What Range fuel pressure guage do I need for TBI
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Car: 88 Camaro
Engine: 305TBI
Transmission: Stock
Axle/Gears: 3.42?
What Range fuel pressure guage do I need for TBI
I am going to install an underhood fuel pressure guage to help with tuning my motor. Will I be better off with a 0 to 15 psi range guage or a 0 to 30 psi? What would be best?
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Car: 88 V6 'bird/89TBI bird/85 T/A
Engine: 2.8/TBI/TPI
Transmission: V8 T-5/700R4 x2
Axle/Gears: 3.42 open/2.73 open/ 3.27 9 bolt
0-30 is better I think.
I think GM TBI runs best at about 20psi anyway...
I think GM TBI runs best at about 20psi anyway...
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Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
If you plan on modding your motor, which I assume you have given the need for a gage, than I would go with a 0 to 50 psi or more. Although the stock pump won't produce over 15psi or so, as mentioned, an aftermarket one (for a multiport set-up) can produce 50+.
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Car: 1988 IROC-Z TBI
Engine: L04.3 = 305-310-336
Transmission: TH-700R4
Axle/Gears: 10-bolt, 3.42 posi
The GM TBI injectors start to leak somewhere around 30 psi (or so I've read in a few places, I've never tried to run them that high). So I think the 0-30psi gauge is ideal. Besides, if you crank the fuel pressure up that high (30+ psi) you'll have so much flow that you probably won't be able to get the thing to idle properly anyway (with decent size injectors anyway).
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Last edited by Casey Butt; 09-02-2006 at 03:26 PM.
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Car: check
Engine: check
Transmission: check
The GM TBI injectors start to leak somewhere around 30 psi (or so I've read in a few places, I've never tried to run them that high). So I think the 0-30psi gauge is ideal. Besides, if you crank the fuel pressure up that high (30+ psi) you'll have so much flow that you probably won't be able to get the thing to idle properly anyway (with decent size injectors anyway).
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RBob.
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Car: 1988 IROC-Z TBI
Engine: L04.3 = 305-310-336
Transmission: TH-700R4
Axle/Gears: 10-bolt, 3.42 posi
That is nice to know, I've been wondering about it for awhile. Take two 90 lbers @ 30+ psi supporting over 550 hp. What size motor would be necessary so that the idle pulse width wouldn't be too low beyond the injectors' ability to cycle properly (assuming a motor with components capable of making 550 hp, of course).
More to the point, what's the minimum pulse width TBI injectors can deal with? Perhaps someday I'll consider supercharging or nitrous and I'd like to know that.
More to the point, what's the minimum pulse width TBI injectors can deal with? Perhaps someday I'll consider supercharging or nitrous and I'd like to know that.
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Car: check
Engine: check
Transmission: check
Once a BBC injector at 22 psi gets to 0.1 - 0.2 msec it gets a little iffy. At that low of PW the fuel flow is not all that stable.
Once the fuel pressure is above 18 psi or so, best is to use a vacuum referenced fuel pressure regulator. This reduces the fuel pressure at lower MAP. There by increasing the required PW. Really works out nice. On the other hand, this shouldn't be done with stock TBI code, it doesn't work out too well.
RBob.
Once the fuel pressure is above 18 psi or so, best is to use a vacuum referenced fuel pressure regulator. This reduces the fuel pressure at lower MAP. There by increasing the required PW. Really works out nice. On the other hand, this shouldn't be done with stock TBI code, it doesn't work out too well.
RBob.
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Car: 91 Camaro RS Convertible
Engine: 305 TBI
Transmission: 5-Speed
Axle/Gears: 3.42
I'm running the 90#/hr injectors on my car at 17psi. Overkill, I know. It idles just fine too, so I know you can go at least that high and still be able to tune the idle in good. I think my BPC is at 61.
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Car: 1988 IROC-Z TBI
Engine: L04.3 = 305-310-336
Transmission: TH-700R4
Axle/Gears: 10-bolt, 3.42 posi
Just curious... why did you go to 17psi and set the BPC so low? You seem to have a fairly strong L03, but did you actually run lean with the 90s at a lower pressure? Were you running nitrous or anything?
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Car: 91 Camaro RS Convertible
Engine: 305 TBI
Transmission: 5-Speed
Axle/Gears: 3.42
Well I had been running them at 11 psi all along, and did a good amount of tuning with them at that setting. Then I installed a Walbro 190 and it jumped to 17psi. I figured I'd try to get it to idle like that without trying to dial down the pressure and it was fine, so I left it. I was actually surprised at how much the pressure spiked with the Walbro.
#13
i ran an aeromotive with the weaker of two springs(0-20) at 17 lbs. swapped cams and required more fuel so swapped in a 20-50 spring and set to 23 lbs and all was well. 80 lb inj's. so easy to adjust FP with the Aero. my gauge is 0-30.
Casey: i was with a BPC of 83. however my VE was maxed at 100 so i moved BPC to 100 to allow more fuel in VE2(EBL).
Casey: i was with a BPC of 83. however my VE was maxed at 100 so i moved BPC to 100 to allow more fuel in VE2(EBL).
Last edited by Ronny; 09-06-2006 at 02:54 PM.
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i ran an aeromotive with the weaker of two springs(0-20) at 17 lbs. swapped cams and required more fuel so swapped in a 20-50 spring and set to 23 lbs and all was well. 80 lb inj's. so easy to adjust FP with the Aero. my gauge is 0-30.
Casey: i was with a BPC of 83. however my VE was maxed at 100 so i moved BPC to 100 to allow more fuel in VE2(EBL).
Casey: i was with a BPC of 83. however my VE was maxed at 100 so i moved BPC to 100 to allow more fuel in VE2(EBL).
With EBL, there now is another solution. Variable BPC settings allowing use of a VAFPR. I've been using it for the past 2 weeks with very good results. Runs 11.5psi at idle and 20psi at WOT. This is with the larger spring that comes with the Aeromotive 13301 VAFPR. All hail RBob!
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Gentlemen,
With EBL, there now is another solution. Variable BPC settings allowing use of a VAFPR. I've been using it for the past 2 weeks with very good results. Runs 11.5psi at idle and 20psi at WOT. This is with the larger spring that comes with the Aeromotive 13301 VAFPR. All hail RBob!![burnout](https://www.thirdgen.org/forums/images/smilies/burnout.gif)
With EBL, there now is another solution. Variable BPC settings allowing use of a VAFPR. I've been using it for the past 2 weeks with very good results. Runs 11.5psi at idle and 20psi at WOT. This is with the larger spring that comes with the Aeromotive 13301 VAFPR. All hail RBob!
![burnout](https://www.thirdgen.org/forums/images/smilies/burnout.gif)
#17
maybe someone else can elaborate on "asynch" fueling at idle. before EBL my tune would fall into asynch in CL idle. expected with high FP and large injs. engine responded to the transition not too well. now running OL at idle with EBL and idle is much improved. i dont think there is a down side to running a bit rich at idle is there? i believe there is a way to run asynch-OL idle but have not yet looked into it. well aware of the VAFPR with EBL. will investigate that next season.
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