BigBirdLS1

Hey guys I've got a question and could use some advice as to what might/or not be wrong with my car. The car is in sig. When I was a cam only car with a 100 shot I gained 95rwhp and 116rwtq. I have since added PRC 2.5 5.3 heads 61cc chambers and I used stock oem headgaskets. With everything being the same except for the heads why did I only pick up 78rwhp and 84rwtq. It was tuned by the same tuner on the same dyno. I'm happy with the numbers I got but just wondering if I need to have the tune looked at.

Phantom

iTrader: (16)

probably way to rich on the jetting, or you don't have 100 jets in there

BigBirdLS1

I forgot its a 100 dry shot sprayed before the MAF. I double checked and according to the mfg. website I have the 100 jet in there. I have the stock MAF stock TB and stock LS6 manifold. Am I simply pushing too much air through it and it can't keep up.

karpetcm

iTrader: (2)

It being a dry system the orientation of the nozzle could've slightly changed, also if you havent make sure your MAF is clean with MAF cleaner. Your nitrous solenoid could also be sticking or not working as it should, like it did before. Otherwise its hard to say to be honest.

Phantom

iTrader: (16)

Could be adding too much fuel, subtracting too much timing, fuel system may not be able to keep up and it's real lean...have you seen what the a/f and timing is doing when you spray it?

BigBirdLS1

I understand the orientation of the nozzle it might have been different. I honestly couldn't tell you if the orientation had changed or not. If it did does it really make that much of a difference. I looked at the MAF and it is CLEAN plus the dyno pulls the A/F never was irratic it was pretty much constant through the entire pull.

Phantom

iTrader: (16)

but if it was constantly 10.xx then it was really fat and there the missing 20+ hp. What about the timing?

BigBirdLS1

As far as fuel I have 36lb injectors and a Walbro 255 pump. The tuner did say that right at soon as he hit the spray that it pulled 1.3 degrees of timing. He said it did that because of the air that was in the line before the nitrous got there. I personally did not see what the timing was set at or the a/f.

My tuner is well known in my area for tuning all kinds of LS motors and I trust him in his abilities and that he would not intentionally do/not do something that could hurt my engine. His reputation is everything to him so a car that he messed up will not be a good reflection on him. Thanks for your help I am still open to ideas.

karpetcm

iTrader: (2)

In my experience the orientation of the nozzle made a big difference. In your case probably not since you have the experience and know how to get it oriented. Its really hard to pinpoint it honestly, i was going to say Phantom made some good points but if your A/F is good and steady not sure what it could be.

Phantom

iTrader: (16)

I'm in no way bashing your tuner. You just gave us very limited info so I'm just throwing out possibilities.

Check your nitrous solenoid. It may need rebuilt. If the bottle has been left on a lot then then the plunger could have a dimple in it which would cost you horsepower.

If you have a pill for 100shot, then it should make atleast 100hp over N/A. If not, there is something not quite right. You have a bunch of leads to track down now. Let us know what you find

Phantom

iTrader: (16)

I'm going to go with, it's too fat which is why it doesn't make the full 100hp.

The cause will have to be determined by the user. Nozzle orientation, plunger in solenoid, pcm adding too much fuel. The a/f can be steady, but be steady rich and kill power

BigBirdLS1

Thanks Phantom I appreciate your help. I honestly don't know alot of the details about the tune and what it looked like because I was not there when it was done. My tuner did tell me that it pulled 1.3 degrees of timing as soon as he hit the spray. He told me that it was because of the air that was in the line before the nitrous got there. Could that have caused me HP. The nitrous kit in all truth hasn't been used very much no more than 2 10 lb. bottles. It is however 3-4 yrs old. Maybe I should look at the solenoid like you said or possibly the wiring.

Just a few thoughts on my end:
1. Is it possible that I am over flowing the amount of air my TB and ls6 manifold can push since I added the heads and kept the spray.
2. If my bottle was say open 90% of the way instead of the for sure 100% could that have cost it. I.E. I opened it all the way till it wouldn't turn anymore then say gave it a 1/4 turn back closed.

sweet99ss

iTrader: (41)

Did you torque your lug nuts in a star pattern?

BigBirdLS1

Not sure where you are going with this but...i'm gonna guess your talking about the wheels/tires and yeah they were torqued down in a star pattern. I did it myself 2 yrs ago.

BigBirdLS1

I completely understand the rich a/f killing power. But on the same tune...I run N/A and spray on the same tune it picked up 38hp and 30tq from the head swap. If it was pig rich I doubt my N/A gains would be that good. I think you are on to something about the solenoid though it really seems as its the logical answer to me. I'll run it and use my butt as the gauge then change the noid and see it I feel a difference.