I don't understand why so many of you guys are having backfires. You search this thread with "backfire" and find a **** ton of threads. Everything from blowing off a lid to melting the car down to the ground.

What are you guys not doing with all the simple safety ****, or am I missing something?

I got my nitrous list all lined up and am going to install a kit in the near future, just a little worried with all the bad luck people have.

Was your backfire your fault?

 

Usually people come out of the hole get nervous and spray alot early and blow from what I see.

 

Shouldn't a window switch keep you out of that though?

 

Backfires happen for various reasons. Dont forget though how damn big this website is and how many LS1 owners use nitrous. Any backfires that happen you will hear about since its so catastrophic.

Still nothing wrong with wet kits.

 

I dunno, I mean what is it, these people having backfires, they never say what was the cause.

Are people on this forum really spraying without the tuning and fuel to back it up? I mean seriously, you buy the kit and yeah, it will work, but why would you spray unsafe?

 

I know the reasons for backfires dude, and there are ways around all the circumstances.

 

There are? You sound supremely confidant that you will NEVER have a backfire. I have seen plenty of properly setup plain ole 150 single nozzle wet hits have backfires for no apparent reason. How do you get around that?

Obvioulsy there WAS a reason...but unless you can figure out the faulty piece of hardware or improper setup configuration...its tough to pinpoint a cause so you might later have an affect.

And of course there is also just plain ole failures that can strike at any given time. There is NO way to curcumvent this with 100% success.

Every time I have ever run a wet kit I have taken all the steps I thought were necessary. And I have run wet setups from 50 shot to a 400 shots. I have never had a backfire. But I am always aware that it is still a possibility even with the best laid plans.

From my experiance over the years the breakdown would be something like this:

Of the people who have backfires

35% were due to the installers negligence on either the actual install...or way the kit was used (IE no window switch, on/off the throttle, miswiring)

35% were due to poor tune up

20% were due to component failure of the engine or car the kit was installed on ( these failures can be owner/operator induced as well, just not nitrous associated)

10% were due to component failure of the kit itself

you could break these catagories up a little more...and slide the percentages around some but IMO it would be something like that.

 

I'm very confident that I very likely shouldn't have one because I'm looking at a complete and tuned setup. I've been studying and reading up on nitrous for years and I can finally soon afford a kit. What I don't understand is how experts, sponsors, and alot of literature say how safe nitrous is when set up properly. I guess my question is what is causing them.

As for your first 35%, why would the kit work one time and not another? Are you referring to guys spraying for the first time and blowing their **** up?

The second 35%, poor tune up? Once you're dyno tuned, AF ratio is right and timing is retarded, that's it, the tune is in. That's what I consider a "tune".

20% on parts, that's understandable, but are you referring to the average guy spraying a 100 dry shot on an otherwise stock car? Or guys going for a H/C 250 shot on a stock bottom end?

10% on nitrous kit failure? So what your saying is that 1 out of every 10 nitrous kits sold is a bomb just waiting to happen?

Your post really hasn't answered any of my questions, but congrats on never having an issue with nitrous over the years, I guess you must be doing something right, just trying to find out what others are doing wrong.

Of course, it's the nature of mechanics and systems to eventually break, and I know that does happen, but what are the reasons for a properly installed kit with all safety systems, tuning, supporting parts and a reasonably sized shot going bad on someone?

 

You sound like you have some basics on nitrous...but there is some gaps in your understanding from what I see. No worries...thats what this forum is for.

On occasion guys spray first time and have issues. But more often they do things like wire in a window switch incorrectly and THINK they are only spraying between 3000-6000. When in reality they are spraying whenever they go WOT. Under curcusmtances like that that could have sprayed 50 times at a relatively safe rpm...and then hit it at 1500 thinking it wouldnt come on until later...and BAM! Or they dont use a window switch at all..and maybe use a button only. Or possibly even the ole getting out of it and then getting right back in it rapidly...thats a big no no for the most part. Then there is also issues with launching techniques on drag cars with two steps and transbrakes that tie in nitrous activation....there have been mistakes in the past on the setup of those items. All these can lead to bad situations.

Not necesarily. I said poor tune up...period. I did not say they had a good tune up that went bad...although that is possible as well if there are certain failures that may occur. Some people slap a kit on and dont tune at all...or atleast dont even check. Others THINK they know what a GOOD tune is but really dont have a clue. Others, as you say in your example, only use a dyno to tune...and dont check thier tune on the street or track. This becomes critical when you start spraying real shots of say 200-300 or more. A good tune on a dyno does not always equate to a good tune at the top of the track. The scenarios to have a poor tune are endless really.

In this instance I am talking about any car. Stock...or even heavily modified. More often though heavily modified cars with large cams, tons of head work, aftermarket valve jobs/valve train, etc etc that can be the initial cause of a backfire. After all the fuel in the intake must have an ignition source. Sometimes it comes from a faulty engine component...and we all know aftermarket stuff probably has a higher likleyhood of not being perfect than stock. But it can happen to either.


