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-   -   FI Tech questions (http://www.ifsja.org/forums/vb/showthread.php?t=182575)

rambling_rebel 04-22-2017 06:33 AM

FI Tech questions
 
Finally got my stepside back from paint

decided to step into a FI Tech EFI system

was a 6cyl, now 360 with R4B
currently have stock exhaust into NOS factory y-pipe
may or may not eventually go to headers and/ or duals

couple of newbie questions
(as in OMG what have i gotten myself into :) )

1 - with the "O2 Bung". I'd like to weld it into the y-pipe today. I was thinking it should go into the collector point of the y-pipe where both bank meet? make sense?

2 - i'd like to do a in-tank fuel pump. All i really know is it needs to be 58psi from what i've been reading. I have a new BJ's sending unit ready to into my tank, i just need to find a fuel pump to meet the requirements.

any comments, random thoughts, idea's are welcome

thanks
rr

babywag 04-22-2017 09:33 AM

Really no need to place the o2 sensor that far back IMHO.
Best spot is right after exhaust collector, where it is closer to engine.
Farther back will add a delay to reading, it'll work after the "y", but there is really no benefit to speak of.

Far as a fuel pump, there are plenty that will supply enough fuel.
Guess-timate your HP, and select one.
For example a generic e2000 is probably good for ~250-300hp.
Pump doesn't have a psi rating, the regulator does that.

TexasJ10 04-23-2017 08:40 AM

The original stock tbi pump in a chevy truck with 5.7 engine was the ac/delco ep386. It was always considered marginal and was frequently replaced with either the ep 241 or ep381 which were later used on the tpi equipped engines. As Babywag stated, the psi of a pump isn't relevant since the pressure regulator will bleed any excess pressure back to the tank.

I put an in tank pump together for my step side a few years ago but haven't installed it yet. Because the 1980 j trucks mount the sender in the front of the tank, the pump could become fuel starved at relatively small angles as the fuel in the tank moves towards the rear. Considering that the stock fuel pickup is also largely oriented towards the front with only the fuel sock located further towards the center, maybe it doesn't matter. I have heard it mentioned on this site that if the fuel sock comes off or rusts through that you have less usable fuel in the tank, but that has never made much sense to me since the sock will simply suck air if it is not covered in fuel. Not a big deal with a carb that has a fuel bowl, but it would be a big deal for a tbi that needs a constant fuel flow.


rambling_rebel 04-24-2017 02:28 PM

thanks Babywag and TexasJ10, good information. Just dug out a new electric fan setup for it i forgot i bought. will be welding the bung on the right bank (FI tech instructions says 8 inches from exhaust port or something to that effect). still pondering the in tank fuel pump but i like the picture you posted...i'm guessing the fuel pressure regulator is built into the FI tech unit...still reading though

didn't get much jeep truck time this weekend, hoping i do this coming weekend.

thanks again

rr

ShagWagon 04-26-2017 08:38 AM

Yes it has a regulator at the TB. You still need 60+ psi to the TB.

Go with babywags intank pump. I bought the FCC because I had some extra cash burning my pocket. It's great but but if I had to do over I'd do the intank pump for the cost.

TexasJ10 04-26-2017 01:46 PM

I think the two TPI delco pumps shown above are rated at or above 60 psi, but I am curious whether the FITECH pressure regulator really is set that high. It seems way overkill for a tbi system. I thought I saw a diagram one time of the system and they were using a combination fuel filter pressure regulator mounted right after an external fuel pump.

ShagWagon 04-26-2017 02:12 PM

They have several models.

Mine is a up to 600hp it says it regulates at 58

Maybe less for 400hp model and more for the higher ones. Not sure.

It gets 92 to the TB from my FCC fuel can pump. It's adjustable. I just haven't got that far yet. As long as more than 58 to the TB it should be good.


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