightened out soon. I really need to get this thing ready for upgrades this summer.
 
Honestly with the drivetrain lose with a stock SC thoughs figures aren't that bad considering 25% lost would be 158hp to the rear wheels.

At least you have something to build from.

-Tim
 
Something looks very wrong with the dyno sheet...it's showing your peak HP about the same RPMs as your peak Torque.

David
 
Dyno operator wasnt' doing you any favors and doesn't seem to have much ability to work his software.

1) the pull should have started at 2800rpm, not 3700rpm.

2) those are some really crappy graphs. he should have at least scaled them so that they look normal.

3) for HP numbers you should not put in 4200lbs car weight. With an IC and no air moving you don't need the car straining that hard. He should have put 3500lbs into the computer which would have let the car rev out quicker.

4) the car appears to be up against the knock sensor. Was it hot? did they have ANY air going through the IC??? Did the car have time to cool down? Did they sit there and run the car on the dyno for 10 minutes prior to doing the pull???

5) I would never allow someone to put a car with an air-air IC through a simulated dyno run on a dyno. That is idiotic. You are lucky you did not blow the motor up.

Those numbers are everything but useless. The only thing you got out of it is that your AFR seems to be safe.
 
An AFR trace that only varies by .2 is good. He just had the resolution set so high it looks rough. You might ask him what his parasitic multipier is set to.
On our Mustang, when the PM is set to 1.0 (the standard setting) we consistently read 12-16% less hp than a dynojet.

If that the case you could have up to 195 internet horsepower:)
 
Dyno operator wasnt' doing you any favors and doesn't seem to have much ability to work his software.

1) the pull should have started at 2800rpm, not 3700rpm.

I am glad I know this now. For some reason when he put the clamp over my plug wire he was never able to get it to read the RPM. He had to use another way to do it. He told me to put the car in gear, in 1st, and hold it at 3000RPM by my tach (yes I know SC tachs aren't great), and he calibrated the rpm that way. I probably should have raised a red flag here, but, I didn't. (My mistake.)

2) those are some really crappy graphs. he should have at least scaled them so that they look normal.

Again, something to do with the operator not knowing the equipment, right?

3) for HP numbers you should not put in 4200lbs car weight. With an IC and no air moving you don't need the car straining that hard. He should have put 3500lbs into the computer which would have let the car rev out quicker.

Ok, I will keep this in mind if I ever take it there again.

4) the car appears to be up against the knock sensor. Was it hot? did they have ANY air going through the IC??? Did the car have time to cool down? Did they sit there and run the car on the dyno for 10 minutes prior to doing the pull???

How can you tell it is on the knock sensor? It was warm, because I had to drive it over to the shop. I had them put a fan on the IC and engine. The car was allowed to cool a bit. No, they did not let it run long before the pull.

5) I would never allow someone to put a car with an air-air IC through a simulated dyno run on a dyno. That is idiotic. You are lucky you did not blow the motor up.

I am not quite understanding this. How do you dyno your cars with a air-to-air? How could it have blown up? What's a simulated dyno run?

Those numbers are everything but useless. The only thing you got out of it is that your AFR seems to be safe.

Sigh. I hate people that don't know how to use their equipment. I probably won't be taking my car there again. I should have been more careful with my own stuff, though.
 
Something looks very wrong with the dyno sheet...it's showing your peak HP about the same RPMs as your peak Torque.

David

David, There is something very wrong with the dyno sheet. If you look at the scaling on the left and the right you will see that they set the window to show the torque from 175 to 235 and the power from 148 to 169. obviously the HP and torque will have the same value at 5252, and it looks like it MIGHT if the torque really starts to drop off after the pull ends. It's difficult to say what will happen with the HP and TQ at lower and higher RPM's.

Estimating all values i tried to create some reasonably scaled charts.
 

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David, There is something very wrong with the dyno sheet. If you look at the scaling on the left and the right you will see that they set the window to show the torque from 175 to 235 and the power from 148 to 169. obviously the HP and torque will have the same value at 5252, and it looks like it MIGHT if the torque really starts to drop off after the pull ends. It's difficult to say what will happen with the HP and TQ at lower and higher RPM's.

Estimating all values i tried to create some reasonably scaled charts.

Nice graphs, man, but from what I am gathering for you all, my sheets are basically useless, right? Even the HP and TQ numbers?
 
They charged me 50 bucks, which is actually 10 bucks lower than their normal price for one pull.

Well your not out a lot of money I would send a PM to XR7 Dave if you have any further questions. He probably has more experence than most on Dynos and tuning and most guys here would agree with his accesment on your Dyno questions

Ken
 
First off I would have to say that that if your transmission is dying that should be the first thing you address.

If the operator lessened the load such as what Dave said..Yes you would have revved quicker and made more internet power as someone else had said.

I dont do any dyno tuning but I would think the closer you can simulate real world load the more accurate.

And the scaling is way off however your AFR isnt bad at all which is the one thing you can take from this dyno run..And the most important
 
The reason your torque never peaked then dropped off is because he started the pull well after your torque peak (likely around 2500-2800rpm). The HP should have peaked at about 4000-4500rpm but obviously it did not.

I can't tell that its against the knock sensor but a jagged and early peaking HP curve is typical of that condition. It could also be a factor of the EEC pulling timing due to heat. If they had to hold rpms at 3000 for awhile to get a tach setup then that alone could have created excess heat. If you have an OD pulley on the blower and a stock IC it takes very little to overheat the intake charge and lose dramatic amounts of power.

