Finally A Run With Nitrous But Inconsistent? Whats Wrong With These Times???

[1jimmy__d]

Ok i finally made it to the track with the nitrous (80 shot)working good. I filled her up and went to the track tonight and ran 4 passes"ill mention three (missed a gear in one pass). My previous best run was a 14.2 at 98. Here are my times for the three runs in order!


60' 330 1/8 mph 1000 1/4 mph


1) 2.16 5.93 8.92 82.65 11.46 13.59 105.85


2) 2.3 6.2 9.3 80.5 11.8 14.0 104.69

3) 2.2 6.2 9.2 80.8 11.8 14.0 104.27


I am very happy with the first run- I had the nitrous turned on ands ready B4 each run. I pretty much punched it from 2nd gear on and the first run it hooked up after a little spin but felt great. The other two runs, I did not feel the pull like the first one. I knew the nitrous kicked in strong the first run, but the other two didnt feel as strong. WHY is this happening? IS it because there was more pressure build up in the first run? If so, is there a way to purge the system after every use of nitrous? Im happy with the 13.5, but didappointed with the 14.0's! Whats wrong? Thanks a lot for any replies.

Jim

[VeNuM]

You can get a purge valve to ensure there is no air in the lines.

[Chris_H]

I am not the most educated person on this site when it comes to cars, but from the looks of it, you have a traction problem. What kind of tires are you running? I know I was getting pretty dissapointed the day I ran with slicks and couldn't break into the 13's at our high elevation. I wasn't getting good 60' times. They were all in the 2.0's. Once I got it into the 1.81, I was able to pull off a 13.88. Once you get those first 60' down, then in my opinion you should be getting a lot better times. Until then, I doubt they will get much lower. Just my opinion from experience. Hope this helps.

Chris

[Mustang_289]

Chris - what did you do to get your 60' times down with slicks? Did you change anything on your suspension?

[Chris_H]

Didn't do a thing to my suspension. I am actually running a completely stock suspension right now, right down to the bushings that came with the car 15yrs ago. I ran a total of 16 times that day, 14 of them on slicks. It was no more than 40-45* outside at the time. I ran about 12psi in the slicks, and on the 13.88 run I heated those slicks up better than I had all day. I had a buddy (who owned the slicks) stand off to the side where I could see him, and tell me to keep spinning them. When he felt there was decent smoke coming off of them, and that they were warmed up enough, he told me to roll out of the burnout. I have noticed that anytime I race with slicks, the more consistent the burnout, the more consistent the run. I was cutting 2.1's for the majority of my runs, a few 2.0's and then finally got it down into the 1.9's and then the 1.81. If you are running slicks, play with the air pressure, and work on the burnout. BTW, we're using the 26x8 MT ET's. Hope this helps.

Chris

[Eric4Nitrous]

Your times sound like your spinning the tires and not hooking. The first 60ft of the race is the most crucial. After that it gets easy. If you can cut a good 60ft your on your way to a good timeslip. Second of all, yes you can purge your nitrous after every use of it. I purge mine all the time and have had no problems. Third, what was your bottle pressure at..and what was the conditions like? I might be able to give you a better tuning advice for the weather. Weather plays a big role in tuning a nitrous car. For instances like this, Hot and muggy, you either have to take timing away, or add it..add fuel, take fuel away. It's all a guessing game.

[bigblockcoupe]

one other thing what was your bottle pressure? it needs to stay between 950-1000 psi for maximum nitrous flow otherwise you will be dumping in too much fuel for the amount of nitrous being delivered if you don't have one get a gauge and a bottle heater pressure is critical you don't want to pull up next to a camaro you should smoke and hit the nitrous and have your car fall on it's face because it dumped in a ton of fuel and just a little nitrous because the bottle pressure was only 600psi. also did you regap your plugs after you put on the nitrous i usually recommened .035-.040 for nos.

