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I'm only speaking for myself but I have Boyd's aluminum tanks in my personal Esprit and as Randy noted we have used them in other cars as well. The quality of the tanks is totally professional. Also we have visited their shop and they have a first class operation, and were very attentive to us and good to deal with when it came to design and suggestions for improvement.

Perhaps some one here can chime in on the similarities/differences between G and S cars to see if the tanks are compatible. If they are, problem solved. If not then another alternative is to deliver old G tanks to Boyd's and have them reproduce the new tanks from their own measurements of the original Lotus G tanks. The first time we ordered tanks from Boyd's we delivered a pair of old S tanks for them to use as a model, and we also discussed the changes we wanted to make to the design of the original tanks.

If you took this approach it would add some expense (shipping old tanks to Boyd's) but it may not be prohibitive, especially if you do not want the old tanks returned. Or if you organize a group buy of G tanks, them the cost of supplying them with a "model set" of old tanks could be shared among the whole group.

In any event I think they are an excellent source of tanks - and we don't have any financial ties to them or anything like that. I just admire craftsmanship - and I've got to say that they do the prettiest damn aluminum welding I have ever seen! And what a great thing t have an American source for new Esprit fuel tanks at a reasonable cost.
 

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Wingless Wonder
1988 Esprit Turbo
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Scott,

The S-cars (with GM MPFI) starting in '89 had different tanks.

Fittings were different, as was capacity. (Ours are 21 gallons while the newer ones are 19)

The Boyd's tank are certain PRETTY. :clap: And easier to install, as I remember Tom and Randy spec'd them to be a little smaller for easy installation.
 

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what baffling is in the OEM tank? just the one divider in the middle of the tank (with the corners trimmed off so fuel can move from front to back.) There aren't any special baffles in the stock tanks to prevent fuel starvation during high-g, high acceleration, high braking maneuvers, are there?
 

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Integrator
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Because of the future legislative meddling, should we specify use of Alloy 5083 or 5086 when ordering tanks ?

Here is why:

The Negative Affects of Ethanol on Recreational Boat Fuel Systems

The National Marine Manufacturers Association (NMMA) opposes the use of marine fuels that contain greater than 10% ethanol content by volume. This position is based on safety and durability concerns and supported by many well documented studies.

According to state boating registrations, there are over 12 million recreational boats in the United States. Boat builders utilize five types of materials to fabricate fuel tanks. These are aluminum, steel, cross-link polyethylene, high density polyethylene and fiberglass. For a rough estimate of today’s numbers, there are approximately four million boats that have aluminum fuel tanks; approximately seven million have steel or polyethylene tanks, and less than one million have fiberglass tanks. The data clearly indicates that the increased use of ethanol in gasoline has raised safety and durability issues for aluminum and fiberglass fuel tanks.

Aluminum Fuel Tanks

In the case of aluminum tanks, aluminum is a highly conductive metal that relies on an oxide layer for its corrosion protection properties. Low levels of ethanol, such as E10 (10%), are usually not a problem in aluminum tanks because the oxide layer provides a good measure of protection. The problem occurs when the ethanol content is increased.

There are two mechanisms that occur with ethanol. Both mechanisms are a result of the hydroscopic property of ethanol, meaning it absorbs water. The more ethanol in the fuel, the more water there will be in the fuel tank. Water not only causes the tank to corrode, it also causes the corrosion particles to clog fuel filters, fuel systems, and damage engine components. The corrosion rate can be accelerated under a number of conditions if other contaminating metals are present such as copper which may be picked up from brass fittings or as a low level contaminant in the aluminum alloy. Chloride, which is a chemical found in salt water, will also accelerate corrosion. In the long term, corrosion can perforate the aluminum to produce leaks that would cause fuel to spill into the bilge and end up in the environment. In the worse case it could cause a fire and/or explosion hazard. Boat fuel tanks are often located under the deck next to the engine where the operator might not be aware of a leak until it was too late. .

The second mechanism that can occurs with the increased use of ethanol based fuel in aluminum tanks is galvanic corrosion. Gasoline fuel is not conductive, but the presence of ethanol or ethanol and water will conduct electricity. The galvanic process that occurs to aluminum trim tabs, stern drives, shaft couplings, etc. will occur within the aluminum fuel tank. Boat builders are able to protect exterior aluminum boat equipment with sacrificial anodes known as zincs. Sacrificial anodes are not a feasible option for the interior of a fuel tank.

Conclusion

As stated in the opening paragraph, the NMMA has serious safety and durability concerns with the incremental increase in ethanol content in gasoline motor fuel. The majority of marine engines in use today are open loop systems that are designed, engineered and calibrated at the factory to operate with fuel containing either 10% MTBE or ethanol. Changing the fuel that these engines were designed, engineered and calibrated for will negatively effect drivability, exhaust and evaporative emissions, and potentially damage the components.

