um, so your not taking into consideration my suggestion about getting http://www.rotaryextreme.com/fuel.html??? even with baffles or a new tank which will cost a lot to make/buy, you can still get starved if you run too low.


at least take a look at rotaryextreme's fuel reservoir
http://www.rotaryextreme.com/fuel.html

I don't want to look into that suggestion, it is expensive, probably gonna cost close to $500+ (I thought I said this in the beginning!)

I know that system. I have seen in in use by a lot of japanese race car and even a US autocross RX-7.

A lot of wiring, tubing/plumbing, losing trunk space etc.
Arghhh too much work and money involved.

Putting in foam in the gas tank is much easier job, and on the wallet to.

Anybody knows the 99 gas tank part number from MazdaComp?

I just chimed in. I've got a 96+ tank in my FD. Previously I couldn't auto-x my car unless it was almost full or I'd get starvation. Since I installed the 96+ tank I ran it down to 3/8 and had one little blip of starvation on a 2.5 min run.

The "baffle" isn't really anything more than a piece of steel that fits over the top of the existing fuel "bucket".

My plan... Use up time:)

it cost 300 dollars just about

So Jeff,

Is it the 96+ tank or the "steel over the fuel bucket"
that's doing the trick? Or is it both?

What is the part number? Where you get it?

hey guys i have had to replace the tank on my '94 base because the baffling came loose too. it DID have the little metal cover for the the little plastic box the fuel pump resides in. comparing it with my mechanic's '93 cym he did not have the cover. i believe mazda made the change in between. however, when researching what to order i did get at least 3 or 4 different mazda part numbers because of different years and superseding parts. i ordered the replacement '94 from the parts diagram though and it had the little cover too.

i took a digital picture of the fuel tank. maybe i can dig it up later when i get home.

i've gone down to 3/8 to 1/2 a tank before getting some starvation on a really big fast sweeper toward the left in an auto-x.

i think the 96+ fuel tanks are probably pretty similar to mine if not the same. maybe we should all open them up and take pics....j/k.

reza, you are a crazy mofo....hahaha.

IIRC it was $320. I got it from Mazdacomp, my salvation:D.

The baffles looked the same to me as my 93 R1 but I didn't closely inspect them. In addition the baffles in my R1 were broken. The design of the 96 baffles looked very similar or the same as my baffles. I've had 3 R1s built in 2/92 and I still have 2 tanks from them, I'll do some investigating.

I've had a 94 and it didn't have any steel over the fuel bucket but I'm sure Mazda could have changed it mid-year. I DO know that if you order a tank for a 95 it has a different part number than a 96.

I don't think the foam will work to prevent fuel starvation in the stock tank. The baffling doesn't help it so the foam really won't either. The problem resides in the design of the plastic box. I tried to create a cover for ours, but it still would starve. My solution was to build a 12 inch tall polyethylene cylinder that fits down the opening of the fuel tank. I then used a ATL 3-door trap door surge tank, having to cut it down smaller to fit inside the tank. I mounted this in the left hand corner of the tank, after taking out the plastic box. I installed a separate fuel pump to draw fuel out of this surge tank and it fills the polyethylene cylinder, where the main fuel pump resides. I installed a fuel cell type fuel level pickup that is a float in a aluminum sleeve, used for Ford application (6-80ohm) I think. It is not as accurate, but close enough to tell you the tank is getting empty. Basically, this system is similar to the Rotary Extreme system, but resides inside the tank. We can run the tank near empty without starvation. It cost about $300 bucks(extra fuel pump, ATL surge tank, fuel level pickup) and time to put the system together.

well if you buy the rotary extreme version, you dont need to custom make anything, its right there, just buy it and hook it up!

So this pump that feeds the surge tank would be a low pressure pump, right?

Erik,

Great idea!.....Sounds somewhat complicated to do....was it? Do you have any pictures of the process?

How did you mount the the surge tank inside the tank?

The rotary extreme unit is nice but I don't like the idea of being in the car with fuel lines and pumps. Setting it up in the tank is great.

ANy more info or advice on how to do this would be great.
Thanks
Niles
ps. Now we know why you were so fast is that car!:-)

Another problem with fuel pick up can be as simple as a vacuum leak. Make sure everything is sealed well. In my case there was a hole in the tree/housing for the fuel pump. The previous owner had drilled a hole for some type of modification and then patched it with shoe goo :)

My fuel was sloshing back up the fill neck and leaking. Also could not maintain good pressure once fuel was below about 5/8 full. I replaced the tree and now I'm not throwing gas all over the track on hard turns. No more fuel cut either unless below 1/4 tank.

Just something to think about. If anyone needs a new pump, tree, or tank, I of course have a couple ;)

Fritz, you have fuel tank? Are the baffle good?

You still have to buy the external fuel pump, an lines and probably some fittings for those lines.
Add the little things up and it'll come out over $400 for sure.

The Rotary Extreme is selling the CAN only, not the lines, nor the pump, nor any other installation item.

So, it's not a "buy it and hook it up!" deal. It's buy the other items, find a location for installation in the car (I've thought about another method of installing it outside the car), measure it out and install.

