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#1053397 - 09/14/17 06:50 AM FiTech fuel injection  
Joined: Feb 2016
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siberhusky0 Offline
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siberhusky0  Offline
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Kelso, WA
Any one have any experience the throttle body fuel injection? Thinking about going with this & curious about what was done for a return line & if a in tank or external pump was used. Also if a bracket was needed to correct the geometry for the throttle valve cable. Any input is welcome.
Thanks...


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#1053399 - 09/14/17 07:12 PM Re: FiTech fuel injection [Re: siberhusky0]  
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thepezking639 Offline
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thepezking639  Offline
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Livonia, MI
Originally Posted by siberhusky0
Any one have any experience the throttle body fuel injection? Thinking about going with this & curious about what was done for a return line & if a in tank or external pump was used. Also if a bracket was needed to correct the geometry for the throttle valve cable. Any input is welcome.
Thanks...


I really don't like throttle body EFI. too much money for a computer controlled carb.

First you have to do something about your factory fuel system. The easiest way is find out what level of pressure the FiTech system will tolerate. If it will handle 58 PSI, run a corvette filter regulator and run a returnless system with a 4.3l EFI tank, and a GN fuel sender with a walbro or aeromotive pump. Or at least that's what i did for my LS motor.

If you're really happy with your existing motor, going aftermarket EFI is a simple way to improve drivability, but if you're under 400 hp, I'd just toss a cammed 5.3L in there, it wont cost that much more in the long run if you can get a complete donor motor, and since you have to do the fuel system anyways, you might as well take the plunge to an LS motor. Just my .02


86 SS 6.0L LQ4, TBSS GEN IV intake, 92mm TB, 30lb injectors, LS3 cam and valvesprings, stainless long tube headers, Microsquirt ECU, Built 200-4R, B&M Megashifter, Torsen LSD, QA1 Lvl 3 Suspension Kit, UMI Front & Rear Braces. Check out my build thread: http://www.pro-touring.com/threads/126188-SSLOW6-0-Build
#1053440 - 09/18/17 12:38 PM Re: FiTech fuel injection [Re: siberhusky0]  
Joined: Apr 2011
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Hunter79764 Offline
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Hunter79764  Offline
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Joined: Apr 2011
Posts: 838
Grand Prairie, Tx
I know it will take regulated 58 psi (a la Corvette Regulator), and I believe it will handle the typical high pressure pump with it's own vacuum referenced regulator but I'm not certain there.
A buddy with a 86 Mustang just installed a kit, and used the Fuel Command Center. They say you don't need a return line, just a vent, but what they don't say is that the vent needs to be about 5/16" line, go directly to the tank, and handle liquid fuel. Also, it can't be the tank vent, as that is still needed. So basically, you need a return line. Other than that, he's very happy with the increased throttle response, cold start, and part throttle power from the FITech unit. It's a 450+ hp 351 (Ford), everything done the right way. He had a tuned Holley that made great power but always needed tweaking, so he switched to an Edelbrock and sacrificed a little performance for easier drivability (it's his daily driver). He compared the full throttle power to the tuned Holley with better midrange power.

On our cars, get a TBI Monte ('85+ 4.3l) or Grand National tank and an in-tank pump. Anything else will probably be more headache than it's worth, and still not provide what you want. All the other band-aid options line external pumps and weld-in sumps are for cars that don't have a drop-in, factory designed EFI tank like we have...


Sometimes you just need a bigger hammer...

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1053444 - 09/18/17 02:36 PM Re: FiTech fuel injection [Re: siberhusky0]  
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MC96 Offline
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MC96  Offline
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Joined: Mar 2012
Posts: 560
St. Johns MI
I agree with Hunter.

Buy a spectra premium EFI sending unit for a 4.3l EFI car and be done. If needed upgrade to a Aeromotive 11169 or the equivalent Quantum brand (supposedly comes from the same manufacturer as AEM and Aeromotive)

I think there is still some debate on whether or not you will need a baffled tank, a lot of guys say even if you are auto crossing as long as you are above 1/4 tank you will be fine.

From what I remember with all the seminars I sat through pretty much every aftermarket TBI only needs 45 PSI at the throttle body. I think 58 psi is what the LS cars need at the rail and that is an oddball number compared to the rest of the industry, but 58 psi going to a TB that only needs 45 is just fine. Note: I could be completely mixed up on that.

Last edited by MC96; 09/18/17 02:37 PM.

86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1053478 - 09/20/17 01:57 AM Re: FiTech fuel injection [Re: siberhusky0]  
Joined: Aug 2011
Posts: 63
Sloe87 Offline
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Sloe87  Offline
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Joined: Aug 2011
Posts: 63
Northern IL
Originally Posted by siberhusky0
Any one have any experience the throttle body fuel injection? Thinking about going with this & curious about what was done for a return line & if a in tank or external pump was used. Also if a bracket was needed to correct the geometry for the throttle valve cable. Any input is welcome.
Thanks...


I am running a FiTech unit. I installed a new baffled tank for 4.3L Monte with a Racetronix in-tank fuel pump. I ran -6 fuel lines along the passenger side frame rail. I am using a Holley corrector bracket that needed to be modified to clear the throttle blade shaft. For the wiring I used weatherpack connectors and placed all the connections between the distributor and the throttle body. You will need to run a relay for the fuel pump per FiTech tech support. I have about 600 miles on it and I'm very pleased so far.


1987 Monte Carlo SS
350 / 2004R
FiTech EFI
T-top
#1053480 - 09/20/17 03:15 AM Re: FiTech fuel injection [Re: siberhusky0]  
Joined: Jun 2009
Posts: 23
Zach Offline
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Zach  Offline
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Posts: 23
Lawrenceville, GA
Running Holley sniper I love it


First car I bought was an 88 Mc ls when I was 16 been in love every since. Currently running 82 Mc cl with holley sniper efi 200-r4 4:10 gears work in progress
#1053505 - 09/21/17 12:49 AM Re: FiTech fuel injection [Re: siberhusky0]  
Joined: Apr 2011
Posts: 838
Hunter79764 Offline
Member
Hunter79764  Offline
Member

Joined: Apr 2011
Posts: 838
Grand Prairie, Tx
I know 43 psi (3 BAR) is a very common injection pressure used by most companies other than GM, but the FiTech unit is based on GM components and runs on a 58 psi (4 BAR) base (although you might be able to modify the programming to run a lower pressure). I remember going through it with my (Ford) buddy who was clueless about how to get 58 psi until I enlightened him to the "Corvette Regulator"...


Sometimes you just need a bigger hammer...

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway

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