Author Topic: EFI and liquid cooling  (Read 6679 times)

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LJRead

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on: September 24, 2009, 04:38:03 am
The other night I was looking at Sports Tourers, like Honda, Yamaha and Kawasaki and got to wondering what the trade offs are for having all the cubic capacity (1300 or 1400 cc) and EFI.  I raised this question in the UCE category, but am hoping other knowledgeable folks will have a go at this.  One idea expressed under UCE is that liquid cooling allows cooler running under the conditions imposed by the EFI of leaner burning.  So  guess it means cooler running and the EFI means leaner burning (more efficient?)  But then there was the idea that cubic capacity of these bikes had to go up due to less power due to EFI, itself required by emission standards.

So what is the air cooled, carburetor  aspirated equivalent of a 1300 cc bike (liquid cooled with EFI)?  And since the new UCE has more abundant power, 28 hp I believe, how was this accomplished and at what cost.

In physics, nothing is if free - there are always trade offs.

Any thoughts on all this?
« Last Edit: September 24, 2009, 08:24:30 am by LJRead »
Lawrence J. Read
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ace.cafe

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Reply #1 on: September 24, 2009, 12:38:00 pm
LJ,
Liquid cooling allows a more stable temperature environment, so that the running parameters for the engine can be better optimized.

And the liquid cooling provides better cooling, so that more hp can be made.

The downsides are generally more weight, and more bulk, more complexity, and chances for  cooling leaks. It's less aesthetically pleasing to my tastes, too.

From a pure performance standpoint, you can do better with liquid cooling. And for emissions too.
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PhilJ

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Reply #2 on: September 24, 2009, 01:37:21 pm
Liquid cooling always trumps air cooling in HP and gas mileage, as Ace implies.


Jeri Danger

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Reply #3 on: September 24, 2009, 02:51:14 pm
Hi
The large capacity(cc) is a trend in the  newer sports bikes.
I think it is just a horsepower war in the go faster crowd.
Jeri


r80rt

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Reply #4 on: September 24, 2009, 03:06:04 pm
Hi
The large capacity(cc) is a trend in the  newer sports bikes.
I think it is just a horsepower war in the go faster crowd.
Jeri
It seems they have forgotten the merits of a simple bike, it's all about who has the biggest engine with the most gadgets. None for me, thanks.
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UncleErnie

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Reply #5 on: September 24, 2009, 03:26:01 pm
Beans.  Different kinds of beans, chili, lots of cumin and spices, onions and fatback, oil and veinegar- still beans.  Ever wonder why these bikes keep getting bigger, but not faster?  Because the average motorcycle consumer is stupid as a bean.  Weather it's a Harley or a Star- these bikes should be capable of twice the speed.

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Reply #6 on: September 24, 2009, 04:32:49 pm
Hi
Yeah, you got it.
My 500cc Daytona is plenty fast for me
Jeri


cyrusb

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Reply #7 on: September 24, 2009, 05:16:39 pm
Beans.  Different kinds of beans, chili, lots of cumin and spices, onions and fatback, oil and veinegar- still beans.  Ever wonder why these bikes keep getting bigger, but not faster?  Because the average motorcycle consumer is stupid as a bean.  Weather it's a Harley or a Star- these bikes should be capable of twice the speed.


Sonething you have to figure in when it comes to power and speed is the law of diminishing returns. If 50 hp gets you 100mph, 100hp is not enough for 200.
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Reply #8 on: September 24, 2009, 05:44:49 pm
I think the power requirement for overcoming air resistance goes up with the square of the speed. So you would need close on 200 hp for 200 mph, i.e. four times the amount needed to reach 100 mph

Also, there are horses and horses! Some of the horses in 1980s Japanese bikes were definitely on the coltish side of full grown. They would tell you there were 67 of them - or whatever - but your motorcycle would be no faster than a Bonneville with 50 British ones.
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Vince

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Reply #9 on: September 24, 2009, 05:57:18 pm
     With better and more stable temperature control you can "optimize" as Ace said. This generally means closer tolerances, and performance touches that will produce more heat with the additional horsepower.
     But wait! There's more!
     The closer tolerances combined with better heat control aid longer engine life, and enable better emission control over longer time.
     The closer tolerances combined with the water jacket allow for better sound control. New bikes have to meet federal sound level standards. A quieter engine can be traded for a less restrictive (usually meaning louder) exhaust with a higher power potential.
     Eventually virtually every bike will wind up water cooled for the above reasons.


ace.cafe

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Reply #10 on: September 24, 2009, 06:07:11 pm
I think the power requirement for overcoming air resistance goes up with the square of the speed. So you would need close on 200 hp for 200 mph, i.e. four times the amount needed to reach 100 mph

Also, there are horses and horses! Some of the horses in 1980s Japanese bikes were definitely on the coltish side of full grown. They would tell you there were 67 of them - or whatever - but your motorcycle would be no faster than a Bonneville with 50 British ones.

It's actually a cubed relationship.
So, to 2 double the speed, you need to have 8 times the hp, or you need a big reduction in aero drag.

This is why in Land Speed Record vehicles, after a certain speed is reached, the aerodynamics of the vehicle will play a more important role than the hp levels, unless competing vehicles have identical aerodynamics, and then the one with more hp will win.
Above about 40mph, aerodynamic drag has the most effect on your speeds vs hp, and also in your mpg.
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LJRead

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Reply #11 on: September 24, 2009, 06:09:33 pm
Thanks Vince -  you have made a point that was missing.  I see that one of the bikes displayed by someone here was to use a Blast engine, and now that they are no longer made, are thinking of going to a Suzuki 600 cc water cooled engine (the new Mac motorcycles?).