It'll be cheaper to have my friend weld a can that is similar and still have flexibility in the reservoir design.

Like the others, I would like to see a solution that resides in the fuel tank.

I think foam would work, but you would significantly eat into your capacity. Thus, the foam block would have to be pretty huge.

J

Have any of you looked at other OEM fuel tanks like from an Acura?

J

hmmm i now see yoru point, i assumed that the rotary extreme version came with everything but can now see how it can nickle and dime you to death. I knew someone selling a his old kit for jsut about 300 bucks which came with all the lines, pumps and can and just figured that rotaryextreme's one would come with the same.

Nah..not on the rotary extreme kit, it will definitely put me into the SM2 class at autocross.
Otherwise, its good for drift car. I am pretty sure with you being in Hawaii, must have seen a lot of drift car with that kind of contraption. :) I wish I am in Hawaii.

It is not that complicated. It took me a day to put it all together. I don't have pictures, so here is quick explanation of the process. First, you need 1/8" thick sheet of polyethelyne or similar polymer plastic that is resistant to gasoline. Cut out an oval using the gasket for the fuel pump assembly cover, making it slightly smaller by 1/8" around. Go to Home Depot or similar and buy some 1/16" aluminum L shaped material 1/2" X 3/4" and a piece of 1 1/2" flat. Pop-rivet multiple 1" or widepiece of the L shaped material around the periphery of the oval template, so that the 3/4" inch side is flush with the outer edge. Then create the tube by pop-riveting a 12" tall piece of the 1/8" polyethylene plastic around the oval that has the L-bracket around the periphery. Pop-rivet the 1 1/2" wide flat aluminum up the seam, and your tube is finished, except for slight leaks at the bottom. I sealed the bottom of the tube with a 2-part epoxy that was would stick "somewhat" to the polyethelyne. Nothing sticks very good. I think in retrospect that the tube would work fine without sealing the bottom, as the bottom is resting at the bottom of the tank, and it is in a small amount of gasoline anyway. The seam did not leak significantly, if you place the rivets close enough. I bought a 3-door trap door surge tank from ATL (Aero Tech Laboratories), and cut it down (I had to cut a section out, and shorten it also) to be able to fit into the oval hole. After you remove the stock plastic tray, there are some metal tabs that are welded to the bottom of the tank, that can be used to wire tie the surge tank in place.
Certainly, as others have mentioned, you can buy the external system from Rotary Extreme, but I didn't want all the hoses in the back hatch, or running outside the tank under the car. This system works, it just takes some time to put it together.

Thanks for the write up.
NIles

Thanks EriK. I assume that you're THE Erik Strelnieks who's ProSolo driver extraordinare? Congratulations on your victories! At some point, can you please send us a note on track comparisons between a your Z06 and an FD?

There are many other ways to do this mod as well. IMO, the simplest way is:

1. Detach the lower plastic baffle (or the only one if you have a 95 or older)

2. Fab or buy the baffle cover from Mazda ($220). I can get you the part number if you like.

3. Fab and rivet a small cover for the large hole on top out of poly (easy to figure out once you've got it in hand).

4. Cap or plug the outlet from the lower baffle (also easy to understand if you're looking at it- it's on the upper right hand side when looking at the baffle from the rear of the car).

5. By three 1" one way ball/chack valves from ATL or fuel safe (about $80) installing them on the right, left, and rear sides of the lower baffle. You'll need to cut 1" holes into the plastic baffle to do this. Be very careful to avoid using a drill or anything that will cause a spark if you're working on a full or partially full (or even an emplty tank with fuel vapor) fuel tank! Use a knockout punch or a hand-crank drill to do this.

6. Reattach the bottom baffle and cover. Snap/bolt everything back together.

I've run my car down to 2 gallons with this mod on the track. It really works!

Gene

Gene...
Is that the instruction/order of making a mod or several mod option to do. I assume you did option 5 then 6. Any photos?
Reza

Gene, I wish I knew of this modification, as it is what I initially was trying to accomplish by buying the ATL surge tank. I knew the plastic tray was the problem, and I even tried to attach higher sides to the stock one. Certainly a cover and better in-lets is what it needed. I am still curious how you were able to get those 3 metal tabs to reattach the bottom part of the tray to the tank. They are a bitch to try and bend back into position.

As far as the comparison, it comes down to one word, torque. Hoping to narrow that gap with a 3-rotor that is on its way from Florida, as our SM2 RX7, will still not beat a SM2 Z06, until we can get off the turns at lower RPM.

All parts need to be done to do this mod correctly. They're roughly in order, but don't have to be.

Most difficult part is removing the lower baffle, cutting holes, and replacing it.

My digital camera was stolen with the pics. I hope to get some time in the near future to replace my Supra pump with a Bosch Motorsports unit. I'll snap some more with the new camera. I'll let you guys know and put them on my website.

Gene

I got lucky with the tabs, but suffered lots of bloody hands and forearms in the process. Not sure that I could do it again!

Good luck with the 3-rotor. I concur on autocross re: Z06 vs FD torque. That's why I do track-only stuff now :)

Wonder how Steve O'Blenes manages to fight off the 'Vettes in BP?

Gene