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Building: Built - Fury '06R1 ...now on with the mods
posted on 4/11/14 at 10:34 AM
quote:Originally posted by Andy D
quote:Originally posted by twybrow
I think it was filmed in 2012 from memory.... I don't think the bike was setup badly deliberately, but I was surprised that when they found the
bike running rough, why not have hot footed it to a rolling road, and of course upgrade the injectors (laughable explanation by narrator!).
Guy is my new man crush. Such a likeable chap, a brilliant mechanic and balls of steel!
I would presume the bike was set up right in the UK, and the altitude cocked it up .. not sure how altitude is compensated for ???
I'd kind of spoiled the ending for myself by looking that up earlier in the week.
I'd guess as far as compensation control...
MAP,Atmospheric Pressure and Lambda to control fueling, as normal but could the boost level could be governed according to atmospheric pressure
reading. So the boost is increased as the height does...
Or it's just rider governed... just has way too much power to use a the start so short shifting and he gradually increases the throttle the
higher he goes as the power drops.
Having been up the Col du Bonnette at just under 9000ft, I can say you start to notice the loss of power up there. Injection motors cope OK but mates
with webers were really struggling; Rich as hell and missfiring.
quote:
Having been up the Col du Bonnette at just under 9000ft, I can say you start to notice the loss of power up there. Injection motors cope OK but mates
with webers were really struggling; Rich as hell and missfiring
Whenever I've driven in the Pyrenees it was the injection cars that seemed to lose power. Carbed Alfas on Webers / Dellortos seemed to cope
fine. This was with older injection on late '80s cars though.
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Building: Built - Fury '06R1 ...now on with the mods
posted on 4/11/14 at 12:10 PM
Travelled with two carbed cars (4age and a zetec, both on twin webers) and they both ran rich at altitude and ended up coughing and spluttering for a
while after due to the sooted plugs. They were probably on the rich side to start with compared to a cabed tin-top. I can imagine earlier Injection
not being great but as the control has improved a lot of the issues hae gone. Cars with closed loop mixture control (lambda sensor) should stay the
same AFR, just less power. Even open loop BECs should compensate to someextent if they have MAP and APS.
I know I notice less change on my 04-06 R1, than others running 02-03 motors, so even in one generation there's an improvement to the system.
Most noticable change for me is the poping from the exhaust reduces and then stops, the higher I go, then gradually comes back on the decent.
I've spluttered over mount Ventoux in a carbed BMW many years ago.
Is this right?
higher altitude = less oxygen content
The turbo pressurizes the intake the same (same psi) as it would at sea level. There will be a power drop as even though the volume of air is the
same, there is less oxygen in a given volume of air. A normally aspirated drag car will loose 1 sec for every 5k feet of altitude. Turbo charged car
looses 4 tenths for every 5k feet of altitude.
This is based on various things I have read on drag racing websites so it is up for interpretation as anyone can be an "armchair expert".
I may have misunderstood but it sounds feasible enough
Does the actual mix of air change with altitude? I presumed it just got thinner, but with the same proportions of oxygen, nitrogen CO2 etc etc.. hence
turbocharging gets round the problem be supplying the mixture at the same boost pressure no matter what height we're driving (or flying? WW2
aero engines??)
quote:Originally posted by mark chandler
Boost will be relative to the surrounding air so 10psi at sea level is not the same volume as 10psi at 5000ft
..so a sealed tank with a gauge registering 10psi at sea level will do what? .. at 5000ft? ..genuine Q, as I'm no expert! I would have thought
it would remain at 10psi with the same volume contained?
Or, does a pressurised plenum with a pop off valve behave differently?
..quickly about to wade way out of my depth here..
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Building: Built - Fury '06R1 ...now on with the mods
posted on 4/11/14 at 04:36 PM
As the presure drops there are less molecules of all constituent gasses for the same volume. There will be some variation of the ratio of gasses due
to altitude but inpractice it's only the reduction in O2 that matters in this case.
A turbo spinning at a set speed will raise the pressure by a set amount (give or take). Remember under most circumstances a turbos boost is being
limited (thats what the waste gate does). So at (moderate) altitude it is allowed to work harder to reach the same set limit, the boost presure will
be close to that of sea-level, hence the power doesn't drop as much relative to a NA engine. Of course above a certain altitude the turbo will
be flat out and still not compensate.
