Z900 Weird Cooling system
ฝัง
- เผยแพร่เมื่อ 14 ต.ค. 2024
- In this video I found something strange......
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If you haven't got Evans in it, its bound to overheat, little things like flow rate, direction or rad capacity are unimportant.
haha magic comment
From heat exchange perspective its a good idea due to the fact that the rate of heat exchange is faster the greater the temperature differential and having the cool inlet next to the hottest part in a heat exchanger provides some efficiency gains over the other way around.
The old system is a bit of a legacy of thermocyclic systems relying on hot water rising to the top in the engine and cooler water failing in the radiator aiding flow through the system but with cross flow radiators that is less the case.
It's always pleasing to see the theory clearly implemented in the application. Great stuff!
Thermostat on ZX6R also opens at the exact same temperature range. In fact, the ECU is programmed to high idle until 140F (59C).
The MAN D38 diesel 15.6L engine has the same head first flow system too. Apparently the head first cooling allows for the valve seats to get cooled faster, longevity increases.
Very nice to hear something like this from bike owner.How many people looking at the bike that deep,and know what they actually ride.
99% of them hear what is popular and 'lets buy it' just to show off,put as much staff on the handle bar as they can.
Gps holder,phone holder,cup holder,mug holder,battery charger,another battery charger an so many things...tall wind screen...at the end they fell they ride bus...
The most important is to have petrol,everything else doesn't really matter
i always thought cup holders were for comedy value, given that you've got a helmet on! I used to have a magic tree air freshener until 'er indoors told me to grow up
Kawasaki knows their stuff. Interesting fact about the Z900.
Reversed cooling can lose a little power compared to the conventional direction. The first time I know of doing it was when we ran the original Yamaha TZ250 reverse cylinder engine which would seize on a regular basis and was even nicknamed the Reverse Seizure. It was done to try and keep the cylinders from going oval due to exhaust heat being on the side of the engine which was in still air and the intake side would have the coolest densest air possible being below the radiator so there would be no heat from the engine to effect BHP. Karts run with their carbs on the front as it does give a power advantage, but karts do not have bodywork to stop heat being drawn away from the rear of the engine. We reversed the coolant to warm up the cylinders to try and keep the cylinders as round as possible but it did lose a couple of BHP. Not sure why Kawasaki reversed the coolant direction but it would help speed up the engine getting up to temperature and may help lower emissions too. As you point out the Z900 and Z1000 are not sportsbikes so they dont need to remove as much heat as possible at high speeds and it is easier to keep them from over heating as they are not fully enclosed engined bikes and not desigined with performance oriented cam profiles which will have an effect on engine temps even at tick over.
Shame the Petronas FP1 didn't run reversed cooling in the race bikes a they would have heat related issues with their reversed cylinder heads and the engine builders had to simulate real running condition heat on the cylinders then hone them hot to try and combat the ovality issues which would blow up their engines and mean every race (not meeting). So between morning and afternoon WSB races they were swapping engines.
Very interesting. I to can confirm about the zx6r (j2) hates town riding, it splutters and backfires in the summer and it always has the fan on and always above 104c yet on a trackday or blasting though Wales it stays at a constant 85c.
head temp is more important for valve temp regulation and air fuel mix gaz temperature. it can really help for efficiency
As you say it will be interesting to see if the new 636 follows the Z cooling system.,.... They seem to be pitching it as a mixture of street and occasional track day riding
I think it balances the temps out, the head is hotter so it kinda shifts the heat down to even it out, maybe to prevent warping in the long run?
It about heat saturation and removing the heat a quick as possible
I was talking to Kawasaki TSD on Friday and asked about this because i was chasing a cooling issue on a Z800.
According to Kawasaki it's all to do with stabilising the overall temperature for extended city use.
As other comments have noted, your best cooling effect happens with the steepest temperature differential, and if you get the measured values for the Z8 while you're warming it up and running it you can see the head temp and the cylinder temp stabilise at a much closer temperature than on the ZX's.
The overall temp diff between cylinder and head on a Z800 comes down to less than 5% as opposed to nearly 15% on the ZX10R gen 5. Over all temp is also dropped because the heat is drawn from the hottest areas first. The Z800 obviously runs much cooler than a ZX10R for a number of reasons including the fairing and combustion volume, but it works like this.
