Hilltop - is it worth it?

[Tractors are go]

All bikes become 'breathless' with altitude - there is less oxygen as one goes higher innit

Sort of yes, but it is more obvious with a big twin than in a 4 cylinder; this of course was where rolls royce scored with the twin speed supercharger on the merlin engine compared to the Daimler benz 605, although they had the advantage of fuel injection, helpful in negative g rolls.

It worked better at altitude.

This lack of oxygen at height, confirms my belief of brain damage in the abnormal 5'9" people.

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[Schtum]

This lack of oxygen at height, confirms my belief of brain damage in the abnormal 5'9" people.

I'm sure you must mean the abnormal 5' 9" + people....? I''ve always maintained that anything over 5' 10" is a waste of DNA.

 

[Tractors are go]

Capitalist society.

A "good" one yes, a bad one maybe 94ish and an average on 98ish.

It's about how it drives; smoothness and flexibility.

Anyway we're all farkle tarts so none of our bikes are as the mothership launched them !

Try to ride an older carbureted in the alps.2-up you won't make the taller passes in france without pushing because of thinner air at altitude...
And yes there is some manipulation going on with the dyno as any 2010 on dohc aircooled boxer makes 100-103 hp at the rearwheel and any 2013 on R1200 LC unit 115-118 rwhp stock !
Don't forget the straight shaftdrive on a boxer has less power loss than any chain...
Of course if you let the dyno read 20 hp low before the update you can tell the customer you gained 20 hp after the update....
The placebo effect will do the rest and everyone is happy,Customer who paid to get "more power" and proprietor who got more money...it's all good.
This is how our system works after all...

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[Tractors are go]

I'm sure you must mean the abnormal 5' 9" + people....? I''ve always maintained that anything over 5' 10" is a waste of DNA.

So true

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[Engineer]

Sort of yes, but it is more obvious with a big twin than in a 4 cylinder; this of course was where rolls royce scored with the twin speed supercharger on the merlin engine compared to the Daimler benz 605, although they had the advantage of fuel injection, helpful in negative g rolls.

It worked better at altitude.

This lack of oxygen at height, confirms my belief of brain damage in the abnormal 5'9" people.

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Supercharger is the only cure for lack of air, more air and more fuel = more go.

 

[tanneman]

Supercharger is the only cure for lack of air, more air and more fuel = more go.

Ahem, turbo charger actually.

 

[yofi]

they both do the same, but differently?

 

[tanneman]

Forced air, yes, but the turbo charger is more efficient both in terms of power consumption, power delivery at altitude and it weighs less plus it is more compact. The design and construction has come on a long way to match superchargers for low rpm torque.

 

[Tractors are go]

Ahem, turbo charger actually.

Actually, splitting hairs the proper phrase was turbo supercharged.

A turbo uses the wasted exhaust gases to cause compression in the air intake, where as a supercharger is mechanically driven by gears or pulley. This means that on the supercharger there is +ve boost from lower revs but has a maximum output restricted by gearing and also absorbs a lot of power, a turbo, the more it spins the more it makes; until kaboom !

As for the H2 SX, I am reminded of when I considered a CX650 obrut; a 100bhp bike still needs 100bhp brakes and suspension and frame whether it's a 650 twin turbo or a 1100cc four. Still costs the same to make.

Now, a F800gsa supercharged producing a 100bhp with 105lb.ft with a 10kg increase in weight and better fuel consumption, that'd be worthwhile.


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[Engineer]

they both do the same, but differently?

Supercharger works better at altitude

 

[Arsey]

Supercharger works better at altitude

Ah yes,but a supercharger giving you,say, 9 lbs boost at sea level will not give you 9 lbs more pressure at altitude. It would seem like that but you need to remember that it is giving you a set percentage more air from a ratio standpoint and not a set amount of pressure in psi. If we put a supercharger in space where we have no pressure in, we'd get no pressure out. We wouldn't get 9 psi.

