Dyno questions

Chris89cougar

Registered User
Hey guys, I recently had my car dynoed and I'm not sure if there is something wrong with my car, or the person who dynoed it. I had 3 pulls. The first pull:
209rwhp and 207rwtq

Second was
218hp and 215tq

Last was
206hp and 201tq

I think the car should have atleast 100ft. lbs more torque than that?
 
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with all that i would say u should have around 375ft/lb but not sure, maybe the blower needs a rebuild? im not too sure with a power loss like that
 
They Dyno shop didn't have any fans for the engine. I dont nkow if that makes any difference or not. Trife86 and Killer SC, do you think I should be making more horsepower too, or just more torque?

Also how do I found out what the rear end gear ratio is? I looked on the door jam and I think the code for the rear end was 8. Is that 3.08 or 3.27?
 
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well that doesnt sound right, if i recall a 8 would be a 2.73 open differantial, but in a 89xr7 i dont think that rear end was even a option maybe someone can post some rear end codes

and IMO with that kind of work done on the car you should have about 240rwhp maybe some more but thats just my guess
 
With that 10% pulley your intercooler was likely heat soaked before you even peaked out your HP. A fan would have certainly helped.

It would be interesting to see the chart. I bet the EEC was pulling timing due to detonation. Did they run a wideband A/F sensor during the dyno?
 
I can't read those very well. But I think those lines should have been smoother. Those waves in the lines I think imply timing being pulled by the EEC.
 
I wouldnt worry about it, until you find a dynojet operator with a clue.


That charts is obviosly very very wrong. 5200-8200rpms???

The ONLY reason is even showed 209/207 was because of the spike on the begining of the chart.

According to the chart...you really only made 185/207.

But whoever did that run has no clue how to operate a dyno and just wanted some money and made an excuse. peroid.


chris
 
CHart was definately off the 2000 like they said...But it seems your detonating....Try going back there with a cool car an IC fan and some good gas and see what happens,,Hey for 50$ its worth a shot
 
I doubt it would be worth going back there, unless I want my engine blown up lol. The guy ran it up to the rev limiter on all three pulls. Also, I thought you were supposed to do dyno pulls in 3rd gear? The person got up to about 2nd gear, stepped on it, and then it downshifted to first. He went up to about 6300rpm in 3rd gear?

Thanks,
Chris
 
6300????????? id bash that guys head in if he did that to my baby, the highest i think with those mods to go the absolute max would be like 5500rpm correct me if im wrong
 
If he did your dyno pulls in 2nd gear that would definately throw your numbers off..WTF..Post this guys place so noone goes there
 
He didnt actually do them in 2nd gear, he stepped on the gas and let it go through 1st, 2nd, and 3rd. Which is probably worse than doing it in just second?
 
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With an AOD you have to let the car shift up into 3rd (normal acceleration) and nail the throttle at around 2800-3100 rpms depending on what converter your using. Hitting the throttle sooner will cause a downshift.

Another mistake some dyno operators make is rolling into the throttle instead of quickly flooring the gas pedal. Any decent shop will ask the owner of the car how high they want it revved.

David
 
Live and learn I guess. I'll just have to spend the extra money and bring it to a shop that knows how to work a dynojet. Thanks for all the replys.

Thanks,
Chris
 
On the other hand this might be a good opportunity for you to build a relationship with with this shop. If they are just learning you might be able to work with them to refine their process. Get some test runs for a way reasonable price.

Ya never know. Certainly the operator needs to be watching the dyno display while running it. He should have shut it down when it quit building power which would be way before 6800rpm. He should also be watching the engine temp as I bet at 6800 she was getting plenty hot if he didn't have any fans.

It depends on the shop and the operator and his ability to see an opportunity.

Ya never know.
 
The car probably makes at least 230rwhp and over 300rwtq. By taking the motor to fuel cut with a 10% pulley on the M90 you were probably seeing 200+ ACT's. This will result in full timing reduction by the EEC and probably some knock retard as well although the graph is pretty smooth. This can easily cost you 20hp or more.

It is also misleading to start the pull at 3500rpm as your motor more than likely peaks torque near the stock 2600rpm. It is difficult on an AOD to register a true peak torque number as they always want to downshift. If the dyno operator allows the car to downshift, then the pull is a waste because the upshift will only allow a 3500rpm and above reading. Not to mention that running the car through the gears under load artificially preheats the IC. Of course if you do another pull imediately afterward, ACT's will spike pretty bad also.

Unfortunately most shops don't take too well to customers telling them how to run their equipment. ;)
 
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