AR headers, dip in Dyno curves?
Thread Starter
Racer
Joined: Mar 2007
Posts: 471
Likes: 2
From: Hillsboro MO
AR headers, dip in Dyno curves?
I have a set of AR 1 7/8" headers on my 01 zO6. I noticed a slight dip in the torque curve on all of my dynos around 3500-4000 RPM and cant seem to tune it out. I thought i remember reading somewhere that this was a common thing with these headers. Does anyone have any charts I can see with similar results?
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
Unless your engine is extensively modified with an increase in displacement, among other things, you are running too large a primary diameter on your header pipes. You should have used the 1 3/4" diameter headers.
Safety Car
Joined: Jun 2006
Posts: 3,787
Likes: 2
From: Wildomar CA
all long tubes I've seen have a slight dip that cannot be tuned out, look at the dyno sheet in my Sig with LG Pro's
Thread Starter
Racer
Joined: Mar 2007
Posts: 471
Likes: 2
From: Hillsboro MO
I am heavily modded, big heads/cam, 13:1 SCR 8.9 DCR, big dry shot. I am not knocking the quality of the headers by all means, just comparing some characteristics ive noticed and want to see how to get rid of it. I didnt have this prob with the LG's i had on it prior, even though they were 1 3/4.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I believe the 2nd harmonic of the intake is at 4K, that might be what you are seeing. As you boost the intake/exhaust capability of the motor this will start showing up according to what I have been told by someone who does a lot of R&D for GM.
