Gauging the market on fuel sender for 22C

[Tidbart]

As some of you know I have been working on the calculations for a customized fuel sender for the 22 Classics from 1994-on. Specifically, the newer style 55-gallon RDS tank. What this amounts to is getting an accurate indication for the level of fuel in your tank, as we all know that just can't happen with the stock float senders we all have. These would be two-wire, plug and play, replacements for standard 33-240 ohm gauges, not electronic gauges.

see other post.... http://www.donzi.net/forums/showthre...ghlight=sender

And yes, other tanks styles can be done. I did this one because it is what I have and I need to replace my sender. I also have the drawings, thanks to George, of the earlier RDS tank, pre 1994, but haven't done any calcs yet. It this one pans out, I can expand the market.

Anyways, I am trying to gauge the market for a small production run of these. I am looking to see who would actually buy one if I had these made. I am trying to keep costs down by having several made and sold. They should end up being well under $100, hopefully under $80. I haven't got a final cost yet, as I don't know how many to have made.

Replacements for the original floats go for about $35-40, but they are still inaccurate.

Yes, this is bling. You just can't see it.

Let me know if this is something you are interested in seeing made. I don't care if you are not interested.

Bob

[Planetwarmer]

Donzi should be the people who are interested in this. They should care enough to insure their gauges read accurately.

I have an 87' model 22C.

[Tidbart]

Donzi should be the people who are interested in this. They should care enough to insure their gauges read accurately.

I have an 87' model 22C.

Well, judging from the responses, or lack thereof, even though it has only been a few hours, maybe Donzi is right in their thinking that nobody really cares about an accurate fuel gauge.

On another note, the other tank diagram I have was drawn in '88, so I believe you tank may be different. Don't really know.

Bob

[Ranman]

Bob,

The Centroid sending units are the way to go. I don't know that I would put much effort into customizing a sender with electronics to get the sender to compensate for "volume" vs. "level". Not a big benefit vs. cost IMO. The concentric tube senders are more robust/reliable and less prone to failure than the float senders. This is the important part to me.

As far as volume versus level. Once you understand the concept that "fuel level" does not equal "fuel volume" as you've documented in your graphs, you can easily understand when you really need to fuel up. I know my needle stays on "full" for a long time and then slowly drops to "half" and then drops like a rock to "empty" as I use the fuel at the bottom "V" of the tank. As far as the sender goes, it's dead on with the level reading it provides.

[Tidbart]

Bob,

The Centronics sending units are the way to go. I don't know that I would put much effort into customizing a sender with electronics to get the sender to compensate for "volume" vs. "level". Not a big benefit vs. cost IMO. The concentric tube senders are more robust/reliable and less prone to failure than the float senders. This is the important part to me.

As far as volume versus level. Once you understand the concept that "fuel level" does not equal "fuel volume" as you've documented in your graphs, you can easily understand when you really need to fuel up. I know my needle says on "full" for a long time and then slowly drops to "half" and then drops like a rock to "empty" as I use the fuel as the bottom "V" of the tank. As far as the sender goes, it's dead on with the level reading it provides.

The value of the gauge accuracy is up to individual and the cost is a consideration. Frankly, I wouldn't mind spending a few extra bucks for that accuracy. It would especially help when I fill at a pump in the fact that I might not have to monitor the gauge as much. If a new sender/gauge reads a 1/4 tank, it is helpful to know that I have 13.75 gallons in it than the 7 gallons that is probably in there.

Anyways, I see your point. If I got some interest, in these I can have them made ad a considerable savings to all as the programming cost could be spread over the number of senders ordered. For sake of argument, if I was going to spend $75 bucks on a sender, would I spend an extra $20 for a steady reading? Hell yes. Would I spend an extra $75? Questionable.

Thanks for chiming in. Good feedback on the product.

B

[gcarter]

While we're just BS'img. What I'de like to see is a digital gauge that tells me how many gallons are left........I'd really like that.
I'd pay for it too. It might be worth $150-$200 for it.
Would that be hard to do?
I like to run longer distances and remaining fuel is really important.
Also it completely takes the mental picture of the shape of the V bottom tank out of the equation.

