Headers and Dyno ?
Thread Starter
Racer
Joined: Jan 2009
Posts: 338
Likes: 43
From: Benson NC/North Myrtle Beach SC
Headers and Dyno ?
Last month I added a Vararam CAI and had a tune done. My base reading was 370RWHP and after the install and tune I had 400 RWHP. Yesterday i had Kooks 1 3/4" headers and x-pipe installed and freshened the tune up and only came out with 410 RWHP. I did pick up 20 lb's torque with the add but was really hoping for more HP. Is this typical gains for a car that has already been tuned? BTW My car is a LS3 A6 . Car Does sound Awesome at WOt though 
Melting Slicks
Joined: Jan 2013
Posts: 2,837
Likes: 41
From: Dallas Tejas
A better comparison would have been to run it at the track before and after... I'd have thought that 430whp would have been around what you should be showing though. You have cats? What exhaust? If stock exhaust do you have NPP or no? You should get a set of bullets if you don't have an exhaust yet. It'll really sound good then. 
Thread Starter
Racer
Joined: Jan 2009
Posts: 338
Likes: 43
From: Benson NC/North Myrtle Beach SC
A better comparison would have been to run it at the track before and after... I'd have thought that 430whp would have been around what you should be showing though. You have cats? What exhaust? If stock exhaust do you have NPP or no? You should get a set of bullets if you don't have an exhaust yet. It'll really sound good then.
Melting Slicks
Joined: Jan 2013
Posts: 2,837
Likes: 41
From: Dallas Tejas
Safety Car
Joined: May 2011
Posts: 3,807
Likes: 508
From: Oshawa, Ontario
bang on
Last month I added a Vararam CAI and had a tune done. My base reading was 370RWHP and after the install and tune I had 400 RWHP. Yesterday i had Kooks 1 3/4" headers and x-pipe installed and freshened the tune up and only came out with 410 RWHP. I did pick up 20 lb's torque with the add but was really hoping for more HP. Is this typical gains for a car that has already been tuned? BTW My car is a LS3 A6 . Car Does sound Awesome at WOt though
Race Director
Joined: Dec 2006
Posts: 12,389
Likes: 2,910
From: Fort Worth, Texas
Just to make sure you're comparing apples to apples both runs were corrected right? Most with headers and a tune pick up ~30rwhp depending on primary size, so your gains sound about right with the smaller primaries. Larger ones would have made more hp with a trade off of torque which I wouldn't do with an auto personally unless chasing a dyno number.
Last edited by PRE-Z06; Jan 22, 2014 at 05:49 PM.
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 26
From: Austin Texas
If the temperature, barometric pressure and humidity weren't the same the dyno wont be accurate.
The Dyno compensates for them all but it can't compensate for the cars computer pulling timing and/or richer/leaner fuel trims due to air temps, MAP & MAF readings and coolant temps.
The Dyno compensates for them all but it can't compensate for the cars computer pulling timing and/or richer/leaner fuel trims due to air temps, MAP & MAF readings and coolant temps.
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Thread Starter
Racer
Joined: Jan 2009
Posts: 338
Likes: 43
From: Benson NC/North Myrtle Beach SC
Im not sure if they were corrected or not but i would think they were..Both times the car was on the same dyno ...so i trust the numbers..was just trying to figure out why it didn't pick up the HP the headers claim to give. Temps were comparable both times it was run..nothing drastic between the 2 days
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 26
From: Austin Texas
Your original 370HP sounds right but the 400HP w/Vararam and tune is high.
Your 410HP W/Headers/Tune/Vararam is about right. I would question the 29.17" barometer vs the 30.03 barometer of the earlier run. The Dyno that is wrong is the 400HP in between.
Remember that the Vararam results won't show on a Dyno since the hood is open for all dynos and you can't get a fan to duplicate actual airflow.
Your 410HP W/Headers/Tune/Vararam is about right. I would question the 29.17" barometer vs the 30.03 barometer of the earlier run. The Dyno that is wrong is the 400HP in between.
Remember that the Vararam results won't show on a Dyno since the hood is open for all dynos and you can't get a fan to duplicate actual airflow.
Drifting
Joined: May 2012
Posts: 1,618
Likes: 105
From: Southport North Carolina
Your original 370HP sounds right but the 400HP w/Vararam and tune is high.
Your 410HP W/Headers/Tune/Vararam is about right. I would question the 29.17" barometer vs the 30.03 barometer of the earlier run. The Dyno that is wrong is the 400HP in between.
Remember that the Vararam results won't show on a Dyno since the hood is open for all dynos and you can't get a fan to duplicate actual airflow.
Your 410HP W/Headers/Tune/Vararam is about right. I would question the 29.17" barometer vs the 30.03 barometer of the earlier run. The Dyno that is wrong is the 400HP in between.
Remember that the Vararam results won't show on a Dyno since the hood is open for all dynos and you can't get a fan to duplicate actual airflow.
I also had a dyno at RPM and it seemed low. 358hp/366tq on an LS2 A6 vert w/ PTB, PIM, Kooks 1 3/4 +Xpipe, Borla Exhaust + mail order tune. But I'm running 12.3 @ 116. with 1.98 60's from an idle... I think the RPM Dyno is low. Let's test and tune at Fayettville MSP when it warns up... I bet you're in the 11's
Edit - and that was on bald run flats...
