Boost a Pump/Injectors for NA + Nitrous motor

[2001 GTS]

I'm shooting for 500rwhp on motor with modifications to the heads/lifters/rockers/exhaust, and was wondering if I need to boost the stock fuel pump or go with bigger injectors to have enough fuel.

I'll be spraying a 150 shot once in awhile too.

 

[Russ M]

If you truly make 500rwhp NA than you will be just over 100% duty cycle on your factory injectors, which means no additional fuel can be supplied. This is fine for NA since there is no need to be very rich on the air/fuel.

But your nitrous is a different story. Is your nitrous a dry kit?

 

[Simms]

I have some 50lb (it may 53lb) black top low impedance injectors for sale (and a boost a pump) if you are interested.

 

[jay01m]

If you truly make 500rwhp NA than you will be just over 100% duty cycle on your factory injectors, which means no additional fuel can be supplied. This is fine for NA since there is no need to be very rich on the air/fuel.

But your nitrous is a different story. Is your nitrous a dry kit?

IMHO, 100% duty cycle is no good for your injectors, or your PCM, as your PCM will be working more to command the injectors since there is so little time between pulses, same with injectors. A rule of thumb I abide by is no more than 80% duty cycle on your injectors. Believe me when I say it will make a huge difference with the fuel trims, A/F mix, and overall performance.

Just my $.02.

 

[2001 GTS]

The nitrous is wet...about 150 to the wheels.

Right now I put down 600rwhp on nitrous with no fuel issues with the stock motor.

So what size injectors should I go with?

 

[Russ M]

While I agree with what jay01m is saying the new school of thought is that close to 100% is fine, factory vipers run over 80% duty cycle.

I don't think you need bigger injectors, but you will need to subsidize your factory pump with something. Maybe a few pusher pumps like the paxton setup, or maybe a boost a pump will be enough.

The most I have seen a totally stock pump provide is 670rwhp, can it make more? To find out hook up a fuel pressure gauge and do some dyno pulls. Watch your fuel pressure like a hawk, if it starts falling then you need to get it sorted.

Either way just make sure the air/fuel readings you are getting are from 02 sensor locations, not tailpipe.

 

[2001 GTS]

How do I get the dyno person to read from the sensor location? Do I need to put something in the header that they can read from?

B&B headers btw

 

[Steve Kleva]

I made 515 at the tires NA. Modified the stock bowl to fit 2 walboro 255s and ran a return with a regulator. Running a 200 shot at the moment and upping it to a 250 with race gas. No drop in fp on bottle. Made 605/725 on a mustang dyno on the 200. I made it a return style because the initial hit of nitrous will drain the rails. This way it maintains fuel pressure. Still running stock injectors. If your running a dry shot youll need to go larger. I suggest at least running a BAP.

Some shops will use a wideband that it placed inside the exhaust pipe. Works but not as accurate as running one more upstream. They will either replace one of your rear o2s with the wideband sensor or put an additional **** in.

what are you cutting for 60' times?

 

[Jack B]

How do I get the dyno person to read from the sensor location? Do I need to put something in the header that they can read from?

B&B headers btw

Merely take out the factory sensor and have them install theirs. Take along a 22 mm wrench, just in case. The heat shield is best taken of with a long 1/4" extension.

 

[2001 GTS]

The computer won't throw a code with out the O2 getting a reading?

and...1.77 60ft when I ran a 10.9

 

[2001 GTS]

Also with the fuel coming off the test port for the nitrous...would there be enough fuel with the stock pump@55 psi to support 650rwhp?

 

[2001 GTS]

Bump

 

[jay01m]

I would say for 650HP, I'd get a boost a pump, which should keep things stable. As for injectors, I'd up those as well to at least the 40-lb neighborhood, just my $.02.

I'd consider taking Simms up on his offer.