fuel delivery problems at the strip

[othtim]

Hi.

So I'm running an 83 monte w/ a 350. Car has a rebuilt and modified quadrajet. I've got a problem where when I get about halfway down the track the car starts leaning out and eventually stalls. It is running out of fuel. I've been told (and i've read online too) that this is because the q-jet has a small bowl. My qjet was modified by a local speed shop but the bowl size was not changed. I currently have a mechanical carter OE replacement pump.

Some people at the track were suggesting that I buy an electric booster pump and put that near the tank, and switch on when I'm at the track.

How would I go about resolving this issue? I realize my fuel pump is OE replacement quality. I have a holley 110 GPH mechanical pump too, sitting on the shelf. I'm open to suggestions on how to resolve this.

 

[pontiacgp]

I got this from the guy who builds my carbs...

"get a larger needle & seat assy. AC Delco's part number 30-142 has a .135". Stock is .125" on most Q-Jets. If your still running out of fuel use the Edelbrock's part # 1980 which has a .149" opening (this is used primarily for racing and can flood a street carb)"

 

[othtim]

How would that help. The problem is the float bowl is empty at half track. how would getting a larger needle and seat help?

 

[74hotrodmalibu]

yea thats not the carb put on that booster pump I would almost guarentee your starving it for fuel my buddy that races street class had to do same thing on his DD when at the track , just flip the pump on and will deliver more fuel the quad just cant keep up at track for pulling fuel thru a stock pump

 

[pontiacgp]

How would that help. The problem is the float bowl is empty at half track. how would getting a larger needle and seat help?

the larger seat and needle allows more fuel to flow so with a good pump you might not be starved for fuel....you don't just start off with a full bowl and that's all you get for the race...

 

[AlanB]

I agree with others that I think your problem is fuel delivery, not the carb. I was running a stock pump and would run out of fuel at the top of 2nd gear. I changed to a Carter Super street mech pump and that solved the problem. I'm running the stock quadrajet needle and seat with no bowl mods. Carter makes a strip version of the same pump, but that one requires an external regulator due to the higher fuel pressure.

 

[othtim]

I agree with others that I think your problem is fuel delivery, not the carb. I was running a stock pump and would run out of fuel at the top of 2nd gear. I changed to a Carter Super street mech pump and that solved the problem. I'm running the stock quadrajet needle and seat with no bowl mods. Carter makes a strip version of the same pump, but that one requires an external regulator due to the higher fuel pressure.

Alan, what are the specs on your motor? My motor should be putting out around 330-350 HP at the crank. It's a 350. I dont know how much higher I want the pressure because I dont want to have problems with TOO high of a pressure. Qjets like low pressure, high throughput.

I'll check out hte Carter SS pumps. Thx.

 

[pontiacgp]

I though you were running more power than what you are and that's why the suggestion about the carb

 

[othtim]

oh, okay.

 

[shotgun]

Qjets are used to get into the 9z by SS guys so I doubt the carb is the issue.

As suggested , the Qjet does not have the reserve a Holley has so the supporting system is more critical.

Go to page 6 on this link for a great booster pump; http://www.google.com/url?sa=t&source=w ... PJ078qR4dw