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fuel pressure regulator what would you run ?

best reulator setup for uping the fuel psi

  • fixed psi spring

    Votes: 1 16.7%

  • mech adjustable reg base kit

    Votes: 2 33.3%

  • manifold ref modification

    Votes: 0 0.0%

  • mech adjustable base AND aftermarket spring

    Votes: 3 50.0%
  • Total voters
    6
sweetk30

sweetk30

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well looking at tweeking fuel pressure and did a bit of searching here in the efi section.

my question is what way is best for uping the pressure and performence? is it fixed psi via spring only or adjustable and or vac refrence for load on motor?

my ultimate plan is for my tbi 355 motor with stock lt1 roller cam and 4 brrl intake with shorty headers. this motor i am going to start running next year finaly http://coloradok5.com/forums/showthread.php?t=238592 . but for now it will be a stock tbi 350 from 1988 .

and YES i do have a fuel pressure gauge coming to monitor the psi on the system. PIC added score off ebay like new dirt cheep :thumb:

$(KGrHqR,!hgE6Z+zQ0RGBOz8cjZJWg~~60_12.jpg
 
Last edited:
sweetk30 said:
well looking at tweeking fuel pressure and did a bit of searching here in the efi section.

my question is what way is best for uping the pressure and performence?
Click to expand...

Not sure exactly what you mean but the only way to increase pressure is to use an adjustable pressure regulator OR make yours adjustable again.
 
The pressure spring will do you no good until you have an adjustable regulator. :deal:
 
Well for a built motor first you need to know estimated HP, then know what size injector you have, then use a caculater to know what pressure you need for all the HP. Then theres a calculator for BPW.

If you have not had your injectors serviced with results none of the above applies.

So then you need an adjustable regulator to get correct pressure, you can use an TPI pump so it will handle higher pressure and higher flow needed, extra fuel is returned to tank.

Gauge in the cab is needed to make sure your pressure is not dropping at WOT high RPM... but I have used one from under hood and long line to windshield wiper for testing... :doah:

Vacuum adjustable are hard to find, expensive and usually not needed till over 400 HP if you have used TPI pump and set up like above then the tuning starts! :D

I just did a 375 HP TBI motor on a dyno with that setup... :bow:
 
well for now i am going to install the pressure gauge in the truck to get use to whats going on for now. and its electric so it will be up front and center to watch all the time.

next the motor i built i copyed from brian at tbichips he did few years ago and only major diffrence i didnt do yet was bored out tbi body for more cfm.

he had about 300hp on the dyno when he was done with it if i recall correctly .

but will have to play with dyno programs to see. any good ones ?

but for now i was lookin to play with my bone stock tbi on stock 350 tbi motor so i can do basic bolt on performance to start my learning curve of this stuff.
 
well i got the gauge today . :D

now need adaptor. :doah:

cfm-tech = 39.95 + 10.36 s&h = 50.31 :eek1::doah:
http://marine-performance-parts.com/cfmtechfuelpsiguageadaptorforgmtbi2843505774.aspx

:rolleyes: search a bit and find guys on thirdgen.org have a place thay deal with a bit with same unit and looks exactly like cfm tech's for less.
http://www.rvmorsemachine.com/newproducts.htm

r.v.morse machine = 29.95 + 8.95 s&h = 38.90 :whistle::D

i think i am gona call friday and check on ths to make sure its real price. :popcorn: 11.41 savings is a lot these days for parts on our trucks.
 
I'm not sure this would be the right fitting for your gauge or if it could be changed to right fitting? $26.99 But it's the gauge and fitting I use. I check pressure at idle and rev engine, if steady I just built a longer middle extension to run the gauge under a windsheild wiper to watch pressure does not drop at WOT high RPM when tuning. If it's OK then I am done and disconnect it.

http://www.ebay.com/itm/GM-TBI-Fuel..._Automotive_Tools&vxp=mtr&hash=item35b79838db
 
ya that uses a shrader valv with diffrent threads.

the autometer eletric uses a 1/8 pipe thread on the sender.
 
IIRC one of those adapters you need or listed have one hole for gauge and 2 holes for gauges! Or I have seen them with one or two.

If it were me I would like the two hole to have a gauge hard mounted on back of TBI for checking while idling under hood or when setting adjustable regulator. Then the other to gauge in cab to watch fuel pressure. Mainly what the in cab fuel pressure gauge is for is making sure fuel pressure is not dropping (supplying enough fuel) at WOT high RPM.

WARNING: Please always use a proper electronic fuel pressure sender to send signal into passenger compartment! Do not ever run a mechanical pressure gauge with flammable fuel into passenger compartment like you can with oil pressure...
:thumb:
 
4X4HIGH said:
The pressure spring will do you no good until you have an adjustable regulator. :deal:
Click to expand...


Well, I put in a stiffer spring with the stock regulator and was got the pressure to 18 psi. In fact, I tried two different stiffer springs and the second one put it at 20 psi.

That ended up being too much pressure so I changed back to a stock spring and adjustable regulator to get 15 psi.
 
Has anyone ever tried to see how far up a stock spring will go with adjustable regulator?
 
eagle mark said:
Has anyone ever tried to see how far up a stock spring will go with adjustable regulator?
Click to expand...

i am going to modify my factory unit for adjustable. then we will see mabye :D

and i ordered the adaptor fitting from r.v.machine link i posted and its on its way at the price listed. :thumb:
 
4X4HIGH said:
You cannot get more than around 14-15psi with the stock spring and fuel pump.
Click to expand...
Is that because of the pump or spring though?

I don't think it's the pump because guys put springs in adjustable regulators without a pump change? But how far up PSI it will go I don't know?

I know a stock spring in an adjustable regulator with TPI pump can hit 17 PSI cause I did one... and at first it was 20PSI...

So I guess I'll rephrase the question to how high the fuel pressure can go with stock spring, stock TBI pump and an adjustable regulator? If anyone has done one and tried the max PSI? Just curious...
 
eagle mark said:
Is that because of the pump or spring though?

I don't think it's the pump because guys put springs in adjustable regulators without a pump change? But how far up PSI it will go I don't know?

I know a stock spring in an adjustable regulator with TPI pump can hit 17 PSI cause I did one... and at first it was 20PSI...

So I guess I'll rephrase the question to how high the fuel pressure can go with stock spring, stock TBI pump and an adjustable regulator? If anyone has done one and tried the max PSI? Just curious...
Click to expand...

I tried this with mine and I was only able to get just above 14psi, probably like 14.5psi. I then installed an 18psi spring and could still only get 15psi so I finally installed a higher pressure pump and i'm now running 18psi with my 454 TBI with 90 lb/hr injectors.
 
I don't know if a stock pump will push more pressure with a stiffer spring. When I changed my spring I had already went with a higher pressure/volume pump.
 
got my adaptor fast delivery via usps flat rate box . :thumb:

big :waytogo: to r.v.morise machine co. for the deal and fast shipping. and 11 bucks cheeper than cfm-tec for the same item. :eek1:

also thay give you a nice small tight 90* fitting for tight clearence areas if you need it.

hope to ge it installed this weekend and the gauge also. :D

1222111635a.jpg
 
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