99-02 LS plastic fuel tank install

[ukcats07]

I finally finished installing my 99-02 Camaro plastic fuel tank into my 73' this week.  I used 2x1" rectangular 1/8" tubing and a 3/4" bushing for the strap hold-downs.  Welds aren't pretty, but they are solid and work.  I think I spent a total of about $20 n the steel, $15 for the straps, $60 for the tank, and $80 for the pump.  I'm posting this to hopefully help somebody else out as the other posts on this topic have good info, but dead picture links.

[idahoskiguy]

Good work! Thanks for posting.

[caperix]

Always good to have more pictures of this swap.  Have you decided on how you are going to do the filler neck?  My tank came with a f body filler & it looks like I could mount it in the factory location with a little work, but the angle may make fill ups difficult.

[ukcats07]

On 9/6/2020 at 10:08 PM, idahoskiguy said:

Good work! Thanks for posting.

Thanks! It's nice to check things off the seemingly never ending list. 

 

18 hours ago, caperix said:

Always good to have more pictures of this swap.  Have you decided on how you are going to do the filler neck?  My tank came with a f body filler & it looks like I could mount it in the factory location with a little work, but the angle may make fill ups difficult.

The input is pretty high on the tank. I just purchased a stock Camaro filler and I'm going to try to make that work once it shows up. Other posts said it's OD matches the ID of the Datsun fill neck. I'm hoping that's the case and it goes somewhat smoothly. 

[ukcats07]

On 9/7/2020 at 6:56 AM, caperix said:

Always good to have more pictures of this swap.  Have you decided on how you are going to do the filler neck?  My tank came with a f body filler & it looks like I could mount it in the factory location with a little work, but the angle may make fill ups difficult.

 I was able to make the camaro filler neck work.  I cut the 60ish degree bend off, and re-welded the nipple to the straight end of the pipe.  I removed the datsun filler neck completely and used an exhaust flange to tack the camaro filler neck in place.  The bolt hole arrangement of the exhaust flange was the exact same as the original datsun hole placement.  I'll take some pics and upload when able, but it looks like it's going to work out nicely.  Just need a 1x1" 90 degree hose barb coupler and some 1" and 1.25" fuel hose to finish it off.

[ukcats07]

Don't mind the disgusting tack weld, that will be ground down before paint.  Pics hopefully show what I'm working with.  I lose the vent-tee on the filler neck, but something can be fab'd I believe.

 

 

[MMaxim]

Just what I was looking for! Thank you for posting. 

[SH4DY]

I'm also running this tank and under hard acceleration with less than 1/2 a tank, there is a ton of fuel movement (gauge will go to empty). And, being a plastic tank, not really much you can do to modify it in terms of baffling. I basically can't run less than 3/8 a tank if I plan on really racing the car. I also cheated the fuel level sending unit to read slightly lower than it is just for some safety. 

I have yet to try some of the Fuel Safe foam blocks to dampen the movement (had bad experiences with cheaper foams breaking down with race gas), but they should help - just need to stay on top of checking filters for any material breakdowns. 

 

Just a heads up for others thinking of going this route. 

[MMaxim]

45 minutes ago, SH4DY said:

I'm also running this tank and under hard acceleration with less than 1/2 a tank, there is a ton of fuel movement (gauge will go to empty). And, being a plastic tank, not really much you can do to modify it in terms of baffling. I basically can't run less than 3/8 a tank if I plan on really racing the car. I also cheated the fuel level sending unit to read slightly lower than it is just for some safety. 

I have yet to try some of the Fuel Safe foam blocks to dampen the movement (had bad experiences with cheaper foams breaking down with race gas), but they should help - just need to stay on top of checking filters for any material breakdowns. 

 

Just a heads up for others thinking of going this route. 

I thought that in that particular tank the pump is sitting inside the enclosure that keeps it submerged in fuel during acceleration and cornering. The return line seems to be dumping fuel inside that enclosure, too. And you are right, the fuel level float is outside that and will not be reliable during cornering. 

 

[SH4DY]

1 hour ago, MMaxim said:

I thought that in that particular tank the pump is sitting inside the enclosure that keeps it submerged in fuel during acceleration and cornering. The return line seems to be dumping fuel inside that enclosure, too. And you are right, the fuel level float is outside that and will not be reliable during cornering. 

 

You are right in that the pump sits in an enclosure but it's not a sealed "bucket" - there are passages to let fuel in from the bottom and unfortunately if running one of the bigger Walbro units, there is trimming needed that can do away with the check valve (its just a small rubber flap) so fuel can drain from the bottom if not submerged. You could probably seal it if you wanted but then you'd be only relying on the return fuel to fill it. Not ideal on a thirsty motor depending on the racing you're doing.  There's always the option of running a surge tank as well. 

