Question about my dyno at TS

longhorn859

longhorn859

Brap.
Joined
Jan 12, 2007
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Hey,
I got on the dyno for the first time in this truck down at the TS drags and with my setup my numbers were very far from what I was expecting. it dynoed 521/1449 with a 64/74/14 charger, ddp comps, and an ADR for tuning. I figured that I would be up close to 600 horse and somewhere around 11xx torque. In my sheet it spiked from about 1000 to 1449 but it wasnt a spike like I have seen bofore, it was a long and steady spike than eased back down at the end of the run but I know for sure that the torque number is not right.
My questions are: how much effect does heat have on a dyno run? My sheet said it was 113 degrees.
Should I be around that horsepower with this setup? I see guys hitting over a hundred more hp with the same charger.
If the horse is close to correct what kind of changes should I make to get above 600hp?
I have a video that is posted on my facebook and I will try to figure out how to post it on here.
 
don't know about the dyno, but i saw your truck there, recognized it from here and didn't get to see it up close but i know i sure liked the look of it!
 
Thanks Dex! I figured heat would effect it but I just didn't know how much. I feel that 521hp is pretty low for that setup, but its only a dyno as they say...
 
longhorn859 said:
Hey,
I got on the dyno for the first time in this truck down at the TS drags and with my setup my numbers were very far from what I was expecting. it dynoed 521/1449 with a 64/74/14 charger, ddp comps, and an ADR for tuning. I figured that I would be up close to 600 horse and somewhere around 11xx torque. In my sheet it spiked from about 1000 to 1449 but it wasnt a spike like I have seen bofore, it was a long and steady spike than eased back down at the end of the run but I know for sure that the torque number is not right.
My questions are: how much effect does heat have on a dyno run? My sheet said it was 113 degrees.
Should I be around that horsepower with this setup? I see guys hitting over a hundred more hp with the same charger.
If the horse is close to correct what kind of changes should I make to get above 600hp?
I have a video that is posted on my facebook and I will try to figure out how to post it on here.
Click to expand...

I remember your truck and it seems we ran it near the end of the day. I also think I remember it running well, just not as good a number than expected.

The torque spike is due to the sensor detecting the reflective tape I put on your damper to get RPM. It's not uncommon for it to lose that signal at which point the dyno is measuring XXX hp at a very low rpm, and the software calculates a high TQ number. This caused the spike on the graph. When this happens, I try to note the best recorded TQ number on the graph. In many cases we will grab the correct number and the spike occurs later in the run. Sorry if I didn't make this clear after you ran.

To answer your questions.

Heat makes it harder for any engine to make power. How much so is determined by set-up. a smaller turbo can produce more "good" air longer when it starts with cold air. This weekend it was hot. So, power would be down almost across the board. That 113 degrees is what was measured at the dyno, which also includes the heat radiated from the pavement.

I will first say my experience tells me that any VP pumped 24v that makes over 500hp on a single turbo of this size is above the majority. Doing that on a 100 degree day was actually pretty impressive to me. I don't remember smoke levels, but on a hot day an overfueled truck will lose more power than one that is not. One that makes 600hp on a 50 degree day could easily see an 80hp loss in 100 degree heat, if the turbo is near or passed it's limits for efficiency.

My personal opinion is 600hp is hard to make on a single street turbo'd VP 24v. Yes it's been done before, but usually conditions warrant it. On the good note, 500+ is great IMO in 100+ degree heat. And I don't remember the truck running had either. Nice smooth power curve wasn't it?

Hopefully this can clear up a few questions anyway. :Cheer:
 
Thanks for the reply David!
It clears up a lot of the confusion that I had. The HP number was very smooth and was above 500 quickly and remained there for most of the run. I have also thought that due to the lack of powerband that a VP has, it makes it even harder to make big power on a overfueled single on a really hot day. My charger lights at about 2000rpm and the ADR box starts falling on its face at about 2850rpm. With this little window to work with im sure it's really hard to get the charger to light hard and "snap the rollers". Like I said, i'm not really disappointed with my numbers, just curious because I know for sure it feels stronger than a 520hp truck. I am definitely overfueled and the smoke never really cleared up during the run until the very end to a haze. When piecing this setup together, I knew it was going to be a lot of fuel for this charger but I was hoping the 64mm compressor would be somewhat easy to spool, and the 74mm wheel would pull hard and make impressive dyno numbers. I guess it is back to the drawing board lol. Thanks for your reply David!
 
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