I have a question about the torque numbers that I got when i dynoed tuned this weekend. I made 400 rwhp at 4800 rpm's but only peeked out at 440 rwtrq at 4800-4900 rpm's. Do you think the reason that I didn't get that much torque was because he didn't go wot from the start. I was looking at the video and he eased into wot, he didn't just nail it. Do you think that i would have better torque numbers around 4000 rpm's if he nailed it from the start? Just curious. I looked at other people's charts and it seems that my torque numbers are good for the rpm it's at but other peoples charts topped out at 470-500 ft/lbs around 3500-4000 rpm's.

thanks
kurt

 

If you have a tune setup for dyno only, you can set it up so the convertor locks up and you can do a WOT run.

Otherwise, since we have automatics they tend to down shift when you punch the gas, which would cause a spike on the dyno graph. (actually had a kid try to tell me his stock L pulled over 600rwtq once, this was caused by the shift spike on his dyno graph/printout) Seen most let it get into 3rd and ease into the throttle. You can kinda hear the idle change a hir when the convertor locks and they nail it. Looking over my dyno sheets, they start at 3000 rpm and that's where my peak torque is at too (3000rpm)

 

so are you saying that my torque would be close to say, what yours is, if he did a wot run with the torque converter locked or if he got on it sooner?

 

Kurt, Congrats on the 400 Club, and don't sweat the TQ it's wrong

As TX said the issue is the downshift HOWEVER any Tuner can work around that, and so should any Dyno Shop making a pull. You did say Dyno Tune so obviously the tuner was there. What they're SUPPOSE to do is pull the chip and set it up for a dyno pull (they shut off OD). Then they take off and let it shift through 123, then once in third they hold it around 62-64 (I believe?)
and then jump out the MF seat and stomp that SOB through the floor boards.
And hellz ya you would have shown more torque.

You ARE going to get your highest Torque at initial WOT and shortly there after, "down in the low RPM's". Of course the Highest HP is the opposite and will happen in the upper RPM's. If he didnt hold it in 3rd and stomp it without a downshift unfortunately you truly do not have accurate numbers, and clearly not peak torque, you DEF have more than it shows.

Example
(and you will see a slight spike here (but not from a downshift)
Torque (the higher 2 of course), will always start the highest and work down.
HP (the lower two on the graph) will start low and climb.
You of course want to hold that tq as long as possible, but on a stock or lightly moded truck you will be loosing it big time by 4K
As seen here I have lets say 600 from 3K-4K, but by 4.5K I'm down a good 50 ft lbs, by 4.75 I'm down a hundred ft lbs.

 

instead of speed I think they go by the Engine RPMS.
Since mine originally came with 3.55 gears, and was last dyno tuned with 4.10's.

Pauls Hi Performance Locked my convertor, and did a pull from LOW rpm's. Like around 1500, all the way up to 6000rpms.

Sal at PSP did it in 3rd gear starting around 3000'ish rpms up to about 6000 rpms.

It all depends on the tuner.

 

thanks for the input guys, i was just worried that maybe there was something wrong with the truck. I thought that there was more torque at the lower rpm's. I'm not sure if he locked it or not but whatever the issue I'm still satisfied with the tune even if I don't have peak trq numbers.

thanks

 

I have always notice when some stomp it on the dyno you get a false reading (spike) that is not true. (like tire spin) Believe me some people on the net always tell false dyno's. If you are running 12.3 with that hp and tq than obviously you have no tq issues.

 

you saying "12.3" im guessing you mean a/f ratio. my a/f ratio was 11.8 at my peak hp.

 

I cant agree more, so many people boast about a SPIKE and not the real deal,
Hence the reason I said you'd see a spike in mine. I DO NOT have 615 TQ on that Dyno, But I do have like 590+ and as I siad if his Dyno was not done as stated he DOES NOT have his Peak Tq #

 

Right I agree with you Rob, I was just stating not to believe everyone ion the net about horsepower and torque.

12.3 I was talking about when we were talking about 1/4 times. If you ran a 12.3 than you have no problem with tq. 11.8 a/f is safe and right where you want to be with a stock block.

SVTpirates: Look at your dyno what is the range of the hp? Most people talk about peak numbers. But really you want a fat hp and tq across the board.
I beleive that is what wille does on his tunes.

If you want a dyno queen then you tune for peak numbers with STD added. Most the mags do this for the aftermarket part companies.

 

People post their peak Horspower and peak Torque, these don't occur at the same RPM.

The operator just didn't go into WOT soon enough to find your peak TQ.

Most people think that Horsepower and Torque are different things. They are just different ways of looking a the same information. If you know HP and RPM you know Torque and if you know RPM and Torque you know HP. When people talk about wanting a engine with more torque not horsepower they don't really understand the relationship between the two. What they mean is that they want the horsepower lower in the RPM band.

Torque = (5250 x Horsepower)/RPM

At peak horsepower
so if you made 400HP at 4800
Torque = (5250 x 400)/4800 = 438 Ft-lbs

At peak Torque (for example) you are making less horsepower
so if you making 350HP at 3800
Torque = (5250 x 350)/3800= 483 Ft-lbs

 

wow has this turned into a discussion. I'm definatly not trying to have a dyno queen, I was just trying to understand if the torque that I saw at 4800 rpm was ok with the hp.

I really like the formula silver. According to your formula I'm right on target. I have a general understanding between the difference of hp and trq in terms of a dyno chart (peak trq=low rpm's peak hp=high rpm's). hence the original question:

"Do you think that i would have better torque numbers around 4000 rpm's if he nailed it from the start?"

I was just looking for a yes answer for a little comfort.

Thanks for all the input guys.
Kurt