 

Also, my issues with the level dropping weren't even cornering - just straight line acceleration. 

[Neverdone]

Due to the way it's mounted, (and it would be hard to mount it reversed due to fuel inlet location and possibly exhaust clashes) it seems like you'd absolutely have to run either fuel foam (fuel safe says it must be replaced every 5 years maximum) or run some sort of fuel surge tank if you're doing any sort of hard acceleration or cornering...which is kinda the whole point of the car.

 

As this is the plan I have as well...I guess it's time to start looking into surge tanks!

[MMaxim]

From Racetronics website:

 

"The 1999 & up LS1 F-body cars have a pump that is inside a plastic fill-bucket. The fill-bucket is equipped with two inlets on the bottom. The equalization checkvalve is used to fill the bucket when the level of fuel in the tank is greater than in the bucket. The equalization checkvalve does not allow fuel to exit the bucket. The venturi system's inlet is a combination checkvalve and powered suction system. The factory pump supplies pressurized fuel via a small tube which feeds a calibrated jet inside the venturi system. This jet of fuel shoots across the base of the checkvalve inlet thereby creating a suction effect which draws more fuel from the bottom of the tank through the filter sock. This venturi system keeps the bucket full all the time even when the fuel tank is almost empty. A full bucket keeps the pump immersed in fuel regardless of the tank level so that when the tank is low on gas and you are doing some hard cornering or acceleration the pump does not run dry and start aerating (air bubbles) the fuel. This happens as the fuel sloshes from side to side in the tank leaving the center low on fuel. This can cause detonation and possible engine damage. The 99+ F-LS1 cars with plastic tanks have no baffling in them so the bucket is very important. The bucket also allows the car to operate with lower fuel levels in the tank due to its scavenging effect. The fill-bucket improves motor crank-to-run time as the priming time is reduced under most conditions. The return line feeds the pressure regulator on the fuel module which diverts fuel back into the bucket so that the unused fuel also helps keep it full at all times.

 

With bucket and venturi system in place there is no need to run foam. At least that's what it looks like to me. 

 

 

[SH4DY]

12 minutes ago, MMaxim said:

From Racetronics website:

 

"The 1999 & up LS1 F-body cars have a pump that is inside a plastic fill-bucket. The fill-bucket is equipped with two inlets on the bottom. The equalization checkvalve is used to fill the bucket when the level of fuel in the tank is greater than in the bucket. The equalization checkvalve does not allow fuel to exit the bucket. The venturi system's inlet is a combination checkvalve and powered suction system. The factory pump supplies pressurized fuel via a small tube which feeds a calibrated jet inside the venturi system. This jet of fuel shoots across the base of the checkvalve inlet thereby creating a suction effect which draws more fuel from the bottom of the tank through the filter sock. This venturi system keeps the bucket full all the time even when the fuel tank is almost empty. A full bucket keeps the pump immersed in fuel regardless of the tank level so that when the tank is low on gas and you are doing some hard cornering or acceleration the pump does not run dry and start aerating (air bubbles) the fuel. This happens as the fuel sloshes from side to side in the tank leaving the center low on fuel. This can cause detonation and possible engine damage. The 99+ F-LS1 cars with plastic tanks have no baffling in them so the bucket is very important. The bucket also allows the car to operate with lower fuel levels in the tank due to its scavenging effect. The fill-bucket improves motor crank-to-run time as the priming time is reduced under most conditions. The return line feeds the pressure regulator on the fuel module which diverts fuel back into the bucket so that the unused fuel also helps keep it full at all times.

 

With bucket and venturi system in place there is no need to run foam. At least that's what it looks like to me. 

 

 

...again though, all of that goes out the window (the venturi primarily) when running an aftermarket pump/ external fuel pressure regulator (which most people run when doing swaps) because the internal regulator gets bypassed.  On a stock F-body, sure, I'm sure it works great. But we are flipping the tank 180 degrees making fuel more prone to move away from the basket and in my case (or anyone with a different pump and external FPR) modifying the basket. 

Feel free to keep it all stock, I'm just telling you that with high power/ high grip, you're going to have issues unless you modify it. This is from real-world experience.

[fusion]

What about using the LS tank with Holley Hydramat?  Should alleviate most fuel movement concerns with aftermarket pumps and regulators.  https://dsportmag.com/the-tech/stopping-fuel-starvation-holley-hydramat/

 

Otherwise, do any vendors offer a custom EFI tank for the 280z?