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my dyno result - v2 + borla

3K views 28 replies 11 participants last post by  Jinx32 
#1 ·
Just had my dyno done with socal group dyno day.. three run for $40... not bad..

03 Accord Coupe EX-L V6 AUTO, Performance mod - v2, borla, always 93 octane gas

Condition - 96.52f to 97.51f, 28.76 in-Hg, 10% humidity

1st - 190.24hp 156.46tq
2nd - 186.40hp 153.43tq
3rd 185.95hp 153.45tq

i was hoping for more.... but oh well.. i just hope the heat didn't made ecu retarded the timing.. being trying to find a base dyno to compare with..

edit: just realized i didn't make nearly as much as tov's baseline dyno?!? what's wrong... :cry: especially the tq is way way way offf... tov dyno - http://sohc.vtec.net/article_files/58735/03accordexv6_dyno.jpg
 
#2 ·
hey brex... . hmm.. those numbers are ok for 240 hp Stock Auto... 20% transmission loss on average gives you..192 hp at the wheels and about 170 lb-ft torque.. and Thats STOCK... so i think your torque numbers are a little low... and the weird part is that you have the AEM V2 and the Borla.... weird....
hope they set up the dyno parameters correctly..... And the numbers you posted I assume are SAE corrected.....
I think you saw my dyno run... stock vs V2 + Greddy evo 2 ( 6 speed manual).... i was putting down 225 whp.. and about 200.1 lb-ft torque... (after ECU reset, before ECU reset --- 219 whp and 195 lb-ft torque.)....
I say.. go to another dyno.. and do it again.. to see if the dyno machines are off...
And you have a very valid point about being super hot and the ECU retarding timing due to heat soak... hope that before they ran your car, they let it cool down and had the fan running during the dyno...
weird anyway...
hope you have the chance to dyno again...
 
#4 ·
You guys need to hook up OBD-II scanners to monitor the timing and coolant temp during runs and then compare with a cold day to confirm timing retard theories. Don't jump to conclusions unless you have the evidence to back it up.

As for the VTEC.net numbers, why hasn't even a single person been able to match them? On one hand I've done a bunch of regression analysis on the dynos with CarTest software and those numbers are very consistent with what the car will do at the tracks. Repeated 15.0's @ 92-93 mph with 2.3x 60' times. So I believe VTEC.net's numbers are accurate. But at the same time, why hasn't anybody been able to match them?

This has been stumping me for awhile. :gotme:

brex - I plugged your numbers into CarTest software and it says 15.56 @ 89.9 mph. You haven't been to a track with your car have you? If so I can take your timeslip and try to see what sort of power is required in the software model to match your times. It'd help in determining if the dyno is reading a bit low perhaps. How were other cars dynoing? Were they lower than expected also? I know there's a dyno around my area that reads a good 10-20 whp/wtq lower than normal for some reason.
 
#5 ·
yeah.. it was an option for $25 more to monitor a/f ratio but i didn't opt for it.. i shoulda done that.. i assume the graph and figures are SAE correctd (it stated SAE: 1.05)...

steve, i haven't run at track before.. there are couple 7gen 4bangers running as well.. i will get their numbers and compare to tov's number see if they're running low as well..

now here is one possibility i just thought of... could the dyno guy run my car in the wrong gear and didn't realized that? i mean cuz my car is in KM reading.. he prob didn't realize that and just run it at 2nd gear based on the speed (which he thought is in mph and thus 3rd gear?)..
 
#6 ·
dynoing in 2nd vs 3rd will make a difference. In 2nd there's higher inertial parasitics, so more of the engine's power is being used to accelerate the engine and drivetrain itself and therefore less of the engine's power will actually make it to the wheels.

BTW, was your A/C on or off? :D
 
#8 ·
ok... back from my testing on freeway.. my 2nd gear tops out around 125km/h.. and third at 180km/h... so i am 95% sure that the dyno was done in the wrong gear.....

steve.. is it possilbe to calculate what hp/tq i will make in 3rd if above # is for 2nd?
 
