shortdog

iTrader: (1)

Like the title states. On a FULL bottle with 62N 31F jets at 1000-1050 psi, my wideband showed high 11s during the start of the pass, but it dipped down into the high 10s, low 11s. Bottle pressure was no less than 950 AFTER the pass.

Now, with only two 1/4 passes on the bottle from when it was full, I made two more passes over the weekend with a 150 shot, 62N 31F. First pass, my a/f started at around 11:6, but it dipped down to around 10:6 with my bottle psi still showing 1000 AFTER the pass. The second pass got even richer, 9:6 at the end of the pass with my bottle psi still showing 1000 afterwards also.

The last two passes, could I still get 1000 psi even with the bottle near empty causing it to get richer and richer?
I have the FAST dual wideband. Could the wideband be off?

ShiznityZ28

iTrader: (11)

You can get good pressure out of a empty bottle. get a cheep $10 bathroom scale and keep it with you at the track. not super acurate but when it gets down to 3lbs in a 10lb bottle its gona get rich and loose power. 15's start sucking at 5lbs.

ShiznityZ28

iTrader: (11)

also on a 150 shot 12.2 would be where i start the run and it will probably fade to 11.7 or so but look at the plug and let it tell you. with out rpm fueling your kind of stuck at what ever the bottle drops to down the track.

shortdog

iTrader: (1)

Thanks for the replies. I forgot to mention that I had the same problem with a 200 shot. I used a 78N 41F, but the a/f was still at around 10:6. That wasn't a full 1/4 mi pass though, more like 5-6 seconds. I put in a 38F jet and it leaned it to around 11:3. The bottle was full before the 200 shot passes and the bottle psi got no lower than 950 afterwards. Btw, the fuel psi drops to about 52 psi at wot on the bottle.

I just don't understand why i'm running so rich to where I have to drop the fuel jet several sizes from the nx recommended specs. On motor, my a/f ratio fluctuates from around 12:6-13:2.

I know widebands can be off (which I hope mine isn't) and the best way is to read plugs right after the pass which i've never done. Silly question, but do you guys just pull over on the side of the road and let your car cool off to check them? Pull out a few plugs or all?

ShiznityZ28

iTrader: (11)

All is best but for the most part get #7 or 8 and then the easyest on your car( #2 probably)

What kit do you have? Wheres the nozzle at? FYI all manufacturers run theres a jet or so rich that i have seen. keeps guys from getting the a/f perfect where the timming will bite them. 90% of nitrous guys run to low of octain,to hot of plug ,to much timming and to much fuel. And it lives a long time that way. the second they lean it out to get all of the hp the timming bites them!

on a 200-300 shot 3 degrees of timing out extra will not effect et by more than .05.

whats your timming at?remeber timing effect a/f also

shortdog

iTrader: (1)

I have the basic nx efi kit, but replaced the nozzle with a hsw throttlebody plate. I also have a #4 sho line from the noid to the plate. I use ngk tr6s gapped at around .033.

Before experimenting with a 200 shot, my timing was set at 22.5-23*. Since then, my tuner has taken out an addtional 3* since I may be upping to a 200 shot. I have a timing switch for NA and n20 that he hooked up somehow by tapping into the coolant sensor wire from the computer.

ShiznityZ28

iTrader: (11)

so your at 20* ?

I have not used that plate much but nx's recomndatyions are out the window when you change to the plate.

go down 1 fuel jet and let us know what it did to the a/f also pull a plug and get a pic after the run.

Nick@HSW

iTrader: (4)

There could be quite a few things going on. I don't see anything too abnormal with your a/f throughout the run as far as the decline is concerned. You're always going to see a pressure drop which is going to affect a/f unless you do a push type set-up. There are however ways around drastic pressure drops. If you're concerned about the a/f ratio itself, that's easily changed with jets.

Just a few thoughts...are you sure you got a full fill? If you're not sure, I would do as the post above stated, just pick up a cheap scale and verify after each fill. Are you running a nitrous filter? If so, have you cracked it open to check for debris? If not, have you inspected parts for blockage?

Concerning the a/f, I would pull some plugs just to verify what is actually happening in the cylinder. At the very least I would verify the wideband accuracy. If you're going to jump up to the 200 shot, verify you have the components capable AND verify you'll be running the correct timing and correct plugs. I wouldn't recommend the TR6's that you currently have.

One last thought, on the fuel line from the solenoid, what size is it? Thanks.

Nick

shortdog

iTrader: (1)

According to my tuner, I'm at 20* when I flip the switch. The jet sizes that came with the plate are same sizes as the nx jets .

The bottle is being filled as I watch the shop refill it on the scale. It weighs close to 26 lbs after the refill (I have a remote opener, regulator attached) I am also running a nitrous filter that I purchased last year, but I didn't realize I can open it up to inspect it until now. A new n20 line and rebuilt n20 solenoids were also done last year as well. The fuel line is what came with the kit which I believe is a #3. As far as the plugs, I see TR7s should fit the bill. I also hear Autolite AR472s are great for big shots of n20 also. Will a colder plug hurt my NA performance?

When we put the 200 shots jets in and made some passes, the tuner logged the passes with his hptuners and said there was no knock.