Dyno pull Length

[Bigggy]

Hey guys, quick question!

I've done some pull this summer and it seems to me that they were pretty long.

MD-500 Mustang Dyno
Very hot and humid day
4th gear
2500-6700RPM
about 16sec

Watching other dyno video it seems to me that 16sec is very long.

Car made about 420 on a starting tune, rich and low timing, on 91 octane.

Any ideas?

 

[CrispyBacon]

in for answer. Mine felt long too

 

[cj428mach]

Add more horsepower and the run won't last nearly as long.

 

[03cobra#694]

Lol

 

[Bigggy]

Add more horsepower and the run won't last nearly as long.

Lol indeed! But I was referring to some video of similar power level on similar dyno (mustang dyno).

 

[CrispyBacon]

I suppose my question would more be is this abusive? may be a gear ratio difference on some of the videos

 

[c6zhombre]

power level, gear ratio seems like likely candidates to alter dyno pull time

also....along with gear ratio is rear tire height. Taller rear tire is going to lengthen the pull versus say a factory 17" 275/40 (25.7" tall)

 

[silver03svt]

Are you counting from the time he actually starts the rear tires rolling, or ONLY the time that the operator is giving the car the hit?

 

[Bigggy]

Are you counting from the time he actually starts the rear tires rolling, or ONLY the time that the operator is giving the car the hit?

Only WOT.

Yeah I know that the grea and tire size will affect the speed...but i,ve seen some 5-8 sec pulls.. maybe in 3rd gear?

 

[cj428mach]

Only WOT.

Yeah I know that the grea and tire size will affect the speed...but i,ve seen some 5-8 sec pulls.. maybe in 3rd gear?

Yeah that sounds really long. I've only ever dynoed my old Fbody which at 350rwhp was able to do the run in 4th in under 16 seconds.

 

[ctgreddy]

16 seconds seems very long for that power level. I just watched some of my video's and back when I made about 440 it was roughly 7 seconds. Now at 650 it's 4.5-5 seconds. Maybe he's running it in 5th or possibly even the dyno brakes are sticking possibly.

 

[MalcolmV8]

Add HP lol. I just checked some old vids and mine are around 4 seconds.

 

[Bigggy]

The things is...i will have to check but cars with lower hp were having faster pull i think. Maybe the dyno was putting too much load?

The setup I have will probably run around 500, but that tune and 91 octane is currently limiting the power.
This summer I will kick my but to do more datalog and send that to the tuner...remember its the first tune, running 10.8 AFR, thats rich.

Could not log during the dyno, first time, the SCT soft made the car PCM crazy, it was the first time seeing that and i was very spooked haha. 2 final run the PCM was fine but I did not log by fear to glitch the PCM again.

I've asked here and guys were saying that it happens with the X3.

 

[Bigggy]

Do a vid would help?

[video=youtube;zbdvAUEEz5Q]https://www.youtube.com/watch?v=zbdvAUEEz5Q[/video]

 

[b_dike]

Damn, it really sounds like he's not going WOT. Just gradually pressing on the throttle until he reaches WOT

 

[MalcolmV8]

That did seem really long. I wonder if they have huge rollers that take a long time to spin up? lol I dunno.

 

[Bigggy]

Damn, it really sounds like he's not going WOT. Just gradually pressing on the throttle hit he reaches WOT...

I was in the car at that time and I can confirm he was WOT and pretty much pulling the steering wheel haha.
The car pulls hard on the street without a miss..so I guess the dyno was putting a lot of load on the rollers.

http://www.mustangdyne.com/mustangdyne/products/chassis-dynamometers/2wd/?prod=MD-500+Series

 

[c6zhombre]

If thats the dyno and that shop intentionally increased the load on that dyno to make your poor car pull up the equivalent of a 40 degree incline hill......run away from that shop

But that seems really weird to only torture your car like that. If I read you right, other cars did not experience this. I'd look at the datalog and make sure your throttle is opening appropriately. It sounds like its just short of WOT? Any modifications to your throttle body or throttle cable? I looked back at my logs and I have a parameter called "TP Absolute" that 04sleeper has me log. It seems to be about 934 in most the datalogs I have once I punch it to the floor

 

[1S1K]

My pull went pretty quick..... :coolman:

 

[Bigggy]

If thats the dyno and that shop intentionally increased the load on that dyno to make your poor car pull up the equivalent of a 40 degree incline hill......run away from that shop

But that seems really weird to only torture your car like that. If I read you right, other cars did not experience this. I'd look at the datalog and make sure your throttle is opening appropriately. It sounds like its just short of WOT? Any modifications to your throttle body or throttle cable? I looked back at my logs and I have a parameter called "TP Absolute" that 04sleeper has me log. It seems to be about 934 in most the datalogs I have once I punch it to the floor

My comparison comes from other video on the net, not from the same dyno. See below for another vid done on the same dyno, same day, about 30min before me.

The skyline was about 330-350 rwhp i think and the pass lasted about 10sec, even if they got to a higher RPM than mine.

[video=youtube;EgWbutEK2Jk]https://www.youtube.com/watch?v=EgWbutEK2Jk[/video]