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Building: Built - Fury '06R1 ...now on with the mods
posted on 4/11/14 at 04:39 PM
quote:Originally posted by whitestu
Won't temperature have an effect? Higher up temperatures are lower and cold air is more dense.
But the pressure has a bigger influence. O2 is still less. Remember you'll die of O2 starvation at the top of Everest despite the temp (though
that'll kill you as well).
We really need the resident Physics professor/turbo experimentor to wade in on this... you out there Matt?
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Building: BMW M52 Haynes Roadster-Quantum ST170
posted on 4/11/14 at 09:30 PM
I did the Stella-Alpine Rally on an XTZ750 years ago. It's amazing how a perfectly fine running carbed engine can barely run up at 10,000ft.
With the clutch pulled in and the throttle wide open it wouldn't rev past 4krpm!! I virtually pushed it up the bloody mountain!!
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Building: up the courage for post thirteen thousand and one
posted on 5/11/14 at 06:35 PM
quote:Originally posted by adithorp
quote:Originally posted by whitestu
Won't temperature have an effect? Higher up temperatures are lower and cold air is more dense.
But the pressure has a bigger influence. O2 is still less. Remember you'll die of O2 starvation at the top of Everest despite the temp (though
that'll kill you as well).
No.
On 8 May 1978, Reinhold Messner stood with Peter Habeler on the summit of Mount Everest; the first men ever to climb Everest without the use of
supplemental oxygen. Prior to this ascent it was disputed whether this was possible at all
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Building: BMW M52 Haynes Roadster-Quantum ST170
posted on 5/11/14 at 07:02 PM
quote:Originally posted by 02GF74
quote:Originally posted by adithorp
quote:Originally posted by whitestu
Won't temperature have an effect? Higher up temperatures are lower and cold air is more dense.
But the pressure has a bigger influence. O2 is still less. Remember you'll die of O2 starvation at the top of Everest despite the temp (though
that'll kill you as well).
No.
On 8 May 1978, Reinhold Messner stood with Peter Habeler on the summit of Mount Everest; the first men ever to climb Everest without the use of
supplemental oxygen. Prior to this ascent it was disputed whether this was possible at all
While all this talk of the effects of altitude on the combustion engine are thrilling, the question that really needed answering at the end of the
program was how he got on with the girl he chatted up.
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Building: BMW M52 Haynes Roadster-Quantum ST170
posted on 5/11/14 at 08:19 PM
quote:Originally posted by red22
While all this talk of the effects of altitude on the combustion engine are thrilling, the question that really needed answering at the end of the
program was how he got on with the girl he chatted up.
Fair point, forgot about that. Does altitude affect your performance in the sack?
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Building: Built - Fury '06R1 ...now on with the mods
posted on 5/11/14 at 08:23 PM
quote:Originally posted by 02GF74
No.
On 8 May 1978, Reinhold Messner stood with Peter Habeler on the summit of Mount Everest; the first men ever to climb Everest without the use of
supplemental oxygen. Prior to this ascent it was disputed whether this was possible at all
Above 8000m is the "Death Zone". Yes it's possible to climb without o2 above that but you are effectively dying (slowly) and have to
summit and descend pretty quick. Time above 8000m is limited before you will suffer to the inevitable; Either cerebral or pulmonary adema.
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Building: Built Stuart Taylor Locosaki-12R
posted on 5/11/14 at 09:22 PM
quote:Originally posted by adithorp
quote:Originally posted by 02GF74
No.
On 8 May 1978, Reinhold Messner stood with Peter Habeler on the summit of Mount Everest; the first men ever to climb Everest without the use of
supplemental oxygen. Prior to this ascent it was disputed whether this was possible at all
Above 8000m is the "Death Zone". Yes it's possible to climb without o2 above that but you are effectively dying (slowly) and have to
summit and descend pretty quick. Time above 8000m is limited before you will suffer to the inevitable; Either cerebral or pulmonary adema.
Supposedly someone spent 3 days on the summit of Everest, but with no ard proof, it is wildly speculated....
I went to a talk from Doug Scott recently (legendary British mountaineer who was cutting edge in the 70s-80s. He has the record for the highest night
survived without a tent. He slept the night in a small snow hole, 200 feet below the summit of Everest. Alititude and temperature should have killed
him, but he survived (albeit with a few less fingers and toes). Amazing stuff....
I virtually pushed it up the bloody mountain!!