And then we get into the advantage of fairings and it begins to look like both fairings and liquid cooling are a good way to go - especially the longer engine life part. 

As I was trying to understand these sports tourers, I saw that one of the videos showed a Kawasaki Concours, very briefly, with all the fairings off.  It was quite impressive, the obvious amount of engineering that went into it.  I wondered why these bike makers don't show more of their bikes with the fairings off as that, to me, is the most interesting part.  Fairings are fairings and bikes with them all seem pretty much alike, especially in this copy cat area of the Sports Tourer.

In one review, there was the comment that a Ducati sports tourer type had less ccs but good torque throughout the range.  When you needed power, it was right there for you, regardless of speed. I don'[t think that one was liquid cooled, and the ccs were maybe a third less, down in the 800 range.

A comment was also made as to how deceptive these bikes are, with their streamlined fairings, curved windshields and all.  One guy said he was up to over 90 mph without even being aware of it. And I have heard of others going ninety and above, cruising across the western states at around a hundred, and it gets me to thinking of how much of a thread their life then hangs on.  Hit a bad place in the road, have a tire blow out, any of a number of things, and you would be dead meat.  Having all that power and speed potential makes dying a bit too easy - and I guess there are some deaths out there.

But, again, it seems to me that a price is paid for all the emission standards and the EFI and things that go with them in that higher power is needed to get the same performance as with the older bikes.
« Last Edit: September 24, 2009, 06:11:34 pm by LJRead »
Lawrence J. Read
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LJRead

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Reply #12 on: September 24, 2009, 07:55:05 pm
Ace's comment about the added weight due to liquid cooling has me wondering if this addition can be quantified.  How much additional weight are we talking about.  The leakage issue wouldn't bother me particularly as with normal maintenance this shouldn't be much of a problem.

Then too is the issue of the 'liquid' in liquid cooling.  Are we always talking about water here or are other liquids sometimes used?  I have heard Beemers referred to as oil heads as opposed to the air heads of earlier bikes, is it really oil that was used?

I know these will seem like rather naive questions, but when it comes to modern bikes I admit to being very naive.
Lawrence J. Read
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Vince

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Reply #13 on: September 24, 2009, 09:18:10 pm
     Larry, racing vehicles-cars, bikes,whatever- use straight water. This is so that in the event of a failure such as a leak or crash damage, only water will contaminate the track. Water dries completely and doesn't leave any kind of slick residue on the track. Coolant mediums (antifreeze) are slick and any leakage on the track will cause someone's tire to slip. (CRASH!) The water is drained after every race or it will cause corrosion in the system.
     Regular use street vehicles will use antifreeze. This chemical mix includes water, but also has corrosion inhibitors and water pump lubrication. The freezing point is much lower than water, thus minimizing system and engine damage in cold weather. It has a higher boiling point than water to help avoid over heating in hot weather.
     Just like multi-viscosity oi, the additives that give it the wide range of use will break down over time and become contaminated. Thus it should be flushed and replaced every couple of years.
     It is hard to quantify how much weight and complexity the addition of liquid cooling will bring to an engine. High performance engines have greater cooling needs. Body work holds in more heat than an open frame. While there is still some air cooling effect, in engines such as a V-twin the front cylinder blocks air flow to the rear cylinder. The front wheel blocks air flow to the radiator. The liquid cooling has to accommodate all  this.
     So the cooling system has to be engineered for the engine. These factors include radiator, water jacket, fan, and water pump size and volume.  These are mated to the engine size, type, power output, and even the engine bay it is mounted in.
     The advent of full fairings has allowed for several economies. With the engine hidden there is no need for engine styling such as is found on an Enfield. It would only have to be functional, not pretty. A motor  head might appreciate an un-stylized  engine, but most people would want slick styling. Just as in a car, the body dampens some sound. This aids in meeting some EPA and DOT requirements.
     Some liquid cooled bikes use oil as the cooling medium. This involves an oil cooler to drop oil temperature to a point that enables it to better transfer heat away from the parts. Sometimes the cooled oil is sprayed at hot spots such as the under side of a piston. Some bikes use both water and oil cooling.
     Body work has to be engineered to enhance air flow through the radiator. That is why a car's fan runs continuously, but a bike's fan only switches on when extra cooling is need such as in stop and go traffic.
     So, with all this engineering you can have larger, more powerful engines. The trade off is weight and complexity.


LJRead

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Reply #14 on: September 25, 2009, 02:03:08 am
Question:  Why are some beemers called 'oil heads'? Are the heads oil cooled?

The fairings on the Cafe racer featured in the CMW catalog seem very moderate and quite nice to me.  I wonder what they wiegh.  Then we have Ace's newly introduced oil cooler - wonder how much cooling that is able to do.

So we could add fairings and liquid cooling and make our bikes real 21st century - right?

Well, at the speeds I drive at, it is probably overkill.  But then I am still thinking of a bit of fairing, like adding some leg fairings to the front engine crash bar, and a bit of a windshield.  Have to wait on tha ' till I finish other projects, but worth thinking about.
Lawrence J. Read
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2002 Machismo, 2003 RE rickshaw with Thunderbird base