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Discussion Starter #1
My 999R is a race bike under (long) development. Gasflowed heads, high compression pistons, large dia exhaust, RS airbox, etc., means much more power than stock.

The most recent problem is now cooling. Yesterday, at a 40 deg C track day (102F) the bike would run great for 3-4 laps, then hit 102 deg C, or 216F and I would have to back off and run one or two cool down laps to get it down to 95 deg C again.

The cooling system is stock and in good condition, the bike runs Samco sillicone hoses. If anything, the bike is running quite rich, so it is not a lean mixture issue.

Aside from waiting for cooler weather, my choices are to:

-try to vary the amount of water / coolant mix in the bike (currently 50/50) - I know, nobody should track a bike with antifreeze, but they do it here, or

-upgrade the radiator and oil cooler (I have a RS set of oil and water radiators, but the hardware to connect it to the bike is a major undertaking, getting hard to find and very expensive - anyone know of a good source for new or used 999RS bits), or

-remove the street thermostat?

I realize that the 999 thermostat fits into that cast water carrier behind the battery and it does not open or close, it turns, to allow water to flow through the thermosat to the radiator. Has anyone ever had it partially fail, only turning some of the way to partially block coolant flow?

I know that is unlikely, the real culprit is more power which produces more heat, so there may not be an easy fix here.

Which leads me back to - does anyone know a good source for some used 999RS race bits?
 

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This is the problem with building high-comp race motors, you have to cool them better. My 749R runs at 100 - 105 degrees most of the time and that isn't a problem. Really, anything after 105 and you should probably back-off a bit. I find my motor likes to settle in at 100 degrees, its very rare that it peaks much over that.

You and I both need an over-sized radiator. There are a few positives with that design, one of which is; you'd have to eliminate the piece of junk stock cooling system entirely, so the cooling manifold would go and you'd have to build/buy a new battery box. This means, you'd get rid of the thermostat and there is a bun plug on the radiator for the temp sensor.

Its the best way to go. I've tried everything from putting holes in my fairing to richening up my fuel map, but nothing really made any difference. The stock radiator can't take the heat. I can't imagine how bad it would be on a 999R.

Ohh and finding those RS parts is hard, which is one reason I'm still getting by with the stock radiator, I just can't afford them.



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How much bigger/more efficient is the RS radiator?

actual #s?
 

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Jan, you are asking a thermodynamics question without providing anything near the amount of information required to provide a numerical answer. You would need to provide a number for each of the following to get anything near a number for an answer:
-energy value for heat input to the cooling system from the engine
-energy coefficient for the coolant
-target operating temp
-radiator heat exchange efficiency
-airflow rate
-design ambient air temp

And I can't recall if that would be actually all of the data required... but at least that....

Do you have a target coolant temperature? It sounds like you want to be sub-boiling point....... Why? The stock fan switches on sportbikes are typically above 100 C.

You can increase the cooling efficiency of the OEM system dramatically by using/adding Water-Wetter to your coolant. I have seen up to 10 C temp drops when Water-Wetter is used with/instead of glycol based anitfreeze. (Be careful, Water-Wetter has NO freeze protection properties!! although it would not seem to be an issue for you.... hahaha)
 

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Track days at this time of the year is very hard on the bikes in this region.

Water Wetter will help if you go by the information in the Hall of Wisdom, I just hand carried a supply from Australia so will give it a go in a couple of weeks once our next track day session is on again.

At current temps my R settles at around 102 Deg C and runs OK on the Lusail track. On the 998 I see temps just under 100 Deg C out on the track, but I dont push that bike as hard as the 999.

All the best

SF
 

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Jan, you are asking a thermodynamics question without providing anything near the amount of information required to provide a numerical answer. You would need to provide a number for each of the following to get anything near a number for an answer:
-energy value for heat input to the cooling system from the engine
-energy coefficient for the coolant
-target operating temp
-radiator heat exchange efficiency
-airflow rate
-design ambient air temp
Sorry, I figured that with my very simple question....how much bigger...it would yield a very simple answer...ie. ~15% bigger...or some such.

In regards to the second part of my post...efficiency...yes, I can see where you're coming from...but wouldn't a simple round about figure even be possible to come up with at all?
 

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Discussion Starter #7
Thanks for the input, I agree that water wetter might be a stop gap (good luck finding some here in Dubai) but the real solution is the big radiators. The thickness and area of both are a significant improvement over stock. I also thought I might try just the huge oil cooler, to see if that might help.

Back to the drawing board. I see the issue not only in terms of the RS bits I need, but also relocating that plastic junk box on the left side of the bike. That means removing things which are there courtesy of the length of the wiring harness. That would be tough to do. A RS harness is not something easy to find and would not work with the stock instruments, injectors, etc.

Once upon a time (just before I ordered the bike from Ducati in early 2006) JHP offered me a real (but heavily used) 999RS. At the time it seemed too expensive and offered only 500 km between engine rebuilds. It is now 2009 and I have yet to put 500 km on my 999R/RS hybrid and I have not saved much money. I guess I never learn.
 

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Bigger radiator.
 

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Water Wetter will help if you go by the information in the Hall of Wisdom, I just hand carried a supply from Australia so will give it a go in a couple of weeks once our next track day session is on again.
Yea, Water Wetter does help, but only slightly. I'm still getting high numbers using it.

Ohh, PM me if you want chris's e-mail address... I shouldn't be putting it on forums.



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Hi,
Im in Perth, West Australia and it gets pretty warm here as well.

I run a 996RS radiator in my 998.
145RWHP - 999S engine is the power plant.
I use water wetter and utilise the big single fan on the left side.
A low temp fan switch is also installed.

