I've become a little obsessed with the heat exchanger pot and opportunities for using it with other stoves. At first I tried lightening the stock JetBoil setup and hacking in a Gnat stove with that setup. It works, but has a couple issues I wanted to work out.
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=58291

Next I abandoned the JetBoil burner setup entirely. This required me to modify the pot a tad. Still 100% useable as a regular Zip, but it gave an option to lighten the setup signficantly with what seemed to be very little compromise in efficiency.
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=59189&skip_to_post=505567

I got some good feedback from folks and recently got my hands on a Soto stove, so I ran another round of tests to play with a couple other setups. I changed the way I calculated fuel usage (thanks, Stuart!). 43 F degree water for all tests. 70% Butane / 30 Propane canister for all tests. Four boils of a pint. 15-30 minutes in between for everything to cool down and dry out. Total fuel usage divided by 4 instead of measuring after each boil to reduce margin of error. Still not the most accurate in the world, but certainly close enough for me to COMPARE, which is my ultimate goal.

Here's what I found:

1. Evernew 900 Pot with Soto + Soto Windscreen - 7.3 ounces
This is a neat idea for a windscreen - light enough and very small. No foil flopping all over the place. No folding anything up and trying to shove it in a pot. Super tough, small, simple. Best idea for a canister windscreen that I've seen. It seems to make a difference, too. 4 boils used 25 grams of fuel. 6.1 gms/pint average. Not bad for a regular titanium pot.

2. Stock JetBoil Stove + Pot + My Lid - 9.1 ounces
Certainly efficient. Included here for comparisons. 4 pints boiled used 20 grams of fuel. 5.0 gms/pint average.

3. Gnat with modified JetBoil pot (setup from JB Hacks Part 2) - 6.7 ounces
I re-did these tests calculating the "Stuart" way. More efficient than the Soto and Titanium pot. 4 boils used 22 grams of fuel. 5.5 gms/pint average.

4. Soto Stove + JetBoil pot - 7.5 ounces
Turns out the Soto stove arms line up EXACTLY with Gnat arms, so my slots cut into the pot allow the Soto to work with the JetBoil pot perfectly. Sweet! Micro regulator, auto-light, canister stove, with a JetBoil pot. If you already own this stove, it's a lighter setup than the Sol JB stoves, sits on the stove nicer (no locking), and you still get the advantages of auto-igniter and regulation. I'm not convinced the micro-regulator does much, but a $40 Companion Cup (assuming you own a Soto already) is a heck of a lot cheaper than the $120 and $150 Sol setups! Pretty darn efficient, too. 4 boils used only 20 grams! 5.0 gms/pint average.


5. Soto Stove + JetBoil pot + Soto windscreen - 8.1 ounces
The Soto doesn't sit up inside the JB pot quite as fully as the Gnat. The flame pattern is almost perfect - it goes right inside the heat exchanger and doesn't spread much. But I thought it might be more vulnerable to winds. So, combining a couple ideas I ran tests with the Soto + windsceen on the JB pot. It sits well as the pot sits on the windscreen itself instead and the arms. It's plenty secure. Obviously a little heavier.
4 boils used 20 grams. 5.0 gms/pint average.


I didn't test for time. It seems like the Soto setups were faster, but I didn't measure and don't really care about the difference between 3 minutes and 6 minutes. I care about consumption.


Takeaways:

1. Lid mod is a no-brainer. Lighter. Securely holds everything inside. Easily replaceable. Doesn't reek like the stock one.
2. ALL of the JetBoil pot setups I tried are lighter than the stock JetBoil setup.
3. ALL of the JetBoil pot setups I tried sit nicer on the various stoves than the stock setup. I imagine there are some folks who like the "locking" mechanism, but I don't. Still more secure than a regular pot. Centers itself. No wrestling with a pot of boiling water to detach it.
4. ALL of the JetBoil pot setups I tried are smaller and more compact than the stock setup.
5. ALL of the JetBoil pot setups were faster than the stock. Again, I don't care much about this, but the stock Zip is really slow in comparison.
5. ALL of the JetBoil pot setups I tried light easier and have much, much better flame control than the stock Zip stove. It's finicky, goes out easily when adjusting it up or down, and is difficult to relight once the pot is locked on. I haven't tried the newer Sol burners, but I imagine they're better than this one.


