My buddies car only acts up when on nitrous and between the 3-4 shift, its a 6 speed. He has a msd coil, dynaspark opti which is practically new. NO problems when On motor only on spray. So I believe its a NOS problem. He has a mallory 685 box on a LT1 and has a nitrous express kit. The kit is practically new and he has never checked or cleaned the system. I told him that it
can be a bottle fill
bad nos filter that is probably clogged with debris
jets that are clogged/dirty

What else can it be and why would it do this

O ya its on a window switch and it does work turns off at 6500 on at 3400rpm

lmk guys so I can help him out

 

its only happens in 4th gear? what kind of WOT switch? maybe hes just not going WOT when he gets in 4th or something....other then that no clue. Everything you listed above would not be a reason why it doesnt spray on only on the 3-4 gear change or whatever it would spray during any other time if any of those were the cause.

 

"acts up when on nitrous" is not a very good description of what it is doing...

 

you shouldn't be spraying between shifts.

 

He is not spraying between shifts, He feels like its missing and not making power as he shifts from 3rd to 4th. So once it goes into fourth thats what it feels like.

He has a WOTswitch on the t.b So its always full throttle, when he is.

 

anyone else

 

Thanks for posting up Rob. this is my turd he's talking about. It only seems to act up at the top of the gear above 5K. To me it feels like the spray is on/off (erratic). It doesn't back fire or pop out the intake, it feels like a miss. the boggling part to me is that it changes from gear to gear. On one run it will do it in 3rd and 4th, the next it will do it in 2nd and 3rd and it's fine in 4th. It's frustrating but overall it doesn't seem like I'm getting the full 150 shot.

How often do nitrous filters go bad or is there a way to tell? I did take it apart about a month ago and I did find aluminum shavings/particals in the housing( bottle side).

Here's a rundown of my setup
Selinoids are used but were supposidly rebuilt before I hooked em up.( large NX )
msd micro switch-wot switch
mallory 685 box
Nitrous works plate
NOS -filter

thank you for the suggestion on the throttle switich, I'll double check that tonight. I'm also going to check the lines/ jets for a restriction

Any other suggestions would be appreciated

 

sounds like a ground issue, maybe the solenoids arent getting consistent power. or its a tuning issue? have you read the plugs?..........also could be a considerable drop in bottle pressure when it seems to miss which is causing it to run richer then it should.

 

Paul, if it feels like that it may be a ground issue on the solenoids as well and they could be turning on/off. But I think that would be all the time not just in a certain gear. The bottle psi dropping could be culprit but doubtful. If your at 1050 psi it will drop to about 1000 or a bit under when the race is done. Do you remember what its at when your done trapping?
The tune was on a dyno tune or not?

Also your running the autolite 104s, they might be a problem for the spray? Others may chime in on this and decide.

 

Are you running a fuel pressure safety switch? They are useless, and I have seen them cycle a nitrous system when used...

Also, could be the micro switch if it isn't adjusted properly... I prefer an electronic controller vs micro switches myself...

 

I do not have a fuel safty switch, so that's out of the equasion. I did double check the micro switch and it was slightly misadjusted. It was being activated but just barely. I do have a spare so I'll swap it out to see if there is a difference.


I did check all the grounds/connections and they are solid.

The plugs look good and I've been running them for quite some time now. I would think if it's the plugs that I would have more a of a nitrous backfire or popping, but nothing.

 

also check the wire connections on the wot switch to make sure that they are good... mine were loose and was causing something like this

 

what coil are you using?

If it the MSD OEM style replacement coil, this "might" be the problem.

I have seen issues with cars having a miss under load that was fixed by upgradeing the coil.

 

Yes it is a MSD replacement coil. The issue I'm experiencing is only on spray. NA it pulls just fine

 

I have a LT1 specific micro switch if your looking for 1. Also arent those plugs to hot for a 150 shot??

 

I have seen many times the OEM replacement style coils not be able to fire the plugs under the extra cylinde pressure of nitrous...runs fine NA but not on the bottle

 

The 104's are gapped at 32. Achotrod, where did you get the switch at?

Any suggestions on the coil?

Thanks for all the help and suggestions everyone!

 

I bought it from the Nitrous outlet but Im using a progressive controller so i dont need it. You can have it for a 12pack of Miller Lite. Only catch is you gotta come pick it up in Arlington Heights. Mine came in black anodized finish not unfinished like in the picture
http://www.nitrousoutlet.com/catalog...1&product=850#

 

I am using this coil...

http://www.summitracing.com/parts/MSD-8252/

 

I wasn't aware it was even made. I might be in your area sunday. I'm picking up a camaro in wisconsin and could possibly swing by on my way back