GulfM3

iTrader: (14)

Quite a few threads have been posted lately regarding the first gen fuel system, pumps, jet pumps, regulator etc.
To help us all share info and compare the different options I have consolidated all the threads I could find with relevant info and added a few diagrams showing how the stock fuel module works. If I missed any threads please post links.

Relevant threads,
https://ls1tech.com/forums/cadillac-...el-pump-s.html

https://ls1tech.com/forums/cadillac-...uel-pumps.html

https://ls1tech.com/forums/cadillac-...ank-pumps.html

https://ls1tech.com/forums/cadillac-...hp-rating.html

https://ls1tech.com/forums/cadillac-...tall-pics.html

https://ls1tech.com/forums/cadillac-...e-running.html


Stock fuel module diagrams & fuel filter diagram.

GulfM3

iTrader: (14)

I also have a plan to add a second, external, pump and return style fuel system on the cheap.

First drop the tank and remove the lock collar and pull the fuel module.

Second remove the fuel pressure regulator and replace it with a 90* fitting so the fuel still returns to the stock location.

Third install a bulkhead fitting similar to A&A corvettes system, this requires drilling the tank... might be a deal breaker for some.
http://www.aacorvette.com/supercharg...&cPath=2_47_62




Fourth mount an external pump, i'll be using a walbro, and run it to the bottom port of the stock fuel filter. This port was previously used for the return to the tank. Your fuel filter is now a "Y" for both the in-tank pump and external walbro. Run the stock fuel feed from the filter to the rails, use whatever rails, adapters, etc you want.

Fifth install a regulator on the fuel rail and run a -6an return line from the regulator to the stock return on the top of the fuel module.

Once I get the DIY 8.8 from hell finished I'll be testing this fuel system out, but I don't see any reason it wont work. It keeps the jet pump functional on the stock bucket for reliable low fuel level performance and the bulkhead fitting will be low and on the back of the tank keeping it submerged in fuel.

With a handful of fittings, 15' of -6an line, external fuel pump, rails, and regulator you can piece together a functional return style system. I would estimate it good for 750-800rwhp.

If someone wants to try this out before I have my car back on the road, please steal my idea and report back with results.

DMM

Thanks for putting this all together! Did Squash give up on the V1 pump assembly?

yessir

iTrader: (5)

Would it be possible to run a surge tank while utilizing the stock returnless pumpas an up pump and use a return style rail and regulator plumbed bak to the surge tank as usual but then omit the surge tank overflow that goes back to oem tank?

cts-vls6

iTrader: (7)

Yes u can. This is what I'm doing for my fuel system. I'm going with a nuke 3l internal 3 pump

vroom_vroom

iTrader: (5)

Would the return line need a one way valve?

raven154

iTrader: (14)

MN_V

iTrader: (5)

I don't think the return line has anything to do with the jet pump. The jet pump is powered from the output of the pump. Many of us bypassed the stock regulator and have the return line dumping directly into the bucket.

yessir

iTrader: (5)

If ctsv runs retunless what are the multiple fuel fiitings on the top of the sending unit for?

raven154

iTrader: (14)

Choppy_Idle

I'm actually in the same situation here, will use a Bosch 044 in line pump external in OEM filter area with a additional return line and the oem spots on pump, to get it back in tank, but I see, they made a 2mm hole maybe back into the bucket, rest is running thru the fpr back in the tank, I'm right here, can someone verify this?

So my question now is, does it make sense to let the whole gas back from return line thru a 5mm hole maybe into the bucket at 3bar, can this create another issue in regards to too much flow or pressure in the bucket, that the OEM pump here gets in trouble to suck their stuff or something similar???

I think, I would feel better, if the same amount like before comes this way back into the bucket, when I see their whole construction there, how they made it, I don't think it's made for a fancy looking, there must be a reason for, why they constructed it this way, what y'all think about, pls discuss here, I'm open for every thought...

Greetz
Ron

MN_V

iTrader: (5)

The return flows back to the stock FPR and bleeds out through it into the open tank and the rest gets routed around and is sprayed back into the bucket through the shooter on the bottom. That helps catch extra gas and keep the bucket full especially during acceleration. Since the stock FPR has to go with any aftermarket fuel pump, I have the return routed directly into the bucket from the top through a hole I drilled out. It works fine but when the tank is low it's possible to run the bucket dry on a long acceleration run when the gas goes to the back and no longer using the stock shooter to try to help shoot it forward. Not really an issue though to be honest. The shooter works like a venturi and you could enlarge it and try to keep it. Without enlarging it your fuel pressure will be through the roof though as it is the bottle neck in the stock return line.

Choppy_Idle

Thanks Matt for explaining here, i think i will go too the full return into bucket, will use the OEM line here and connect a 90° fitting into oem inlet on bucket or fabb something by myself...

Regards
Ron

54inches

iTrader: (4)

Anyone have a diagram of where the fuel access door goes?

Still searching....

54inches

iTrader: (4)

I found a few photos but they were incomplete and without measurements, so here you go, done on my Silver car, so it is easier to see.

yessir

iTrader: (5)

Would it be possible to use the fuel line from the OEM pump to feed an inline pump and just use the Corvette fuel filter/ pressure regulator between the inline pump and the rail ?

54inches

iTrader: (4)

You COULD, but there are better options. a drop in e85 pump would be a better option....

54inches

iTrader: (4)

Bought a Hinson Motorsports Dual Fuel pump setup and installed last summer with their installation kit. Wonderful setup.