I don't know about all these safety features lol. I have sprayed my car 20-25 passes on both a 100 and 150 without any problems until last night. All of the previous passes were on a motor tune with no timing pulled. However, I did mix a little 101 or 110 on most of the passes.

Last night I went to the track to make some nitrous passes. I intalled my MSD timing twister, and set it to pull 6 degrees of timing when my kit is activated. FJO progressive controller is set to spray in 1-3 from 3000k to 6000k. FPSS is set at 45lbs coming. Car idles at 60lbs.

The track was cold, and the temp was about 40 degrees. The DA was real good at 500 vs the normal 1500-2500.

First pass of the night. I had my bottle heater on so the temp was 1050# with the same 150 jets I made 5-6 passes with last week. Car has never backfired or had any problems until now.

I left the fairly hard and got a little bit of spin in first. It shifted to second at about 50-60' out. Then it pulled real hard in second until about 300' out where it was shifting into third. For some reason it bounced twice off the rev limiter instead of shifting into 3rd and POP.

It didn't do a lot of damage, but I haven't looked at the plugs or dug real deep into it yet. It blow the nozzle out of the factory flexible intake tube between the MAF and TB. I didn't see any cracks in the ls6 intake or other issues. So we taped up the intake tubeing with black tape and I drove back home 60 miles with no problems.

So what caused this problem? I wouldn't think it was running out of fuel since I have already made several 150 hits on it? I looked down and the tach was about 6000-6200 when it sounded like it was on the limiter going into 3rd.

Other posts that had this problem said it was detonation, that sounded like it was on the limiter. But I pulled 6* timing, just didn't have any race gas to mix. My car has been blowing through the convertor a lot more on a 150 than a 100 (TCI 3200 NA stall). Could it have been that with the good weather, plus less timing, = lots more power which caused it to blow completely through the convertor and hit the limiter? I'm guessing the FJO controller did cut off the kit, but it had enough in the intake to explode.

I am going to figure something out about the 98 computer and shift points. I think the car is tuned for 3.73's and 26" tires. I have 4:10's and 28's on it and haven't gotten it retuned so the shift points are all jacked up.

I got a video and will put it up soon.

 

"bounced twice off the rev limiter" <That is why it popped.

 

I figured thats why it popped. But why did it do this after I pulled timing?

Like I said, I ran 150 shot on it several times before without any problems with stock timing and a little race gas. But I pulled 6* on pump gas this time.

I believe its a problem with shift points, and blowing through the convertor harder on the 150. But this is the first time it bounced twice off the limiter going into 3rd. Uploading video to youtube now.

 

VIdeo uploaded

http://www.youtube.com/watch?v=jUDHK...=youtube_gdata

 

If you have a window switch setup to kill it before the rev limiter, why would it be spraying when it hits it?

 

Factory rev limiter pulls fuel not spark so you went lean and POP! when it hit the limiter. Get your shift point dialed in and you will ok.

 

They are a lot more sensitive on cold days ! ( timing and fuel wise )

Rev limiter = bad.

 

Get a window switch. U are lucky that is the only damage......

 

hmm this is interesting, so u have it on the fjo. wat rpm do u have it to shut off at. and what % throttle?

 

I have it shut off at 6000. I had a flat line in the progressive in stead of fading it in because the track usually holds 1.49-.150 on my car and I wanted to run 10's. So I left on 150 from 3000-6000. Usually shift at 6300-6500 on motor and 100 shot.

When I got my kestrel out and saw 600DA and low temps I knew it was giong to be running strong. Looking at the above video when it popped, it was right at the 300' mark looking down at the cones.

Looking back, I should have put the 100 pills in it with the good weather. But I felt real safe pulling the timing.

Video of how it shifts/ leave on 100 shot at the same track. Trap prep is a lot better on a sunday instead of midnight madness and 50 degree track.

http://www.youtube.com/watch?v=hYezrpdJqRo

 

I figured when I saw the DA and temp it was gonna real its best time. But pulling the timing (6*) for the first time made be feel safe I guess.

For the 98 PCM, I need to change the gear ration/ tire setting first I suppose. Then look at the shift points? Not sure if it shifts by speed, but it was actually .2 faster in the quarter with the 3:73 and 10-bolt on motor before I went 9" and 4:10s with the same tune. Or get rid of the 4:10 since its running out of cam/head in those RPMs.

I would manually shift, but its my sleeper street car and I dont want a 10" monster tach on the dash.

Prob also need a PTC nitrous convertor so it doesn't blow through so hard on a 150.

 

I have a window switch/progressive controller (FJO),FPSS and timing retard. Made a bunch of passed without pulling timing and it never got on the limiter like than before into 2-3 shift.

 

Thats what I'm thinking . But weird thing is. I ran it 4-5 passes on 150 without pulling timing and it never bounced like that going into 2-3.

Doesnt sound like detonation to me in the video, but it seemed like it hit the rev limiter early in 2-3. Again. THis could be blowing through the convertor since it made more power.

 

i see you run @ steele.

 

Yeah its my favorite local track and seems to always work good for my car. Last fri night for "midnight madness" it wasn't prepped anyting like on Sundays.

But them again you have all the street cars going down the track draggind dirt and water. Hope to be back out testing next weekend.

 

have u ran it since? what if the noid got stuck with debri

 

I haven't ran it since this happened Fri night. I'm in the process of installing a new intake tube and plumbing the nozzle back in.

I do have a nitrous filter about 2' upstream from the nitrous solenoid to help keep debris out but I wouldn't rule that out.

 

why all the reving ? hope your not purging into the intake ?

 

Yes I purge the kit through the intake. Just arm the kit and make a few WOT revs in N.

I just listen to when it clears up and I know its purged.