nitrous

[redsnake97]

i have a 97 cobra stock, i bought a nx 150 dry shoot from a buddy, i also bought a 75 shot jet nosel(to convert it to only 75 shot), so is 75 safe for my motor. oh yeah my motor only has 5000 miles on it.

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[hj16]

Back when I was a NA 2V owner and dreamed of 96-01 Cobras I researched this alot. The general consensus is that 100 and below is safe with a good tune... 125 is safe with a great tune... and 150 plus is on borrowed time no matter what tune.

If I went 125 Id mix the tank up to 96-97octane just for added safety.

 

[Snowman]

75 is safe for the motor. When you get to 100 back off 2 degrees of timing and switch to copper plugs 1 heat range colder(you will need a tune). When you get to 125 take out 4 degrees of timing(another tune). With 150 things tend to get a little lean around 5800 rpm as the injectors start flowing their max. These things like about 900 psi of bottle pressure so if you like get a bottle heater.

 

[abad46]

In my 97, I ran a 150 dry shot for many years and many miles! Stock injectors, I got a base tune with 900 psi bottle pressure, and ran it and ran it and ran it! I had a in-tank 255lph fuel pump, and a external 255 to keep the pressure for added insurance. I ran the stock 24lbs'ers and shifted at 7200 rpms. Before you do anything, check/clean your IMRCs.

 

[abad46]

the biggest thing if you are going to go drag racing at the track is if you don't have a gear, be careful on the launch, and launch as high as the stock rev-limiter will let you, if you bog...Nitrous backfires happen all to quickly and easily!

 

[abad46]

With 150 things tend to get a little lean around 5800 rpm as the injectors start flowing their max.

I don't agree with this. Everything else I do.

 

[Snowman]

That is because you upped your fuel pump.

 

[abad46]

That is because you upped your fuel pump.

Then your injectors aren't maxing out, are they? You should correct your statement to say, the stock fuel pump will max out!

 

[Snowman]

Then your injectors aren't maxing out, are they? You should correct your statement to say, the stock fuel pump will max out!

With the stock fuel pump pressure exactly. BTW what is your fuel pump pressure now with the 255? Also are you running a wet kit?

 

[abad46]

I ran a dry shot 150 and the fuel pressure with nitrous activated was like 85-90 psi w/o nitrous was stock 45 psi.

 

[voj]

no2

Dry kits are nice because they do not have fuel flowing through the manifold (no backfire), but rely upon the computer to compensate for the added fuel. Dry systems will cause a/f to be off as all of the cylinders will not recieve the same amount of air/nitrous (lean & rich cylinders).

Wet kits do not rely on the computer for extra fuel, but rather injects fuel independently through a nitrous/fuel mixture through the manifold. The flowing fuel through the manifold will cause a backfire (puddling fuel) if sufficient air velocity is not achieved (~3000rpms).

75 shot-hardly noticable
100 shot-"safe"
125 shot-"safe" fuel support needed
150 shot-borrowed time

A tune would add safety (especially w/ a dry kit).

 

[abad46]

Dry kits are nice because they do not have fuel flowing through the manifold (no backfire), but rely upon the computer to compensate for the added fuel. Dry systems will cause a/f to be off as all of the cylinders will not recieve the same amount of air/nitrous (lean & rich cylinders).

Wet kits do not rely on the computer for extra fuel, but rather injects fuel independently through a nitrous/fuel mixture through the manifold. The flowing fuel through the manifold will cause a backfire (puddling fuel) if sufficient air velocity is not achieved (~3000rpms).

75 shot-hardly noticable
100 shot-"safe"
125 shot-"safe" fuel support needed
150 shot-borrowed time

A tune would add safety (especially w/ a dry kit).

If you know how to use it, and how it works, it will last for as long as you want. What "computer" are you speaking of for a dry shot...If you mean extra solenoid to reference nitrous pressure to the fuel pressure regulator to boost fuel pressure for added fuel, then ok.

 

[voj]

If you mean extra solenoid to reference nitrous pressure to the fuel pressure regulator to boost fuel pressure for added fuel, then ok.

Correct.
Depending on the system you have, there may be an extra solenoid to pressurise the fuel rail to add more fuel, or to increase the time the fuel injector stays on. The key is to not get greedy and test how much your engine can take.

Either way, the system you choose comes down to preference...