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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Seen a number of post again lately (which seem to come up again every few years) talking about the differences in DynoJet RWHP figures when using SAE versus Standard correction......well, here they are
Same run file from my car, using SAE, Standard, then "inflating" the numbers by using Standard and smoothing 0.
First, SAE correction and Smoothing 5.....
Runtime conditions on the dyno that day...
correction factor using Standard....
Finally, Standard correction with Smoothing set to 0.... magically picking up 15 RWHP and 10 ft/lbs of torque
Keep in mind that even dyno files don't show the whole picture, as ECT, knock retard, et al, play a part in this too. You'd need the data log file from the run (HP Tuner, EFI, et al) to go along with the dyno files to see a more complete picture
Thanks for posting. I don't really consider dyno numbers valid unless they are SAE smoothing 5. I am sure that this thread is going to be very popular today. Happy Friday.
Last edited by lamboworld; 06-15-2018 at 08:49 AM.
The difference is usually 2-3% but I have seen more or less, depending on the conditions. I have never messed around with the smoothing. I didn't know it would have that effect. It makes sense though. Smoothing out the small peaks and dips will definitely show lesser power.
My difference was 9 rwhp STD to SAE. I plan on doing a little more to mine for more power. SAE is 572 rwhp on mine.
Why is it that SAE on smoothing 5 (SAE in general) the most looked at number? Since both STD/SAE are corrected, would it not matter or is it because SAE is an excuse for the other person to have the lower number?
I also have to fix a puncture in the LR tire and my passenger window regulator before I go to Mexico. I want to find a 600+ Z to play with to see where I currently stack up.
My difference was 9 rwhp STD to SAE. I plan on doing a little more to mine for more power. SAE is 572 rwhp on mine.
Why is it that SAE on smoothing 5 (SAE in general) the most looked at number? Since both STD/SAE are corrected, would it not matter or is it because SAE is an excuse for the other person to have the lower number?
I also have to fix a puncture in the LR tire and my passenger window regulator before I go to Mexico. I want to find a 600+ Z to play with to see where I currently stack up.
STD isn't corrected, it's what the car did that day in those conditions.
Last edited by Millenium Z06; 06-15-2018 at 09:55 AM.
My difference was 9 rwhp STD to SAE. I plan on doing a little more to mine for more power. SAE is 572 rwhp on mine.
Why is it that SAE on smoothing 5 (SAE in general) the most looked at number? Since both STD/SAE are corrected, would it not matter or is it because SAE is an excuse for the other person to have the lower number?
I also have to fix a puncture in the LR tire and my passenger window regulator before I go to Mexico. I want to find a 600+ Z to play with to see where I currently stack up.
SAE smoothing 5 is basically the settings that every platform uses, which allows some consistency with numbers on different dynos, cars, etc..
STD isn't corrected, it's what the car did that day in those conditions.
I think you meant to say UNCORRECTED is what the car did that day in those conditions.
Standard correction factor is still a number that has adjustments made to the final number, just a bit more optimistic values are used versus the SAE factor, which is the industry standard used by the manufactures nowadays
FYI, my UNCORRECTED numbers were 576 RWHP...or more specifically, the TRUE RWHP my car makes in Phoenix, AZ at altitude.
The correction factor was 4% (correction factor 1.04)
This is also why I chuckle when people use trap speeds to validate the dyno numbers. Make no mistake, while I may make "600 RWHP" using the most conservative numbers for showing the power of my engine, it will "trap" MPH consistent with what a 576 RWHP car would run here at altitude in Phoenix, AZ.
Uncorrected DynoJet dyno numbers with Smoothing set to 5. 576 RWHP/490 TQ
Why is it that SAE on smoothing 5 (SAE in general) the most looked at number?
SAE is the manufacture's standard for advertising the rated HP for your engine....... the LS7 is rated/advertised as 505 crank HP, SAE corrected
Smoothing 5 removes the spikes (or noise, if you prefer) in the measured signals coming from the spark leads. It averages the highs and lows to display a "smoother" graph.
SAE correction corrects to 77* F, 29.23inhg and 0% humidity.
STD corrects to 62*F 29.92inhg and 0% humidity.
