Experiment and thoughts: Alternate 5EAT dyno test method

So I have noticed that most 5EAT dynos of modded LGTs looks like a big pile of waste of money, yet the 1/4 mile times and the trap speed says otherwise.

 

Typically, during a dyno they monitor your RPM with a pickup and compare the acceleration of the car's wheel that is translated into the rollers (or hub)

 

But I've downloaded virtual dyno and noticed the same thing as a traditional dyno. Knowing this is a slipping transmission system (TC automatics) i thought maybe the slipping is confusing the calculation, so i tried something else.

 

I logged vehicle speed during my pull, converted the speed back into RPM using

=(MPH*final gear ratio*336)/tire height

 

which in my case was =(MPH*3.58*2.264*336)/24.7 (JDM ratio, 2nd gear, 215-45-17)

 

And then the sheet showed me this..

http://legacygt.com/forums/attachment.php?attachmentid=226745&stc=1&d=1458574993

Blue is the MPH-to-RPM converted run

 

What do you think?

 

car is Vf34 Ej20X 19.5 psi to 16psi / 17 degree timing

Looks more like a linear N/A curve.

here is a better pic. remember it's a 2.0 and i'm soft in the midrange.

http://legacygt.com/forums/attachment.php?attachmentid=227588&stc=1&d=1459603224

 

 

Just an idea i had though. My HP on these charts better reflects my trap speed and 1/4 time

Looking in airboy dyno and seen that he's done something very similar. So now 5EAT guys, it's confirmed you can use this method in virtual dyno

 

Be sure to log vehicle speed (MPH) when you do this and then select the Auto (MPH) option in Airboy

ive had my 5eat on 2 different dynos. both showed similar curves. peak at the start due to the TC then levels down to normal levels all the way to redline.

 

360 ft-lb then leveled to 285 and pulled to the end. this is on 17 psi.

 

pile of waste of money? on the stock vf46 i was hitting 255awhp at redline before running out of exhaust. they put it down to 252. downpipe and intercooler and air filter is all i have. on a mustang dyno of all things.

 

there is nothing to reinvent.

there is nothing to reinvent.

 

Lol. I don't think you understand whats going on in this thread.

Lol. I don't think you understand whats going on in this thread.

 

Yeah, i'll try to get some pulls on my way home to convert.

My rpm end up being way off for some reason though when I do the conversion.

Lol. I don't think you understand whats going on in this thread.

 

you are probably right. as ive been to 2 actual different and very real dyno. not using math in a spread sheet.

 

ive seen my dyno numbers and how they are.

 

as i said...theres nothing to reinvent. you want to push numbers in. go right ahead. they will be discounted until you go to a real dyno. the op never stated he went to a real dyno either.

 

id take real over paper any day. was giving my opinion that doing this isnt the same as a real dyno so dont waste too much time.

Yeah, i'll try to get some pulls on my way home to convert.

My rpm end up being way off for some reason though when I do the conversion.

 

because a real dyno is more viable

because a real dyno is more viable

Here's your uber accurate paper numbers...

 

http://uploads.tapatalk-cdn.com/20160430/c6f5aa95fc7c0ec245b69fa48d04e8f7.jpg

mine. pulls to redline. no oil burn. haha. has ALWAYS pulled to redline. they said it would drop off with stage 2. it did not. got dyno tuned and it didnt drop off.

http://legacygt.com/forums/attachment.php?attachmentid=192022&d=1411026117

id take real over paper any day. was giving my opinion that doing this isnt the same as a real dyno so dont waste too much time.

 

whats your trap speed and 1/4 time?

 

 

A real dyno typically guesses your gear final ratio by using RPM pickup and roller speed. With the transmission slipping it throws them off. Here we know our final ratios from factory specs and tyre size.

 

 

 

Yeah, i'll try to get some pulls on my way home to convert.

My rpm end up being way off for some reason though when I do the conversion.

As do mine sometimes. It's because it's slipping. Use a smaller/larger tyre size until the RPM at redline is closer to the real one. THe logged RPM should be higher in the midrange. Remember to copy and "paste values" in excel over the original RPM

 

For those who don't know how, you can use Airboy's spreadsheet to make it easier.

1. Open spreadsheet,

2. Import Data -> select your log file

3. Click Filter WOT (Data)

4. GO over to acceleration sheet, Clear data

5. Over the yellow section, enter gear ratio to get Engine to Speed number (mine was 110, yours prob 99.9 USDM ratios). Enter this number in the white section, cell N9. Enter the weight and your weight also.

6. Check the Auto option in the green box. Then click clear data, click grab headers, click get data, then click calculate acceleration.

whats your trap speed and 1/4 time?

 

i dont go to the track. i think its a little out of my way and im rather too lazy to drive an hour and wait in line to spend seconds worth of full throttle.

