[Hippie at Heart]

Yogesh thanks for PM invite, but I find it little difficult to devote time on other forum. First things first let’s not mix the rider fatigue or AMS with optimum performance of a machine. Machines don’t develop AMS but they are depended on oxygen as well in a way, to perform best what they are supposed to.

Whatever attitude you ride has effect on your carburetion, Pang – Tanglung La is no comparison with Upshi –Leh. Pang to Tanglunga La is relentless accent at considerable altitude, Upshi –Leh is a near –level decent at lower altitude. In first situation you need torque to translate into kinetic energy, in second situation you need just enough to keep rolling. Consider the difference between altitudes of both sections as well… there is the key. In early 90’s I have done Upshi –Leh on RD many times in excess of 120 kmph esp. after Karoo…. Speed isn’t the thing… she could have managed some more, I have an RD that still does 120+ in Delhi with her almost worn out stock bore and doesn’t go to pieces.

Now I don’t worry about issues like mileage and top speed. Idea of a bike that performs optimum in given situation irrespective of her breed is what appeals to me. And in your post I could not relate to the idea of underperforming bike, illusions of what else she could have performed and wide abyss between both situations. Let’s have a look at basics:
1) at sea level best carburetion happens in ratio of 25:1 air to fuel ratio
2) you gain height and loose some of the air/oxygen to above ratio thereby riding on rich mixture
3) so when you try and fight off the rich setting by tuning lean mixture (or believing Indian bikes are mostly lean anyways) you are compromising on kinetic energy, getting less torque to haul up bike and you sitting atop.
4) So what you do now? U have more fuel to burn but not enough air to aid the burning, lean mixture will give you less power anyway.
5) So instead of fighting the mixture screws just feed them more air, and how can you do that? The answers is in your air filter, just to illustrate the point an RD stroke goes 660 times up and down in one second at 8000 RPM, can you imagine how much air intake and out flow we are referring here? See this fact in the light when we are talking about ascending for hours  …. Of course the RPM wont go crazy but still it’s a lot of hauling in there..and where is the air/oxygen is going to come from to feed that continuous intake?
6) Now imagine what massive block is there in shape of a filter is preventing ‘free flow’ of the air that could have gone straight into carbs? Uni Pods and K&N are another biking myth.. their performance have not shown any better results then around 5% improvement on stocks.. that too on a static Dyno test, forget real time testing. What could you do up there with 5% extra improvement?
7) Bottom line is if there is even a single strip placed before the carb intake… its going to hinder the air flow and not allow whatever air thin available at high altitude, just remove the air filter and let your carbs breath as free as they can in the rarified air.

Then there are other factors about carbs breathing out as well but that would be getting too techie for nothing. I rarely comment on four stokers but carburetion is a universal idea, hence my twuppence worth suggestion.
Food for thought: by a scientific calculation every 1000 feet ascend from sea level, translate into drop of X % of engine efficiency.. Which if allowed to be continued means, it is impossible to drive after 12,000 feet from sea level…………

Happy Riding

[Yogesh Sarkar]

Hmm… nice points, however if I remove the air filter I will also be allowing dust along with air in. In ladakh there is a lot of dust, wouldn’t that effect the bikes engine in long term? Since the basic purpose of air filter is to prevent dust from entering the engine and it there by protects the engine.

Also at what altitude would you do that, 12000ft or 15000+ft? Wouldn’t fixing an air filter that provides more air flow, but still restricts dust a better option?

[-m2-]

Excellent technical explanation, H@H.  Personally I haven't driven much over 3000m or 10,000 ft; at that elevation I noted a considerable drop in available power but driveability was still OK.  Are some types of carburettors superior to others for dealing with altitude change and 'thinner' air?  I was curious if CV carbs reduced fuel intake to match the reduced air volume available and thereby running fairly well at higher altitudes but with reduced power or is performance similar to more basic units?  

How about with cars; does fuel injection automatically adapt to altitude by regulating fuel flow and mixture ratios (with loss of power) and therefore give satisfactory driveability without adjustment.  Do turbocharged engines offer near-normal performance at altitude?

