Well, the LT1 Cam, Edelbrock Performer TBI Intake, VAFPR and 1/2" spacer known as a nitrous plate are on the car. The thing runs absolutely pig rich and doesn't really pull much. I was wondering, which way do you turn the screw on the VAFPR to lean out the mixture? Simple question, but I really don't want to take off the injector pod 4 times to figure it out. Also guys with similar setups, what kind of base timing are you guys running? ummm that should be it, thanks

Tony

 

Please?

 

You might have to replace the spring to a softer one. I wasn't aware that the VRFPR was adjustable with a screw. Did you hook it up to sraight manifold vacuum?

Steve

 

If you have the GM VAFPR than you must get the softer sping. The spring it comes with with has to high a spring rate and you will run rich. The stock srping is to soft and will cause you to run lean. The spring that Lon sells at top down solutions is the one to get and all of his testing was done with an LT1 cam. I am running on on the stock cam and I am about 15 PSI at WOT and 11 at idle.

 

you can dink with that FPR crap all day long and get nowhere. You need to go over the PROM tuning forum and read up.

 

Already have Lonsal's spring in there. Which way do you turn the screw to lower the pressure? Also, is there a "break in" period for the cam considering that both the cam and lifters are used?

 

Roller cams do not need to be broken in so you should be set to go. As for the adjustment on the regulator, 2.5 turns in increases pressure roughly 1 PSI. Turning it out does the same thing. I was told to start turning the screw once it is flush with the housing. That is your starting point. Hope that helps.

 

Oh? Check my sig, pard.

To the original poster, clockwise raises the FP on that regulator, adn the others are right, you need a different spring. The stock spring worked in my application.

 

Tony, Did you install the vacuum delay valve I recommended in the installation instructions I included with the spring? I have a few in stock. I just haven't had a chance to add them to my web site yet.

http://www.top-downsolutions.com/Doc...structions.pdf

Lon Salgren
Top-Down Solutions

 

The vafpr wont replace burning but it would sure help. I think Im going to order one soon here when I redo my fuel lines and use it along with my chip.

Whats the stock pressure on that vafpr? I thought it was higher than 15 psi (~17 ish)?
nm, the answer was two lines above me in the install article on top down solutions!

 

i am in the process of installing the lt1 cam in my car... how much is the vafpr. and the spring. also can you get the vaccumn fpr from another car in the junkyard???? and then order the correct spring?

 

I'll be putting a few new items on my web site soon including a complete VAFPR package. This consists of the GM VAFPR, the spring installed and the vacuum delay switch.

I doubt you'll find the VAFPR in a junkyard. I believe it was used on a marine application.

Lon Salgren
Top-Down Solutions

 

I do have the Vac Delay valve in place. The thing is that, I turned that stupid screw on the regulator forever and it didn't seem to do anything. I also hooked up my FP guage and it said that it was running at ~16 psi at idle. The injectors were just puking fuel. It seemed like the FP didn't change at all when I hit the gas. I taped the guage to my windsheild and drove around for a while, and it seemed to just stay at ~16, I didn't punch it past 50% throttle though because the thing would just kinda fall on its face if I did. I'm using the vacuum port that the thermac is hooked up to when using the stock air intake. With my open element it was already open, so I just took off the vac. cap and used that. What sucks is, I'm back in Wisconsin now, so I can't test anything until I go back to school in August

 

If the fuel pressure isn't moving at all I'd suspect the diaphragm is broken, torn or you have a vacuum leak either at the gasket or vacuum line. The gauge should register max pressure when you turn on the key to run without starting the engine. Turn on the engine and it will drop to the lowest pressure at idle.

Lon

 

Or your fuel pump is weak. I'd put money on the fuel pump -I had the same issue and it was a weak pump.


That's correct. That is how it should work. I bet you've just dead-headed your fuel system at the regulator at this point, and 16 PSI is all your pump is capable of. Physically plug your return line, and if your pressure is still 16 PSI, then you need a new pump. Good luck!

 

Sorry guys, but I've been gone for a while, so this may be a dumb question. But has the VAFPR replaced the DIY AFPR as the standard operating procedure to upgrade one's fuel pressure?? And if so, this must play havoc with our stock chips, no?

Like I said, this might be a dumb question though.

-The Gunny

 

No it doesn't play havoc with the stock chip. It is a way of boosting the fuel pressure under load a bit without having to program a new chip.

Lon

 

Any luck with that VAFPR package??? I've got a pot of money just waitin for ya.

 

I've had the VAFPR, springs and vac delay switches sitting here for a while. I just need to make the time to swap the spring and get some vacuum hose and fitting to include it with the package. Then sit down and price the package, snap some pic's...

It won't happen for a few weeks at the minimum. I'm in the middle of playing Travel Agent and book my flight, hotel, car rental for my first show at the ThirdGen Nationals in Frederick, MD next weekend. I've still got to build some more inventory and package everything to either take with me or ship ahead (haven't finalized that yet).

Lon

 

Unfortunately I won't be able to mess with it until August when I get back to AZ...where my car is