CrawlinWS6

iTrader: (41)

I went to the track over the weekend to attempt a new PB! I started out bad, because is was over 95degrees .

Here is a summary of my set-up.

T-rex cam
Fast 90/90
42lb injectors
Fast rails
Yank ss4000
NX wet kit (150 jets)
3.73's


So my first pass on the hose, was 12.9 with a 2.4 60ft, (28x10 sportsman's) did a burn out down the whole track!
Problem on this pass, (I thought my n2o pressure gauge was screwed, so I did not bother to check it, because I did not have the bottle heater on. After that run, I realized the psi was over 1600lbs. I got lucky as hell nothing broke!
So between the 300ft burnout, heat. And I felt the n2o spraying thru the converter.

After I put the slicks on the car. I ran a 11.4 @ 116mph with a 1.57 60ft. NOw here is the problem. I ran a 11.02 @ 120 mph last year with a 1.57 60ft, with a 230x224 (rather then the t-rex), stock injectors, rails, intake and a 3500 stall.

THe car was not shifting till about 6800 rpms, and I was traping at around the same rpm. As the rpm climbed the car sounded like it was sputting kinda. My only guess is that I was blowing thru the converter. My window switch is set up from 3000 to 6000 activation

What would you suggest in doing to fix this?

A) Change rear gears!
B) Lower the activation from 6000 to maybe 5600
C) Lower the shot to (100shot)
D) Get a smaller converter.

I would like to leave the converter in. So that would be my last option!

tektrans

iTrader: (23)

1600 psi, coulda bee running a little lean plus that was after the run so who knows how high it was before. 95 degrees didn't help either. I wouldn't change anything yet until you get a clean pass with correct bottle pressure.

Pro Stock John

iTrader: (34)

So you went 11.4@116 on the gas?

CrawlinWS6

iTrader: (41)

I corrected the bottle pressure. After I put the slicks on. I dropped it to 1000 psi. Trust me I did not want it to be 1600+psi. I did do another pass ay 100psi and I went 11.4. But that is 4 tenths slower then I went when I had the 3500 stall, and over 50 less rwhp.

So with the new 4000 stall and 50 more rwhp. I ran the 11.4 I know it was hot. But if felt like the car was surging at top end. Like it was blowing through the converter.

However, running n/a I did drop 3tenths, and there is alot more in it, because of the 95+ degree weather and the 1.69 60ft. So this problem is just on the hose!

CrawlinWS6

iTrader: (41)

Yes, sure!

93LS1RX7

iTrader: (8)

Well you are wasting 800 rpm off the bottle. Raise the limiter to 7000 and spray it to 6800.

How much nitrous was in the bottle? Is the bottle mounted properly? Do you have a FPSS?

The "surging" you were feeling wasnt the car blowing through the converter. That would just make the car rev to fast (Almost like a slipping clucth on a manual). Sounds like you were running out of nitrous and the car was stumbling.

I wouldnt do any of the suggestions you made. You need to figure out the surging and it isnt from blowing through the converter or having the cutoff at 6000 rpm.

I had a similar setup as you 2 years ago and without the Fast 90/90 setup, on stock manifolds and a 100 shot I was running 10.78@127

CrawlinWS6

iTrader: (41)

It is a 15lb bottle and it was only down a lb. I do not have a fpss.But damn spraying it up to 6800 is

93LS1RX7

iTrader: (8)

You only used 1lb of nitrous on a 150 shot over the course of 2 passes????

Sounds like your nitrous solenoid isnt opening or you have junk in the line.

My motor was bone stock other than the cam and an oil pump and I spun it to 7200 spraying to 7000.

CrawlinWS6

iTrader: (41)

Let me correct myself. I went to the track with the bottle only being down 1 lbs. I made the one pass with the psi being over 1600, and then made the second pass with the psi being 1000. (I had to use an icebag too cool it down). The psi in the bottle only dropped to 900psi after the second run. So there was more than enough n2o in the tank.

So your saying pull the 6000 pill, and put in the 6800, and raise the rev to 7000. Correct me if I am wrong, but that would cause me to bounce off the rev limiter still.

Pro Stock John

iTrader: (34)

Surging can be from running too rich/ and running out of nitrous.

What is your raceweight?

I'd try to run 11's n/a first, ideally 11.5 or better.

93LS1RX7

iTrader: (8)

You never said you were bouncing off the limiter. You stated the car was surging.

Surging is from to much fuel not enough nitrous. Or a FPSS cutting the system but you said you dont have a fpss.

CrawlinWS6

iTrader: (41)

My race weight with me in it is just over 4000lbs! the car def has sold 11's in it running na. the car never did bounce off the rev limiter. just was surging at higher rpms. to the point that you can hear it on the video of me going down the track!

tektrans

iTrader: (23)

It is a 15lb bottle and it was only down a lb. I do not have a fpss.But damn spraying it up to 6800 is

It might sound bad to you but at the higher rpms there is actually less nitrous filling the chamber per rpm. That's why it's so important not to spray under 3000 rpm (for most applications) because the time the chamber is "open" allows more nitrous to fill at the lower rpms.