I'm not sure all the physics of how the heat exchanger works, but I'm confident it's doing SOMETHING. I'd love to see a slightly wider/shorter pot with an exchanger that dips below 4 ounces. I think it's possible, and the reality of a 5 or 6 ounce canister stove/heat exchanger pot combo starts to make the decision of what stove to take on any trip more than a couple days pretty easy.

Still to tinker with .... 1) a reworked cozy to see if it helps with efficiency and makes handling easy. 2) maybe other fuel blends 3) ways to lighten the Soto ??

At this point I really like the Soto setup. Especially for my spring trips (windy, no trees, desert/steppe) it seems like a solid combo. Lighter, works better in my opinion, and just as efficient as the JetBoil stock setup. It sure seems to me like the magic is in the pot, not the burner.

Edited by curtpeterson on 02/11/2012 14:05:30 MST.

This is all very interesting stuff.

I was considering getting the Sol Ti,but now I'm thinking I should get the JetBoil SOL Aluminum companion cup, and a Gnat stove, make the three cutouts in the HX you suggested, and get the lid from Target?

Do people advocate ditching the bottom HX cover? Any concerns about damaging the fins?

Are there any concerns about increased CO emissions when using a burner other than the one that comes with the Jetboil? Is the distance from the burner to the pot when using the Gnat essentially the same when using the JB Pot/HX as when placing a regular pot on the Gnat?

Thanks

Well, I didn't realize you made a new thread but heres my comment from the old one.

It doesn't look like it in the picture but you know they make a titanium pot for this right? It is expensive however. I replaced my pot from the original PCS system from years ago with the titanium one and saved a bit of weight. Unfortunately I don't use the jetboil anymore so that darned expensive titanium pot is worthless to me now.

@Jeff - The way the fins are protected on the aluminum pot seems pretty solid. They're plenty tough from what I can tell. I can't bend them around with my fingers intentionally, for example. I've read that the titanium pot fins are much more fragile, but I have no real experience with those so I'm not sure. I will say that I'm not worried at all about packing the aluminum without it. Heck, shove a sock in there if you're worried about it, but you'd have to almost intentionally pack it poorly to damage it.

As far as the CO2 goes, that's a question for Roger or one of the pros that monitor that kind of thing. I don't cook inside small areas. I'm almost always in a hammock or just outside, so this is not an issue for me. If it's a concern for you and your cooking style, obviously you'll want to look into that a little closer.

@Phillip - Yep, I'm aware of the titanium pot. If I remember correctly, it's not really that much lighter - especially for the price premium. Do you have an accurate "naked" weight? I was looking into checking out the JetBoil concepts as cheaply as possible since most of it was for experimental purposes. The Zip seemed the logical choice and then the tinkering began!

I think the whole stock setup is something like 12 or 13 ounces. When I head out in a couple weeks I'll be going with about a 7 ounce setup, so I'm pretty happy with that so far. Basically eliminated the weight of a full 100 gram canister!

Any interest in selling that Ti pot ?

I took the plunge and bought the Ebay kettle that is advertised @ 180g. It has a 6" diameter so it should work great with either my Snow Peak stove or my Supercat.

I'm doubtful it will give me 30% efficiency gains. I guess we shall see. Heavier than the Jetboil pot but lower center of gravity and I may be able to lighten it a little. With the Supercat stove it should be < 7oz. total.

The jetboil titanium pot with all plastic pieces is right at about 6.05oz.

Broken down:
Plain titanium pot = 3.7oz
Cozy = .5oz
Lid = .6oz
Measuring cup = 1.25

I'd sell the pot. Someone else PMed me about it but hasn't responded. It originally cost $89 at REI but I'm sure you could get it for $79 online. I would like to get $50 shipped for it since I've used it <5 times.

When I went through this phase of lightening my original jetboil I even went as far as to grind down the extra brass on the valve with a dremel. I was only able to get it down to 10oz not including the canister. I guess that shoes that the newest burners are pretty light compared to the old one.

I also see you have that piezo igniter on your snow peak. I always just assumed take that off because it will fail sooner or later on a backpacking trip and you probably have a lighter already.

Edited by pdcolelli42 on 02/12/2012 13:06:32 MST.

Thanks for all the work. Really cool stuff. I need to go back thru and figure out what you are talking about when it comes to the JB parts, I'm not familiar with the stove, other than it's been out for a while now and more of the people I bp with have one now. Have you given much thought to giving the replacment stoves flame some protection from a wind?
Duane

Another lid that will work for the JetBoil pots is the clear lid on a Trader Joe's carton of Quick Cook Steel Cut Oats (yellow label). It's basically identical to the anchor lid above.