If you have something that is 100*C and you remove 20% of that temp, it's 80*C. if you have something 90*C and you remove 10% of that you have 81*C. total temp is approximately 80*C.
if you remove 20% of the 90*C and 10* of the 100*C you have a higher overall temp of approximately 5*C.
That's a lot when you're dealing with small closed systems like these.
And the issue i was chasing ended up being an occluded hose from a missed casting flash.
Are you sure Matt? Maybe you should ask the guys at TST Industries which way the coolant enters the engine :D
at the beginning i thought this was a joke video about that (because i read the picture from the system wrong) xD
I want to get the yamaha XSR 900 . you can get a kit that makes it look like a yamaha RZ 350. And it's basically the same bike and engine as the MT-09 , so all the ohlins kits and engine mods will fit.
I have a ZZR600 and it has the traditional cooling loop. It's a touring bike and the coolant system is overkill for it. During summer around 35C in traffic the fan will stay on, but the needle almost never goes over half. In any colder weather it barely goes over the "don't ride it hard" range.
Maybe I would be a good candidate for Evans
there's defo nothing wrong with it?!
@@chrisdavidson911 No this is just a common thing for many sport motorcycles. It was the same for my Ninja EX500
I got mine flashed and got the fan to start earlier, much more comfy temps on my z 900 now
this reminds me of the rover k-series. a bit. thermostat's on the wrong end of the head, and a few other daft things, which made it great as a quick-warm-up city engine for light city things, but then when it got fitted to other stuff (land rovers, for example), the head gaskets started popping because by the time the thermostat got open (constant heavy load pulling some gutbucket it wasn't designed for up a long incline) it was too late. Don't know why they lived with gasket problems instead of sorting that out! Also, the vfr fan comes on briefly while it's still fairly cold (can't remember the actual temp) then goes off again
In my oldschool world, a Z900 / Z1000 does not have any coolant :-)
Hey Matt.
I have a drz 400e (suzuki dual sport), I believe that it doesn't have a thermostat, it is the more off-road orientated version of the drz400
However, the more road orientated versions of the same bike, 400s & 400sm have thermostats.
I have installed a temp gauge and notice that in winter it runs between 40-50C, in summer it can get as high as 100C.
Is there a reason that most bikes designed for offroad do not run a thermostat?
Since I'm mostly riding on-road, would there be any advantage in installing one. Should I be concerned that the oil isn't lubricating the engine properly during the winter? I usually give it around 30sec to warm up before taking off, and then take it easy for the next few mins of riding.
Cheers, David.
what?i have a ktm exc (only designed for offroad,not a bit dual sport)and it has a thermostat also my ktm lc4 sc (bit dual sport but more offroad,so more or less like the drz e) and it has a thermostat too
i fitted an oil temp sensor to the lc4 and in winter it goes to 60-70°C (more 60°C) after 10 km of riding and doesn´t really get higher (and it has the little oil circuit with just 1,6l oil)
Lol I’ve got a 2010 Harley Streetbob, 59 degrees would just be about the end of my road! It’s one of the dyna series so it is oil cooled only.
From reading a few year ago, I might be wrong, LS engines are reverse cooling and depending on the generation so are the big block chevy
Interesting...
I wonder if the flow rate of coolant is higher than other bikes ?
Cool design👍
probably not as common because of air beading against flow.
There's a few odbal cooling system like,
VW circulation tanks bleed automatically using hoses.
Some systems like Buick 3.8L had bleeder screws.
Jeep amc 6 cylinders tend to warp if not done right best to run them little to steam up then shut off and let cool and hope air pockets work their way out of the long head.
i wonder if the conventional flow from bottom up is because, as my chemistry teacher taught us, you always run liquid coolant bottom up so it fills the entire chamber, as opposed to just running down the sides and not really coming in contact with the area being cooled. but if there's no air possible in the system, then this logic wouldn't apply.
