I keep seeing people saying to bumb up fuel pressure. What do you need for this, New injectors, addjustable fuel regulator or can it be done on a stock tbi engine? Thanks...

 

Stock cars do not need their fuel pressure adjusted. But many of us have upgraded our exhaust, headers, TBI mods, open element and the 40lb/hr stock injectors don't supply enough fuel for our mods. Raising the fuel pressure increases the lb/hr rating of your injectors. Or you can replace your 40lb/hr injectors with 350 TBI injectors 55lb/hr to accomplish the same thing. Your injectors will only withstand so much pressure before they die. If you change injectors your really suppose to have computer chip changed to get full use of it. Mine has worked ok for months though.

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91 Camaro RS 5.0L Black Convertible 700R4
** Added so far **
*GM Wonderbar,Alston SFC's,spohn LCA's and Panhard rod
*Turbo City Inj Spacer
*Dual Snorkel Air Filter
*March Performance Pulleys
*GM 3.42 Gears with OEM Zexel POSI
*Edelbrock headers
*3" High Flow Cat
*3" Dynomax Exhaust
*Walbro 255 lph Fuel Pump
***Future 330hp Vortec Crate with LT4 hotcam and 454 TBI

 

Thanks for response. I have gone with 1.6 rollers, hearders and 3' exhust, shift kit and converter, accell ignition, lowering springs, shocks, struts, and some other stuff. Also have 160* stat probably pop a 180* in for winter once it get real cold. So from whats stated i should probably get the 55lbs injectors from the 350? How would I bump up the ones I have now?

Also looking for dual snorkel setup. Or might have to go to open elem,
Opions?

[This message has been edited by 88firebird305 (edited October 19, 2001).]

 

Well before you knock on the ammount of the stock TBI injectors. You can see in my signature what mods I have and I can see with my (and Jon Prevost) software that I am running too rich with the Fuel pressure turned up ( a little too much) so I can tell you they can feed any 305.....

Need any help let me know
Brian Felts

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

www.geocities.com/feltsb

 

Slight Fuel pressure adjustments can make a BIG difference, especially since our fuel pressure is only going to 2 injectors and it's already a low pressure system. The difference between 8 and 10 is a LOT on TBI but it's a 'fine' adjustment on TPI cars with high pressure. SO, don't start cranking away on the fuel pressure after you make your stock unit adjustable. A few turns and looking at a scan tool can tell you a lot.

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, Jon (350 TBI!)
91 Red My website

 

where can i get some injectors, and about how much do they run, the ones ive seen are sold in packs of 8?

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Trent
---Car---
89 Firebird/305 L03 TBI A4/t-tops
Open Element Edelbrock Aircleaner w/ K&N air filter/Summit Chrome Valve Covers
---Stero---
Pioneer DEH-P730 Premium
Infinity 2way 4652 4x6's/Pioneer 4way ts-a6985 6x9's
profile cl640 110x4
----Comming in a few days----
Edelbrock TES headers 3" out/flowmaster American thunder 3" exaust/Catco HighFlow catco cat

 

the ones you have seen are port injectors, not like ours. you want specific injectors. declo throttle body injection injectors. in my opinion, you shouldnt ever have to buy injectors from a parts store, just go to the junk yard, you should be able to find at least 2 that are right for you.

 

GM (AC Delco) Injectors for 350 TBI are part #17112493 if that helps.Also Turbo City sells them in Flow-Matched Sets.They also sell adjustable fuel pressure regulators for TBI.
-Rich-

 

Huh, 55# injectors in the 350? When I pick apart my BPW constant in the PROM, it shows up as 62.55# injectors.

 

55# can = 80# depending on the fuel pressure during the flow testing! This is why I hate turbocity and most other EFI places. They never tell you outright what pressure they tested the TBI injectors at. The standard for the saturated injectors and 1:1 cylinder:injectors are usually 43.5psi
TBI injectors are anybodis guess.

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, Jon (350 TBI!)
91 Red My website