Death by nitrous
11-02-2011, 02:51 PM
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Death by nitrous Anyone blow your motor from too much nitrous?
got a 5.3 that ticked bad after the first shot (75 horse for about 3 seconds)
and backfired the intake tube off the throttle body. Drove it for a few trips and finally died. Both rear cylinders had some little parts bouncing around inside and tore up the pistons and heads. the next 2 cylinders up from the back had a few nicks, and the front 4 cylinders had nothing. Found one piece of metal about 1/4 long and 1/8 wide/thick in one cylinder but don't know where it would have come from. Any ideas, will post pics
got a 5.3 that ticked bad after the first shot (75 horse for about 3 seconds)
and backfired the intake tube off the throttle body. Drove it for a few trips and finally died. Both rear cylinders had some little parts bouncing around inside and tore up the pistons and heads. the next 2 cylinders up from the back had a few nicks, and the front 4 cylinders had nothing. Found one piece of metal about 1/4 long and 1/8 wide/thick in one cylinder but don't know where it would have come from. Any ideas, will post pics
11-02-2011, 04:16 PM
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That engine can handle much more N20 than 75 hp.
Did you
Pull timing? you should have been pulling 3 degrees to start with
What octane fuel when I start changing my nitrous i make sure I have 93 oct
What RPM did the spray come on at?
Air fuel ratio?
wet or dry shot?
Did you
Pull timing? you should have been pulling 3 degrees to start with
What octane fuel when I start changing my nitrous i make sure I have 93 oct
What RPM did the spray come on at?
Air fuel ratio?
wet or dry shot?
11-02-2011, 04:58 PM
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I ran a 125 shot plate system on my 302 DZ small block for years. 36 degrees of timing in at 2500. I probably triggered it by accident at 12 or 13 hundred rpms 10 times, never broken anything. Had forged pistons and a high volume fuel pump. Very odd that this happened so quickly to you, was it a dry system?
11-02-2011, 05:13 PM
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11-02-2011, 05:41 PM
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This was a zex dry kit with a single nozzle in the intake tube 8 inches before the TB. Jets as per zex tech guys. This system pushes some pressure from the bottle into the fuel pressure regulator to push more fuel through the injectors. Stock tune. Always run 92/93 octane for all the power I can get. Called zex and they didn't return my calls. Afraid to try nitrous again
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11-03-2011, 08:11 AM
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4000 seems a high but still ok range to introduce n2o, mine sprays at 3000.. I have a wetkit that has a solenoid that runs off the stock fuel rail, can u tell us more about how your system uses pressure from the bottle to push more fuel from the injectors? Think of all your cylinders fighting for the same thing at the same time, looks like the front cylinders were getting what they needed while the back were starved the worst. From what I remember (I think) the rule of thumb is 2 degrees of timing should be pulled for every 50 shot of n2o aka 3 degrees. What spark plugs as well? Also a higher milage motor def won't take well to being hit from the bottle at 4000rpm during a 3rd gear pull..just my .02 how many miles on the motor?
11-03-2011, 08:47 AM
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132k on the motor.
The way I understand this system is the stock regulator works off of vacuum. When there is a lot of vacuum, ie. idling/cruising, it pulls the diaphragm up to lower the pressure. When accelerating and the vacuum goes way down on the regulator, it's movement allows for higher pressure to the rails/injectors. When the nitrous is hit, the pressure of the nitrous is messured and sends pressure to the regulator which is supposed to make fuel pressure even higher so the injectors spray more. That's how I understood it. So this wasn't an all out drag set up, just for fun, never had the laughin gas before. So I don't know what went wrong.
-Plugs were ngk don't have the number right now but were recomended by a tuner I used for nitrous.
- Did not take any timing out, didn't have any way to.
The way I understand this system is the stock regulator works off of vacuum. When there is a lot of vacuum, ie. idling/cruising, it pulls the diaphragm up to lower the pressure. When accelerating and the vacuum goes way down on the regulator, it's movement allows for higher pressure to the rails/injectors. When the nitrous is hit, the pressure of the nitrous is messured and sends pressure to the regulator which is supposed to make fuel pressure even higher so the injectors spray more. That's how I understood it. So this wasn't an all out drag set up, just for fun, never had the laughin gas before. So I don't know what went wrong.
-Plugs were ngk don't have the number right now but were recomended by a tuner I used for nitrous.
- Did not take any timing out, didn't have any way to.
11-03-2011, 12:18 PM
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The higher the RPM that you hit the button, the easier on the engine as cylinder pressure will be lower. Where you really feel a strong nitrous hit is at lower rpm, which could also cause more stress on the engine components or detonation. 4000 rpms is safer for the nitrous unless your engine was really tired. I'm guessing that you managed to go too lean, maybe a bad fuel pump or something else in the fuel system.
11-03-2011, 09:53 PM
#12
zex and nos increase fuel pressure to add fuel on their dry kits. i would have tested it to see if the added fuel was actually happening by activating the system without allowing nitrous to enter the intake (idk how exactly in this case, maybe screw in a 2 or 3an plug where the line would attach to the nozzle or something). this would let you feel it sort of fall on its face so you know its working as it should.
nothing melted? i'm just guessing, but it may have been a lean backfire.
i had a backfire through my intake when i went lean once (100 shot on a v6). not sure where your maf is located, but if you could spray through the maf and the nitrous still had a chance to get to the motor before it completely vaporized, you could effectively use the maf to add enough fuel... i'd probably try a 100 shot that way on that motor.
so where did that metal come from?
nothing melted? i'm just guessing, but it may have been a lean backfire.
i had a backfire through my intake when i went lean once (100 shot on a v6). not sure where your maf is located, but if you could spray through the maf and the nitrous still had a chance to get to the motor before it completely vaporized, you could effectively use the maf to add enough fuel... i'd probably try a 100 shot that way on that motor.
so where did that metal come from?