Perhaps I missed it, but was time to boil using the Soto burner the same as with the original Jetboil burner?

The JetBoil manufacturer lists about 2:15 for 16oz of water. Your benchmarks up above were focused on fuel consumption.

I didn't really care about cooking time. Without measuring it, I'd say the Soto - and Gnat - were much faster than the JetBoil. The JetBoil burner - at least on the Zip - is weak and very picky. Not a fan, but others may like it. I never got anything close to 2 minutes with the JetBoil, by the way. That must be a lab number with very optimal conditions and warm starting temps.

Thanks for the response, Curt.

I really like the idea of combining the efficient Jetboil pot with a stove of my choice, like the Soto or Gnat.

It also sprung to mind that it may also be combined with an inverted canister stove, like the MSR Winpro II for colder weather use. The burner head on the Windpro II seems kind of large, however. I'll have to do some research to see if there are other remote canister stoves with smaller burner heads that may be a better fit for the Jetboil pot.

OK, this has got me going and I just got a Ti Sol companion cup to work with. I want to do some boiling time tests w/ the Sol and my MLD 850 pot, which is almost identical to the Ti Sol in dimensions. I'm going to use my Snowpeak Litemax stove.
My question is that I noticed that your slits you made to raise the burner under your Jetboil cup only go to the bottom of the exchanger fins, not the pot. I would think the efficiency of your stove would want the pot supports up to the bottom of the pot?
Someone help me out here.

I based my burner height on the Jetboil stock setup. I figured they'd made it that distance for a reason. It would be interesting to see if there are gains/losses by moving it up and down, but you can't add metal back if you cut too deep, so I stopped there. If you go further, definitely post what you find!

Could you tell me how far the top of the burner is from the bottom of the pot?

I guess what I'm trying to get at is what is the ideal distance from the Sol pot bottom to the Litemax burner for optimum performance. The setting for the Jetboil burner was ,I'm sure, optimized for that burner. That may not be the best for your Gnat or my Snowpeak.
I wonder if the flux ring changes the equation for any given burner?
I wish Roger C. or Tony B. would chime in. I believe Roger thought that the Litemax as designed was a bit too close to the pot bottom. Well, here's my opportunity to get it perfect. HELP GUYS!

Hi Mark,

>I wish Roger C. or Tony B. would chime in. I believe Roger thought that the Litemax as designed was a bit too close to the pot bottom. Well, here's my opportunity to get it perfect. HELP GUYS!

Sorry about not chiming in earlier but I usually like to do things other than surf the net on weekends (like go bushwalking).

The most efficient burner to to boil water is a burner that is small compared to the size of the pot, this gives the hot gasses more time to travel over the bottom before the gasses travel up the edges, therefore exchanging more heat into the water.

With the small PCS/Sol pots this is still the case that is why the JetBoil burners have the flame pointing upwards so the main heat is absorbed by the bottom of the pot, the flux ring absorbs some of the heat that the bottom did not, the most efficient pot I have tested is the GCS pot which has a much larger bottom surface for the hot gasses to travel over before the gasses hit the flux ring. With using larger burners like the Gnat, that has the flame going out at an angle on the small PCS/Sol pots is that the flame could directly hit the flux ring, in my opinion this would reduce efficiency and possibly cause damage to the flux ring.

With using the LiteMax stove (called Kovea Supalite here) which has a small angled burner, I have noticed that when there is no pot on top the flame does not spread out, it actually flows into the middle so if used on a PCS/Sol pot with enough height it may work Ok, I have not yet tested a PCS pot with my Kovea Supalite stove and probably will not for a while.

Tony

Tony, thanks so much. I knew you would have some thoughts on this. So, w/ my Snowpeak it sounds like it would be better to have some gap. The nice thing is, when the pot supports are folded, the supports fit right up into the flux ring. And, the burner would be almost completely out of the wind ,if there was any. I guess I'll have to run some tests.

Very few stoves would not benefit by having another 10 mm between the pot and the supports. The CO drops considerably, and the heating rate does not suffer very much at all. A good windscreen - which is always *good*, and you're fine.

Cheers

Curt,
Anything new on this front?

Windscreens?

The fire ban along the JMT has me planning alternative approaches to stoves.

So FYI to one and all - Oregon Mountain Community has FluxRing Sol Aluminum Companion Cups on sale till August 1st, priced at $31.95. (Free shipping starts at $50).

Edited by greg23 on 07/19/2012 14:56:35 MDT.