The correction factor is what applying these does to your actual conditions during the run. Around here we are in the 70-80 degree range at sea level with low humidity so regardless of correction type the CF tends to float between .98-1.02.
Someone in Denver during the summer for example may see a CF of 1.2 or more ( meaning the correction factor is adding 20%+ to try and simulate numbers in the conditions specified.
At the end of the day its a tuning tool and not something where you race dyno sheets. Trap speed tells the true story as there is no correction factor out on the road, the car runs uncorrected.
I should post some DIN numbers. That would cause all kinds of chaos around here lol
Then to add to this... mustang numbers read approx 7% less than a dynojet. I know of one car that made 600 on a dynojet and only 560 on a mustang. Same tune and setup. Even my car last year made around 620 on a dynojet and then only put down 580 on a mustang. Same tune and mods also.
So when people say they make 600 on a DJ, put it on the heartbreaker (mustang) and really see what it makes.
Then to add to this... mustang numbers read approx 7% less than a dynojet. I know of one car that made 600 on a dynojet and only 560 on a mustang. Same tune and setup. Even my car last year made around 620 on a dynojet and then only put down 580 on a mustang. Same tune and mods also.
So when people say they make 600 on a DJ, put it on the heartbreaker (mustang) and really see what it makes.
not always true. DJ are pretty consistent and less tamperable as they spin a known mass to calculate hp. Mustang dynos use an eddy current brake to do so. What thisbtranslates to is a dyno that will read much lower or higher depending how it’s set. I have seen mustang dynos that so exactly as you describe based o the setting then other mustang dynos that read higher than a DJ.
not always true. DJ are pretty consistent and less tamperable as they spin a known mass to calculate hp. Mustang dynos use an eddy current brake to do so. What thisbtranslates to is a dyno that will read much lower or higher depending how it’s set. I have seen mustang dynos that so exactly as you describe based o the setting then other mustang dynos that read higher than a DJ.
^This.
The old school mustang dyno settings read low like a dyno dynamics. Some of these older machines were given a new calibration factor to provide more dynojet like numbers. Now some mustangs read high, some read like a dynojet, and some read low. Its very inconsistent and hard to compare to other shops. However, they are a great tuning tool.
SAE correction corrects to 77* F, 29.23inhg and 0% humidity.
STD corrects to 62*F 29.92inhg and 0% humidity.
The correction factor is what applying these does to your actual conditions during the run. Around here we are in the 70-80 degree range at sea level with low humidity so regardless of correction type the CF tends to float between .98-1.02.
Someone in Denver during the summer for example may see a CF of 1.2 or more ( meaning the correction factor is adding 20%+ to try and simulate numbers in the conditions specified.
At the end of the day its a tuning tool and not something where you race dyno sheets. Trap speed tells the true story as there is no correction factor out on the road, the car runs uncorrected.
I should post some DIN numbers. That would cause all kinds of chaos around here lol
DIN correction was almost identical to Standard correction
Put a cup of coffee near the thermocouple and watch the HP increase.
There's a youtube video showing the difference between 2 pulls with the second one having two extra clicks on the rear hold down straps.
The bottom line it's a tuning tool. You can't race dyno sheets as much as the guys at the car shows would like you to believe.
Great thread. My points exactly. All these Disney Dynos and crazy alogrylims and calculations.
The standard for 20 years have been Dyno Jets and SAE and even know they are consistant from dyno to dyno, there are some who's weather stations may be placed on more or less ventilated areas, calibrated differently etc.
For me, if you are going to compare power numbers they have to be from the same stardard that in theory ahoild be within 10rw with eachother if calibrations are similar.
All these dynos: Mustang, Dyna Pack, Super Flow, etc. They all produce a diferent standard so you cant compare numbers among each other you will have to baseline with a Dyno Jet.
Now, if you do all your mods and tunning on one type, any dyno is a good for documenting changes.
IMHO, the best dyno for Tunning purposes is the Super Flow wheel dyno but they are far and few and more dificult to find.
For "standarized" power numbers, the Dyno Jet is the end all.
06-15-2018, 08:37 AM
DynoJet runs, SAE versus Standard correction