But, now I have a NEMESIS I can set what temp the fan will come one.

the 996RS radiator does a good job keeping the heat down.
 

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Discussion Starter #13
Hi,
Im in Perth, West Australia and it gets pretty warm here as well.

I run a 996RS radiator in my 998.
145RWHP - 999S engine is the power plant.
I use water wetter and utilise the big single fan on the left side.
A low temp fan switch is also installed.

But, now I have a NEMESIS I can set what temp the fan will come one.

the 996RS radiator does a good job keeping the heat down.
That would be great, but the bike runs about 175 hp (crank) and has no fans. 4 laps and I am at 102 degrees. Fun 4 laps though.

I have a D16RR with the termignoni "kit" and race ECU as well which I rode back to back last Friday. The 999R has way more torque, the D16 has more top end rev. Not much between them but totally different to ride. The 999R will do strange uprovoked wheelies but is as long as a bus. The D16 is tiny but just crouches down and accelerates. Happily, the D16 will run cool all day with the same sized radiator and twice the pistons. Go figure.
 

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I've been reading this, and I hate to say this but your bike is heating up very quickly based on reading.

I'd expect the a bike with significant modifications to overheat after a while but not 4 laps (<10 mins running), considering the first is a sighting / settling in lap.

Normally at race speeds the main straight is the enemy (full throttle) and the rest of the lap allows the bike to cool.

Is the temperature changing during the lap?
Do you warm the bike up before setting out (if so to what temperature)?
Does the bike suffer from heat soak (i.e. after you return the the pits and switch off the engine does the engine continue to get hotter or even begin boiling)?
102 degrees is hot for a race bike (but not necessarilly for a road bike) does it stabilise?

If there is a basic problem, a bigger radiator will only mask it for a little longer than normal.

What I'm saying is if your bike does make that much power you need a bigger radiator, however because you bike is heating up so quickly there is probably another more serious problem such as:
Running overly lean accross the rev range
A blown head gasket
Detonation due to poor fuel
Inadequate oil cooling (unlikely in 4 laps - will manifest in heat soak issues)
Water pump is worn or faulty
Faulty thermostat
Plus the obvious - unbalanced throttle bodies, too much spark advance, poorly timed cams, carbon build-up in the combustion chambers etc etc.

Basically everything needs to be just right - and as the engine gets more powerfuls so this becommes more critical. I'd be starting with the water pump...

I never recommend removing the thermostat (I don't normally tune race bikes though), however for a highly tuned engine I'd be inclined to fit one with a lower opening temperature to try and lower the engine temperature when running.

Good luck

Andrew...
 

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I'd expect the a bike with significant modifications to overheat after a while but not 4 laps (<10 mins running), considering the first is a sighting / settling in lap.
My bike will over-heat on the starting grid when its 110F outside. I race with other guys who have the same bike and they all have the same issues. Some of them don't even bother coming out when its that hot. Once ya get going, it cools off right away and stays between 98 and 101c.

I don't think thats at all wrong, my 848 gets that hot if you leave it sitting in the 110f degree sun for 15 min.

The big radiator fixes all of those issues almost immediately, especially with the larger oil cooler. I've seen bikes drop 20 degree's C with just a radiator change.



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I have a 05 999R and it is only track duty! The thing is bullit proof with 8000 track miles and never gets too hot even if it is 100 plus degrees on the track! Your bike is made for the track! Put the fans back on. That isn't going to save enough wt for you to tell anyways.
 

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Discussion Starter #17
The fans will also not help with an average track speed of 145 km/h. There are 2 long straights on the track (approx 270 km/h) which is where the engine does its heavy lifting. I also worry about draining the battery as I run a smaller racing alternator and may switch to a smaller battery.

The bike runs rich not lean (I had it on the dyno three weeks ago and used the gas analyzer). There is not much carbon in the cylinders as the bike has less than 500 km on it. The plugs are slightly tan/brown, not white.

The gas is 98 octane, ok with the higher compression but not race gas. It seems to work in everything else. I cannot feel any detonation, but if I could get race gas I would run it.

The ignition timing is stock. The bodywork is aftermarket, but the cooling openings seem the same as stock.

4 laps is over 10 miles. The bike is slowly warmed until the coolant temperature is about 70-80 degrees C. I always run a cool off lap, the temp drops to about 95-97 deg C, the bike never pushes coolant past the stock 1:1 rad cap.

I think that there is a corellation betweeen compression, horsepower and heat and the capacities of the radiator and oil cooler are now borderline insufficient. The easiest way to fix this without a complete rethink of the left side of the engine is to try to fit only the huge oil cooler. 2 short oil lines and c clips ought to do it. About $700.
 

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man, i just pulled the therm. and pluged the hole in the standoff that held it in place. the therm in my opinion does not block the coolant totally when hot so it only goes through the radiator.
my bike is far from stock and i have does many track days on it, the nemesis helped greatly also as i swear just the better mapping cooled it even more not to mention the ability to turn the fans on when i want
 

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If you pull the thermostat out, the coolant will not remain in the radiator long enough to cool down. It eventually will overheat and spew your coolant out. I'd say your thermostat is stuck open; but 4 laps is not long enough to over heat an engine with the thermostat stuck open or removed. Higher compression usually means more heat so your oil cooler idea may be the best way to go aside from replacing your radiator. Also, use distilled water if you can...sediments from tap water can deposit themselves on cooling jacket surfaces and radiator tubes. Once a coating builds up, heat transfer is affected. If you get calcium build up on your coffee or tea pot, I wouldn't put that water in my cooling system....sean
 
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