tuning with twin pumps?

[gta324]

How do you do It?

My nr2 pump kicks in at 5 psi and them ny FP goes up to 60psi and the car is pig rich.....

Would it be easier to tune if it starts @ 1psi then I have 60psi all the time under boost?

 

[Razor]

Why are you using twin pumps?

 

[vader87]

What are you running as far as upgrades. I hope it is not a stock setup. Anyway most set it to come on at 10-15 pounds of boost instead of 5. Try to have it come on at a higher boost.

 

[Grumpy]

I turned the second pump on @ the 1000 ft mark old tech with bluetop inj ...running low-mid11s@ 121mph

 

[gta324]

1 Walbro 340SS wasent enough, FP dropped above 5k rpms and 5spi of boost.

Its a 415cui with a procharger F1 :biggrin:

 

[Razor]

If it leans out past 5k.. turn it on at 4800 RPM's :tongue:

Wow I have only 1 walbro 307 and trap 132+ in the 1/4 3800 lb race weight :redface:










And use a teeeny amount of alky to supplement :wink:

 

[gta324]

The problem is that when second pump activates the FP goes up to 60psi and the car went rich.....

 

[Razor]

The problem is that when second pump activates the FP goes up to 60psi and the car went rich.....

Then you have two choices,
Install larger return lines,
Activate it latter

Easy :redface:

 

[JPN800]

my second pump goes on at 17#

 

[Vett-Klr]

A bit off topic but...
I bought my car with 2 pumps in the tank. How dow I even know if the second one comes on? How can I adjust it?

 

[gta324]

It depend on how its wired up.......

My activates with a adj boost switch.

First
You could look if it has seperate wires, if it does you must trace the wires to see where its connected...

or maybe just look for a boost switch...........

/N.

 

[Googs]

How do you do It?

My nr2 pump kicks in at 5 psi and them ny FP goes up to 60psi and the car is pig rich.....

Would it be easier to tune if it starts @ 1psi then I have 60psi all the time under boost?

If it's activated with a Hobbs switch, just switch it out for a higher pressure one. You can find them at Napa for about $30. When I replaced mine, I think they could get 5, 10, 15, & 60 psi switches.

 

[gta324]

Changed it yeasterday to 7-8psi will test it this weekend.....

/N.

 

[Vett-Klr]

Where is the switch?

 

[ahollowtub]

Run em both full time and put on the appropriate size return....

 

[gta324]

I will log the fuel pressure this weekend, its hard to keep an eye on the gauge when driving...

/N.