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01-03-2014, 10:53 AM
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#1
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Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
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cause of diesel nitrous backfire ?
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.
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01-05-2014, 09:08 AM
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#2
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Name: Fahlin Racing
Title: Too Much Time
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Join Date: May 2012
Location: NE Ohio
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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.
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01-25-2014, 03:43 PM
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#4
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Name: Leiffi
Title: Too Much Time
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Quote:
Originally Posted by Nukem
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?
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02-01-2014, 10:14 PM
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#5
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Name: Fahlin Racing
Title: Too Much Time
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Location: NE Ohio
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As long as you have fuel, enough heat and enough oxygen around you can have re-ignition.
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02-01-2014, 11:09 PM
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#6
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Name: imelmo
Title: Go away, I'm 'batin'!
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Location: Slidell, LA
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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.
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.
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__________________
ZMBYKLR, '03 Reg Cab Short Bed 4x4
Truck Source Diesel, Warren Diesel, Gardner Racing, Diesel Innovations, 1018 rear wheel llamathrust
10.38 @ 129.60mph
The FORDOTA, '86 Toyota reg cab tube chassis to be powered by a 6.0 Powerstroke; finally back in progress
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02-12-2014, 08:39 PM
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#7
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Name: Cummins12Club
Title: Happy Dinosaur
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Pretty sure it is from injecting too much at too low of an rpm with little to no boost and heavy fuel
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93 Dodge, going racing. Special Thanks to Tim Wright & Pro Street Diesel
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02-12-2014, 08:46 PM
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#8
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Name: 90dodge
Title: Always Broke
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They are being much more technical than that.
__________________
-What's his name
I own too much crap.
Quote:
Originally Posted by displacedtexan
Can I get my screen name changed to NickatFirepunk?
I don't work there or anything, but it won't cause any confusion.
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02-12-2014, 08:51 PM
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#9
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Name: Cummins12Club
Title: Happy Dinosaur
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But it does answer the question
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93 Dodge, going racing. Special Thanks to Tim Wright & Pro Street Diesel
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02-12-2014, 09:34 PM
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#10
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Name: TMONEYDIESEL
Title: Comp Diesel Sponsor
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Posts: 8,706
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Quote:
Originally Posted by Cummins12Club
But it does answer the question
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Depends when the backfire happens
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02-13-2014, 05:05 AM
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#11
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Name: Cummins12Club
Title: Happy Dinosaur
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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
__________________
93 Dodge, going racing. Special Thanks to Tim Wright & Pro Street Diesel
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02-13-2014, 05:19 AM
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#12
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Name: kjpcummins
Title: Too Much Time
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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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1997 2500 4x4 5spd
2011 2500 4x4 6spd
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02-17-2014, 02:02 PM
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#13
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Name: Leiffi
Title: Too Much Time
Status: Not Here
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Posts: 1,381
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Quote:
Originally Posted by kjpcummins
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.
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02-17-2014, 02:21 PM
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#14
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Name: 90dodge
Title: Always Broke
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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?
__________________
-What's his name
I own too much crap.
Quote:
Originally Posted by displacedtexan
Can I get my screen name changed to NickatFirepunk?
I don't work there or anything, but it won't cause any confusion.
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02-17-2014, 02:29 PM
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#15
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Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
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Posts: 1,381
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Quote:
Originally Posted by 90dodge
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?
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Can't lean out diesel engine.
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02-17-2014, 02:32 PM
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#16
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Name: 90dodge
Title: Always Broke
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Join Date: Mar 2013
Location: Oklahoma
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Posts: 2,274
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I realize you cant cause detonation per say, but there are negative power effects right?
__________________
-What's his name
I own too much crap.
Quote:
Originally Posted by displacedtexan
Can I get my screen name changed to NickatFirepunk?
I don't work there or anything, but it won't cause any confusion.
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02-18-2014, 01:27 AM
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#17
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Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
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Posts: 1,381
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Quote:
Originally Posted by 90dodge
I realize you cant cause detonation per say, but there are negative power effects right?
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Only negative I can think of is pumping losses from excess air/nitrous.
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02-25-2014, 01:30 PM
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#18
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Name: nskyline34
Title: Green Behind the Ears
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Join Date: Apr 2013
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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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