Are there any po folks out there that have modified the stock fuel regulator on their L98. I"ve put a bigger cam in plus port & polished the heads & intake system, modified exhaust, air box & MAF, plus 2600 stall, thought that I"d play with the fuel reg.,tpis seems to condone this adjustment, I just don"t have the extra $$$.

 

A fuel regulator can and does effect HP.
At the Dyno - By increasing pressure to 48# vs 40# I picked up 3 to 4 hp across the board.

If you are interested in one - be sure you buy one that includes a new fuel pressure regulator and not just the outside casting.

I purchased a kit from Lingenfelter that included all new parts. It is well built, this is the second adjustable regulator that I have purchased. On the first one, I broke off the vacuum hose connector the first time I connected a hose to it. It was a piece of poopie, even though it had a fancy chrome plating.

When I am not going to the track, I put the pressure back to 40 for normal driving.
:chevy


[Modified by 85vet, 8:45 PM 1/26/2002]

 

What brand did you have to start with?

 

Sorry,

I had to go back into my records to see where I got the 1st adjustable fuel regulator and it was at TPIS. I couldn't return it because I had it for a few months before I installed it.

My new one is an accell and it is a complete kit including a new regulator, not just the outside case.

 

I use the HyperTech AFPR and an ACCEL FP gauge that sits atop the Schraeder valve on the fuel rail.

Attach the gauge and get the stock FP setting (with vacuum line disconnected) so you have a baseline for setting the AFPR.

There is a table on my site that shows what HP is supported by various FP values. With my mods a FP of 47-48psi gave a WOT air/ruel value of 12.7:1 on a recent dyno pull.

 

has anyone actually made their own afpr. using the stock one?

 

There was a thread a few days ago about a Holley AFPR. There was also a photo of it installed. It looks great and had a screw in connection for the vacuum line so you don't pull it out when trying to disconnect!!! I ordered one from Jegs to replace the one which I had. ($79).

 

Vettedreams,

There was a thread a while back where a member did make one on his own.

All it is, is a threaded bolt with a round piece of metal under the case (on top of the diaphram) used to push the diaphram down to adjust pressure.

:chevy

 

Vettedreams,
Here's a link to a Camaro/Firebird board on how to make an A.F.P.R.: http://www.gmtips.com/3rd-degree/dox/tips/afpr/afpr.htm

Actually, this link has alot of useful tech tips on polishing, porting, etc.: http://www.gmtips.com/3rd-degree/dox/tips/tips.htm

I'd recommend the Holley afpr ($80) if you are going to buy one. It comes with the machined housing, along with new innards.

You might as well replace the screws that you are likely to damage while taking them out: http://forums.corvetteforum.com/zerothread?id=159466

I made my own according to the first link above, and it probably would have worked, but when I re-installed the modified housing, I somehow got the inner spring/rod/seat/diaphragm assembly cockeyed, and when I thightened it down, I damaged the inner assembly. I then ordered the Holley unit because it came with new innards and installed it. I was having a problem with being able to turn up the pressure high enough, and would bleed off pressure almost instantly. I took it back apart, and when I had jammed the original innards in there cockeyed, I made a slight dent in the "sealing" surface in the regulator base. I tried polishing it flat & smooth, but couldn't get it right, so just yesterday got done with installing a new regulator base, put the Holley back on and it works like a champ. If I hadn't screwed up putting the original unit back together after I had made the adjusting mod, I think it would have worked fine. One bit of advice though if you make you own, don't make the adjusting screw any longer than it has to be because it will hit the plenum, and be careful when reassembling it.

Here's a pic of mine with the Holley AFPR, and new screws


Later,

Carl

 

I wish I had seen the Holley before I bought mine.

That is sweet.

 

Thanks cohocarl, that was an excellent site very info. orientated.

 

I made mine according to the instructions on thirdgen.org. works great. after I ported the plenum and runners, I adjusted the pressure all the way up to 60lbs...I'm at 45 lbs now and it works great!!!. Easy to do, and I couldn't see paying all that money for something I could do in 5 minutes.... :seeya