Such good info. Thanks so much 👍
I think, there is another reason for that: you want combustion chamber to be relatively cool (to avoid knocking), and cylinders relatively hot (for the best efficiency). Citation from a car engine manual which uses dual thermostat system (80 deg C for the head, and 95 deg C for the engine block):
"The dual-circuit cooling system has the following
advantages:
- The cylinder block warms up faster because the coolant remains in the cylinder block until 95°C is reached.
- Less friction in the crankshaft drive due to the higher temperature level in the cylinder block.
- Better cooling of the combustion chambers due to the lower temperature level of 80°C in the cylinder head. This achieves better filling with a lower knocking tendency. "
Since dual system would be to heavy and complicated for a motorcycle, why not just reverse the flow?
My 08 ZX6R definitely gets hot with no airflow through the radiator. They have an overheat protection that turns the thing off in the danger zone. I fitted a fan bypass switch so at slower speeds I switch it on to run constantly which greatly reduces overall temp but cooks your fuckin shins 🙄
Overheating on any ZX is a feature, not a fault. I am unsure if this has been addressed in newer models.
My roommate has the new ninja400 and it runs hot in the city, too. I'll have too look at the cooling system and see how it compares.
Looking at my FZ1's manual I think (picture isn't nice like the Kawa manual's) it's using the tradition ZX6 design and thermostat opens at 71C, it runs bloody hot in London but I ain't complaining during the winter :)
It's raining over there man I'm jealous. These California fires are horrid :(
Dude that must be shite, never seen a forest fire in person, and I never want to.....
@@dirtygarageguy super shite! My area isn't too affected aside from haze. Rode a couple cities north, parked for an hour, and came to my bike with a bit of ash on it. We'll ride sometime!
Matt, This might be all about getting it up to temp earlier...My 1200r is barely warm after 12 miles and the fan has never come on...overcooled.
It has a fast idle start-up
Im not a big fan of running an engine at 2500rpm from dead cold soyou are stuck with an ecu that knows better.(we all hope it knows better)..good stuff matt..thankyou
Matt, so your okay with the motor spinning 2500 rpm from deadcold?
Yes, the engine isn't under load (apart from its own inertia) There's a trade of to be had. The longer the engine is cold the more wear occurs, but the faster the engine spins, the more wear occurs. Like everything there is a compromise.
The longer the engine is cold..? modern synthetics run pretty wellcold and would recommend after your break-in..Thanks matt...
Mmmmm very interesting
Where is the thermostat in the system, is there a bypass to cut out the radiator
If coolant flow is from head to block ant the stat is at the head with a bypass I can only think this has been done to decrease warmup time and reduce delta t accros the engine and therefore reduce thermal stress accros the engine. What say you
This is exactly what I was thinking. To my knowledge a lot of cars with Rover K-series engines were doing this 20~30 years ago for that reason. Having the thermostat on the inlet was the cause of a lot of headgasket failures as it took too long to open. When it did eventually open the engine was flooded with cold coolant and warped the head.
Hopefully Kawasaki have done a better job of it!
Matt, do you have a preferred supplier for manuals, either hard or soft copy? I'm a bit wary of providing my contact details or hard-earned over the web.
I would like to see the restriction of coolant flow in reverse system. I believe it is NOT same head gasket ( btw. want to see head gasket too ) design as most of the flow is going downwards after passing the head gasket so it must be restricted somewhere "down there".
The temperature indicator on the dash seems to be calibrated only within the operating range of the thermostat rather than over all.
On many cars the indicator works like this: 80-95 degrees shows the same temperature, to make people feel like everything is fine and normal, only if you leave this temperature range, the indicator will start to show a correct temperature.
A reverse flow system strikes me as something that would not self-bleed very well when you change the coolant. Saying that, my bike has an actual bleed nipple that you have to use to bleed the coolant system.
How would this change anything? The system is basically the same, just when the fluid is being pumped its the other way.
The 59 degrees thermostat is no big issue. even no thermostat would no cause anywhere near the problems it would on a car. Bikes are almost fighting too stay cool all the time. Cars struggle to stay warm. My car even has shutters over the radiator.
Would one reason to reverse the glow be to stop the passive circulation of coolant while the engine is off to keep the engine warmer longer for your next ride? It's not a race focused bike after all
I have a 2019 Z900 ABS and if I stop at a red-light when it's hot outside, I have to shut it off so that it doesn't overheat. It'll max the temp gauge in a minute or two.🤣
A minute or two? Where do you live?
