So im tired of my car running too rich at idle and too lean at higher rpms. So im switching from the holley tbi to 454 tbi with 80# injectors. I want to run a vacuum adjustable fuel pressure regulator and I know a lot of you have done this. I know the aermotive 13301 is a popular choice and I am fine with it.

The problem or well questions I need to ask are these. Well first let me say this car is my only car at the moment and I am trying to not have it down for more than 1-2 days.

So I install the regulator on the return side correct?

And I figure that I will have to run all new fuel hoses from the metal lines on drivers inner fender to TBI, out of TBI to regulator, and regulator back to fender metal lines.

I am okay with mounting the regualtor right there on the intake manifold. I have room.

So I wanted to see people's pictures of how they did it. And if not too big of a hassle a possible parts list. So I can get all the parts needed here before I do it. To again, keep the car down for as little amount of time as possible.

Thank you

 

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Not the best angle but you can see where the push on AN attach to a stock hard line. Not sure is a FBody same but I suspect similar.

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Is that the 13301 regulator? Looks similar if not it. Does it have a port to run a fuel pressure gauge or is their something there that I am not seeing?

 

yes. I forget the # of ports. for sure there is the return, lead from TB, lead from N20, and the FPG. I believe the remaining side is treaded for mounting bracket.

 

any third gen applications I could look at?

 

I honestly don't mean to hijack your thread, but what does that vacuum port do? I have one on my mallory AFPR, and I wasn't sure if I should keep it plugged, or hook it up. Would it serve a purpose on a completely N/A motor? Again, sorry for the hijack.

 

Yes, FPR goes on the return line. If you don't replace the stock FPR with a block off plate the lowest the fuel pressure can go will be regulated by the stock one. Can fab a block off plate out of some aluminum plate, then cut the center out of the stock diaphragm to use the outer ring as a gasket.

As for the lines, no need to do anything with the feed line. That remains as-is.

For the return line, there are a couple of ways to go. It is a little tricky as the OD of the return line is 5/16". I'm not sure if there is an -6 AN tube adapter for that size. There is a fitting that will fit onto the 14 mm Saginaw end of the line (female Saginaw to male -6 AN):

9894DBH Female 14mm x 1.5" to -6: Fuel Injection Female "O" Ring Seal

This fitting should fit into the adapter in the TBI unit (return side):

991954 14mm x 1.50" to -6: Fuel Injection - "O" Ring Seal

They are both Earls/Holley parts.

RBob.

 

Yeah I figured I did not have to change the inlet side. But for a more matching look. I was going to do the feed and return with braided fuel line so it looks better together. Thank you for the part #'s Rbob

But about the stock regulator. So if the stock regulator allows for say 12 psi. If I dont touch that but install the VAFPR inline. I can still get the 20+ PSI I need. And the lowest it will go is to 12 psi? I did not know that. If I understood that properly.

 

Correct when leaving the stock FPR in place. If it is set to 12 psi, then can't go any lower when adjusting the FP via the external regulator. Note that this can occur during low manifold pressure with a VRFPR.

You can set the FP higher then the stock regulator setting.

If you want to change out the feed side too. They are 16 x 1.5 MM Saginaw fittings.

9894DBJ Female 16mm x 1.5" to -6: Fuel Injection Female "O" Ring Seal
991955 Make 16mm x 1.5" to -6: Fuel Injection - "O" Ring Seal

Personally, I wouldn't if they didn't need to be changed. The biggest reason is that Teflon lined hoses should be used. As the braided rubber hoses weep fumes and over time start to break down.

I'm going through this now and am doing some replacements. The Teflon stuff is expensive, and the jury is still out on longevity. Apparently, dirt buildup in the braiding can wear through the Teflon liner causing failures.

RBob.

 

Hmm. Wow that is some good information Bob. Thanks. I may just do the return side. Or fab metal tubing.

 

 

Hey one92rs. I heard you don't want to mount the regulator below the TBI because of fuel leakdown problems. How does your setup do? extended cranking or anything like that?

Oh and it is routed up the backside of the motor to the tbi? the fuel lines i mean.

 

no i did not want it on the intake. yes my lines are routed up to the back of the engine. now when i do my 350 swap i am going to move the regulator back where the relays are near the firewall. or i will get rid of the external regulator all together and just use the tbi one. have not decided yet. but i do like the flexability of having the external one. as far as extended cranking nope.

 

So does anyone know what size the fittings that screw into the TBI unit are? not the female end, the male end?

My idea is since the regulator is 3/8 npt. I can run steel tubing. If I can find an adapter that goes into the tbi unit, that converts it from 14 x 1.5 to 3/8 NPT then I can run all steel line and do not have to worry about braided hose failure etc. If it isnt possible then I will go with the -6AN way. I have been looking on summit but have not found what I was looking for yet.

 

i went with rubber hose that is rated for 300psi. not really needed. you could still use steel tubing with female nuts on the ends. i got away from steel due to heat. rubber wont rub thru if you route it right.

 

This is what I always reference when I'm looking for the hoses...

 

this is the exact info i been looking for , thanks guys

 

can this be mounted on the inner fender an hooked in where the hardlines meet the flexline ?

 

that picture helps a ton. thank you very much.

now im debating if i want to mount it on the intake or on the fenderwell.

 

OK so I have decided to leave my holley tbi unit in place. bump up the pressure to about 34 psi via an external VAFPR. set the holley unit at like 16 psi.

Then I can get the 34 psi I need right? and the fuel pressure wont drop below the 16 psi that I set the holley regulator at?


And technically a 454 80# injectors at a lower psi than the holley injectors would still be providing the same amount of gas so it is not like If I ran the 454 injectors at 22 psi and they went to 10 at idle id be saving any gas over running the holley's at 34 psi and getting 22 at idle correct?

hope that makes sense.

 

VAFPR is downstream of the TBI correct?

If you FPG reads 34 key on engine off then you will be at 34 at WOT and idle will be what ever the reg spring with vac provides.

I am at 26 lbs WOT and I recall 15 lbs at idle. 1.6 msec PW.

 

Yeah it is going to be installed on the return hose.

So even with the holley's regulator still installed and set to 16, I can get the maximum pressure I am looking to get and have it drop roughly to 20-24 psi at idle. correct?

 

When you install the VAFPR with engine off ign on you set the WOT FP. You will hear the pump run and shut off. Mine bleeds down to lower pressure right away so my assistant (wife) does the ign on while I witness the FP. After I turn the adjustment screw I will recheck and we redo ign on eng off. Lets say it finally reads 26 and that is what I want WOT. when I start car the VAC from a non ported source pulls pressure down to 15 at idle. If I crack throttle wide open the FP pressure increases and VAC decreases.

You want lower press at idle as it allows a larger PW. PW under 1.5 causes erratic idle.

 

correct but the regulator on the holley tbi will be a non factor and the pressure will be adjusted by the external one I install correct

 

Remove the Holley reg and use a gasket and block off plate. I made the plate with a dremel. I used a gasket from a blown reg diaphram.

 

I absolutely have to do that? I cant keep it there?

 

You would then have 2 regulators? Not sure how that would work! I believe the Holley unit attached to Holley TBI has to go.