aspeters

I have a '92 C4 with 130k for 70/30 HPDE/street use (not a DD but is street legal).

Looks like some of the fuel starvation problems in the C4 are due to the fuel pickup not being close enough to the bottom of the tank, and this is fixed with simply bending down the tube closer to the bottom of the tank.

While the tank is apart, I'd like to add some fuel cell foam as both an added safety measure and to prevent excessive slosh.

I've heard that a "tube style" fuel level sender is necessary if foam is in the tank. And to replace the fuel tank lock ring. Summit Racing seems to carry both foam and generic tube senders in their own brand.

A few questions:

• How many foam 'bricks' will fill a tank? I guess knowing tank dimensions would help this...I can do the math.
• Beyond the obvious, what happens if you underfill (loose/floating around) or overfill (packed too tight) with foam?
• What length of tube sender would I need? Again, tank dimensions...
• Confirm that the stock sender is a 90-0 ohm?
• Is it worth replacing the Fuel Pump while apart? Or at minimum the sock? What socks work? best

Also willing to consider other alternatives, though a $500+ fuel cell is beyond what I'm aiming for...

Thanks for the tips,
Andy

ZR1 MK

Aftermarket fuel sending units operate on a different ohm reading than the stock unit and wont work. You will need an aftermarket gauge too.

If you opt to use the stock tank, you can do the foam on the side of the tank where the sending unit arm doensnt operate. Half is better than nothing.

Luckily the ZR1 has two pumps so I dont have the pickup issue others have, but the added safety and weight distribution is a plus.

Aardwolf

The stock tank is ginormous and will cost a lot to fill with foam. I considered it and will use a fuel cell instead, the weight loss is quite a bit. I will likely not use a fuel gauge and just check the level, that can save on cost.

aspeters

thanks. Any other tips from folks?