 

so...yeah.

 

as stated before...you can always go to a real dyno instead of plugging numbers into a sheet and hoping you find something to brag about. the dyno may not tell you that your car has 400hp but it will tell you the powerband and where the power is.

OK your opinion is noted.

 

For others, you can log your car and try. OR send me your logs. Esp those who have been to a real dyno or the Drag Strip.

Red is raw data

Blue is Speed to RPM

3rd gear pull on e85

 

http://uploads.tapatalk-cdn.com/20160512/5d815d7d0224e733b8b323190ba09846.jpg

Looking good. How do you feel about it? It looks great. And if you changed the Sim mode to dyno jet you would be at 300 with the blue.

you could also right click the chart and select "Chart to file" to save as PNG/JPG etc

That's actually higher numbers in all of the other pulls I have graphed, but the peaks and curves look about right.

 

Also, that's the smoothing set to 6, if I go lower it goes over 300 tq.

I didn't use that airboy thing though.

Just opened up excel and put your equation in a new column and labeled it RPM

Good. Send me the log if you want to post up the airboy comparison

When I get internet at my place, I'll send it

I very much agree with what you did here! Great job JMLegacy.

I'll give it a shot with some new logs.

 

Typical combined average drive train loss on a Subaru with 5EAT or HTCVT is ~30-31% vs say 19-21% on a typical 5/6MT STI/WRX.

 

I've asked Dyno Dynamics (as an example) to account for this and create a different shootout mode for AT Subarus

(Shoot44 works well for 5/6MTs, but NOT ATs). They have done similar for other brands.

 

Airboy explains a bit here:

http://www.airboytuning.com/archives/138

 

DynoDynamics Shootout modes:

http://www.airboytuning.com/archives/103

 

 

BTW - speed convert back to RPM = (MPH*final gear ratio*336)/tire height

which in my case was =(MPH*3.58*2.264*336)/24.7 (JDM ratio, 2nd gear, 215-45-17)

Tire diameter for a 215/45R17 is ~24.62 inches ~62.53cm

(I'm assuming that's what you mean and use inches since you show 24.7 in the calc)

 

Final gear ratio represented as 3.58*2.264 (JDM final drive * 2nd gear ratio?)

For me final drive is 3.083 (2.99 with new tires/wheels) and 2nd is 2.264 (2.19 now) or 3rd is 1.471 (1.43) so....

I'd use 3.083*2.19 if logging a pull in 2nd or 3.083*1.43 if logging a pull in 3rd?

Hey,

 

Yes the formula seems correct. Once your ratios and tyre size is correct it should give the proper output. I wouldn't change the final drive like that. Enter the factory final drive and factory gear ratio then use the proper tyre size and you should be good.

 

 

Edit: What are the ratios for the 2010 LGT? Is it a 5EAT?

I very much agree with what you did here! Great job JMLegacy.

I'll give it a shot with some new logs.

 

Typical combined average drive train loss on a Subaru with 5EAT or HTCVT is ~30-31% vs say 19-21% on a typical 5/6MT STI/WRX.

 

I've asked Dyno Dynamics (as an example) to account for this and create a different shootout mode for AT Subarus

(Shoot44 works well for 5/6MTs, but NOT ATs). They have done similar for other brands.

 

Airboy explains a bit here:

http://www.airboytuning.com/archives/138

 

DynoDynamics Shootout modes:

http://www.airboytuning.com/archives/103

 

 

BTW - speed convert back to RPM = (MPH*final gear ratio*336)/tire height

which in my case was =(MPH*3.58*2.264*336)/24.7 (JDM ratio, 2nd gear, 215-45-17)

Tire diameter for a 215/45R17 is ~24.62 inches ~62.53cm

(I'm assuming that's what you mean and use inches since you show 24.7 in the calc)

 

Final gear ratio represented as 3.58*2.264 (JDM final drive * 2nd gear ratio?)

For me final drive is 3.083 (2.99 with new tires/wheels) and 2nd is 2.264 (2.19 now) or 3rd is 1.471 (1.43) so....

I'd use 3.083*2.19 if logging a pull in 2nd or 3.083*1.43 if logging a pull in 3rd?

 

"Final drive" meaning diff ratio.

Mine is 3.272

Red is raw data

Blue is Speed to RPM

3rd gear pull on e85

 

http://uploads.tapatalk-cdn.com/20160512/5d815d7d0224e733b8b323190ba09846.jpg

 

heres my 3rd gear pull

 

tires are 24.97"

diff is 3.272

datalog8.00 5-10-16.csv

Hey Root, I don't know your tuning story, but something seems wrong with that log. AFR is high, timing is low, and it shows in the power output. Check the Airboy & VD output I graphed