How many minutes will Optimus No.8 or 8R boil one liter water

I have checked out the instructions,they said boil a quate water in about seven minutes
Here are US quate Or UK quate
How long will your boil a water test ？
And how much was No.8 output by watt

 

US Customary Standard Quart = 32 Oz
UK Imperial Quart =40 Oz
Four quarts to a gallon
1 US Gallon = 3.8 L
1 Imp. Gallon = 4.5 L

 

@Tantra ,

The Optimus 8R is rated at 3,300 BTU’s, and as a comparison, the SVEA 123 and 123R are rated at 4,700 BTU’s. I hope this helps answer your question. Take care, and God Bless!

Doc

 

Yes, I seem to understand,1 BTU change to 0.293 watt
Optimus 8R almost 1000 watt

 

Its Swedish, so it will be a Metric Quart.

Alec.

 

Good point. A US Metric Quart is .946952946 Litre.

 

My experiments indicate 8 to 10 minutes to boil tap water at room temperature, with stove on full setting. Two primes with methylated spirit gets the burner nice and hot and warms up the tank faster. This is for an 8R in good order.

Cheers
Simon Foxxx

 

Simon's proviso here is the nub if the problem. The Optimus operating instructions give no hint as to what temperature water they started with. Even freshly drawn water will vary dramatically from place to place and according to time of year. Middle of summer in Arizona or just filled the pot from a Scottish Highland stream in January after breaking the surface ice to reach it? Without a standardised start temperature claims like those made by Optimus are meaningless.
Ian

 

Tantra, Ian, all,
I'm inspired to comment re A. "Without a standardised start temperature claims like those made by Optimus are meaningless."

There are 3 sides:
1st along lines of disregard for published boil times (Ian & plenty others).
2nd manufacturer's stated boil times and
3rd user boil time testing results (in my view 2 & 3 are not far off if stove is at optimum performance).
Myself, as long time proponent of boil time results (printed & actual) as method to evaluate performance I take exception to "A.".
Not wanting debate but my position is opposite, with opinion the published boil times are an excellent reference. Imperfect yes, occasional mistakes yes.

BASIC BOIL TESTS: indoor, no wind, pot bottom wider than flame, aluminum covered pot.
ambient AIR indoor / room temp. (60-70F),
indoor tap water *55 - 60F drawn from vessel at room temp. Granted in northern locales in winter tap water is below 50F. *We can accept / expect Swede makers avoided using below average room temp water, I do.
-----------------------------------

Re: "Here are US quate Or UK quate" ?
Re 8 & 8R: Swedish makers refer to UK, imperial quarts & pints.
HOWEVER such specs are available in a preferable term "per liter".

Re: "And how much was No.8 output by watt"
"Optimus 8R almost 1000 watt" [*8R 4700 BTU 965 watt]
There is a 1980s Optimus *source for these specs., myself, I would stick to decades of boil time comparisons.

*1980s "boils 1 liter in 12 mins." <-- that, compared to most other Optimus sources under rates the 8R. Maybe an odd manipulation to promote another model?].
1934 - 72 Optimus 8 & 8R boil times are
1 liter 6-7 min, 1/2 liter 5 mins.
Note Simon's test 8 - 10 mins.
Years ago I tested many 8R, 99 and copies. I stopped a unit test at 10 mins if not at a rolling boil and rate that unit as a FAIL re performance [an aside, my result, a Taiwan 99 copy was the hottest / quickest boil time, I'd guess in hindsight 1 liter under 7 mins].
---------------------------------------

Lastly re "How long will your boil a water test ？"
Tantra has 8s as i recall. The 8R and 8 "might" consistently have different boil times? (or might be too close to call). For myself I have 8s & 8Rs but none of my 8s are at optimal performance.

Re Tantra last question I also defer to a Staffan comment on topic: "Would be fun if someone has the possibility to do a live test using identical setting/testing configuration." source.

I would add an interest beyond No.8 to: 8, 8R, 99, Sievert 123, Optimus 123 & 123R. No small task I know. Initially tests would be no wind. Might test with wind and wind screens flip the results?
From various more recent sources, we can expect boil tests between the Svea 123 & 123R vs 8R & 99 will favor the Svea 123s.
Worth noting early reports from Optimus are to the contrary favoring the the 8 & 8R vs the Op 80.
cc @Staffan Rönn FYI, i made mention

TMI: I prefer all things older/earlier, I'll go out on a limb and cheer for a Tantra no.8 to make a respectable showing, with a rolling boil at under 8 mins.
???

