Trials and tribulations of the dyno

[spoolinmp3]

Ok guys,
I went to the dyno again yesterday with Rick (redwagon02). I have some good and bad results.

I pulled 212.6 lbs/ tq @ 3700 rpm. This was at a mere 6 psi of boost . Also my last dyno torque numbers were 213 lbs/tq @ 4400 rpm I believe at 7.5 psi so that was an improvement.

At 6 psi I also pulled a run of 198 whp. That was also fairly well for my first run.

Now the bad news:mad:
Each progressive run got worse and worse. 2nd run I over boosted so I let off.

The 3rd run I attempted to raise the boost to 8 psi but the car was bogging out due to an overly rich condition. Then the 4th run I was leaning out and was unable to finish the run.

This dyno I used was slightly different than the previous model I used and perhaps this is why I was having problems

But I could not get a damn good run the rest of the time there and decided to call it quits.

Next week I will go back to my old dyno and grab my 210 whp at 8psi. Then I will turn it up a notch and make some 10psi passes. Hopefully that should yield me 230 whp

Also Rick took a couple pics so If you are reading this Rick chime in and hook us up wid some pics(thumb)

 

[Kooldino]

Wow, for 6PSI, that's just amazing. I wish we could all be cat-less like you.

 

[Keith@FP]

Terry, a couple of questions.

- what kind of dyno? They do report differently, so the numbers aren't necessarily directly comparable.
- do you have charts? I'd love to see them.
- are you using the Link boost control?

Impressive numbers! I wonder why you had so much trouble with back-to-back runs. Obviously something's not quite right.

Keith

 

[blynzoo]

Impressive numbers! I wonder why you had so much trouble with back-to-back runs. Obviously something's not quite right.

Keith

I would assume that runs get worse on a dyno because you're pulling warmer air each time. Under normal driving, the air in the compartment is exchanged. Even with the hood up, the ambient air around the intake and motor is going to be warmer as the turbo and motor heats up. And as the turbo heats up, it's going to heat up the air it's sending in (duh).
I have similar results when racing, each run is a little worse as the compartment heats up.
Or it could be something else. Ice your turbo and find out.

 

[Keith@FP]

Yes, things will heatsoak if they are unable to dissipate heat with the fans you run on a dyno. It depends how much excess cooling capacity you have.

However, heatsoak shouldn't cause overboosting. Nor should it cause problems with A/F ratio. I'm wondering about boost control problems.

Keith

 

[blynzoo]

Yes, things will heatsoak if they are unable to dissipate heat with the fans you run on a dyno. It depends how much excess cooling capacity you have.

However, heatsoak shouldn't cause overboosting. Nor should it cause problems with A/F ratio. I'm wondering about boost control problems.

Keith

true, true......you dont think that heatsoak could change the timing and cause A/F probs? but the overboosting is wierd indeed....

 

[Keith@FP]

I don't see how heatsoak could change timing. It just means you've got a hotter intake charge.

Keith

 

[spoolinmp3]

what kind of dyno? They do report differently, so the numbers aren't necessarily directly comparable.

I am unsure on what dyno I just used but the one I regularly use is a dynojet.

- do you have charts? I'd love to see them.

I have charts from the last runs but I do not have a scanner. I will try to get a buddys scanner so I can upload them asap.

are you using the Link boost control?

Yes I am using the LINK to control boost. I was having problems with boost on the dyno. Once I got to the street though everything is fine and boost is holding steady

 

[Keith@FP]

There's less load on the car on the dyno - no aerodynamic drag. That's probably the source of your problems. It's also why you can run more advanced timing on the dyno than you can on the street.

If you want a hand setting up the boost control, give us a call.

Keith

 

[blynzoo]

There's less load on the car on the dyno - no aerodynamic drag. That's probably the source of your problems. It's also why you can run more advanced timing on the dyno than you can on the street.

If you want a hand setting up the boost control, give us a call.

Keith

Awww, now that just brings a tear to my eye, I love everybody here. One turbo seller helping another turbo seller. (sniff):'(

(excuse me for a moment).....

 

[Kooldino]

I don't see how heatsoak could change timing. It just means you've got a hotter intake charge.

Keith

Well, if it heated the air before it hit the MAF, wouldn't the CPU retard the timing accordingly?

 

[blynzoo]

Well, if it heated the air before it hit the MAF, wouldn't the CPU retard the timing accordingly?

That's what I was referring to, just as changes timing with a CAI, but in the opposite direction.
Although LINK might solve that problem, I'm not real familiar with all the bells and whistles of it.

 

[spoolinmp3]

There's less load on the car on the dyno - no aerodynamic drag. That's probably the source of your problems. It's also why you can run more advanced timing on the dyno than you can on the street.

That seems to be my problem there I imagine. Hot air will not affect air fuel ratios so drastically as that day on the dyno and boost perhaps was an issue due to less load on the vehicle.............however my cofusion is why did this not happen on previous dyno runs? Perhaps that dyno in paticular had different load charecteristics resulting in unsteady boost..

The boost is holding fine now Kieth thanks for the help though.