Back from the dyno and disappointed

[Billy Mild]

After all the rushing around I have done this past week the ZR1 was able to make its appearance to the dyno. Last year I had the car dyno'd and it made the best of 330 WHP. The only mods at the time were Borla Axle back exhaust, center resonator delete, and airlid opened up with KN filter.

This past week I have installed a chip from Haibeck with mods to support the following, SW headers, high flow cats(C6z06), and a new x pipe midway through the exhaust. The car put down 334 WHP as it's best run. To say the least I am very disappointed with all the mods I only gained 4 whp. I will say that it's 90 degrees outside and really humid. The dyno operator told me I am running way too rich. It's in the low 11's for AFR. He said it should be 12.5-12.8 for an NA application. Last year it was cooler outside. The dyno is at the same shop so that can't be any different as far as correction factors go.

Any ideas WTF is going on?

Video below: https://youtu.be/bCJuFdR_M2c

[efnfast]

Did Marc know you were doing headers when he did your chip? Running rich will cost you a lot of hp.

[Billy Mild]

Yes I told him about all my mods. He enabled anti backfire mode and extra fueling for the headers.

Sounds like I may need less fuel.

Sent from my Nexus 6 using ZR-1 Net Registry mobile app

[Billy Mild]

I have attached the dyno runs. The one when I was stock all I had was 3.73 gears and a crappy "tune" and Borla axleback with center resonator delete. The chip looked stock but who knows.

STOCK with center resonator delete and Borla Axleback


SW Headers, C6Z06 cats, 3" exhaust with x-pipe, Borla Axleback, Haibeck TOON

[efnfast]

Headers, exhaust, retune, took me from 311 to 353 RWHP.
Something is wrong if you only had 4 hp gain

[tpepmeie]

Weather like that can play a big role in the results, despite the correction factors. Hot, sticky air seems to really hurt the performance in these engines. The bad air will also show richer air-fuel ratio than you'd see on a cool, dense day. I'd look for better weather, and try again.

[Billy Mild]

That is exactly why I made this post. I have new O2 sensors, air filter is clean, spark plugs only have a few thousand miles on them.

The temp today was 20 degrees hotter than the last time I dyno'd the car and humidity was less, but that would only account for maybe 5-10 WHP I think. Would a computer reset help at all? What could be causing something like this?

[-=Jeff=-]

I saw you have C6Z06 cats listed.. where did you find them at? were they a reasonable price?

[Billy Mild]

Originally Posted by -=Jeff=-

I saw you have C6Z06 cats listed.. where did you find them at? were they a reasonable price?

http://zr1.net/forum/showthread.php?...hlight=exhaust

I followed this thread about the cats. I purchased them used off of Corvette Forum for around $200. They are kind of heavy so shipping is what added so much money.

[XfireZ51]

Originally Posted by Billy Mild

http://zr1.net/forum/showthread.php?...hlight=exhaust

I followed this thread about the cats. I purchased them used off of Corvette Forum for around $200. They are kind of heavy so shipping is what added so much money.

Looks like your last run was your best run. What was the coolant temp for these runs? You should also ask them to use SAE correction and provide a graph using rpm instead of mph. In fact, I always request the run file so I can look at it on my own laptop.
And yes a leaner AFR will make a difference. Any change to timing?

**sorry bout that. I see the rpm scale on the other graphs.