Limit of stock fuel system

[dustbuster]

I have read that the 3.0 fuel system doesn't have much capability left in reserve. So I am wondering, if I use an adjustable pressure regulator, how much more fuel pressure is safe for the stock injectors and pump? (I guess the stock fuel pressure is about 45 psi)

I am considering a 50-ish dry shot of nitrous (I don't have a turbo) and I need the absolute cheapest way to increase the fuel

[Harvii]

Quote:

Originally Posted by dustbuster I have read that the 3.0 fuel system doesn't have much capability left in reserve. So I am wondering, if I use an adjustable pressure regulator, how much more fuel pressure is safe for the stock injectors and pump? (I guess the stock fuel pressure is about 45 psi) I am considering a 50-ish dry shot of nitrous (I don't have a turbo) and I need the absolute cheapest way to increase the fuel

Probably a B&M Command Flow AFPR kit. I think summitracing.com carries them for ~$60

[c2xejk]

How much capability depends on how you setup the system... For normally aspirated setups, nothing needs to be done to support a bunch of extra hp. The stock computer is very adaptive...

For a turbo, auxillary injectors and RRG's need to be used when in boost. So far the stock pump has been able to keep up on Stein. I have turned down the base pressure, used oversized injectors, RRG, and auxillary injectors... So far DaytonaStein has put out enough power to pull off a 98+MPH run with two people in the car...

The fuel pressure deadheaded at 78-80psi... plenty of fuel and still more available...


For nitrous I would recommend a wet setup (ie nitrous and fuel.) No need for AFPR or RRG.

[dustbuster]

The only B&M Command Flows I can find are for Hondas and the 95-99 Eclipse 2.0 turbo (but they're only $40 on jazzproparts.com).
Will the mitsu one fit on my Duster 3.0? I thought all the engine management stuff was Chrysler parts.

Ebay has some universal regulators with built in gauges for about $40, I was thinking about getting one of those, but I'm not sure how precise the adjustability will be on them.

[dustbuster]

Quote:

Originally Posted by c2xejk How much capability depends on how you setup the system... For normally aspirated setups, nothing needs to be done to support a bunch of extra hp. The stock computer is very adaptive... For a turbo, auxillary injectors and RRG's need to be used when in boost. So far the stock pump has been able to keep up on Stein. I have turned down the base pressure, used oversized injectors, RRG, and auxillary injectors... So far DaytonaStein has put out enough power to pull off a 98+MPH run with two people in the car... The fuel pressure deadheaded at 78-80psi... plenty of fuel and still more available... For nitrous I would recommend a wet setup (ie nitrous and fuel.) No need for AFPR or RRG.

The one thing I'm worried about with wet-nitrous (at the throttle body) is pooling of fuel in the manifold. Do you think this is a concern? The bottom is nice and flat, looks like a good place for fuel to collect.

[Boogieman142]

port the plenum if ur worried about it. I wouldn't be worried about it.

[Ondonti]

the dry setup will run like crap.

[dustbuster]

Ok, wet it is, I kinda figured that.
I saw some Zex kits on ebay for around $200, that sounds like a good deal. Zex sounds like a good system, and it will probably work much better when I do the turbo too.

[mwinkle353]

Keep in mind that the stock pump is only good to about 240-260hp. Now matter what size injectors or extra fueling components you install, that pump just won't flow above that power level without leaning out.

[c2xejk]

Quote:

Originally Posted by dustbuster The one thing I'm worried about with wet-nitrous (at the throttle body) is pooling of fuel in the manifold. Do you think this is a concern? The bottom is nice and flat, looks like a good place for fuel to collect.

I don't believe that fuel puddling is a significant issue. A bigger issue would be variations in fuel charge going to each cylinder... So far on Stein, cyl 5&6 appear to run a little richer than rest. (based on pulling the sparkplugs.)

[c2xejk]

Quote:

Originally Posted by mwinkle353 Keep in mind that the stock pump is only good to about 240-260hp. Now matter what size injectors or extra fueling components you install, that pump just won't flow above that power level without leaning out.

The exact limit of the fuel pump _is_ effected by fuel pressure. The higher the pressure, the lower the hp limit.

That said, I would bet you can squeeze a little more out of the pump if you are creative...

[mwinkle353]

voltage augmentation.

[Ondonti]

Quote:

Originally Posted by c2xejk The exact limit of the fuel pump _is_ effected by fuel pressure. The higher the pressure, the lower the hp limit. That said, I would bet you can squeeze a little more out of the pump if you are creative...

That is strange. On my turbo 3.0 spirit, I had 5& 6 going lean under boost......I figured this was because air was being forced to the rear cylinders with my backwards plenum.

You running 5&6 lean worries me though. That doesnt make sense.

[c2xejk]

I have two cold start injectors that I think provide a little more fuel to 5&6 than to 1-4... Plugs 1-4 looked "right", 5&6 looked slightly rich...

[c2xejk]

Quote:

Originally Posted by mwinkle353 voltage augmentation.

Just running big wires to the fuel pump would probably be good enough to get atleast another 5-10 hp worth of fuel out of it... From their you could always add one of those devices to boost fuel pump voltage.

With my current setup, turning down the voltage (when the manifold is at vacuum) would help me get a little more hp out of the stock pump. Then I could turn down the base fuel pressure a little more and run larger injectors...