Nitrous Issues

[Sukkoi19]

I have an 88 Coupe with basicly a stock motor sans GT40 Irons/TFS 1/Cobra. I have an NX EFI kit on it and Im having a hell of a time getting it to work.

Basicly I have verified:
It is spraying at least with the key over and the microswitch engaged.
It uses nitrous as the bottle gets lighter
The fuel works as I have taken the line off and hit the switch and verified that fuel is coming out.
Timing is at 10* initial (probably too low)
Plugs are TR6 gapped at .032
Has .072 nitrous .041 fuel for a customish 175 shot.

The car just won't pull consistantly on the spray. It is for sure slower on the bottle. It feels like its starved for fuel when spraying as the engine revs slowling and surges throughout the RPM range. The plugs are the normal EFI white and I don't get any black smoke when spraying.

Some things I have considered.

Bad fuel pump, it runs hard on the motor but maybe the nitrous is too much for it. I have a 255 low pressure in there which I would think would be sufficient. When checked for fuel I noticed it dropped about 4-5# when I hit the switch, but I figured since it was -4 line open then that would account for it rather than just the jet spraying.

[D-Man]

Sounds like low bottle pressure.. Get a good gauge (good luck there!!) on the nitrous line and a bottle heater.

Also check any screens in your nitrous fittings to make sure none of them are clogged.

[gnklr50]

why didnt you bring this up at the dyno today?

[Sukkoi19]

My mind was so set on Ben's car that I just didn't think about it.

[Sukkoi19]

Sounds like low bottle pressure.. Get a good gauge (good luck there!!) on the nitrous line and a bottle heater.

Also check any screens in your nitrous fittings to make sure none of them are clogged.

I don't have any screens in the fittings. I have a new NOS gauge that I use and try to keep the bottle pressure around 1000 psi.

I have since tested it more, with a super lean fuel jet the car runs much better on the spray. I puta .029 fuel jet in with a .076 nitrous and the car felt much better.

I find this puzzling. I am going to put my wideband on it and do some expirementing.

[D-Man]

What fuel pressure gauge are you using?
Try using a different gauge to verify your readings.

You can also leave your bottle turned off, remove your nozzle and spray it into a container (with the car running) and test the "TRUE" flowing fuel pressure. Your fuel jet will commonly change depending on what fuel pressure your running.

[Sukkoi19]

I have used two different guages and they both are within 1# or so of each other.

I did actually test the fuel solenoid in that fashion. I experienced a 2-4# drop in pressure with just the open -3 line going into a canister. I am curious if that is a normal drop or not.

Really I have given up on the thing. My other project is coming along nicely well and I have to re-allocate time for it. Thanks for all the replies.

[dgrobels]

it seems to me that its not working at all

13.2 @ 105 is what I would expect your car to go on the motor by itself

if you are using the hobs fuel pressure safety switch , you may want to try this

if you look down at it youll see that you can adjust it, i would test that

when my car was runnign 13.4`s all motor it would go mid to high 11`s on a 150 shot , this was on slikcs and the mph was 112-114 and would turn 1.5 60ft times