JS12

anyone else having this problem. it sucks the rails dry and leans out for a split second. anyone have a cure for this besides a dedicated fuel system? i have the walbro 255lph intank pump right now and can install a NOS inline if it will help any.

also is anyone running a purge with this kit? i have mine set up with T's at the end of the fuel rail coming into a Y in the purge.

JF WS6

If you've already got an extra inline pump I'd try it, but have you tried running it setup as-is without the T's on the rail and the purge setup how it is? Shouldn't make a difference I wouldn't think, but I'd make sure you are going lean with it setup straight how it was intended to be. Who knows, maybe because your purge is right at the rails nitrous is getting into the cylinders before the fuel causing you to go lean momentarily.

Did you tune with this kit at all? I'd try it setup just with the purge at the nitrous Y connector with no T's on the end of the rail first and see what happens, then I'd try adding your inline pump...... if that doesn't work sounds like you need a beefier fuel system - replace the feed line with a bigger one and dual intank's or a big external.

Last question, what total RWHP with the N20 are you at? If you're over 600 I think you need a beefier fuel system.

bad2000ss

iTrader: (6)

This may be a stupid question, but has anyone thought of doing a fuel purge? I've read many times these direct port systems will have a tendancy to run lean because it take just a little extra time for the short fuel lines to fill before the N2O hits. Perhaps a manual type purge set up to the fuel solenoid to click it open for just a second and let fuel run down the line to the motor. The motor would probably go rich for a second but wouldn't cause any damage.

JF WS6

That's an interesting idea, but I was wondering if the engineers didn't design the NXL to have a slightly delayed feed of nitrous into the rails to give the fuel kind of a "head start" sort of. That might be the reason there is a ever so slight hesitation noted with this kit. It's been noted that it does take a second for the fuel lines to fill up.

I personally was thinking of purging the system at the rails before, but this got me to thinking about if that's a good idea.... so far he's the only guy I've heard doing this and he's the only one I've heard about going lean also.

JS12

i will run it without the purge and see what it does. i will still have that slight hesitation right? the car picked up 125 on the 120 shot at about 975psi. total it was 550/566rwtq

JF WS6

Yeah, try it without the purge, or if it's easy, take the T's off and just connect the nitrous lines straight to the rails. You will have a slight hesitation - NX is coming out with a fix for that soon that will go on the back of the fuel rails in that tapped fitting in the back.

I'm glad someone is finally getting the advertised power on the dyno with how the jets are rated. There was only 1 other person's results posted before and they were like 50HP short of the rated jetting to the tires.

Your Walbro intank pump should be fine up to 600RWHP. Let us know what happens with the purge disconnected from the rails. BTW, really nice HP for stock heads man - especially on just motor. Was that 429 through a 12 bolt or stock rear?

JS12

through a 12 bolt with 4.11's and a steel driveshaft. i also had the shortbelt on which netted me 4rwhp and about 7rwtq. besides slicks i always dyno the car the way i run it at the track. should see some 1/4 times out of the car tomorrow at the GMHTP event. looking for some 10.30s@132ish

L4m3r

I did try to purge the fuel also. First I closed the bottle and purged all the nitrous out.. Then I turned on the nitrous system without the car running but with the ignition on. I tapped the wide open switch 2 times and fuel was pushed into the system.. Ran it on the dyno again, and the spike was actually leaner but not as noticeable of a hesitation bottle pressure was around 975psi. after the spike the a/f was about 11.8:1 and flat. Jamie try it again but dont wait as long as we did after i did the purge.

JF WS6

Hmmm. Interesting. What size of injectors are on Jamie's car? Stock? Just curious. Do you know what the fuel pressure was during the lean spike? If it is the fuel system you'd have a noticeable FP drop I'd think. What's the regular FP?
When was the last time the fuel filter was changed?

I'm just wondering how he went more lean when all you did was introduce more fuel into the cylinders? Or when you ran it again you did it with the nitrous and the bottle opened again. Were you tuning with edit on the dyno or just making runs?

I've heard of the rails being maxed out on fuel before on a system like this, but it's usually pushing quite a bit more HP than 550-600. I could see maxing out the fuel rails on like a 300 shot, but with the 120 that certainly shouldn't be happening. I think there's something else going on there, not sure what though.

