cause of diesel nitrous backfire ?

Leiffi

Leiffi

New member
I see lot's of videos on Youtube. Is it too much nitrous cooling the intake air so much that diesel is not igniting and it is pushed to exhaust where it ignites ? At least it seems like it's happening in the exhaust, not in the intake.
 
Interested. Is it smoking white at all similar to how a delayed ignition due to cold weather at beginning minutes of startup? If the nitrous oxide has delayed the burn cycle ignition point due to its heat absoprtion capabilities then I would believe your viewpoint. However, until more things are know we can only guess at which I am sure you know. I am not sure though with an excess of oxygen molecules would still show a white incomplete combustion exhuast, albeit, the area in the runner verse the area within the bowl is greatly different at which we will expand in two directions not allowing the entire heat envelope to completely consume the fuel/air charge IMO.
 
Nukem said:
Its due to the much more dense oxygen ratio causing faster/easier ignition and faster burn rate.

My idea is that partially combusted diesel left in the exhaust stroke when running dirty (as nitrous users always do) is able to reignite and make its way out during the intake stroke.
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to me it seems like it happens mostly on the exhaust side ? You can get a flameout without nitrous just adding enough fuel, then it burns in the exhaust manifold when it gets air from somewhere else, and heat from exhaust wheel maybe? [ame="http://www.youtube.com/watch?v=WtlMd_2RaVI"]http://www.youtube.com/watch?v=WtlMd_2RaVI[/ame]
 
My old truck at Bandimere in Colorado for Truckfest. I didn't know I had leaking uppipes and the altitude let me know I did. LOL

I was spraying some on the line to help it spool up. Thought I blew my engine at first, lol. But it cranked right back up and I got on it again. Would've been a long walk back to Louisiana. I ended up getting 2nd in my class. :D


[ame="http://www.youtube.com/watch?v=3bJgIXWzIdg&sns=em"]http://www.youtube.com/watch?v=3bJgIXWzIdg&sns=em[/ame]

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I've always seen them do so at low rpm, I be we understood how you guy get kit using nitrous I always assumed you would have a back fire issue
 
The tractors in the video are lower compression and the engine block is cold. Most of them are running headers which heat up rather quickly and along with the turbine heat cause the unburnt fuel to ignite and cause a flame out the stack.
 
kjpcummins said:
The tractors in the video are lower compression and the engine block is cold. Most of them are running headers which heat up rather quickly and along with the turbine heat cause the unburnt fuel to ignite and cause a flame out the stack.
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Nitrous makes intake air very cold, so it's like cold engine and low compression. Diesel engine can not ignite too early because there's no fuel to ignite too early so it must be igniting too late.
 
Can there be a backfire when your on top if the charger and you lean out the fuel with too much nitrous? Say if somebody just opened the bottle on the dyno?
 
Seems to me that all the backfires occur at low RPM with way too much over fueling. This leaves me to believe what nukem said is true.

Also I think that since it carries so much oxygen and people inject it to help spool the turbo(s) (most times when the backfires happen) that at the low RPM the valve is open a longer duration of time and gets too much oxy and diesel in the cylinders and cant burn it all upon combusion. Then the partly burned mix is emptied into the exhaust and a little nitrous goes straight from the intake to the exhaust because of valve overlap and the high EGT's that are produced during the spool up ignite the mixture in the exhaust manifold. That's my vote.

Basically: The nitrous gets from the intake to the exhaust because of the length of time both valves are open at lower RPMs (like when spooling); The high temps in the manifold and abundance of unbrunt diesel fuel and the oxygenation from N2O to ignite and thus the backfire.
 
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