06-28-2017, 11:00 PM | #1 |
Drippin' Wet Auto Detail
|
Heat causes loss of 80rwhp???
Hi all,
First off, I am not an expert when it comes to dynos and numbers, just understand the basics. I completed a custom NPP exhaust on my SS recently eliminating the secondary cats and using magnaflow straight through mufflers. Before the exhaust project, the shop threw the car on their dyno and it made 380rwhp. Now (2 months later) I brought it back to them for another run. Now I know different factors make a difference, but after 2 runs, it topped out at 302rwhp. Temperature difference then from now was 82 degrees then and 105 today. The shop is stating that the temperature change caused this drop but this seems quite ridiculous. What could be the cause of this massive drop? Can outside temp really affect that much? Hoping someone with some more knowledge can chime in on this. Thanks! |
06-28-2017, 11:25 PM | #2 |
Drives: 2016 Chevy Camaro Join Date: Jun 2016
Location: Dallas,Tx
Posts: 259
|
VERY possible too lose a few ponies do to heat soak but it sounds like something is wrong..
|
06-29-2017, 06:31 AM | #3 |
Drives: '17 2SS, NGM, MRC, DPP; '19 F150 Join Date: Apr 2017
Location: Katy (Houston), TX
Posts: 440
|
So, that would say take it back when it's like 40F and you'll see 500hp... total BS! From just the temperature change alone (assuming no other changes, and dyno runs done similarly), the HP difference would not even be 8hp, let alone 80hp!
Heat soak would be another matter, but 80hp is still absurd! |
06-29-2017, 06:52 AM | #4 |
Drives: 2016 SS Join Date: Jan 2016
Location: PHOENIX
Posts: 156
|
your car was heat soak, this is the same trick some shop will do to show a low # before any mods, after mods will show some crazy gain....lol you should be around 400rwhp WITHOUT heat soak.
|
06-29-2017, 08:25 AM | #5 |
Drives: 2023 2SS Convertible Join Date: May 2009
Location: Metro Detroit
Posts: 1,102
|
Did they give you corrected numbers? I thought they could punch something in that accounted for the temperature and barometric pressure. It might even say it on your graph. If both runs are corrected, then you have something wrong.
-Geoff
__________________
'12 2SS RS Convertible - Traded in.
'16 2SS Convertible - White on white, mag-ride, NPP, nav. Sold! '23 2SS Convertible -Same as above except orange. |
06-29-2017, 09:43 AM | #6 | |
Drippin' Wet Auto Detail
|
Quote:
They said we will have to try again when the weather conditions are similar to what they were the first time |
|
06-29-2017, 10:51 AM | #7 |
Drippin' Wet Auto Detail
|
So obviously there is an issue, would you lean on the side of the car or the shop doing the dyno incorrectly?
|
06-29-2017, 12:34 PM | #8 |
雪の玉
Drives: '22 Z71 RST Silverado Join Date: Feb 2011
Location: South
Posts: 3,415
|
Yes temp, humidity, barometric pressure and altitude do effect the numbers, loosing 10 probably maybe a little bit more given the 23 degree increase in temp, but 80hp that seems like a lot.
Is your car is running the same as before? Runs smooth ?, getting similar gas mileage ?, oil life % ?, acceleration feel the same?, etc.??? Maybe there's an issue with their dyno and/or software ??? If it's possible maybe you can go to another place to get a 2nd opinion (and get corrected numbers). that may help narrow down if issue is with your car or their dyno. Last edited by nancygrl; 06-29-2017 at 02:09 PM. |
06-29-2017, 01:57 PM | #9 |
Drives: 2017 Camaro SS Join Date: Jul 2016
Location: Altoona Iowa
Posts: 90
|
Ask them to turn on SAE for both runs (or the older STP) correction factor and print them out. Both of these will correct for weather and give you a more consistent difference between each run.
(I've been able to do this with 3 different dyno shops)
__________________
2017 2SS Black NPP A8 - 422 HP 427 TQ
|
06-29-2017, 02:57 PM | #10 | |
Drippin' Wet Auto Detail
|
Quote:
It runs smooth, gas mileage is almost identical, oil change actually happened in between dynos, acceleration seems the same |
|
06-29-2017, 03:20 PM | #11 |
Drives: HB 2SS Join Date: Apr 2017
Location: Vancouver, BC
Posts: 518
|
Something must have been off with the dyno then. Maybe it needed a re-calibration? Or someone fudged the settings up. Cause you would feel the 80rwhp difference in power when you stomp on it.
|
06-29-2017, 03:28 PM | #12 | |
雪の玉
Drives: '22 Z71 RST Silverado Join Date: Feb 2011
Location: South
Posts: 3,415
|
Quote:
Even the difference between the different "correction factors" STD vs SAE-J607 vs SAE-J1349 wouldn't account for 80hp difference, 10-15 at best. I'd have to lean towards some setting or something not input correctly. |
|
06-29-2017, 03:51 PM | #13 | |
Drippin' Wet Auto Detail
|
Quote:
|
|
06-29-2017, 09:58 PM | #14 |
Drives: 2017 Hyper Blue 1LE Join Date: Dec 2016
Location: Tampa
Posts: 579
|
Instead of focusing on dyno numbers, have you noticed an 80+ hp loss? You would.
|
|
|
Post Reply
|
|
|