If we had a standard 14.7 psi reference pressure at sea level and our supercharger was setup to give us 9 lbs of gauge pressure, that's going to be a total of 23.7 psi or a ratio of 1.61. However if we were up in the mountains and our ambient pressure was 11 psi, our same supercharger is still going to give us the same 1.61 ratio which equals 17.71 psi or a total of 6.71 lbs over our starting pressure. However pressure as compared to sea level would only be 3 psi!

A turbo is setup so the wastegate opens after a set amount of total pressure is reached. It doesn't matter what level you started at. When it gets high enough, it bleeds off. This means that as air thins out with altitude, the turbo will spin faster and faster to hit the required pressure. While you should theoretically have 9 psi at sea level or in the mountains, keep in mind that your temps will be different between them so while a turbo does much better than a supercharger at altitude, it still has some loss. It is the best option for altitude though.

 

[Engineer]

What you need to fit to your GS is a two stage Spitfire supercharger - can Hilltop do that for £300?

 

[tanneman]

Thanks Arsey for the explanation and why I couldn't bother to reply.

 

[Tractors are go]

What you need to fit to your GS is a two stage Spitfire supercharger - can Hilltop do that for £300?

Is that one for each cylinder ?

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[Engineer]

Ah yes,but a supercharger giving you,say, 9 lbs boost at sea level will not give you 9 lbs more pressure at altitude. It would seem like that but you need to remember that it is giving you a set percentage more air from a ratio standpoint and not a set amount of pressure in psi. If we put a supercharger in space where we have no pressure in, we'd get no pressure out. We wouldn't get 9 psi.

If we had a standard 14.7 psi reference pressure at sea level and our supercharger was setup to give us 9 lbs of gauge pressure, that's going to be a total of 23.7 psi or a ratio of 1.61. However if we were up in the mountains and our ambient pressure was 11 psi, our same supercharger is still going to give us the same 1.61 ratio which equals 17.71 psi or a total of 6.71 lbs over our starting pressure. However pressure as compared to sea level would only be 3 psi!

A turbo is setup so the wastegate opens after a set amount of total pressure is reached. It doesn't matter what level you started at. When it gets high enough, it bleeds off. This means that as air thins out with altitude, the turbo will spin faster and faster to hit the required pressure. While you should theoretically have 9 psi at sea level or in the mountains, keep in mind that your temps will be different between them so while a turbo does much better than a supercharger at altitude, it still has some loss. It is the best option for altitude though.

Yeah but - you don’t want turbo lag on hairpin bends when you are fully loaded two-up on a tight hair pin bend.

Turbo probably better for constant speed? but if you want immediate response is not a supercharger better? is this why they fitted two stage intercooled gear driven super chargers to Spitfires as they were fighters not high altitude bombers?

I’d want instant response on the bike in the Alps.

How does a Hilltop tune compensate for lower air pressure?

 

[Tractors are go]

Any tune should compensate for variations in atmospheric pressure, as an example a high of 1027mb compaired to a low of 970mb.

The best option is, as they were called a turbo supercharger; which allowed +ve boost from supercharger up to a certain level when the turbo overtook the supercharger its clutches disengaged and you were now running on the Turbo's boost limit.

Yeah but - you don’t want turbo lag on hairpin bends when you are fully loaded two-up on a tight hair pin bend.

Turbo probably better for constant speed? but if you want immediate response is not a supercharger better? is this why they fitted two stage intercooled gear driven super chargers to Spitfires as they were fighters not high altitude bombers?

I’d want instant response on the bike in the Alps.

How does a Hilltop tune compensate for lower air pressure?

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[Warlord]

Put one Hilltop GSA and one none Hilltop GSA with similar weight riders side by side.

Do some straight line side by side wide open throttle runs in a selection of gears.

I'll be very surprised if there was any noticeable difference in actual performance.

 

[Wapping]

Be sure to film it.

 

[Tractors are go]

Prepare to be surprised !

Put one Hilltop GSA and one none Hilltop GSA with similar weight riders side by side.

Do some straight line side by side wide open throttle runs in a selection of gears.

I'll be very surprised if there was any noticeable difference in actual performance.

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[Nin]

SO having re-read this - I conclude the answer to the OPs question is:

Yes;
No;
You're an idiot;
No you're an idiot.