Did the 'conventional' cooling route come about due to the fact that heat rises I wonder?
I wonder if this cooling would work worse on the track compared to another naked with the traditional one.
Cool video
Did you get the R3 engine wrong then Matt? Could be worth a re-visit
LOL - no its not wrong. The R3 is the 'standard' flow.
Sean Sluman maybe the guys from tst modified it themselves to this correct way to find that there is a little more to it than swapping hoses
it is a more efficient design as I understand it. Asian cars been doing it a while. I guess bikes now need the additional cooling or maybe because its lacking in fairings to direct air flow
Please ... you need to sync your apparel to the brand under discussion ... do you even have any Kwaka gearz? ;-)
That rain is annoying...never heard it after a min 👍😀
Hitting hottest part first sounds good to me
When you show the Z900 exploded view, the little arrows showing coolant flow go from the radiator to the water pump and up and out of the head, so a 'normal' flow. Have I missed something?
Look at the flow in the cylinders jacket, it goes from the top to the bottom, that's what he's referring to.
@@ho2sorellestupide Yeah but that's just the flow in the cylinder jacket, the overall flow is from the bottom of the engine up to the head.
What? The flow goes into the engine at the HEAD and then DOWN the water jacket and out of the CYLINDERS.
@@dirtygarageguy No worries, just edited my reply as I see where you're coming from now, I was carried away with the overall flow but watching your whiteboard bit again I see where you're coming from :)
@@ho2sorellestupide it's ok, was just me being thick ;)
*laughs in air-cooled* lol
Do you have a Service manual for Z900?
I do
Can I ride z900 in day to day trafic?
Currently using z650
Well yeah - it is pretty much the same thing...
The Workshop thanks
Is quite interesting. I would have thought that from a cooling perspective using a reverse flow and trying to recreate a counter flow heat exchanger sort of thing would be more usual rather than reverse flow being unusual.
Do you know why they don't do this more oftenly? Require more plumbing etc so make is less practical for bikes?
Edit: as you say the counter flow is more efficient, so why isn't it used more commonly? Just to avoid over cooling? Surely having more efficient hear exchange would allow for a smaller radiator and less mass/ space taken up even if marginal. I could just be being a fuckin numpty but I can't figure out an explanation for why it's not the standard.
Oh so do regular cars have coolant flow through the heads first?
depends, chevy were the first cars to reverse flow cool with the LT1 v8 engines.on subaru Boxer engines is a common modification for performance and longevity but most cars use conventional flow cooling to this day cool in the bottom , hot out the top, im trying to think of some car with thermostats up the top of the block but im struggling, i think a few higher performance motors from mercedes and bmw might have the coolant enter through the head and exit lower, maybe peugeout too im sure there are a few made this way but its not so much an issue on cars due to the lack of restriction on weight of coolant, rad size etc.
when your finely balancing a bikes thermodynamics vs its weight , i think this stuff is more important , and on high performance stuff where the head can get so hot it boils the coolant and bangs happens- like in the case of the subaru...
and there are dual systems out there, two thermostats , one at the head, one in the block...
why does the rain on ur garage sound like a 2000 series ford diesel transit hahahah
It's not weird, It's the Sugomi Style.
That's Japanese for bullshit
I think Corvette tried the reserve flow system, it was garbage
pretty much all GM stuff is
The later half of the C4 Corvette series with the LT1 and LT4, 5.7l engines pioneered a reverse flow cooling system. It was an interesting engineering exercise at the time and worked quite well. My '96 Vette LT4 works great with this system but there are some critical design compromises that followed along with it; such as the camshaft-derived water pump drive and the delicate (and expensive) Optispark distributor. I have no complaints other than to cuss out loud at the previous 'pro' mechanic that built this V8 and serviced the drive train. I had many corrections to make and oil leaks to halt.
2nd WEEEEEEEEEEEEEEE!!!
designed for missions..
I agree...Dont know what Matt thinks...other than its better for city bikes.
my z750r start cooling at 100C then drop to 97C only
4st
1st