Fuel Tank Options/Opinions (from old site)

[derekf]

Steve68
Registered User
Posts: 508
(12/3/03 9:25 am)
Reply Fuel Tank Options/opinions
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I'm going to start mocking parts up on the body soon,

The engine I'm running is a TPIS Mini Rammed 383, I have a high volume fuel pump, inline, My plan is to run the stock tank with the above fuel pump and I inline type of fuel filter, and a return line, since I will be running high pressure I don't need to run bigger than a 3/8" line but I'm worried about the tank, I know that RV baffles there tanks, but that's because of the in tank pump, should I run a baffled tank or will have problems, I'm thinking I won't because I will be drawing from the top of the tank, That's my plan, what do you guys think, I'm trying to get things sorted out, thanks Steve

camcojb
Registered User
Posts: 617
(12/3/03 9:49 am)
Reply Re: Fuel Tank Options/opinions
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I would run a baffled tank or a sump on the bottom rear. We are switching from the stock tank and modified pickup on my buddies 69 for this exact reason. He's taking my RV unit and ordering me a new one. At even 5-6 gallons from full the car will move the gas from the pickup on acceleration. And on an efi car that's an immediate stutter.

Jody
MY CARS

SDMAN
Registered User
Posts: 11
(12/3/03 12:04 pm)
Reply sumps
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A correctly installed sump will go a long way toward keeping the inlet to the pump covered with fuel. We put a fairly large sump on my tank (the size will be dictated by the type of car and fuel tank mounts). With an EFI setup, Im going to get in the habit of filling the tank sooner than I usually do (no more games like how far can I drive with the needle on E)

Steve68
Registered User
Posts: 510
(12/3/03 12:40 pm)
Reply Re: sumps
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Thanks Jodi, I new you'd have some insite on this, that was an option I forgot to add, I have a sump on my Nova, I guess thats a good alternatve to buying a RV, I'm open to others though, no beer kegs in the trunk though!! Steve

camcojb
Registered User
Posts: 618
(12/3/03 1:52 pm)
Reply Re: sumps
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No problem. It's just really critical on these EFI deals; the stock tank has no baffling and you'd be surprised how little fuel has to be used to get them to uncover the pick-up. At least I was!

A sump is a lower dollar alternative that works just fine.

Jody
MY CARS

Steve68
Registered User
Posts: 513
(12/3/03 4:29 pm)
Reply Re: sumps
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Jodi, what experiences did you have any you want to share? did you run a vent to a charcol canister, what about a return line? thanks Steve

camcojb
Registered User
Posts: 619
(12/3/03 5:38 pm)
Reply Re: sumps
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Initially on the yellow car I modified the stock fuel sender, adding a 1/2" line out the top for a feed line. I used the stock 3/8" line as a return line, after removing the sock off the end of it. It worked fine as long as you kept the tank full. Even 5-6 gallons down caused problems. This was a temporary thing for me as I had already ordered a RV stainless baffled tank (minus pump) and wanted to drive the car while the tank was being built.

A lower cost option would be to buy a new reproduction tank and have a sump welded into the bottom rear. Being as it's new it's easy to weld (no gas fumes) and would be a fraction of the cost of the RV tank.

I haven't used a vent yet because I use the vented gas caps. There isn't anything wrong with using a vent instead. I like a #8 or better yet (on the big pumps) a #10 inlet to the pump, and a #8 return line. A #6 is fine in most any application, but I always err on the larger side to prevent any pressure build-up in the return line which can monkey with the fuel pressure. The external pumps like the Aeromotive like the large inlets; much easier to draw through. The outlet can be #8 without problems. I run a coarse (100 micron) stainless filter between the tank and pump and the standard 10 micron EFI filter after the pump. Again I like the Aeromotive, but SX, Weldon, and others make nice stuff also. I ordered my RV tanks with a 1/2" NPT fitting for the pump inlet and a 3/8" NPT fitting for the return line. I generally run stainless (aluminum also works fine and is much less expensive) hard line for the feed and return lines with short sections of braided in the flex areas like between the frame rail and fuel rails.

The advantage of a baffled tank like the RV or the one that John Parsons here makes is that you can run the gas way down in the tank and still keep the pump fed. Also road course, autocross, etc. fun can be done whereas a stock un-baffled tank will give you problems once some of the gas is run out.

