This is topic Weird stuff on the Dyno in forum Tech Talk at Northern California Ford Owners  .


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Posted by twstd5o (Member # 1981) on :
 
Have any of you ever experienced weird syptoms on the dyno but not on the street? My car can rev way past 5500 rpms on the street with ease but struggles on the dyno. It was fine on the way over to the dyno. On the dyno it struggled. Took it off the dyno and went around the block with the tuner and it was fine again... [Confused]
 
Posted by HungryHippo (Member # 537) on :
 
depending on the dyno, the roller brake might be putting more of a load on the car than on the street
 
Posted by 66 AC COBRA (Member # 904) on :
 
or the dyno operator was doing something wrong, which has happened before

where did you guy

if it was know place then i doubt it was operator error, so i dont know

either way your combo should be able to go above 5500 on the dyno

the motor in my cobra has less power than your motor by quite a bit (not for long [Razz] ), and it went to 6400 no problem
 
Posted by twstd5o (Member # 1981) on :
 
I think it's time for a compression test and leakdown. Man I hope nothing is wrong with the motor. [Frown] It's only 5500 miles old.

I've heard the stock processors act up sometime. If the motors ok I guess I'll swap out the processor.
 
Posted by TRIXSNK (Member # 2844) on :
 
quote:
Originally posted by HungryHippo:
depending on the dyno, the roller brake might be putting more of a load on the car than on the street
I would look down this path unless the operator was well know for running the dybo which wouldn't make much sense.

Maybe just a simple mistake (human error)

[Confused]
 
Posted by Mr JoCo (Member # 1549) on :
 
I heard this somewhere: Dyno's don't like Auto's
 
Posted by gt40 (Member # 3587) on :
 
where did you have it dyno?
 
Posted by 66 InjectedCobra (Member # 819) on :
 
LOL a dyno is twice as hard to spin when compared to just pulling gears down the street. It will take RPM's longer to pull up on a dyno everytime.

What precentage of dyno brake was he using? Also who dynoed the car? What Shop?

What power did it make?
 
Posted by Jeff S (Member # 371) on :
 
quote:
Originally posted by 66 InjectedCobra:
LOL a dyno is twice as hard to spin when compared to just pulling gears down the street. It will take RPM's longer to pull up on a dyno everytime.

What precentage of dyno brake was he using? Also who dynoed the car? What Shop?

What power did it make?
Actually you are incorrect if you are refering to any Dynojet or any load bearing dyno set to anything less than double the weight of the car. The Dynojet roller weighs only 2500 pounds. There is more of a load on a car when it is actually on the street compared to being on a Dynojet.
 
Posted by twstd5o (Member # 1981) on :
 
I'm not sure what percentage the dyno brake was set too. It was at DynoLabs. The tuner Ray has always done an excellent job on my car and is extremely fair when it comes to pricing. I've had better luck with him vs. Byron...

It's funny cause when we test drove it after it crapped out on the dyno, we went up a hill and it felt pretty strong.

I don't even know the numbers from today as we kinda threw in the towel until the compression and leakdown tests come back. The previous numbers are in my sig. I was hoping for them to be a little more.

After confirming that nothing is wrong with the motor, Ray and I are gonna hook up the data logger and drive it on the street to see how it reacts.

The thing that's killing me is that I've been going to the track with the car acting like this and have had decent results. This lead me to believe that there wasn't anything major wrong with the car. [Frown]


quote:
I heard this somewhere: Dyno's don't like Auto's
I've heard this before too...not sure if it's true or not. [Confused]

Thanks guys...Tony
 
Posted by CDT (Member # 5004) on :
 
dyno jets are usually really easy to spin, because they dont apply load other then the roller weight itself.
 
Posted by twstd5o (Member # 1981) on :
 
I'm gonna change my plugs again in the morning for one last ditch effort to get it running right.
 
Posted by Mr JoCo (Member # 1549) on :
 
who cares what it does on the dyno, I mean it doesn't do it on the street... that should tell u something, unless im drunk to make any sense of anything

-cheers
 
Posted by twstd5o (Member # 1981) on :
 
I agree...what I was worried about was he was tuning the chip on the dyno. That why I wanted to run good on there so he could tune it to it's full potential.
 
Posted by twstd5o (Member # 1981) on :
 
Well I just had a leak down and compression test done. The motor seems fine:

Compression - all cylinders measured 180 with exception of one that was 185.

Leak Down - 5% with the exception of one that was 6%.

What next??? [Confused]
 
Posted by BlueOvalRacing (Member # 1531) on :
 
What speed are you showing in high gear at 5500 rpm? Depending on tire size, rear gear ratio (and speedo gear accuracy), you could be tripping the speed limiter. I have seen conflicting reports of the top speed limits of Mustangs. Maybe???
 




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