 

TYPO, oops my "*8R 4700 BTU 965 watt" .. is wrong. Sorry.

the detail per that catalog is
*8R at 3300 BTU/h, 965 watt, boils 1 liter water in 12 mins.
*123R at 4700 BTU/h, 1380 watt, boils 1 liter water in 7 mins.
*source mid 1980s Optimus catalog

Re 8R specs in that catalog, above I question if 8R is oddly under rated?

 

That sounds very much like setting very specific parameters for a standardised boil time test Mark!

I think for comparative purposes it is very easy for us all to set our own 'standardised' test conditions to test our own stoves against each other. The resultant rank order should then be comparable to some degree to others' equivalent tests. The problem is that we can never be certain that our actual test timings can be validly compared with others', or even with manufacturers' claims as we don't know what test conditions they themselves used.

Ian

 

I've never done stove boiling comparisons or timing, but we've boiled a lot of water on the Svea/Sigg combo over the years. A big pot of cold stream water boils amazingly fast. I'll have to time it one day.

 

My results are an average of many tests, of different 8R stoves using 1 litre of tap water, at room temperature. A plain aluminium billy. The Optimus and Primus pots with the heat exchanger ring on the base, give a much shorter boil time. This is of course, unsurprising, but an important consideration for longer journeys in the outdoors, for saving fuel. Some stoves, from their design, are hotter and have a much faster boil time for 1 litre water. For example the Coleman 400 brown on full power the time is 5 - 6 minutes.

Incidentally, I have found the PT - 1 Russian Turist stove copy of the 8R, to boil water faster than the 8R.

Cheers
Simon Foxxx

 

The pot/kettle the water is to be boiled in also has an effect on how long it takes the water to boil. A small diameter container will take longer than a wide diameter container,,, given the same amount of water in each. Or so it seems to me...

 

Thank you I learned more information
I test my five Optimus No.8
I use 0.6L trangia pot and cooking 0.5L water
First visions No.8 and second Vision need 3min 30 second
Sometimes 3 minuets 10 second
For 8R because I change to silent and one use gasoline one use kerosene
Need 3 minuets thirty seconds or forty five seconds
I guess they are different valve
8R fule tube have one more turn
Have self clean needle
So the fule speed is slow down

 

I have always considered the efficiency to be more of how much fuel was needed rather than the time it took.

 

Thank you Tantra,
Oh boy...
Topic / title is No.8 & 8R 1 liter boil times and your boil time results are with...
half liter oy yoy yoy yoy yoy.
Half liter can work, your test results are much appreciated and far superior to my "no test", lol.

You ponder 8R might have slightly less heat output...
"I guess they are different valve,
8R fule tube have one more turn
Have self clean needle,
So the fule speed is slow down"

No.8 being just slightly hotter is 1st I've heard but that may hold true and pass the test of time.
One potential counter point: Optimus performance requirement for 8R may have been, 8R must match No.8 performance, at minimum.

Re: "For 8R because I change to silent and one use gasoline one use kerosene. Need 3 minuets thirty seconds or forty five seconds "
The
>>> BREAKING NEWS >>> is You're running your 8R (silent) on kerosene!! -and- initially reporting your boil times are comparable with white gas...
say what and whaaaat! ?
I would have expected longer boil time with kero. A related upside of kero being, kero should have longer burn time on 1 tank (vs white gas).

I presume initial vaporization of kero requires at least a focus on the priming (more difficult in cold).
IMO this is worthy of starting new thread:
your experience with "8R running on kerosene" .
thx again

 

I boiled 1 litre of Tap water (17 dec C) in a 22 degC kitchen in 9min 50 (rolling boil) with my 8r last night
Interestingly 500ml tool 7 min. I plan to retest again tonight

 

One thing to think about with the 8r is that the close proximity of the tank means more reflected heat. Put a big pot on and it will exceed rated capacity. When these were the go to stoves in NZ my 123r could not keep up with an 8r under an 8 pint billy. 12 minutes might boil a litre but 15 would boil 4 litres. Both stoves have the same burner so should give the same performance if pressure which is controlled by tank temperature is the same. Yes srv releases were not uncommon
I might have to put my 8r 99 and 123r under the stopwatch

 

A different measure of efficiency is how much fuel is used to boil the same amount of water.