While these issues are significant, the boaters have a far more serious issue. The available data indicates that aluminum and fiberglass fuel tanks and butyl rubber fuel hoses that are currently being used will fail if the ethanol content is increased to 20%. That is not an emissions issue; it is not a drivability or durability issue. It is an issue that needs to be taken far more seriously. It is a threat to the health and safety of the boaters in your state.
 

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what baffling is in the OEM tank? just the one divider in the middle of the tank (with the corners trimmed off so fuel can move from front to back.) There aren't any special baffles in the stock tanks to prevent fuel starvation during high-g, high acceleration, high braking maneuvers, are there?
Yes, the tanks have a vertical and horizontal baffle iirc. The pump intake is in a low well on the right tank, so you'd have to run really low to get starvation... I've never seen an esprit have fuel starvation on track.
 

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Speechless, thanks for the write up and info!
 

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Discussion Starter #32
Here's some more interesting info about aluminum tanks (for boats)

Aluminum Fuel Tanks
Yes aluminum fuel tanks have had problems in boats, the reasons include improper alloys, salt water, and foaming of tanks which until recently was a common way to install tanks. Certainly Ethanol has been a huge problem in boats, and any increase to E15 or beyond will be worse.

However, proper alloys, avoidance of foam and not storing tanks with Ethanol fuels seems to,avoid problems.

In our cars salt water is not a problem, foam should be avoided and layed up cars should have the tank drained. Doing that will avoid any corrosion. Aluminum corrosion is self limiting unless it is wet in an oxygen starved environment, which is why foaming causes so much trouble. Steel on the other hand will continue to corrode forever once started. Aluminum can also be coated for further protection.

I will talk to Boyd next time about the alloy type, but he is well aware of the issue since he builds a lot of boat tanks.

BTW our other shop partner just dropped his new alu tanks from Boyd in his Esprit and they look great. He is an engineer and had Boyd make them to his own design and drawings. I will try to post some pics soon

Randy
 

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Many motorcycles (including my 1987 K75S BMW) have been using aluminum tanks for decades with no problems as long as proper maintenance and common sense prevail. I have no doubt that the aluminum tanks in my car will last at least as long as the 23 years the steel tanks managed to accomplish. The issues with aluminum have largely to do with maintenance (storing them with ethanol-laced fuel for long periods of time) or improper installation/oxygen starvation.
 

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Thank you, Atwell. It looks like I'm going to eventually (after a general "flush and fill" of the tanks per TLF and LT instructions) remove the tanks (oh, by "eventually" I mean, "This winter break") and have them shipped to Boyd's for fabrication. Besides the benefit of never again having to worry about rust, I believe alloy tanks should (key word: "should") be a bit lighter than the steel tanks.

Edit: once the tanks are removed, what procedure do I follow for shipping? Does this require a hazardous materials permit/ORM-D (considering that even if it's flushed out with water, it may still have residual gas--and attendant explosive vapors--inside)?

Cheers,

Scott
 

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Discussion Starter #35
Thank you, Atwell. It looks like I'm going to eventually (after a general "flush and fill" of the tanks per TLF and LT instructions) remove the tanks (oh, by "eventually" I mean, "This winter break") and have them shipped to Boyd's for fabrication. Besides the benefit of never again having to worry about rust, I believe alloy tanks should (key word: "should") be a bit lighter than the steel tanks.

Edit: once the tanks are removed, what procedure do I follow for shipping? Does this require a hazardous materials permit/ORM-D (considering that even if it's flushed out with water, it may still have residual gas--and attendant explosive vapors--inside)?

Cheers,

Scott
They WILL be lighter.

If you pull the tank, and open all the holes, clean the outside and pull any foam, and then clean the inside with a degreaser and flush it well you will not have any residual gasoline vapors in the tank.


Randy
 

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yes, the sumps have drain plugs in them (8mm x 1.50).Boyd's tanks have a drain plug in the square sump. The square sump was used instead of a round for cost savings. It was much cheaper than buying a stock length of 4" aluminum thick wall tubing. If you look at the pictures I posted you can see the drain assembly on the bottom of the sumps on the passenger side tanks.
 

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Alloy tanks offer 25-30 lbs weight savings, depending on the gauge used.
just taking an educated guess here, but I don't think it will be that significant of a difference.

Steel is approximately 3 times the weight of Aluminum, but the Boyds tanks are .125" Aluminum. The stock steel tanks are .050" Steel. Thus the Aluminum tank is 2.5 times thicker than the stocker.

The stock passenger side tank weighs 22.8# without the fuel pump assembly, sender, etc. As such, I'd expect the Boyd's tank to weigh around 19#. That's only a 3.8# difference per side....for a total of 7.6#.

I think .125" wall aluminum is pretty standard in the marine industy, but I think the NHRA only specs .090" for aluminum fuel cells. If you drop down to .090" wall AL, you'd likely drop each tank down to only 13.7#......saving a total of about 18# for both tanks over mild steel tanks.
 
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