transsam

iTrader: (5)

Clearly something is wrong. On my last dyno (more than a year ago), I put down about the same. Last time I didn't have an ls6 intake, I had a smaller cam (224 581 114) and ls1 heads. New setup has the intake, 230/235 cam, good velocity 300 cfm@.600 ls6 style heads and open headers.
On nitrous, I sprayed a 75 shot dry and only picked up just under 30 rwhp and similarly poor torque gains.
A/F ratios on both pulls were just over 12:1. Tuned slightly rich to accomidate for dry shots, but not enough to drop huge power like it did.
The car is only getting about 10 mpg around town.
Something is clearly wrong and I don't know what. Any suggestions or recommendations would really help. Thanks. BTW, if it looks bad, I plan on just junking the whole damned thing and going to a stroker setup, so it isn't the end of the world.

orangeapeel

iTrader: (18)

Even if it is not bad. You could probably part it out and get a nice shotblock setup from one of the sponsors ------>

A 408 or a 402 would be a nice choice for the kind of power you are looking to get but just were not able to acheive. Here is some manufacturers if you want to check it out.
LME
HPE
SDPC (my personal fav)
Thunder
Speed inc.
TSP
.....the list goes on.

Are you an A4 or an M6? Make sure that you don't have the dreaded Wal-Mart bag stuck to your lid and around the bottom of the filter. I had the same problem. Gas mileage cut in half and had **** for power as well.

Crazy Man

iTrader: (6)

I dont know man have you done a compression check?

goober35

iTrader: (1)

sounds like you got your self some bad rings or some bent vavles. Do a comprettion test. If it you dont have any to very low compresion i would say it is a vavle. If it is high and then bleeds off you got some bad rings.

PREDATOR-Z

12.0:1 AFR is way too rich, like waaayy too rich.
I run 12.6 with a 150 dry (98 octane fuel), and I'm still too rich.

If you ran that 12.0:1 for a long time, you could have washed your cylinders and damaged them, but that is just speculation right now.

You should wideband dyno your car again and find optimum AFR for NA then back it up .1 or .2 (93 octane) and do the same for WOT timing. If let us say your car makes peak power at 28* and 29/30/31 does not increase power, then back it up to 27*.

Also might want to do leakdown /compression tests. Just to know if you have any mechanical damage.

LS1 BU

iTrader: (13)

I would start with a leakdown and compression test. If that is ok. I would make sure the cam is installed right. Do you have a dyno graph to look at??