Black02SS

iTrader: (36)

Just got my car dyno'd today for spay and had a quick question. The car made some great numbers on spray, but the car falls on its face as soon as the kit hits at 3800 rpms and then a split second later picks back up. Has anyone had any similar results with the TNT kit? Here is a link to my dyno from that run. You can also see the dip in the graph that I am refering to.

TNT Dyno
Thanks Guys!!

Here is my mod list. It would let me add it all to my sig.

2002 Black SS 6 Speed
Performance Mods: CC 224/224 .581/.581 112 LSA, TEA Stage 2 5.7L Heads, Comp Dual Springs, Chromemoly Pushrods, Titanium Retainers, Comp High Energy Lifter’s, Ferrea Valves, Ported ARE LS6 Oil Pump, SLP Lid, Mac Headers, 3” True Dual Exhaust with Dynomax Bullet’s, Walbro 255lph Inline Fuel Pump, S2 Ported/Polished TB, Moser 12 bolt w/4.11’s, Eaton Posi, 1350 Yoke, T/A Cover, B&M Ripper Shifter, Nitto 275’s
N20 Mods: TNT F1 100 hp, MSD WS, NOS Bottle Heater, TR6's

411 RWHP 379 RWTQ (N/A)
532.3 RWHP 649.2 RWTQ (N20)

VINCE

iTrader: (1)

Nice..

EVIL

i have seen tnt kits do the same thing, we never figured it out.


did you make anymore pulls? i have also seen that happen on one pull and then go away on the other.

oOoLy

Sweet

theblur98ss

iTrader: (71)

Do you have a purge? I've heard that too much fuel right off the bat mixed with too much air in the nitrous will do that.

WICKED SS

iTrader: (36)

Nice numbers,
why didnt you try the 150 shot?

The only thing I could think of is maybe your lines werent clear? If you have a purge then it would have to be something else.

Black02SS

iTrader: (36)

Thanks for the replys guys! There were 2 runs done back to back and on both runs you can see the dip in the curve. I tried changing the window switch to a different pill for the turn on and that didn't help either. I was wondering about the purge also. I ran at the track today just to see what I could get out of her, bear in mind I don't live in texas and have access to really fast tracks, me best on motor was a 12.0 @ 116 and on a 75 shot I managed a 11.5 @ 119. Both runs had almost identical 60' of 1.7's. I know I can pick up at least another tenth or two if I can figure out the dip problem. It just really falls on its face as soon as the kit kicks on now matter where you set it at. Maybe my inline fuel pump isn't enough for the spray???

Black02SS

iTrader: (36)

Well, if you look at my graphs, a 100 n20 jet and a 150 fuel jet gained me about 125 hp to the rear wheels. I don't want to press my luck to much with the stock bottom end.

bad2000ss

iTrader: (6)

Sounds to me like it is going rich for a second before the nitrous kicks in. As everyone else has said, if you don't have a purge kit, get one, because for the first second you might be spraying just vapor which will cause a rich condition. Could also be because of your big fuel jet. That big fuel jet might cause it to go rich for a second before the nitrous has a chance to catch up.

Black02SS

iTrader: (36)

I will get a purge and see if that helps. I don't think it is the fuel jet because if you notice with a smaler fuel jet, it did the same thing.

Thanks for the reply's guys!!!

bad2000ss

iTrader: (6)

Hey black02, i just looked at your dyno graph, and i did see that both the 100 and 150 jet did the same thing. Not having a purge, i bet anyone can guarantee that is the problem. You're just spraying off the vapor in the line for a second, its going rich and falling on its face. If you did back to back dyno runs on the nitrous, no more than a few minutes apart, you'd probably see a difference because the line had "purged" itself out on the first run, and the second run you wouldn't see as big of a drop if any at all.

Black02SS

iTrader: (36)

The dyno's were done back to back. You can see there is only about 7 min between the two. I called and talked to TNT about the problem, and he said the reason it is doing so is because I am running out of fuel. He also said that there is no way I should have to use the 100 n20 jet with the 150 fuel jet to richen it up. That may be the reason I gained so much from the jetting because it is running too lean.

juiSSed1172

The reason you gained so much from the jetting is because it's a TNT kit.

120+ rwhp from a "100hp" kit is very common.

Zturd

iTrader: (12)

OK mine used to do it that severe then I did the following. Raised my bottle pressure to approx 1100psi before purging. Then it may drop no lower then 1050psi for the hit. I also removed my 3800Pill and put in a 3400pill and then a 3200pill. The lower it hit the less of spike to the negative on the HP/TQ i had. I also use the 100jets on a similar cam. I put a fuel pressure gauge on and noticed this. Party because of the LS1 returnless fuel system there is a spike in fuel pressure very very quickly becuase when the fuel noid opens the rail can't keep up the pressure for a very brief moment. Thus my a/f shows a dip up towards lean when the nitrous hits and thus reduces the HP/TQ about 60RWHP approx for less then a 100rpm. I have not found out how to remove it just lesson it. It was almost a 100rwhp it would lose before. The purge may be a very small part of it but not much cause i've done my pulls with and w/o the purge being used. Didn't see a difference.
What i can't figure out is you have one of the best looking a/f curves i've seen on a nitrous car. My a/f goes from 13:1 to 14:1 for about 100rpm then drops as the car grabs for more fuel to keep up and drops it too 11:1 then comes up to 12:1 and stays then leans out a tad towards the top. Your bottle pressure will play a huge part in your a/f and hp and the dip thats all i have to tell you. Hence make sure you have a bottle warmer and consistancy is the key. My car can run identical runs back to back on the bottle as long as you keep after your bottle pressure. I get 11.41 at 123MPH with a 1.77 60ft but i have a nice track to go to near sea level. Good luck

Black02SS

iTrader: (36)

My bottle pressure is at 950 psi consistatly. I didn't want to raise it anymore then that due to the fact I didn't want to inject any more n20 then I already am. I contacted TNT on this matter and he said a fuel pump. I'll give that a try and re-dyno. I'll post my results when I get them. It won't be for awhile.

BigE

iTrader: (2)

Have you done any tuning? I'm no nitrous expert but your A:F numbers are a little lean. I think the sweet spot is around 12.5-13.0 to 1. The flat spot you're feeling is when your A:F goes damn near 14 to 1. However, the 100/100 jetting gives a very flat A:F graph. I would stick with that jetting and just lower the A:F overall. Seeing how it comes as a sudden spike I would suspect fuel delivery. I have heard that the stock fuel system can only support up to 450 RWHP. If that doesn't work, I would suggest using a MAF translator or tuning to drop the A:F by about 0.5. Like I said, I'm no expert, but looking at your numbers, I think it's worth considering.

Black02SS

iTrader: (36)

The whole point of a wet kit is so you don't have to adjust your N/A tune. I know the problem is lack of fuel. I am still on the stock fuel pump and it isn't enough. I like for my a/f to be around 11.5-11.9 while I am on the spray so the bigger pump will allow this.

Nickn20

you are quite lean for nitrous, what does your A/F look like NA?

Black02SS

iTrader: (36)

Here is a link to my n/a dyno.


Dyno

Also, if you didn't notice I have a inline fuel pump.