#9 · (Edited)
SteVTEC said:
As for the VTEC.net numbers, why hasn't even a single person been able to match them? On one hand I've done a bunch of regression analysis on the dynos with CarTest software and those numbers are very consistent with what the car will do at the tracks. Repeated 15.0's @ 92-93 mph with 2.3x 60' times. So I believe VTEC.net's numbers are accurate. But at the same time, why hasn't anybody been able to match them?

This has been stumping me for awhile. :gotme:

How were other cars dynoing? Were they lower than expected also? I know there's a dyno around my area that reads a good 10-20 whp/wtq lower than normal for some reason.
dyno for james (is this outersquare?).. i4 auto, no mod - best 127.71hp 124.43tq



also very far off from tov's dyno.. http://sohc.vtec.net/article_files/80004/03accord2.4dyno.gif

:gotme:
 
#10 ·
Careful running on a different dyno. There are different types and comparing numbers from different ones, is inconclusive.

Sounds like you found the issue with them running in 2nd gear. I would be interested to see what any other auto-V6's ran at the same place. Any way to find out?
 
#11 ·
#13 ·
chinoamigo said:
would his 19" have anything to do with it?
Oh, I missed that on brex. Does outersquare have 19's too?

19's = heavier (in most cases) and much more weight at the outside and therefore a greater moment of inertia. More inertia = more load on the engine during acceleration and therefore less power gets to the wheels.
 
#15 ·
brex said:
ok... back from my testing on freeway.. my 2nd gear tops out around 125km/h.. and third at 180km/h... so i am 95% sure that the dyno was done in the wrong gear.....

steve.. is it possilbe to calculate what hp/tq i will make in 3rd if above # is for 2nd?
Dynoing in 2nd gear is still fine as long as you do all of your other dynos in 2nd for consistency.

Yes, there is a way to reverse calculate (or at least make a good guess at) what your numbers "might" have been in 3rd gear. There was an excellent paper published at the SAE by the Southwest Research Institute that looked at comparing SAE J1349 rated NET power vs what you get on chassis inertia dynos like the Dynojet 248C.

2002-01-0887 : Listening to the Voice of the Customer: Inertia Dyno Horsepower Versus Oem-Rated Net Horsepower

I just reviewed it. According to that, the static (no acceleration) efficiency of an automatic transmission (torque converter unlocked) is about 87.5%. After inertial effects are accounted for in 3rd gear the overall efficiency drops to about 78% which is about what you'll see on a Dynojet 248C with an automatic. So inertial components are about 10%. Since 2nd gear is 50% shorter than 3rd, that means your acceleration would have been about 50% stronger in 2nd, and hence a 50% increase in the inertial component. So maybe 15% total inertial component instead of 10%. That would have theoretically made your total driveline efficiency at around 73%.

So in theory (take like a grain of salt), 190 whp / 156 wtq becomes 199 whp and 163 wtq.

BTW, that SAE white paper is definitely worth the $12 I paid for it. :)
 
#16 · (Edited)
chinoamigo said:
his 19s are 18 lbs + tires (if i remember correctly) so i dont know the gross weight..
yeah.. even tho its light.. it will still be effected by "moment of inertia" more than stock 16" wheel... since there is more weight on the outside of the circle..

(tho i certainly kick ass on other 19"s or maybe 18's too.. hehehehe.. :hide:
 
#17 · (Edited)
SteVTEC said:
Well that one is easy. That's an automatic vs the TOV dyno which was a manual. 15-17% inertial parasitics for a manual vs 22% or so for an automatic.
oh.. didn't realized it is manual.. my bad.. :p

luckly. .we do have tim's car to compare with.. (he is a coupe instead of sedan).. and he is i4 manual too, with no performance mod..

looks like the number is much closer on this one..



guess it is just me.... sigh..
 
#18 · (Edited)
03Accord said:
Careful running on a different dyno. There are different types and comparing numbers from different ones, is inconclusive.

Sounds like you found the issue with them running in 2nd gear. I would be interested to see what any other auto-V6's ran at the same place. Any way to find out?
i am the only 7genner v6 running.. there are few 6genner run on the same day too.. all pix and result can be seen here..

http://www.v6performance.net/forums/showthread.php?t=33379
http://www.v6performance.net/forums/showthread.php?t=33380
http://www.v6performance.net/forums/showthread.php?t=33381

not famalier with 6gen numbers.. maybe someone can comment on it to see if this shop does produce lower than average dyno numbers..
 
