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.
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.
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.
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.