Jody
MY CARS

Edited by: camcojb at: 12/3/03 5:42 pm

walapus
Registered User
Posts: 96
(12/3/03 8:10 pm)
Reply minimizing slosh
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This subject came up on another board I read, and they recommended fuel safe foam. A much simpler alternative that would work very well for the average enthusiast

parsonsj
Registered User
Posts: 1315
(12/3/03 9:22 pm)
Reply tank baffling
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As Jody mentioned, I have made some baffled tanks. I use 10AN fittings on the sump, and 6AN for the vent and return. Here's a link to some fabrication pictures:

II Much Fabrication tanks

John Parsons


Edited by: parsonsj at: 12/3/03 9:23 pm

camcojb
Registered User
Posts: 621
(12/4/03 12:00 am)
Reply Re: tank baffling
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Quote:
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This subject came up on another board I read, and they recommended fuel safe foam. A much simpler alternative that would work very well for the average enthusiast
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That's true, should help a lot. You'd have to adapt to a different type of fuel level sender like the enclosed ones the fuel cells use as the foam would definitely interfere; or don't run a fuel gauge. By the time you welded up the hole for the sender might be just as easy to put a sump in.

Jody
MY CARS

Steve68
Registered User
Posts: 517
(12/4/03 6:22 am)
Reply Re: tank baffling
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JP, do you make a tank to fit in the stock location for a 68, with the sump incorporated, if you do how much?,

Jody, if were using FI and high pressure pumps, why such large line sizes, I know for large fuel volumes, My Nova has 1/2 lines, just trying to get everything set up,

Weighing my options before I start installing and have to rip it all out, Steve

parsonsj
Registered User
Posts: 1318
(12/4/03 6:51 am)
Reply 68 tank
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Steve,

Yes I do make them to fit a 68 Camaro. But for now, I have all the work I can handle. Once I get my car off to David Sloan's for paint, then I can build a few tanks. That is a couple of months away.

I have two guys waiting on me right now ... if that sort of relaxed timeline works for you, send me an email:

[email protected]

thanks,
jp


camcojb
Registered User
Posts: 623
(12/4/03 11:27 am)
Reply Re: 68 tank
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Quote:
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Jody, if were using FI and high pressure pumps, why such large line sizes, I know for large fuel volumes, My Nova has 1/2 lines, just trying to get everything set up,
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Yeah, that's pretty much it. The Aeromotive pumps I use prefer a #10 inlet so that's what I do. The 1/2" stainless hardline is #8 which really doesn't cost any more than #6 and with the blown cars I don't want to restrict the fuel. Probably overkill as I've seen a lot of power made with #6 feed lines. It's just that the price is so close I opt for the bigger stuff.

Jody
MY CARS

Steve68
Registered User
Posts: 528
(12/5/03 6:49 am)
Reply lines and pumps
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Jody, are you bending all your own lines or using braided, where are you getting your supplys?, I was thinking of running all braided, but I like hard lines too, JP e-mailed me about the tanks, no to get ahold of Ralph, my have to drag him away from the car , Steve

camcojb
Registered User
Posts: 631
(12/5/03 8:29 am)
Reply Re: lines and pumps
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I do all the main lines in hard line, with the flex areas done in braided. There's a couple of local tubing and fitting shops near me I buy them from. I have the Ridgid tubing benders for any tubing up to 1/2"; three different tools. I also use a Ridgid 37 degree flare tool and tube nuts to adapt the hardlines to the braided lines.

All of this stuff is easy to use and work with. I've been using stainless hard lines on the last couple of cars. The aluminum tubing is much easier to bend and more forgiving; never had a problem with either. I just keep them well supported with adel clamps or something similar to what the factory used for the brake and fuel lines.

Jody
MY CARS

Steve68
Registered User
Posts: 532
(12/5/03 12:04 pm)
Reply Re: lines and pumps
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Jody,
Thats the way I have my Nova set up, I used the soft aluminium, worked fine, what thickness of stainless did you use? I think stainless will look better than alum, but harder to bend, but easier, did you have a problem with it collapesing while doing *90 bends, Steve

camcojb
Registered User
Posts: 634
(12/5/03 12:20 pm)
Reply Re: lines and pumps
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None at all with the current tubing, but I don't know the thickness. I bought some a while back that collapsed with any bending; just too thin. Unfortunately I don't know the thickness of either.

Jody
MY CARS

davidpozzi
Moderator
Posts: 966
(12/6/03 10:23 pm)
Reply
Re: lines and pumps
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A stock tank could be used if the fuel were first pumped to a "makeup" tank.
The makeup tank is a 3" dia piece of tube vertical in the car with the top vented back to the main tank.
You can pump to it with a regular electric "primary" fuel pump, the EFI pump can draw from the Makeup tank which is allways full. A 3" by 14" tall tank would hold around a half gallon. I made one for my Lola, they are very common on road race cars.

I now have a makeup tank installed inside my fuel cell (actually a surge tank) with flapper trap doors in it. This eliminated the need for the primary pump.