#19 · (Edited)
SteVTEC said:
Dynoing in 2nd gear is still fine as long as you do all of your other dynos in 2nd for consistency.

Yes, there is a way to reverse calculate (or at least make a good guess at) what your numbers "might" have been in 3rd gear. There was an excellent paper published at the SAE by the Southwest Research Institute that looked at comparing SAE J1349 rated NET power vs what you get on chassis inertia dynos like the Dynojet 248C.

2002-01-0887 : Listening to the Voice of the Customer: Inertia Dyno Horsepower Versus Oem-Rated Net Horsepower

I just reviewed it. According to that, the static (no acceleration) efficiency of an automatic transmission (torque converter unlocked) is about 87.5%. After inertial effects are accounted for in 3rd gear the overall efficiency drops to about 78% which is about what you'll see on a Dynojet 248C with an automatic. So inertial components are about 10%. Since 2nd gear is 50% shorter than 3rd, that means your acceleration would have been about 50% stronger in 2nd, and hence a 50% increase in the inertial component. So maybe 15% total inertial component instead of 10%. That would have theoretically made your total driveline efficiency at around 73%.

So in theory (take like a grain of salt), 190 whp / 156 wtq becomes 199 whp and 163 wtq.

BTW, that SAE white paper is definitely worth the $12 I paid for it. :)
nice.. :up: i know u would make us proud.. hehehe.. :hide:

the number still fall short what i hope for and tq is still far below even base line dyno.. :( i guess i won't be really satisfied until i go back for another dyno in 3rd gear..
 
#20 ·
brex said:
oh.. didn't realized it is manual.. my bad.. :p

luckly. .we do have tim's car to compare with.. (he is a coupe instead of sedan).. and he is i4 manual too, with no performance mod..

looks like the number is much closer on this one..
http://pic16.picturetrail.com/VOL645/2417286/4772198/60356123.jpg[/IMG]
http://pic16.picturetrail.com/VOL645/2417286/4772198/60356129.jpg[/IMG]

guess it is just me.... sigh..
If his car is stock then that pretty much matches what VTEC.net got for theirs.
 
#21 ·
brex said:
nice.. :up: i know u would make us proud.. hehehe.. :hide:

the number still fall short what i hope for and tq is still far below even base line dyno.. :( i guess i won't be really satisfied until i go back for another dyno in 3rd gear..
Well there's still a few unanswered questions.

First off you don't have a baseline dyno, do you? For best accuracy you need to do baseline and modded dynos on the same dyno. And if you go to the track and pull some high-14's that shows you're making better power than stock no matter what a dyno says. For all you know your car could be fine but the ECU might have gotten some knock retard and put the engine back on the regular (safe) timing map. I guess according to that one post if there's any knock retard the ECU will knock the timing back for a whole 300 miles before it'll readvance it again (search username "Montoya" where he pwn3d me :D). If it was over 90F, I wouldn't be surprised if that's what happened. The SAE correction will account for the high temps, but not extreme heat soak, nor will it account for timing retard. It assumes that the engine is still making the most power that it can given conditions, but that changes with extreme heat soak and timing retard.

Still waiting for somebody to put together a good full picture of the timing mapping on a 7g via an OBD-II scanner.
 
#23 ·
One of the downpoints of that day was that not enough v6 accords went on the dyno. I would have wanted atleast 2 more 7th gen v6 accords (manual or auto, doesnt matter) and maybe 2 6th gen av6s to run, but a bunch of 4 bangers showed up (me being one of them) I know the temp was horrible, but the guy said all the autos run in 2nd gear and he said it doesn't deviate the numbers as long as done right. He also did tell me that brex's wheels rob about 8 hp to the wheels and a few lbs of torque too....
 
#25 ·
Unichp did a base dyno with stock intake and exhaust.. (with same 19" wheel)... i am still waiting for them to email it to me... it would be funny if base dyno actually shown even better #.. :p

In any case.. I am not really worried about this dyno anymore.. eventually i will still go back to Unichip to do individual staged dyno.. and that would be a lot more accurate than this..
 
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