VAFPR Questions and timing on LT1 Cam
#1
Supreme Member
Thread Starter
iTrader: (1)
Join Date: Dec 2000
Location: Mesa, AZ
Posts: 1,463
Likes: 0
Received 0 Likes
on
0 Posts
Car: A Camaro
Engine: Weak
Transmission: Weaker
VAFPR Questions and timing on LT1 Cam
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
Tony
#3
Supreme Member
Join Date: Apr 2000
Location: clinton,tn
Posts: 1,686
Likes: 0
Received 0 Likes
on
0 Posts
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
Steve
#4
Supporter/Moderator
iTrader: (7)
Join Date: Feb 2001
Location: Cincinnati, OH
Posts: 13,345
Likes: 0
Received 425 Likes
on
326 Posts
Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
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.
#5
Supreme Member
iTrader: (1)
Join Date: Jun 2001
Location: 600 yds out
Posts: 1,520
Likes: 0
Received 0 Likes
on
0 Posts
Car: Bee-Bowdy
Engine: blowd tree-fity
Transmission: sebin hunnerd
Axle/Gears: fo-tins
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.
#6
Supreme Member
Thread Starter
iTrader: (1)
Join Date: Dec 2000
Location: Mesa, AZ
Posts: 1,463
Likes: 0
Received 0 Likes
on
0 Posts
Car: A Camaro
Engine: Weak
Transmission: Weaker
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?
#7
Supporter/Moderator
iTrader: (7)
Join Date: Feb 2001
Location: Cincinnati, OH
Posts: 13,345
Likes: 0
Received 425 Likes
on
326 Posts
Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
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.
Trending Topics
#8
Supreme Member
Join Date: Oct 2000
Location: Park City, UT
Posts: 2,152
Received 401 Likes
on
270 Posts
Car: '92 Corvette, '89 1/2-a-'Vette
Engine: LT1, L98
Transmission: ZF6, ZF6
Axle/Gears: 3.45, 3.31
Originally posted by V8Astro Captain
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.
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.
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.
#9
Moderator
iTrader: (2)
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
http://www.top-downsolutions.com/Doc...structions.pdf
Lon Salgren
Top-Down Solutions
Last edited by lonsal; 05-22-2003 at 02:49 PM.
#10
Supreme Member
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!
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!
#11
Banned
Join Date: Sep 2002
Posts: 422
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 camaro rs 97 yoyota camry
Engine: lo3 carbed
Transmission: t 5
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?
#12
Moderator
iTrader: (2)
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 doubt you'll find the VAFPR in a junkyard. I believe it was used on a marine application.
Lon Salgren
Top-Down Solutions
#13
Supreme Member
Thread Starter
iTrader: (1)
Join Date: Dec 2000
Location: Mesa, AZ
Posts: 1,463
Likes: 0
Received 0 Likes
on
0 Posts
Car: A Camaro
Engine: Weak
Transmission: Weaker
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
#14
Moderator
iTrader: (2)
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
Lon
#15
Supreme Member
Join Date: Oct 2000
Location: Park City, UT
Posts: 2,152
Received 401 Likes
on
270 Posts
Car: '92 Corvette, '89 1/2-a-'Vette
Engine: LT1, L98
Transmission: ZF6, ZF6
Axle/Gears: 3.45, 3.31
Fuel Pump
Originally posted by lonsal
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.
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.
Originally posted by lonsal
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.
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.
#16
Supreme Member
iTrader: (1)
Join Date: Mar 2002
Location: The nation's capital
Posts: 2,467
Likes: 0
Received 1 Like
on
1 Post
Car: 91 RS
Engine: 350 TBI
Transmission: 700R4
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
Like I said, this might be a dumb question though.
-The Gunny
#19
Moderator
iTrader: (2)
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
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
Thread
Thread Starter
Forum
Replies
Last Post