[1jimmy__d]

I was running street tires with the normal psi in them. My suspension is totally stock. I wanted to stay away from the "extra" nitrous accessories. The temp was in the 70's with mid to high humidity (dont have the slip with me). I dont have a bottle pressure reader or fuel pressure gauge, so i dont know them. MY plugs are gapped at the right gap .035. It ran pretty good over all. But, I dont think it has to do with the tire pressure or temperature. My first run was the best, and it was the first one on the bottle. So im thinking it has to be the bottle pressure. How do i purge it each time? Can i turn the bottle off, and then on (would that matter?) I want to stay away from buying the heater, and pressure gauges (my wife would kill me). I know the nitrous was working a little bit the other two times cause my best ever B4 the NOS was 14.2 and that was last year. I did kick a camaro's *** on the 13.5 run though!

[JaxTheDJ]

I am only guessing,but from your sig you need subframe connectors and drag radials,if you want sub 1.8 60's you also need to change the uppers and lowers and the stock springs,you were probably spinning like mad. also did you let it cool down between runs? if not the extra heat will KILL your times,Stangs dont like heat.....cool it down good between runs and work on the suspension and watch your 60's drop... good luck.

[tireburner163]

Those "extras" are very helpful....you should get them

Also look at your 60 foot times.....you were spinning more on you 2nd and 3rd runs....that's prob. a lot of it.

I doubt it was bottle pressure.

[fiveohpatrol]

your 60ft and 330ft times are absolutely that cause of your inconsistent times. see how the 330ft slowed down by almost 3 tenths? I'm guessing your best run, it hooked up in 2nd gear and pulled hard right? and your other runs, you hit 2nd and it spun.

If you dont use slicks, or atleast dragradials, then you should not have your nitrous on in 1st gear. Its a waste of nitrous in 1st gear with street tires because all it does is spin. My suggestion would be to hit the switch about halfway through 2nd gear, and go from there.

But if you really want to see some good ET/mph's you are gonna need traction of some sort. Street tires and drag strips are not a fun mix, you'll go home dissappointed most of the time.

Chris_H, how were you launching on those slicks to get 2.0 60ft times? Dump the clutch at 3500-4000 and you'll have 1.7's easy.

[Dark_5.0]

Do your self a favor and ditch the street tires. Your ET's will drop Alot.

You definitely need to get a pressure guage for you nitrous bottle. Your wife probably won't kill you, as the guage is only $15-$20 and screws right onto the bottle with a T-connector, or under the hood by the nitrous solenoids. I guess this is a dry system you are running, kit#5115? You did retard your timing down to around 8 degrees BTDC before the nitrous run, right? Who installed the system? Did you? You can get a under the hood fuel pressure guage (again, fairly cheap...maybe $30??) that screws right into the fuel line on the passenger side of the engine compartment, where the stock Schraeder valve is. I don't remember the exact details because it's been a while since I've done it...but you can test your NOS system to make sure it is working properly and that your fuel system is boosting the fuel pressure up to the desired 80-85psi. The NOS techline can walk you through the test if you don't have the manual that came with the kit. The test instructions are in the manual if you still have that though. Do you still have your stock fuel pump? If you do, the stock pump doesn't flow enough volume to boost the fuel pressure up that high. Just some things to think about. Let us know if you figure this thing out.

[1jimmy__d]

I didnt spin hardly at all in 2nd gear (even when i felt the nitrous kick in)! I have a new theory! I think that the nitrous wasnt working at all during the other two runs, which is why they are 14 flat (what i should be rtunning with my mods, right?). I was on my way home tonight and hit the nitrous to see if i could feel it, and all i heard was a "click" when i punched it. It sounded like it came from right behind the toggle switch. Sounded like maybe dropping a penny on a pan or something. Anyways, maybe something is wrong with the system itself. Everything looks like it is still tight and the fuse isnt blown! I tested my fuel pressure two weeks ago and it was fine ( I have previous posts about that from then). People told me that i have "plenty" of fuel pressure and that stock fuel pumps should be plenty of fuel! So do you think you klnow what that "click" might be. I cant feel any pull at all now!

Thanks!

PS it is a 5115 kit and the timing is retarded to wher people said it should be! 10 i think it was! Brand new plugs a degree colder and gapped at .035!

