It feels like 150 horsepower but the dealer says it's fine.
I have 7000 miles on and know how it should run.
What do I do next?
Any SS experts in the Phila area?

Fuel air ratio now goes to 18/max at constant throttle position.
Spark advance goes to 40 at constant throttle position.

 

any tune or mods?

 

no mods or tunes

 

take it to a dyno if u can...

 

Should the dealer cover that cost?

 

100% unlikley

 

can I expect the dealer to have a dyno?

 

that'd be cool but i HIGHLY doubt it

 

Dealers don't have dynos, but I'd see what you have in your area. Plan on putting up the costs if you really are sure it's losing power. If you have proof that it's putting out less power than it's suppose to and it's under warranty, you can go legal and get them to fix the problem.

 

Sounds about right on the timing, your afr I though should be stoich, which isn't 18

 

minor clogged cat would do it and wont set any codes ?I work fo a gm dealer/ive seen it but not on a tc yet

 

The stock COT should take care of that though.

 

What are you using to get those readings? Your timing should be around 10 degrees at wot and afr around 12.8-14:1 depending on rpm.

 

I am using the A pillar computer.

 

long drillbit and a makita

 

Turn your rpd to the ignition screen and do a couple pulls. If you are seeing knock then that is where your power is going. At lower rpms I see as much as 4* of knock retard and it tappers off to 0* by about 5500rpm. As the knock retard goes away I can feel the power come back.

Not sure why the hell im knocking like that on a stock car running 93 in the tank, but supposedly the lnf sees as much as 6* of knock in stock form

 

The RPD's got a calculated HP/tq page too.. I'd be interested in knowing what it "thinks" it's actually making.

 

ive never seen any knock in my 11,600 miles on stock or Superchips

 

^x2 I've never seen knock for as long as I've owned the car (~18000 miles). Maybe some of that has to do with the aftermarket IC though before it got to be Summer... don't know.

 

Weird, the ecm is simply not programmed to run that afr and timing at wot. If there was something wrong it would pull timing/close the throttle and limit boost.
How much boost are you seeing at wot?

 

I'll check the boost reading when I get the car back - its still a the dealer. No one there knows anything about our SS cars.

So what do you guys think about the fuel air ratio at 18 when the gas pedal is neutral? It never did that before. Do GM offer any specs on what these gauges should read?

 

You will only read 18 if you let off the gas while in 5th gear or you're letting the engine decelerate you and you're above like 2200 RPM. If you're getting that while you're cruising and on the gas, even slightly, then something's up. You should be reading somewhere between 14s and maybe 15 (max) probably during light throttle/cruise. There's no way you should be getting 18 though unless you're getting the fuel cutoff because you're engine braking.

I don't know what you mean about neutral though, unless you mean with your foot off the gas, in which case it is normal. It basically means that you're not injecting any fuel and it also cools the engine a bit, since it's basically windmilling your engine. Check your fuel pressure on the RPD. You'll notice that it slowly rises while your AFR is 18 and drops drops for a second after you start slightly getting on the gas.

The guages should read what the stock tune tells the car to do. I don't have a copy of the stock tune though to give you an idea, but others may be able to offer assistance.

 

It is because the midrange WOT A/F is commanded at 13.6 stock which is too lean.

 

Has anybody taken notice of the spart advance numbers? Mine now reads 45 when I'm just steadily cruising along - I know this is not right.

Does anybody know what these gauges should be reading according to GM?

 

at partial throttle, the spark advance can be in the 30s and 40s.

We can't really diagnose if there is a problem with a log of the car or a dyno graph.