What valve springs do you have and how old are they?

 

Haven't really felt any float issues, but have never had the car on a dyno to see any. Springs are 2 seasons old--maybe 100 total runs with about 40 nitrous runs. They are just a set of duals.

 

Change them before this season, maybe shim them up a little.

We finally figured out mine was backfiring down track because of weak springs (not worn out, just couldnt handle the what we were doing) and there were no signs of float on the dyno to 8,000 but as soon as I turned on both kits and tried to shift past 7500 BANG !!

 

Good info. Thanks

 

Was it poping out of the intake or the exhaust?
Dave

 

Intake--They were decent sized. Broke/burned the lid and everything.

 

Hmm. Like stated above checking valve springs is not an bad idea. Did you have a way of monitoring airfuel or reading plugs?

Have you cheacked the fuel solinoids to make sure they are all flowing ok?

The reason why I ask is alot of time poping through the intake is a lean pop.
Dave

 

I'm not the greatest at reading plugs, but a very reputable old school guy showed me where 7 and 8 were lean.

Noids have no known defects. Flowed great all year, and the first 2 runs of the weekend. I was only running 100 per kit, so I don't think I was over taxing them.

 

I would just test flow them. If you have a plunger starting to hang up that could be a reeason. If the back to runners are running a lean enough that could be the problem.
When yall were reading the plugs you were shutting the car off after wide open throttle and then yanking them correct? No idle and no partial throttle driving?
Dave

 

Yeah. Backfire--shutdown--coast in--towed in. I've got some new noids for this year, so I'm hoping that takes those out of the equation.

 

gotcha, I wonder what was making those two back runners burn so differently. It must have not liked the way the nitrous was been introduced into the air stream. Did it run lean on motor in those cylinders as well?
Dave

 

No real problems at all on motor. I think th ebackfires are a result of alot of little things piled up on each other. I know for sure that the elbow does not like to have a wet kit pushed through it from the TB area. Hopefully with this new setup I can make a run at the # I've been trying to hit.

 

I would get the intake flowed. for the most part the single plain should have good distribution, as long as it's flowed. maybe you have, but I didn't see it mentioned.

Do you have logs of your runs?
Robert

 

My super vic. set up still ran hot on the back 2 holes.
Dry fogger, showed very little heat until we turned the 2nd stage on.

We had the same issue with the sheetmetal intake.

 

I know when atv's backfired the plugs where usless. they sotted up to fast. where yours still readable?

 

Plugs were still readable.

 

Its funny reading this post...it brings back quite a few memories. Back in the day people would actually play quite a bit with the intakes. You would see guys make small channels to route the fuel that dropped out of suspension to the lean cylinders. And conversely small dams that would re-direct rich cylinders. As dumb as it sounds it actually worked for the most part. Its very dated technology but technology was limited and people did what they had to with what was available. I would have to dig in my garage but I have an old intake that I bought at a swap meet many years ago that was actually channeled like this. The sad part was I didn't buy it to use it but rather that it intrigued me so much. I'm the worst impulse buyer .

I wouldn't port the intake uneven especially since you're switching combos. There are a few other tricks to address the back cylinders and I wouldn't use the dated technology to do so. Get squared with the intake first and the new set up and go from there.

Nick

 

Are you calling me old? ****, I'm only 30!!! I do hang out with a bunch of old timers though.

 

Relax, I said dated not expired.

 

Nice.....Real nice.