omore001

iTrader: (1)

I had my car dyno'ed recently along with another LS1 Trans am. My car has a stock block and stock internals LS1 running with TR6 plugs gapped @ 33, Alluminum intake manifold, (after cracking the plastic one on nitrous), intake, catless catback, (I had a bad clutch at the time of the dyno but i dont think it makes a difference.) I made 281 RWHP and 330 TRQ. I started leaning out badly after 4500 RPM, the A/F ratio went from 12.0 @ 2000-4400 and SPIKED to 17.9 @ 4500+ and stayed there. Then I did a run on a 150 shot of nitrous numbers were 406 RWHP and 461 TRQ. This is through an NX wet kit. The A/F ratio on this run stayed at 11.9 up to 5300 RPM and then spiked to 16 above that engine speed.

I would like to know what is going on. I can only think of a HORRIBLE stock tuning, or some kind of fuel malfunction most probably the stock fuel pump. Why is my car running better on nitrous and leaning out so horribly N/A? PLEASE HELP.

Magnet

iTrader: (36)

well of course the aluminum intake in hurting you...but also the cat is probly playin games with your computer...did you throw an SES light?? i would also say that you probly need a tune...

omore001

iTrader: (1)

yes I have an SES light for the cats but as I was told the rear O2 sensors do nothing to the engine performance. I doubt changing to an alluminum manifold is going to kill 24 RWHP, (friend with similar mods made 305 RWHP N/A). I want to get a tune but not before I decide if I want to do a heads and cam swap or go FI. would be a waste of $$$ if I have to retune right after. Should I buy HP tuners and try to tune myself?

ls1wannabe

iTrader: (2)

I would say getting tuning software is not a bad idea at all.

Billiumss

iTrader: (11)

Get rid of that POS intake. They have a lot of heat soak and don't seal that well.

Maybe at a certain RPM the intake won't seal right and draws in fresh air to screw your A/F reading.

What does the dyno graph look like, post it.......

chris77

281 to the wheels on a stock car is not bad at all also like said before get rid of that intake(heat soke is a bi**h) you are a bit short on the NO2 pull. is it a dry or wet shot. all you probly need is a good tune .

omore001

iTrader: (1)

I know the intake robs some hp but 24 RWHP sounds like too much. I doubt the intake is drawing air from the sides. I cracked the plastic LS6 intake manifold so it made me want to go with something stronger like allunimun weiand in case i go FI later on. Should have run much leaner on the N20 wet shot if the intake had a vacuum leak. I got weiands upgraded manifold gasket and torqued the manifold down to spec. The engine started leaning out north or 4500 RPM. I'm guessing either I have a faulty fuel pump or in just in terrible need of a tune. I will have the fuel pressure checked soon. And I am highly considering HP tuners. I will try and scan the dyno graphs tonight.

ExceSSive

iTrader: (13)

I don't think you should run lean with a wet kit, that is the whole purpose of the wet kit unless your fuel pump is not getting enough voltage or some other problem