From my experience, fuel cell foam only slightly slows fuel slosh. It would probably help some, but I think you would still have problems when the fuel level got a little lower. Look how fast the NASCAR and Indy guys fill their tanks. The foam doesn't slow them from filling very quickly.
David
67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
http://ourworld.compuserve.com/homepages/David_Pozzi/

Edited by: davidpozzi at: 12/9/03 11:22 pm

68ssconvt
Unregistered User
(12/9/03 9:59 pm)
Reply Homemade (Anti-)Surge Tank
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I made a tank similar to what David is talking about. But I used a unique approach. I created it from an inline water filter housing. It even uses an intank style pump, which are generally cheaper than inline equivalents.

See more here:
www.geocities.com/hrayhou...etank.html

I'm sure a custom tank or sump is a better option, but this is a cheap and easy yet very functional way to go. I could run until the fuel tank is totally empty with this setup, with virtually no chance of the pickup ever coming uncovered. (This setup works better than baffling/sumps in extreme situations such as road racing.)

Just giving another (low cost) option,

Ray

keithq
Registered User
Posts: 743
(12/10/03 10:30 am)
Reply Fuel tank.
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I am going to use a new stock tank and modify it for my LS1.
I am adding a sump on the back of the tank. Then I am going to use the Stock 99 LS1 pump system. This comes with a can that the pump sits in, the return line dumps into this also. There is a screen on the bottom and a flapper valve so that fuel can only flow in.
I am sure I will have no trouble with this setup and it came free with the engine and tranny so I figure why spend money on something else.

Keith Quinn.


parsonsj
Registered User
Posts: 1352
(12/10/03 10:55 am)
Reply Re: Fuel tank.
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Keith,

That will work fine. I've modified a tank to do exactly that (68 Camaro tank with 99 f-body pump), including re-using the late model flange so one can buy replacement hi-po pumps from places like Jegs. I also baffled it so it has dual baffles.

The problems I encountered doing this are: The sump is a solid 2.25 inches below the tank. Not the prettiest looking fuel tank I've seen. The fuel level sending unit has to be significantly "tweaked" by bending the ss rod that holds the float. Since the fuel level sensor is right by the fuel pickup unit, the sump has to be flat to work.

But it should work great.

jp


keithq
Registered User
Posts: 746
(12/12/03 8:44 pm)
Reply Tanks.
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Hey John.

"Tanks" for the response (sorry.)



Do you have any pics of the tank you did. What did you use in the top of the tank for the unit to sit in. The tank that mine came from is plastic so I can't cut the section out and weld it into mine.
I will probably have my friend spin something up on the lathe out of stainless and then weld that in.

I am going to compress the springs on the bucket as much as possible to keep it short but you are right it is a tall unit.

I considered using a factory 69 sender in the front opening, have not decided yet.

Keith Quinn.


parsonsj
Registered User
Posts: 1362
(12/13/03 6:36 am)
Reply You're welcome
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Hey Keith,

The plastic tank has a metal seat for the pump o-ring to sit on and metal tangs that stick up to hold the tank retaining ring. I cut that out of the plastic tank, welded it to a fabricated sheet metal recesss, and then welded the whole assembly to the top of the 68 tank. You must recess it about an inch or the pump will hit your trunk floor.

I baffled it by cutting a large section out of the bottom of the tank, placing a U shaped piece of sheet metal inside the cut that went all the way to the top of tank and that also functioned as the sides of the new sump. I plasma cut 3 1 inch holes to allow fuel to flow into the new "chamber". Then I welded the original bottom back on.

It functioned very well .. but it wasn't nearly as pretty as my aluminum tanks.

jp


Norm Peterson
Registered User
Posts: 126
(12/15/03 4:39 am)
Reply Re: Homemade (Anti-)Surge Tank
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Quote:
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I'm sure a custom tank or sump is a better option, but this is a cheap and easy yet very functional way to go. I could run until the fuel tank is totally empty with this setup, with virtually no chance of the pickup ever coming uncovered. (This setup works better than baffling/sumps in extreme situations such as road racing.)
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Another data point on the separate tank approach - whether the EFI pump suction ever gets uncovered depends to a large extent on how well the first pump can re-establish flow after fuel sloshes away from the sock and also on the volume of the transfer tank. With a transfer tank volume only a little more than 1 qt I still need my unbaffled OE '79 tank to be more than 1/4 full to avoid momentary stumbling toward the end of a 50 second auto-x, though it will work in easy normal driving down to somewhere under a gallon and a half remaining in the main tank (out of 18.1) before letting you know . . .

Norm