Nitrous: Fuel Issues

[702GT]

Went to get tuned for my 75 shot and ran into several issues. First my bottle warmer wasn't getting hot, so I never got to dyno it above 900psi, it would drop to 860 as soon as I hit it. So I didn't make jack for torque, but made 407whp. Wished it wasn't so hot and humid out here on my dyno day LOL.

The real issues. The tuner is telling me, even with the 40A KB BAP at max, I'm running my FPDC at 80% at WOT. I know the M90 Roushes run bigger injectors and make more HP than I am WITHOUT a BAP, what gives? Am I that Badass N/A? I sure as hell don't feel it. Possible he's wrong? I really want to bump up to my .52/.33 jets, but not at the cost of maxing everything out.

Another issue is fuel rail pressure. Because ZEX taps into the fuel rails with a T that sits literally under the fuel rail pressure sensor, the dyno shows a drop from 41 psi to 15psi within 100rpm before FPDC catches up and puts it back at 41-45psi. For only 100rpm it doesn't worry me, AFR doesn't change so I know the jet and injectors aren't getting starved but the fuel jet doesn't have the correct psi for that 100 rpm. Will this affect me if I spray from a higher rpm? Say, 5000 instead of 3500? I'm actually glad the fuel gets tapped on the sensor, so it can manage fuel pressure faster for the spray, but I'm curious if the fuel system will max out on the .33 fuel jet? Do I need to step up to bigger rails? Bigger pumps? Seems like a lot of demand for the power I'm making, and now that I've got the heater working, with bottle pressure up that torque is going to wake up and want fuel for breakfast!

What do you guys think?

 

[Corpo]

Don't fret, you aren't alone. Same issues off the 75 jet here. I have bigger rails, no bap though.. Discovered it isn't working. It's wired right. Check the output voltage at the bap when it's on. I'm going gt500 pumps the hitting a 125 shot

 

[07 procharger]

Somthing doesint sound right. i was spraying a 125 shot with my stock pump 2 years ago. No issues at all. that was thru a Ny-Trex wet fogger system, not Zex, but it tees into the fuel rail the same as Zex system does. 11.6 AFR on a old Bamachips email nitrous tune. He did turn up the FRP in that nitrous tune if I recall.

I have upgraded to the 500 pumps and 39 pounders since though.

P.S 950 PSI is optimum for bottle pressure. Some guys go higher but you have to keep in mind what pressure rating your noids are good for.

 

[Corpo]

I'm at 440rwhp/410rwtq off the 75 shot... The data log I sent Jim jr at jdm he warned me I need a upgrade.

 

[5.0lightning]

I run the zex kit and never saw any issues on the 75 shot. The only thing I changed for the 125 shot was a colder plug. The stock pump and injectors should be more than enough for the 75 shot. Somethings definitely not right. You said your bottle heater would not get hot, mine did the same thing on a hot day at Dragging Rights this year. This was due to the automatic heater temp sensor cutting it off due to the temperature outside, since it's based on temp and not pressure. I use the zex automatic heater. I've determined it's complete junk. If you want one for the street the dyno tune heater is the one to get for sure. I now just heat it up to temp with a mapp gas torch and turn the heater on to keep it at or above 950 psi in the staging lanes and purge it. Relying on those heaters are a waste for track duty. Why did your tuner not get a torch and heat it up for you? The car should be tuned at the pressure your going to run it at. I did not bring one on my dyno tune session and the heater would not get it up to 950 psi fast enough, he just grabbed his torch and lit it up. Seems like any tuner worth the cash would at least do that for you. I'll be switching mine over to the Nano system as soon as I find a way to remote open the Nano bottle. I haven't found a bottle opener small enough yet. I may just have my shop fab one up for me.

 

[07 procharger]

your torque is lower than your Hp on the spray? weird. but good numbers

 

[Corpo]

It's the cams.

 

[jeffie on juice]

I ran my 150 shot for 5-6 years with no issue in fuel pressure. on stock pump and injectors
Only time i ran into any fuel issue was if i sprayed it when i had like 1-2 gal left in the take i would get some weird codes. fuck it keep a torch in your car for the bottle

 

[702GT]

Out here we spray at 1100. I don't like the idea of putting a torch to my bottle, especially after having spent the time painting it lol! I'll be putting it back on the dyno now that I got the heater working. I'm call Zex tomorrow and let them know how I feel about their bottle heaters. I'll look into that Dyno Tune heater. It'd be nice to have a heater that doesn't puss out on me.

I'm thinking the only real way to beat the fuel pressure drop is to go to a return system. You don't want to put too much pressure to the rails on a returnless system, otherwise when the pressure does drop, and it will, the FPDC will spike to catch back up, but if you're already ramped up, you'll have too much when the pressure comes back. I could see bigger rails being an added cushion, at least when the pressure drops you'll have enough fuel in the rails to feed the motor while the pumps compensate. When I go back to the dyno, I'm going to bump it up the fuel jet and see if the pressure drops the same or worse before I bump the nitrous jet.