L4m3r

maybe i missed the part where i said i cracked the bottle back open and did another run but i dont know the pressure in the fuel system.. also it has the stock 28s that come with the 02

bad2000ss

iTrader: (6)

Very nice info dudes. I've been debating on the NXL or the Noszle kit for a while, and now it looks like people are getting good numbers with the kit. I don't mean to hyjack the thread, but would stock 2000 injectors and pump be sufficient for a 120 or 150 shot?

JF WS6

Injectors yes, because the fuel for the system is provided seperately via the fuel solenoids but you really do need a fuel pump. Especially if you're looking at a 150 shot.

The stock fuel pump is probably only good to about 450RWHP or so, so as long as you're under that you'd be ok - anything above and you will need to go ahead and get a Walbro 340 intank, which when wired with a power wire from the alternator or batt. will support 600RWHP or a little more.

CAT3

iTrader: (9)

JF WS6, actually you have heard of someone else going lean *with the wink of an eye*.

I had logged the lean spike to be about .25seconds, going from stoich, to 22.8:1 afr and down to 10.x:1 in that short little time. There were replies as to that being the "torque spike" so many see on a dyno, from the fuel at 55-58psi and weighing in heavy, trying to catch up to the N2O at 900+psi and light as hell. So, the lean spike I have is obviously nothing related to purging, but the above sounds abuot right. Is there anything to worry about, not that I can see. The dual purge on the end of the rail may make it more noticable, but thats about it.

Charlie.

93LS1RX7

iTrader: (8)

Hey guys this is exactly what I was talking about. The rails lose all pressure for a split second that is why you get that hesitation/spike. NX has an accumulator coming out that you can attach to the rails that will allow the pressure to stay up. "priming" the lines isnt going to work because as soon as the fuel solenoid closes the fuel pressure doesnt stay up it drops because it equalizes the pressure through the jets into the engine.

As far as the nitrous getting to the NXL injector before the fuel that just isnt the case. Believe it or not the fuel gets there before the nitrous does. The nitrous has to travel through the lines then turn back into a liquid at the jet then get pushed into the combustion chamber. It is hard to believe but that is what happens so the purge location doesnt really matter.

Bottomline is that the rails have to build pressure past the fuel solenoid that is why there is a hesitation.

Mike

JF WS6

Aha........ yeah Charlie, I guess I just selectively tuned that out.... I guess I didn't realize that the "hesitation" part actually showed a lean spike. I was thinking they were 2 unrelated issues. My bad...

bad2000ss

iTrader: (6)

Would going lean for a 1/4 of a second cause any serious damage? I've seen people post with NOS 5177 dry kits and other alike that have a slight lean spike on the initial hit as well as others with select wet kits. It almost seems like this is normal for any type of nitrous kit.

JS12

i believe it would. when you hit the nitrous and it has that hesitation that is not very good for the motor, i am not going to spray the car again until i have a seperate fuel system. i cannot live with this hesitation cause the car bogs out of the hole and drops below 3k and then shoots right back up when the juice hits.

JF WS6

I hope someone else chimes in here as I haven't heard anyone's experience with this seem to be as severe so far.

I'm still waiting for parts to complete my setup (accessory stuff not related to the NXL kit directly) so I haven't had a chance to test it out yet, but I haven't heard of anyone's experience being this severe. If the car bogs badly off the line that's definatley no good, you can't get a decent 60' like that.

Maybe CAT3 will chime in here about his experience at the strip - he seemed to be running pretty well with the kit.

CAT3

iTrader: (9)

I havent had that bad a time with it really. JS12 I assume is a M6, and if so that might contribute to the bogging more so, anyway. I logged the car at launch and runs, again it only spikes for a quarter of a second, more so on the first full run, seems to be it gets less of a hesitation after that, but I only got 4 runs off a bottle due to storing in an AC'd room. Duh. So, that was also low bottle pressure at the track, on the testing road...humm I had better bottle pressure and again seen the hesitation time reduced dramatically.
I have run the 3 1/2 bottles so far, no problems really except maybe loose fittings/split o-rings either being my fault.
The car runs just as good on the DP 180 as it did a wet kit 175, but again this was with WAY lower bottle pressure, so I was running VERY rich, and my 60' were slower. So there is more testing this sat, Nov 22, as we in here in Hawaii head out for the Fastest Street Car Shootout. Will post back any new findings.

Good-luck

Charlie.

Slowhawk

iTrader: (12)

Have you guy's tried moving the Nitrous solinoid back so the Nitrous takes longer to hit the nozzle?I've done this before on another kit and really helped the lean spike.On direct ports alot of people make sure the fuel lines are shorter than the N2O lines.