Boost with Nitrous

[phoenix64]

So I still have some questions, kind of related to my previous post about not buying a kit.

Does anyone know if the NOS5175 kit will still richen the mixture the correct amount with a custom tune, and 43lb injectors?

My injectors are running at something like 40-50% duty cycle. Thats why I asked about not using the kit. Makes more sense to just use the extra duty cycle to add fuel.

Boost pressure is already raising the fuel pressure aboove stock levels, will whatever devic that adds fuel with the NOS kit work with or agains this? and can someone explain how the NOS kit adds fuel?

[1DangerousV6]

43# is pretty big...but as long as you have the pump/accessories to support the fuel flow...it should still work fine with a custom tune [img]smile.gif[/img]

[phoenix64]

I heard that the kit adds fuel primarily by cooling the MAF, and causing it to read more air. In my case the MAF is already nearly maxed out, so hopefully I heard wrong.

[ November 22, 2004, 01:33 PM: Message edited by: phoenix64 ]

[12secondv6]

43 lb injectors????

I run 19's.

Explore the route of wideband tuning and HP tuners to make sure.

Difficult question.... but that is a HELL of a lot of fuel!

[phoenix64]

My final goal with the nitrous is 550hp, so I got a lot of injector up front. 255lph walboro as well.

I have both HPtuners, and a wideband. I'm the guy that wants to make his own kit, and tune it using hptuners. I don't understand how using HPtuners to add fuel is any more dangerous than using a kit? I thought it would be safer. Its an awsome program, I know I could get the A/F ratio a lot more exact than some kit would. I'm trying to figure out why a kit would be better?

[phoenix64]

I guess I'll just have to try it.

[1DangerousV6]

Originally posted by phoenix64:
I heard that the kit adds fuel primarily by cooling the MAF, and causing it to read more air. In my case the MAF is already nearly maxed out, so hopefully I heard wrong.

noooo...this kit uses vacuum pressure and a jet installed in a bypass T to increase fuel pressure at the rail when it senses nitrous flow...you can run it after the MAF...but you HAVE to use the bypass T...if you are not using the bypass..then yes...you MUST run it before the MAF...after i removed my blower...i've run it both ways and it seems to run the same [img]smile.gif[/img]

[Nachius]

30-36# injectors should support around 500-550 HP with the proper tune, and would probably be eaiser to tune than the 43s.

How much boost and how big of a shot do you plan on running?

Other than a fuel pump and injectors you will HAVE to have a really good tune, and do you plan on any other supporting fuel mods?

[phoenix64]

Car runs better with 43's, than it did with 22's Why would I run 30-36's? 1 hour with a wideband was all it took to tune it at 12psi. What other fuel mods would you sugest? Bigger rail? Everything with this project has been easier than people said it would be, in particular the tuning, because of HPtuners.

You need bigger injectors with boost for a given HP than you would need with N2o, the pressure in the intake manifold reduces the effectiveness of the injectors. Final goal is 15psi and a 100 shot, but not till I get a built motor.

1dangerousv6 could you explan this t? Does it somehow reroute the the fuel supply? I don't get it, vacume on the FPR would reduce fuel pressure?

[1DangerousV6]

hmmm...its kinda hard to explain..John D explained it really good not too long ago...basically...you should have a big blue thing in between two nitrous solenoids that senses nitrous pressure (you might be able to see it on my site)...a vacuum line runs from that blue thing to another fuel vacuum line in your car...when it meets up with that line it forms a T where you put the fuel jet for 5175 (a 42 i think it is...you can actually adjust this jet too to adjust fuel pressure)...i believe those fuel lines run to the rail and increase pressure there...they do not run to the FPR you use for the boost...try to search posts by John D in nitrous or call NOS tech for a better explanation...but thats the jist of it...if you're not using this on your setup you are probably fine since you run the nitrous before the MAF and you utilize a FPR [img]smile.gif[/img]

[12secondv6]

http://www.holley.com/HiOctn/TechSer.../NOSTech1.html