What could make a direct port system backfire thru the intake????? Heres what happened we put the car on a dyno for tuning proposes and on the fifth run "BOOM" big flame shots out the throttle body. We were spraying a 300 shot. Little info on the car for ya. bottle pressure 1050 w/ nano, low pressure stand alone fuel tank at 8.5 psi w/ some cam2 in it, #8 non projected plugs, as for timing phil99vette should step in here to fill you on that. I weighted the bottle after I got home and it weighed 22.2lbs so there plenty of nitrous. Any ideas?????????????

 

What was the timming at.? On a shot like that i figure to be safe your timing should be around 12. Did it go lean on that run?
Something happen like that to me on my old nozzle system and I had a bad ground that cause the fuel to cut out and it went lean. I would post up your log.

 

Timing was set to 28 degrees and Ken was trying a LPE retard box set to 12, the logger showed 23 degrees which we know is way too much. We pulled the timing back to 21 in the ECu and left the LPE at -12 and it still showed 23. A/F had a slight lean spike and than settled in to 11.1 to 10.7. I am not a fan of tghe LPE box but maybe it works, just not yesterday.

 

when the lpe box pulls timing it will not show up on the datalogger, I dont trust those boxes one bit, if it were me throw it in the trash and take the timing out from the computer itself.

Id also pull back more timing then 12 and then put it back in if the plug looks ok. I also wouldnt tune that big of a shot on the dyno either. what looks ok for a 3-5 second dyno pull will not be the same on a 8-9-10 second street/track pass.

 

Rich will make it back fire.
Also valve float ... found that one out the hard way, a few times.


300 shot #8 plugs and some cam2 ... I predict some hurt parts sooner or later.
300 shot will tear some **** up quick.

 

What would you suggest I do to get things right?

 

Not a guru but...

Dont reccomend spraying/tuning a large hit like that on the dyno. Take it to the track and start with some 1/8 mile hits.

Whats you jet spread ? 11:1 too rich

Give us some more info on the car/engine

Get rid of the lpe box also . IMO

Spark plugs should be a 10

Got myself in trouble doing the same thing you are doing a few years ago . mine turned out alot worse.

 

I for one dont like retard boxes. For that shot i would just pull from the spark table, cheap insurance. Rich and excess timing can make it hiccup. I've always started a little lean on the fuel and pull'n some extra * then work your way up till the plugs are happy. IMO this is better than starting off rich and working backwards. A little safer as well.

My plugs are real nice at 11.9-12.2 AF on a 200 shot
c16 in the cell

 

How far do you plan to go with it? is 300 the max your going to spray?

Answer that I will give you my opinion.

 

Thats it. Just 300 max.

 

-C16 minimum for fuel (not much more than cam2 but alot more consistant and safer for that much N20)
-#10 plugs (colder plug will not hurt HP at all but it will help if you have a little to much timing in it. You can always try a hotter plug when you get it dailed in if you want.)
-Get rid of the retard box
-Start with the timing low, where ever you think it should be pull 2 more out and start there.
-Rich is not safe you need to be in the low 12's For A/F at a minimum, We run ours closer to 13.0 with low timing. I wouldnt suggest anyone to start at 13.0 but 10.7-11.0 is WAY off.

Is this a hyd. roller set up or solid?

 

At what RPM are you activating the nitrous?

As for the rest.... Listen to ATV, he is pointing you in the right direction.

 

hyd. setup. It activates at 4k