[BUIZILLA]

Dakota Digital

[Tidbart]

While we're just BS'img. What I'de like to see is a digital gauge that tells me how many gallons are left........I'd really like that.
I'd pay for it too. It might be worth $150-$200 for it.
Would that be hard to do?
I like to run longer distances and remaining fuel is really important.
Also it completely takes the mental picture of the shape of the V bottom tank out of the equation.

The Dakota, Jim spoke of, has a preset for 240/33. I am sure they set that at the factory. This should work with the Centroid sender, would need to ask. $95. You would have to paint the bezel yourself as red is not available.

Also, the programmable sender should remove the tank picture as it will not care about the tank shape. So an analog gauge will be highly accurate.

Bob

[Ranman]

The value of the gauge accuracy is up to individual and the cost is a consideration. Frankly, I wouldn't mind spending a few extra bucks for that accuracy. It would especially help when I fill at a pump in the fact that I might not have to monitor the gauge as much. If a new sender/gauge reads a 1/4 tank, it is helpful to know that I have 13.75 gallons in it than the 7 gallons that is probably in there.

Anyways, I see your point. If I got some interest, in these I can have them made ad a considerable savings to all as the programming cost could be spread over the number of senders ordered. For sake of argument, if I was going to spend $75 bucks on a sender, would I spend an extra $20 for a steady reading? Hell yes. Would I spend an extra $75? Questionable.

Thanks for chiming in. Good feedback on the product.

B

I see what you're getting at. If it was a small, incremental charge like $20 I would agree too. I wonder if there's a way to split the difference between the 55Gal (22C) tanks and the 40Gal (18C) tanks since they hav similar profiles to still get a good needle read and double your potential "market"?

[Tidbart]

I see what you're getting at. If it was a small, incremental charge like $20 I would agree too. I wonder if there's a way to split the difference between the 55Gal (22C) tanks and the 40Gal (18C) tanks since they hav similar profiles to still get a good needle read and double your potential "market"?

I am currently integrating the other 55 gallon tank from '88-'94 to see the differences between the two. Currently, they are the only two drawings I have. If the differences are minor, I would consider programming one sender to cover both tanks. Time will tell on that.
I would look at other tanks if I had the drawings, or all the dimensions to see if they would be compatible also.

Bob

[BUIZILLA]

this is a very worthwhile effort on Bob's part, especially if the 18 hull is incorporated.... I hope everyone takes advantage of this... not sure what I need for the Critter being 30 years old... all I know is when mine says 5/8, it's really 1/2...

[gcarter]

I'll try to find the 40 gal. dwg. It's on here somewhere.
Wes talked about doing this but didn't.
Bob stepped up and I also appreciate it.

[Cuda]

Wouldn't a fuel usage sender be more accurate?

I had the fuel float go bad years ago in my fishboat. I couldn't get the right one, so I bought one that was shorter. That way if I though I was out of gas, I had about three inches of gas left.

[Tidbart]

I am going to take the liberty of redirecting the other post I started to this one.


I did some more work. I integrated the Older 22 tank and compared it to the Newer 22 tank. I've attached a graph to show the comparison. They are amazingly similar. This is good news.

[Tidbart]

So I took it a step further and looked at the averages and variances in the two tanks and came up with another chart showing what could be setting for the programming of a sensor that would consolidate both tanks. If you look at the table below the graph, I listed the variances from what would be the proposed new sender to both tanks. Yes, those are OUNCES. All the levels were from 0-3%, except the0-1" level which is off by about 7%.

I have to go back and check all the math again. The first tank I did on paper, the second on spread sheet. I want to make sure I am correct on all this data.

If I can make this happen, it would mean 22 Classics with the 55 gallon tanks from about 1988 through about 1999, and maybe more as I don't know the dimensions of the newer tanks or older ones, could use this sender and have a very accurate idea as to how much fuel they have (providing the gauge is OK).