Well, Buschur said he'll gladly give us a datalog of his "Project White" stock ECU Evo when he has a chance to throw it on the dyno again when business slows down so he has some free time

So now we'll have data from 2 of the most widely used mustang dyno's on this forum. Cant complain about that!

I'm still trying to figure out why the peak torque doesn't match up though. The torque formula is correct which means the HP values are incorrect at least down in the low RPM range because it seems to be pretty darn close in the upper RPM range. Hmm.

 

Maybe it's simply because of our 1-byte RPM logging. We jump about 31RPM increments and maybe the true slope of the RPM curve isn't captured well enough where it is truly increasing the fastest, down low. The peak torque is simply the point at which the slope of RPM is maximum.

It would be interesting to do a log with 2-byte RPM to compare. Maybe I can try it over the next few days, or this weekend, when I have time, since I have the live mapping and a MUT table in RAM that I can change readily to log different things.

 

Thanks very much for helping out Bryan, can you also list the mods & vehicle year, if you have time.

Cheers Steve

 

I could be confused here, but are you hoping to paste data from a dyno run into the spreadsheet and compare the resulting graphs with the dyno graphs? If so that won't work. The time of the dyno run will be different, usually longer, than an actual pull on the road, giving a completely different graph.

 

^^^^^^^^
Graphs may be different, but I think the idea is to adjust the formula so the peak HP and torque will be as close as possible to the real dyno.

I suggest a check off box for both the Dyno Jet and the Mustang, each using the appropriate formula of course.

 

The ideal scenario would be to do a dyno run then immediately do the same on the road. The spreadsheet formula could then be adjusted to match the dyno graph. Evoscan data from the dyno run would be irrelevant to the issue.

Good idea about the checkbox.

 

I'm not certain on Mustang dyno's (never looked into how they work), but with a dynojet, you can use the logs from the dyno. Instead of using the weight of the car, you use the weight of the rollers or weight being turned.

 

Not if the dyno is setup correctly:

https://www.evolutionm.net/forums/ev...reet-load.html

https://www.evolutionm.net/forums/5622945-post91.html

 

i agree my loads on the dyno are comparable on the street.

 

The problem is that there are other drags (like coeff of drag) that are part of the excel equations that are not on the car while at teh dyno. The force of the drag is not linear.

A street run to double check the numbers is the best way to do it.

 

The mustang dyno, when setup correctly does simulate that non-liner force of drag. It puts more drag on the car the faster it goes on the dyno. There is no set time of acceleration on our dyno, it accelerates as quickly as it's power dictates, just like the street. Make more power, it goes through the power band quicker.

Of course you cannot simulate different wind speeds and direction on different times of the day.

Those are overlays of dyno vs street.

Anyway, I agree doing both is the best.

 

I got this from another thread:

Another thing that would be very intetresing is to run a log through DLL an then run the same log through the Excel Dyno to compare results (peaks and plot graphs).

 

But the rate of acceleration on a mustang dyno IS the same as the real world, if you weren't follow the posts above. Also, the Dynojet Correction Factor already counteracts the drag coefficient difference between a street pull and a dynojet pull. We will be able to get the simulator in the "ballpark" at least with a Mustang Dyno since its basically the same results as a street pull. I'm pretty sure it just measures RPM,time and acceleration...all of which we can simulate fairly close with datalogging and formula's.

we're not trying to make this thing EXACT guys, dont look too deep into this. We're just trying to get it as close as we can with the resources we have to minimize REAL dyno tuning time.

 

Also, I just did a pull while logging 1 byte RPM and 2 byte RPM with ZERO difference in the results.....other than the 2 byte RPM spiked its signal during one of the pulls and TOTALLY threw the readings out of whack. The clean 2 byte RPM run was exactly the same as the 1 byte run though.


MrFred, would you be able to post up a breakdown of the HP formula's you used and the source (if possible) so we can double check the spreadsheet formulas just to eliminate the possibility of a formula error?

 

Hmmm...thanks for trying. I have a few equations from LogWorks, DSMlink, etc, for TQ and HP calculations as well that I can compare if need be. I'm sure mrfred used a pretty good formula though and looking at his, it is doing the same thing for finding the peak, which is basically the point of greatest slope of RPM.

The peak torque issue has to be something with the way we are recording the data and some limitation thereof. I plan on tuning my car this weekend, so maybe I can throw some data in from DMA logs and see what I can come up with.