15gal vs. 21gal Poly Tank

Need to get around to putting a new tank in my HEEP. After reading through a bunch of threads here, I think I've finally decided on poly. Now the question is to go back with 15gal, or 21gal.

It looks to me that the 21 gal tank will fit between the frame rails the same, but hangs down 4" or 5" lower using skid plate extensions. Does anyone have a picture of this?

Also, fuel injection is in my future. Contemplating an in-tank pump. Are there OEM pumps made that will reach the bottom of the 21gal tank?

 

Can't asnwer to the tank but I would stay away from the in tank pump and stick with one like Ford uses that mounts to the frame rail, much easier to replace or repair on the trail with FI if something goes wrong.

 

I don't have any pictures but I have seen the 21 gal tank. IMHO it hangs too low, like way low, like getting caught on a lot of rocks low.

 

Went with the 15 for the reasons noted above for mine. The tank relocation to the rear is still a work in progress.

 

Mmm. You want in-tank to accommodate EFI? I thought you had to have a specific flange for an in-tank pump, unless you went with something homebrew like this: http://www.justih.org/Binder-Bench/showthread.php?p=3677#post3677



Maybe a Wrangler tank will fit, give you a few extra gallons, and provide a flange for a Wrangler EFI pump?

 

I have a photo of 21 gallon tank but not sure how to post it?

 

Posted for jarbidge09:

 

Thanks for all the replies. I think I'm going to get the 15 gal. I'll look into the Ford inline pump since that might also solve how I am going to draw from dual tanks.

 

That doesn't look all that low to me. It's what I'm planning to put in with an external pump.

 

NB this Jeep is a spring-over, so the ride height is higher than most.

 

Good point.

 

I'm using a Ford-style external inline pump on my Scrambler. I believe it's the Airtex E2000. But it pumps WAY too much PSI for a TBI application. So you have to match your EFI with your pump. The E2000 is around 65psi, and it has to run through a Grand Cherokee fuel filter with built in pressure regulator to drop it down to the 49.5psi required by my 97 4.0L system.

They claim the E2000 works better as a pusher than a puller and will not be able to pull all the fuel out of the tank. Ford used a small internal pump to prime the external high pressure pump. I have a small low pressure primer pump mounted at the tank to feed the E2000 and it seems to work just fine even at low fuel levels in the tank.

Finally, MTS, who make the poly tanks for Jeeps sold by various vendors, say they now market in-tank fuel pumps. If you know the specs of the pump you need before you buy the tank you can have them make you a tank with the pump built in: http://www.mtscompany.com/custom.htm

 

IIRC, the spacers used for a 21 poly tank drop the tank something close to 4".......