surge topend

General Nitrous Discussion

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jaspermaggie
Posts: 212
Joined: Fri Mar 14, 2008 2:52 pm
Location: Plano Texas

surge topend

#1 Post by jaspermaggie » Tue Oct 05, 2010 5:49 am

I made 3 runs fist nitrous off. Second did grate. Third had a surge on the topend. It went off on off on off then just got out. It was about 5200 rpm 6200 red line. It was about 80* I have a heater and blanket psi was almost 950 bottle was 21lb out of 25. I run 125 nos shot. I do have a fuel switch. Think it is the switch or bottle or something else?
My car is not as fast as I think it is.

silvanova
Posts: 143
Joined: Sun Aug 27, 2006 11:55 am
Location: KY

Re: surge topend

#2 Post by silvanova » Tue Oct 05, 2010 7:43 am

Does it have a hobbs fuel switch? How are you turning the nitrous on?
5.004 @142.6

jaspermaggie
Posts: 212
Joined: Fri Mar 14, 2008 2:52 pm
Location: Plano Texas

Re: surge topend

#3 Post by jaspermaggie » Tue Oct 05, 2010 6:42 pm

I use an msd window 3200 on, activated with switch on the cab. It is an nos safety switch.
My car is not as fast as I think it is.

silvanova
Posts: 143
Joined: Sun Aug 27, 2006 11:55 am
Location: KY

Re: surge topend

#4 Post by silvanova » Tue Oct 05, 2010 7:51 pm

By-pass the safety switch and see if it still shuts on and off. What is your jet numbers and fuel pressure?
5.004 @142.6

71Hellride
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Joined: Sat May 30, 2009 7:35 pm

Re: surge topend

#5 Post by 71Hellride » Wed Oct 06, 2010 9:50 am

I'd say it's the fuel pressure switch, but could also be the rpm switch. Seen guys talk about them messing up and turn the nitrous on and off. Jump the fuel switch first, and if it doesn't fix it bypass everything with a push button switch just so you know it's keeping power. Like Tommy said it the tune ups could be extremly rich making it seem to shut off. :-)

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John_Heard
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Re: surge topend

#6 Post by John_Heard » Wed Oct 06, 2010 10:15 am

Just pitch the fuel pressure switch, you'll be wondering it that thing is causing problems forever if you leave it in the circuit. Keep it as simple as possible.

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