How in the world did you get that idea from my assesment?!?! Stay with me now....of the cars that HAVE HAD NITROUS BACKFIRES...I estimate 10% are due to kit component failure. That means...like in my very first initial post...of the tens of THOUSANDS of LS1 WET nitrous kits on the road...only a SMALL HANDFUL have EVER had a backfire. Of that small handful 10% may have come from kit component failure such as fuel noids or line problems that cause a lean condition. In no way shape or form does that equate to 10% of all wet kits are bombs.
If there are 10,000 LS1 users out there running wet kits...and 10 of those people had a backfire this year..that would be 1 out of 1000 odds. And of that 10...10% were due to component failure of the nitrous kit...that would be 1 out of those 10. So that would make it 1 out of 10,000 failed due to nitrous parts failures. And these failed parts could be new...or they could be old and very very very used and abused. Which many times is the case.


Oh believe me... I have had plenty of issues with nitrous. Most were the result of my own negligance by far. I just havent had a backfire.
Hopefully the scenarios outlined above may help you out.

 

I installed my first wet kit in about 1977, and never had an issue until 2007. My backfire was caused by a couple things. I will lay the ground work first, new 408 with a linear 450rwtq that revs so freaking fast, add spray to the mix and you better be able to shift fast. On top of this is the fact that the factory Vette tachs are off by a few hundred rpm. Then going to the track find some issues with my first stage, so bypass it. Used an RPM activation sw on 2nd stage (other WS normally used was on the blink allready). So being very confident of my driving/shifting abilities, I make a pass. Well the combo of the above issues came around and bit me in the ****. Hit the rev limiter at 7000rpm and it pulled, or rather shut down the fuel. On a dry hit this is not good. Resulting in a high rpm lean backfire. Blew a small hole in back of intake. Sounded like a sonic boom, and everyone in the pits new who it was, lol. I contend, that not having gasoline vapors and/or puddled fuel in the intake tract save my azz from some serious/potential fire issues as it would have surely blew the intake apart and sent fuel/flames through out the engine bay.

A properly set-up wet sysytem can still have mech failures even with all the safety stuff. Now the mech failure considering a dry set-up is much less of an issue. Just look at all the different scenerios and you'll see there is no absolute gurantee, wet or dry, but better odds with the dry.

If ya can't pay, and want to play, don't spray.
But this goes for any power adder and/or drag racing in general.
Robert

 

Yeah...Roberts scenario is a prime example of just how convoluted the reasons for backfires can be. There is probably a thousand different scenarios..mainly because many times a backfire is the combo of TWO or more items.

 

383, thanks for clearing some of that up for me.

Basically I'm lined up to buy a strip only 150 wet shot, and luckily I have a very competent performance shop to help with my tuning and looking over my system after I install one of Daves kits, when I tune, and before I spray. Hopefully that should eliminate any "installation" problems and unforseen initial mechanical/electical problems. This isn't an all out drag car yet, and I don't plan on running a HUGE shot, multiple stages or anything like that.

And I could be going overkill on my system for as small of a shot but I just want to be as safe as possible with the setup. I would hate to see my car burn to the ground. So along with the kit I'm going with a Racetronix and 42 lb.ers, Wideband A/F, and fuel pressure gauge. Hopefully if a problem is iminent with fuel, I should know it before I spray. These are some possibilities that weren't mentioned previously. Are guys with backfires and bolt-on cars making sure they have the fuel system before they even spray? Do they have the ability to monitor their fuel system before, during and after spraying? I'm hoping this will negate a possible problem, at any RPM, any time, on the street or the track, am I wrong in thinking this? This is almost a way to verify your PCM "tuning" due to minor conditions that may alter an otherwise good dyno-tune.

I know there's lots of other **** that can go wrong. But let's talk about noids sticking. Has this problem happened to anyone with a nitrous filter that you know of? I would like to know that. Generally, the noids are pretty stout and would need some sort of internal obstruction to keep them from closing. That doesn't rule out mechanical failure though I know.

1:10,000? That sounds pretty reliable to me and very good odds that you won't have an issue if you're doing it properly. Maybe I'm overexagerting the possibilities of a nitrous backfire?

BTW, what were some of your issues you've had in the past other than backfires?

 

I ahve had two or three noids stick...but like most...they were just stuck shut and would not open. I have never had a fuel noid stick shut though. A filter on the nitrous noid is a good idea and just further helps reduce any potential malfnction.

Id say you are concentrating a bit too much on a nitrous backfire....especially if you are just running a basic 150 wet shot.

Other issues I have had where usually setup or wiring issues...or issues where I put the wrong jets in while not paying attantion and sprayed a 300 shot on pump gas tune at 3000 rpm when I was supposed to be on a 200 shot etc etc.

 

I chose no fpss, not enough fuel, untuned, and my dumbass. Pretty much i didnt get enough fuel, went lean, no timing pulled, just went downhill from there.

 

After you have system up and running then dont forget about maintenance mine was caused by a clogged noid after many passes

 

What about a filter? Do you have to replace them often?

 

My story was that I had a window switch but I was lazy to install it before going to the track. I did two Na passes and then I decided to spray at the end of 1st, through second and went to fifth instead of 3rd. And I saw the rpms drop, a second later boom, back of manifold cracked. On the street I never had any problems, even with a 200 shot untune.

PS. I am now going to putting a cam and getting a tune.