 

[702GT]

I ran my 150 shot for 5-6 years with no issue in fuel pressure. on stock pump and injectors
Only time i ran into any fuel issue was if i sprayed it when i had like 1-2 gal left in the take i would get some weird codes. fuck it keep a torch in your car for the bottle

What did you have done to the motor at the time?

 

[blue streak]

I ran a .063 and .038 for a while.. But it did chew up plugs often. Im getting a 2gal fuel cell, holley blue pump and reg. and running the fuel for n2o off that. but im going to a 200-250 hit with a nx plate kit.

 

[jeffie on juice]

what did you have done to the motor at the time?

just a on the spot nos tune for it. And changed spark plugs every 6 months, went with the ford racing plugs single heat range plugs.
Only ran the bottle for 4 runs about 5 pounds then would change them out. And always ran 2 bottles into 1 line so never had to worry about bottle pressure dropping to low


just DON'T EVER SPRAY IN 5TH, VERY BAD MY CAR SOUNDED LIKE A TRAIN ALL THE WAY HOME

 

[702GT]

just a on the spot nos tune for it. And changed spark plugs every 6 months, went with the ford racing plugs single heat range plugs.
Only ran the bottle for 4 runs about 5 pounds then would change them out. And always ran 2 bottles into 1 line so never had to worry about bottle pressure dropping to low


just DON'T EVER SPRAY IN 5TH, VERY BAD MY CAR SOUNDED LIKE A TRAIN ALL THE WAY HOME

I meant what did you have done to the engine mods-wise. I'm pretty sure if I strapped a 150 shot to mine it'd be the first and last time. Were you N/A, did you have cams, intake, exhaust, stock bottom end. I'm pretty sure a bone stock GT would take a 150 shot at max, but delivery would have to be in the form of a fogger plate of some kind, I would think a nozzle would puddle quick. Even then, I don't see how you'd get away with a 150 shot without at least a BAP.

WOT in any gear lower than 1:1 is generally a bad idea. Boost or Spray in O/D, if you don't pop your motor due to load, you're sure to grenade your tranny.

 

[jeffie on juice]

Never had a issue until 3 months ago, and i finally cracked the intake on the #4 runner. with a 150 shot on a plate kit with a not so good email tune. i should of replaced spark plugs but whatever

no BAP no injectors.
i would always run 103 vp fuel in the car. for years i sprayed on the 125-150 with the zex nozzle. going through some weekends 4-5 bottles
my tune was dead on
fuck i just got a window switch for the car 6 months ago, would never spray the car under 3k and would stop at 6,750 rpms and never spray in 5th.
I had all the bolt ons you can think of.

 

[Corpo]

Never had a issue until 3 months ago, and i finally cracked the intake on the #4 runner. with a 150 shot on a plate kit with a not so good email tune. i should of replaced spark plugs but whatever

no BAP no injectors.
i would always run 103 vp fuel in the car. for years i sprayed on the 125-150 with the zex nozzle. going through some weekends 4-5 bottles
my tune was dead on
fuck i just got a window switch for the car 6 months ago, would never spray the car under 3k and would stop at 6,750 rpms and never spray in 5th.
I had all the bolt ons you can think of.

what times you get?

 

[waldogt07]

It's the cams.

I have the Hot Rod cams and I still make great torque off of my 125 shot.....last dyno pull I made was 471 rwhp and 543rwtq off of the 125 shot at 5950 rpms......
What type of cams do you have??

 

[Corpo]

I have the Hot Rod cams and I still make great torque off of my 125 shot.....last dyno pull I made was 471 rwhp and 543rwtq off of the 125 shot at 5950 rpms......
What type of cams do you have??

Basically 127600's. Except they have a 105 degree intake centerline. I mean, I'm still gaining 100ft/lb of tq. My na numbers were 360rwhp/305rwtq. Seems off to me, gonna have to get a dyno tune in the future I think

 

[s8v4o]

When you say you're running "FPDC at 80%" I'm assuming you're talking about the boost a pump. Datalogging your real fuel pump duty cycle would help out a lot. Take a couple datalogs NA and then on the juice and let us know what's going on.

 

[Corpo]

Op is 345 na and running a 75 shot with bap. I'm 360 na running a 75 shot without bap (my bap is not boosting output voltage.) I got a feeling op's ain't working either. But if it is then I dunno. My fp dc jumps to 0.480 ish on the datalog when the nitrous turns on. What does that work out to in %?

 

[3VPOWA]

This thread makes me nervous. I'm putting my Zex kit on but still want to buy a few things before I run a 75-shot through it; namely a window switch and different bottle mount bracket.