I assumed from your 1/4 mile slip that you did a simulated 1/4. Mustang dyno's can do this and some people get a kick out of doing it so I assumed you had. However, a 1/4 mile simulation takes at least 15 seconds of continuous WOT on the dyno which, without air moving (and no the fans are not good enough as they only simulate about 10mph) could be disasterous to an SC motor. If you did not do this then forget my comments about he 1/4 mile simulation.

"Real world" dyno numbers are fine for tuning but they do nothing to help a person gauge how well his car may or may not be doing compared to others. Call it internet bragging if you want, but without comparing his numbers to other SC's he can't even guess how well his car is or isn't running compared to other similarly modded SC's. I would suggest that for interest and comparison sake, people seek out dyno jets. You will get numbers there that look more familiar to you and make a lot more sense when comparing results with others on SCCOA and other internet sites.

As much as some people like to bash dynojet numbers, I have found they are more easily translated to real 1/4 mile time. Give me a dynojet number and I can typically give you a very close to accurate estimated 1/4 mile time. Give me a possibly low balled Mustang dyno number and who knows? The Mustang dyno by me reads very close to dyno jet #'s, usually within 2-4%. Others not so. It has a lot to do with how the dyno is set up, calibrated, and used.

On SC's it is not abnormal to have a hard time getting a tach signal. Often times when you can't get a tach signal it is also indicative of a DIS that is going bad or other power/ground issues in the car. Not always, but often. So the fact that he had trouble getting the signal does not point to incompetence.

I didn't miss the part about transmission issues, but I assumed that with the AOD being in direct drive that it shouldn't be a problem in D, but I may be mistaken on that.
 
Nice graphs, man, but from what I am gathering for you all, my sheets are basically useless, right? Even the HP and TQ numbers?

As Damon said, the biggest thing you can pull from the dyno session is that your AFR is safe and flat. Both are good things and make the $50 worth it for that reason alone. But yes, the HP and torque readings are probably junk - either that or your SC runs like crap. LOL!
 
The reason your torque never peaked then dropped off is because he started the pull well after your torque peak (likely around 2500-2800rpm). The HP should have peaked at about 4000-4500rpm but obviously it did not.

Ok, that is what I was thinking.

I can't tell that its against the knock sensor but a jagged and early peaking HP curve is typical of that condition. It could also be a factor of the EEC pulling timing due to heat. If they had to hold rpms at 3000 for awhile to get a tach setup then that alone could have created excess heat. If you have an OD pulley on the blower and a stock IC it takes very little to overheat the intake charge and lose dramatic amounts of power.

Ok, if it the EEC will pull timing, that's probably what was happening. It probably was heat-soaked, so that's that. I do not have a OD pulley on it, either, because of this very reason.

I assumed from your 1/4 mile slip that you did a simulated 1/4. Mustang dyno's can do this and some people get a kick out of doing it so I assumed you had. However, a 1/4 mile simulation takes at least 15 seconds of continuous WOT on the dyno which, without air moving (and no the fans are not good enough as they only simulate about 10mph) could be disasterous to an SC motor. If you did not do this then forget my comments about he 1/4 mile simulation.

Yes, I did do a simulated 1/4. When you said simulated dyno run, you threw me off. ;) It was fun, and knowing what I do now, I will never do that again. Thanks for letting me know, I really had no idea.

"Real world" dyno numbers are fine for tuning but they do nothing to help a person gauge how well his car may or may not be doing compared to others. Call it internet bragging if you want, but without comparing his numbers to other SC's he can't even guess how well his car is or isn't running compared to other similarly modded SC's. I would suggest that for interest and comparison sake, people seek out dyno jets. You will get numbers there that look more familiar to you and make a lot more sense when comparing results with others on SCCOA and other internet sites.

I understand. What you are saying makes sense, but unfortunately, there are no Dyno Jets around here.

As much as some people like to bash dynojet numbers, I have found they are more easily translated to real 1/4 mile time. Give me a dynojet number and I can typically give you a very close to accurate estimated 1/4 mile time. Give me a possibly low balled Mustang dyno number and who knows? The Mustang dyno by me reads very close to dyno jet #'s, usually within 2-4%. Others not so. It has a lot to do with how the dyno is set up, calibrated, and used.

Do you do your tuning on a Dyno jet? If so, what would a bone stock AOD SC make on it?

On SC's it is not abnormal to have a hard time getting a tach signal. Often times when you can't get a tach signal it is also indicative of a DIS that is going bad or other power/ground issues in the car. Not always, but often. So the fact that he had trouble getting the signal does not point to incompetence.

Yeah, that makes sense. What made no sense to me was that when he first put the clamp on it, it picked up the engine RPM, then he was never able to get it afterwards.

I didn't miss the part about transmission issues, but I assumed that with the AOD being in direct drive that it shouldn't be a problem in D, but I may be mistaken on that.

Yeah, it was in D, so the transmission probably didn't hold me back any for that very reason.

As Damon said, the biggest thing you can pull from the dyno session is that your AFR is safe and flat. Both are good things and make the $50 worth it for that reason alone. But yes, the HP and torque readings are probably junk - either that or your SC runs like crap. LOL!

Ok, well, I learned some valuable lessons here that also make it worth it, such as never doing a 1/4 mile sim with it. And, no, my SC runs fine, so I am going with the option of junk readings. And, actually, I talked to a guy that took his twin turbo mustang there, and he said they suck. He said that they dyno'd him at ~330HP, and around ~550TQ. That's way off, considering he only runs 5PSI.
 
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