Hi All.
I have a late '03 C5Z with the incredibly simple & user friendly C6 fuel system. My car has an LSA blower. I want to get rid of my external 2nd pump and put a big single pump or duals INSIDE my tank and create a true return style system. Tanks are available. I will be within 7 minutes of one of the big Corvette salvage yards tomorrow and can save shipping if I get it myself. I only need the Driver side tank.
My question is...
The tank is advertised as for Coupe or Convertible. Some of the ones I've seen are advertised as JUST for Z06 and have a big orange sticker that says Z06 / XLRV.
Is there a difference between a 'base model' Late C5 / C6 tank and a similar year's Z06 tank?
The sales guy at the yard says they are all the same - I just want to be sure. Maybe the only difference the bigger pump for the Z? His pics don't show the sticker that some have.
Any thoughts on this?? The Auction number of this is 373834957656 (no Sticker) 155301313188 (Z06 Sticker) if that is allowed to be posted? Hence my confusion.
Thank you for any input!

 

my catalog shows ls3 and ls7/ls9 cars all have the same tanks. I don't have the early C6 listings, but I'm pretty confident the tank itself is the same. I didn't really realize the late C5 used the exact same tank, although I did know they share the top-loading fuel system.

 

Thanks for the reply - I just sat down at my desk and POW !! - there it was.
I did not get the tank today. I had something come up and am going tomorrow. (Buying a truck in Phila - 4 hours each way - plus time at the dealer - didn't work)
I will get it tomorrow. I have talked with many frustrated Late C5 owners that just F'n HATE the fuel system. I can't do anything about it - I own it. The Blower is causing me to re-do my fuel delivery and I already put a hole in my tank for the ECS external system. I'd rather have a virgin tank and sell the external pump and bulkhead fitting as a 'kit'. It looks like the tank is the same and just the pump was different in a Z or XLR Caddy.
Hopefully someone can confirm that?
Thanks again

 

The tanks themselves are the same. The rubber filler tube is a different shape between the C5 and C6 tanks. The pumps are different. I use a C6Z pump in all the C5's I convert to the later tanks. The senders are different depending on the year. If the wrong year sender is installed, the fuel gauge will read opposite (full tanks would show empty on the gauge), but this can be corrected with hp tuners.

 

Thanks for that 3X2 - I knew about the reversed readings from the sender - glad you reminded me!
I'm still struggling with the whole thing...
quick & dirty way is to use the Schrader valve port as a return and be done with it. I've read SOOO many posts about the In-Tank regulator causing that to NOT work. I have the new tank but have spent TONS of money on the fittings and lines to do it from the Schrader port. I just do NOT want to deal with the tanks - ever! But I will have the T-Tube out for a clutch so that would be my best shot at it. Such a *****!
Best thing would be for me to just walk away from this PC and go to the garage and get to work.
Thanks again

 

It's my understanding that the fuel system needs to see a restriction. If not, the r/s jet pump will not work and transfer fuel to the left tank. Using the schrader port for fuel return removes that restriction. I've read on the Buick forums, although not paying much attention, that a Demon or hellcat or whatever Dodge's ultra perfoemance car fuel pump is the way to go assuming it fits into the fuel pump module. You may also want to look into racetronix and this: https://www.racetronix.biz/p/c56-fue...rness/fpwh-008

 

I'm sure you know, I just want to double check.

If you use the schrader valve as a return, you need to add a standalone fuel pressure regulator and block off the stock one that sits in the fuel pump module.
This is in fact the case no matter how you add a return line to the tank.

Well sorry, in fact people running dual outboard pumps fit aftermarket fuel pressure regulators setup with 58psi fuel pressure. But they can't be affected by boost. And keeping the stock tank, well stock.

As mentioned, if you just add a return line, and nothing else, you will have a massive "bleed" in the system, and it won't pressurize.

 

Thanks for that reply Pierrel. I'm not quite following you though....
My goal is to NOT drop the tanks. If I block off the in tank regulator I might as well put a new pump in there and create a true return system - the tank has to come out to do the block-off.

What do you mean by 'Bleed'?

I have an aftermarket external pump that T's into the line coming from the tank going forward. It activates by a hobbs switch. It is giving unpredictable pressure and causing issues with the tune. I know there are MANY people that run this system - with NO return - and have success. It isn't working for me though. I felt that Pump 2 was back feeding into the tank AND sending fuel forward as well - confusing / overwhelming the pump - regulator combo. I put a check valve at the T and that made things worse. I now have unregulated fuel from Pump 2 heading to the rails - it caused a leak and I'm lucky there was not a fire!
The stock pump puts out 58 PSI - why can't I set the regulator to 57 or 56 and use the schrader port to feed the regulator AFTER the rail? I think the check valve has to be eliminated too. I have read MANY posts on this. And there are MANY versions of why it will / will NOT work. There is one guy, UPP, that has an unusual way to do it that makes sense but is not 'normal'.
I appreciate the education - thanks for the help.

 

Like I said - reading a L O T. If you get bored...
This is an old thread. Lots of 'good' info here. My FP looked like the pic in post 26. Not good for the tuner...

https://www.corvetteforum.com/forums...ours-best.html

This is the UPP 'install instruction'. Unique for sure - is it do-able? Safe? Seems to make sense but I'm an Old Skool HotRodder. Fuel, Blowers and computers are new to me but I am having fun learning.


Had I known about the Late C5 fuel system's 'features' when I was Corvette shopping I would have hunted an early '03 (I wanted an '03 vs '02). You all are FANTASTIC!
I love this forum

 

All of this is relatively new to me too.
I'll try my best to explain to my knowledge but I'm still learning and like always, there's a few ways to skin a cat... And I hope others will chime in an correct/educate me.

By "bleed" I mean that if you only fit an return line, and nothing else, you will effectively have a leak in the system. With the return line the pump won't be able to flow enough to build enough pressure, it will just circulate the fuel around.

Sounds like you have something similar to a stage 1 of what ECS describes in that other thread, correct?
From what I understand in that thread a check valve is not going to work. As pump 2 fires, the check valve will close and now only pump 2 will supply fuel to the rail.

How big/what 2nd pump are you running? Maybe the guys that use the ECS way uses smaller pumps than you?
With the right size pump it should not be a problem with back feeding if it's Hobbs switch regulated as it will only turn on when the stock fuel pump starts to not keep up.
Is your Hobbs switch working as intended?

If you're mounting a FPR it will go after the rail.
If you put the pressure lower than the stock 58 psi, the stock internal pump will open the FPR in the engine bay, and you will run the whole system at that pressure I think.
If you put it just above stock pressure or at 60 psi, it will backfeed just slightly to the tank I think.

Might be worth contacting doug at ECS asking for advice? Just please let us know what you come up with!