The definitive fuel tank/sump/surge setup thread.
 

So I've been searching for a little while and I see some things here and there in regards to sump/surge setup threads. Nothing really current that I noticed and a lot with missing pics now.

One of the upcoming winter projects I'd like to do is address my new fuel concerns. I am now running twin Bosch 044s in tank. While this is all nice and all, since they flow so damn much, and we all know the stock FD baffle sucks even more than these pumps do, I need to rethink.

My goal is not to go gaudy. By that I mean obvious by way of visibility. I'd rather not have a surge tank sitting in the hatch as well. What this may mean is a new, custom aluminum tank with a built in surge tank. And yes, I do track it. No, not in a straight line. :D

But, before I do that or go there, I'd like to see what everyone is running tank wise. The other benefit for all is a one stop shop of fuel setups, differences, (dis)advantages, and potential road blocks whether due to cost, skill, or what have you. Obviously anything other than a simple drop in pump. Please post as many pics of the setup as you can including any interior tank pics if applicable.

This is JUST the tank setup. The motor side of the fuel setup isn't needed.

Attachment 386296
soon this will be my surge tank...should hold about 1.2-1.3 gallons of fuel (e85)

Seriously??? Wasn't there a thread on surge/swirl tanks less than a month ago?

I remember scrolling though it and seeing pics of various setups. Am I wrong here???

---edit---

Well, maybe I was just remembering this thread, from late last year...

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/write-up-poor-mans-fuel-swirl-tank-setup-also-known-surge-tank-861608/

...doesn't seem to be missing images though.

just to add a note, most of the time you can get away with using a stock fuel pump in the tank if you use an external surge tank. this is because there is essentially no pressure on the internal pump and it can turn freely. you need an excellent external pump that is gravity fed from the surge tank though. i love doing the external fuel surge tanks because they are extremely effective and extremely cheap to build.

I've been fine with hyperion's surge tank cover. Can track and autox the car down to below 1/4 tank w/o issue.

Twin Bosch 044's?!?!?!?
 

Jesus man, what are you running? (power goals, fuel type & flow rating???)

Did you fit both 044's in tank?

That's awesome, but seems like overkill.

Is one just ran as a back up, in case one fails?

I'm running dual denso pumps with my setup, and have the return dropping back into the baffle area. That got me thinking... if i had an in-tank chamber (i guess like a swirl pot) that can accumulate the returned fuel (anything but redline at full boost I should have a good amount of fuel to return) I should theoretically be able to run off of whatever is in that chamber while at high lateral G's. The problem with this idea is filling that chamber up with the fuel pumps INSIDE the chamber (without running a 3rd low-pressure pump) and then (slightly less of a problem) locating that pump or mechanism so that it's not affected by low fuel levels. Now I'm aware that the z and g35 have some sort of "siphon" system but I havent been able to get any decent pictures of it or read up on how it works... but i havent looked too hard. A siphon system would fix the starvation issues if the chamber it feeds is somewhat tall (which is i believe how the z/g35 works).

Seriously. :rolleyes:

I'm in the process of building that right now for my FC.
Basic dimensions are something along the lines of 17"x27"x10". In the center is a 7"Diameter tube that runs the depth of the tank - 10" or about 5 qts. The tube is welded to the top of the tank to prevent leaks and a single bosch 044 pump will drop in. There's enough fuel in there for something like 90 seconds of 90% duty on the injectors (which I should never hit) with no return which won't be the case either. In other words, incredibly safe math.
A denso supra tt pump is the lift pump which will be in basically the stock location with it's own little sump A la stock style.
Vented and will be connected to the factory fill so unless you look under the car, you won't be able to tell the cell is there.
I have no pics as of yet. Everything is cut and fitted, I just need to find about thirteen hundred hours to sit down and weld it altogether.

Where are you planning to install that? Just sitting in the hatch I assume?

Heh...power goals are TBD. Using E85 with 6 ID1000 injectors. They are both in tank and I've built a lot of redundancy in terms of how they're working but they both run simultaneously.

But, using the stock tank isn't feasible long term.

theorie,

That was one thread that I hadn't seen. And it was Damian explaining his setup. It didn't really foster a larger discussion, not that his threads don't warrant a lot of responses. Cut a little slack.

+1 +1, I tested to see how far I could go last year with the cover and went all the way down to the empty line before it fuel cut on turn 2 at Mosport (which is a right-hander). You honestly don't need anything else.

thewird

Well, I'm not looking for what I need per se as opposed to out of the box ideas that may be easier than some to implement, maintain, modify (from a pump or line size perspective)...that kind of thing.

Working with the smallish hole on the stock tank isn't good for intact fingers...or anything really.

Christian, Not to get too far off topic but what redundancy have you built in to the twin pump setup? If they 'T' together into one line, and one goes out/blow a fuse/etc how will you know about the failure? If the safety device is a light on the dash for example, but it illuminates on a full throttle run when you need fuel from both pumps, what prevents running lean and blowing the motor ?

Also since the fuel itself is used to dissipate heat from the pumps, but you are returning a large portion of fuel (heat) to the tank, have you thought about any external means to cool the fuel? Any additional in-tank heat will increase the chance of failure over time.

The reason I ask is not to be obnoxious, but because I have been dealing with trying to design around the same issues with my own twin pump system, so I'm wondering what you've done. I realize this is kinda outside the scope of the thread so I'm happy to talk over PM or in a twin-pump thread :)


Anyway, back on topic... I'm definitely in favor of some sort of in-tank setup. if the stock tank can be made to work safely, why redesign it from scratch? I mean simply taking the stock tank and welding in a sump area will do the trick. I don't know why mazda didn't add a sump type area to the tank.... even the rear euro water tank has a sump section on the lower side ;)
-Heath

Can I pull my fuel pump out with the hyperion tank cover in place? or do i have to remove the straps and loosen the hyperion cover to get the fuel pump assembly out? I opened the fuel pump cover and tried to remove it but it seems really tight inside the cover. Does anyone have detailed install pictures or instructions that would help shed some light on this. I did not install it.

Radium and Built 2 Apex both have in-tank surge systems available, you'll need to change the pumps though.

You should be able to remove the pump assembly without having to remove the Hyperion cover.

We just put these covers back into production and there shouldn't be anything stopping the pump from being removed. My only thought is the rubber gasket is giving resistance against the pump as you pull it.

https://cdn.shopify.com/s/files/1/00...G?v=1554228019