[NotchJohnson]

Are you sure you still have some nitrous in the bottle? That click could be the solenoid. Maybe you have a slight leak somewhere and it all leaked out last night. Good Luck man - John

The clicking was most likely the nitrous solenoid. Do you still have the manual that came with your kit? If it is kit#5115 from NOS then I could e-mail you the instruction manual. The manual has a couple of different ways to test your system, not to mention troubleshooting questions and answers. Give me your e-mail address if you need it. Did you install the nitrous kit yourself? Sounds like you need to go through your entire system to pinpoint your problem.

[1jimmy__d]

i had my mechanic who works from his own home garage install it- he knows what hes doing- I dont. I took the bottle out and weighed it- i still have 7-8 lbs left in it. I hooked it back up and opened the bottle and i heard the nitrous flow through the lines. I dont know whats up. I will call him and see if he has the manual still. what a pita! Simi, i will email you if i need the manual- i appreciate the offer.

thanks for all responses!

Can someone tell me how to purge the system each time you run?

You should ask that mechanic if he used teflon paste or tape. If he knows what he's doing, then he should have known that you should not use the tape. It can clog up your solenoids. You should check out your nitrous filter (before the first solenoid). Unscrew it with a wrench and check to see if there is any debri in there and clean it out. You may want to unhook the nitrous line from the bottle & the tank and blow compressed air through it to make sure there is no blockage.
Is this the kit#5115? If so, you have a fuel pressure safety switch that is hooked up to your fuel line (where the Schreider valve is on the passenger side of the engine compartment). This switch detects if your fuel system is not supplying enough fuel "volume" to make the adequate boost in fuel pressure. If at any time during a nitrous run, your fuel pressure drops below 85-80psi., this safety switch will not allow the nitrous to go into your motor. It's a great safety feature which should never be bypassed. If your stock pump is still in your tank, than that is most likely your problem. You should upgrade to at least a 155lph intank pump, if not a 190lph intank pump. That should be sufficient for nitrous shots up to around 100hp. If you ever want more juice than that (like me!) you would have to install an additional external inline pump to boost the volume of fuel even more to mix with the additional nitrous.
You really don't need to purge the system. Let alone, after every run. The little bit of air that is in the 14-20 inches of the braided nitrous line, between the NOS solenoids and the throttle body is the only place that "regular" air can collect. I doubt you will feel a difference between a non-purged run and a purged run. But that doesn't mean don't get one. I just don't think that is your problem. Although purge valves do look cool as hell! I'll be getting one eventually, but not so much for the performance gains. LOL. Let us know the outcome.

[fiveohpatrol]

I asked an NOS rep about the fuel pump matter with the #5115 kit which is the one i have. NOS says that the stock fuel pump (in good working order) is fine for the 75-100hp settings. They also said that a 255lph intake pump is enough to support the 175shot which is the highest you can take this kit without doing other mods to the kit besides the jets and shim.

I would also suggest asking your mechanic if he used teflon tape on the fittings. It says specifically in the directions to use only a teflon based paste on all pipe fittings and NOTHING on the AN fittings.

Also make sure that your WOT microswitch is being depressed when the car is floored. Its kind of a cheap setup with that kit (if thats the one you have) and it seems like it could be moved easily, and therefore cause the system not to work.

[1jimmy__d]

ok i called my mechanic and talked to him for a brief moment (he was running ou t the door). He mentioned what you all had said. He did NOT use teflon tape. He said to check the filter and the line that runs to the throttle body. I un screwed the line to the manifold first and saw nothing in there clogging it up. I then unscrewed the line from the bottle to the solenoid (is this where the filter is?) when i did this, i could hear the nitrous coming out and it turned to ice for a second (pretty cool). Anyways, I didnt see any screen or filter (is it an actual screen?) I hooked it back up after. I drove it and turned the switch on and then punched it in third gear and felt nothing again. I then tried again and instead of starting witht the toggle on, I punched it and THEN flipped the switch and did feel the NOS kick in. I only kept it floored for like a second. ( I dont want to waste everything thats in the bottle just to diagnose).

Anyways, did i disconnect the right line (from the bottle to the solenoid) for the filter? It looked just like a regular line to me!

I really dont think its the fuel pump, but then again what do i know.