Jetted up to 125hp tonight...
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I had mys hsw wet plate kit jetted at 100 for about a week. It ran fine with no issues. On the Gtech, no track times sorry, it ran 14.47 @ 103. That was with a passenger and a full bottle at about 900 psi. I have the timing tuner and timing was advanced 3* on the motor and 0* (stock timing) with the nitrous on.
After jetting up to 125, it ran 14.57 @ 100. It felt quicker in first gear, but second and third felt the same as the 100 jetting. The bottle pressure was lower at 800, and there was only about five pounds in the bottle. The bottle is mounted sideways behind the seat. I noticed that in third it felt like it was surging.
After letting it cool, I made another pass and this time it ran even slower and I had to get out of it. In third it stumbled and it felt like it went rich and lost power, but at the same time I got a check engine light. Code P0300, engine misfire. I havent pulled the plugs after that run, but I will tomorrow. I hope it was going rich rather than lean, but does anyone here know what might be going on? I'm also thinking I need to pull timing, but the last time we scanned it, the timing was in the low 20's.
After jetting up to 125, it ran 14.57 @ 100. It felt quicker in first gear, but second and third felt the same as the 100 jetting. The bottle pressure was lower at 800, and there was only about five pounds in the bottle. The bottle is mounted sideways behind the seat. I noticed that in third it felt like it was surging.
![](http://i252.photobucket.com/albums/hh4/chevy_truck_guy/bottle1.jpg)
After letting it cool, I made another pass and this time it ran even slower and I had to get out of it. In third it stumbled and it felt like it went rich and lost power, but at the same time I got a check engine light. Code P0300, engine misfire. I havent pulled the plugs after that run, but I will tomorrow. I hope it was going rich rather than lean, but does anyone here know what might be going on? I'm also thinking I need to pull timing, but the last time we scanned it, the timing was in the low 20's.
Last edited by chevytruckguy; 03-27-2008 at 12:39 AM.
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What size are your jets? I bet you have the fuel jetting for a 150, if so that with low PSI caused a rich shot. I spray @ 1100-1200 PSI.
Also make sure you put the right jet in the right spot.
Nitrous jet = bigger number, this will also cause a very rich shot!
Having a half empty bottle does not help in maintaining pressure either, id def. recommend a bottle heater!
Also make sure you put the right jet in the right spot.
Nitrous jet = bigger number, this will also cause a very rich shot!
Having a half empty bottle does not help in maintaining pressure either, id def. recommend a bottle heater!
Last edited by Derek @ EDO; 03-27-2008 at 12:53 AM.
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I checked my jets and I have the right ones in there. The bottle placement might be the problem. I want to pull the plugs and see whats going on in there to be sure. Thanks for the info.
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I believe the pickup tube in the bottle is at a slight angle.It would only pick up liquid if the bottle was mounted correctly once you run past a certain level.Low bottle pressure is not helping optimal is around 1100 psi.How are you getting your bottles filled.Hopefully you are freeze filling.
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Sounds like low bottle pressure....get the bottle re-filled and make sure you have the psi to the recommended amount. Remember the jets are rated for the psi. So a 125 shot jet is only a 125 shot at the recomended 950psi. So when your at 800 psi it is less than 125 shot.
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i had the same problem, i have my bottle mounted on the humb in the back of my crew cab. with the label faced up and the valve towards the front?...that sound about right. Whenmine missed like this i was running like 800 some punds of pressure. I took the bottle and put it in front of the floor vents and cranked the heat wide open and it made the biggest difference.
Also i have the MSD Digital Switch. I am kinna new to this kinna electronics, i have always run nitrous on a WOT micro on the Carb. When i dynoed my truck it made peak hp and torque at 5500 rpms. I am running a stock verter and it stalls about 1600-1700. Were should i set the on and off on the window switch?...also my cam range was like 2000 to 6000rpms. if that makes n e difference
Also i have the MSD Digital Switch. I am kinna new to this kinna electronics, i have always run nitrous on a WOT micro on the Carb. When i dynoed my truck it made peak hp and torque at 5500 rpms. I am running a stock verter and it stalls about 1600-1700. Were should i set the on and off on the window switch?...also my cam range was like 2000 to 6000rpms. if that makes n e difference
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I think optimal is 1000-1050, no need to go any higher going over somtimes makes it more difficult for noids to open. Bottle angle is a big deal too since the force of taking off make the Nitrous go to the back and bottom of the bottle where the pick up tube is. Low bottle pressure only adds to you mounting location problem. Do what everyone else said, refill the bottle and remount.
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I checked the plugs this morning and they were ok. No melted electrodes or signs of detonation, and regapped to .035. The plugs looked a little black on the plug base, so I dont' think its leaning out. Weighed the bottle and it was nearly empty, so it tells me its low pressure causing the misfire, i.e. rich. I'm filling the bottle tomorrow and going to run it again with a full bottle. Before I move the bottle, I'm going to try turning so its more level, not so tilted, since my truck isn't pulling that hard in second and third. If this were a faster vehicle, I'd leave the angle alone. If this doesnt fix it I'm moving the bottle and mounting it vertical.
I have my timing tuner on at 2750 and off at 5900. I'd like it to turn off lower, but thats all i get. I have a pushbutton so I can turn it off during the shifts. If its a close race, I'll spray through the shifts
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I have my timing tuner on at 2750 and off at 5900. I'd like it to turn off lower, but thats all i get. I have a pushbutton so I can turn it off during the shifts. If its a close race, I'll spray through the shifts
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