[Hippie at Heart]

Hi mike, I don’t have personal experience with CV carbs, but I imagine life would be marginally better with them and somewhat better drivability too. I assume CVs would be mostly operating on midrange supply. But the problem is very pecuiler up there, even with CVs and everything in place… there is air supply that’s constantly fluctuating and flipping to the lower side every time you gain couple of hundred feet. You would still end up with less torque, CVs trying to adjust your intake with what air is available you will end up matching right fuel:air ratio but the net result will still be a dismal jimmy. Instead of flowing with what’s available you have no option but to try and provide more air flow or force feed it in other manner. Past 13,500 feet the whole thing become so weary to drive that your knuckles are aching with boredom. You may understand the acuteness of supply if I say : it is possible to drive a 100cc Yamaha with same thrust and torque as you would drive at sea level, IF it is kitted with a nitrous oxide supply bottle with 5 psi trickle to carbs…… imagine 5 psi feed to carbs for a puny 100 cc, down here in plain will make as much power that will probably wreck your tranny or con-rods within 200 meters.  

As far cars available in India are concerned, most entry and mid level cars have a primary and fixed value fuel injection systems installed in them. Most petrol cars don’t employ a turbo charger. But since most diesel vehicles can be manually tuned, commercial jeep drivers in hills use the ‘advance’ timing to run engine at a slightly higher rave and they usually make a good speed. Once I asked a driver if at advance timing they must be spending extra diesel as well, he told me it gets even out when they hardly use any, when rolling down freely (not a good driving practice but effective cost breaking for them) some private car models have turbo, TATA Indica V2 is one such but the unit is laughably small to do anything that can be discerned immediately. Bigger cars of atleast 2000 cc plus category might have some real punch but I hvn’t driven any yet.

[vinayverma]

okay no techie stuff,
when I used to ride Royal Enfield Bullet we uesd to change the jets on the carb and later on we had wire mesh air filter, which we replaced with the original one once we hit sarchu or baralacha-la or tangla-la (on Leh highway) or after Gramphoo (on the way to spiiti) on relatively 'high altitude" for many

Edited by vinayverma, 24 May 2006 - 01:06 AM.

[darkside_of_d_sun]

Didnot face any significant loss of power when I toured Ladakh last year on my Unicorn, that includes Bara lacha La, Tanglang La and Chang La. I guess the CV carbs make a good deal of difference here. But the point raised by Hippie@ Heart is a nice one. My choice for an Indian two stroke & four stroke ( except Bullet)  will be putting in a good air filter like UNI with stock jetting only for 12000ft+ altitude. UNIs have better filtration quality than K & Ns and will definitely increase the air intake to match the needs up there!

But for my Unicorn, I will follow the rule as of now, "If its not broken, dont fix it."    

Cheers,

[Hippie at Heart]

Vinay, bullets have been fun to drive, while as a last resort I’d recommend new ‘Electra’ for the novice and technically challenged alike… but your old CB Point system was much fun to drive, you could always tweak the CB point plate to little advance, noticeable improvement immediately but the cost would be …. wearing out engine, which I feel is a small trade off.

Yogesh, Dark Sun. ditto for no filter policy, if there is any filter its an impediment, if there is performance there is a price to pay for it, no lunch is free up there. With bikes or any engine capable of kinetic energy there is an inherent element of best working compromise between various things, if one feels there is no need to improve upon a mediocre aspect or to pay any price, the safety cocoon can go only as far as existing dynamics will allow it go.

[-m2-]

Hi Darkside, good to hear the Unicorn was up to the job.  I guess the combo of a CV carb and electronic ignition preserves the driveability at such high altitude, but the lack of oxygen would surely reduce performance somewhat -- you were probably too cold to notice .

H@H: My curiosity regarding turbocharging relates to some 'advance thinking' I've been doing about a possible car purchase.  Maruti is going to be putting a turbocharged diesel in the Swift later this year and it might be a pretty good compromise for my future needs -- I'm building a place in Goa and expect to be spending around half the year in India for the forseeable future.  Apart from some goofing around in Goa, I'd expect to fill in a few of the major gaps in my India travels to justify the outlay so the ability to handle altitude would be a consideration, along with diesel economy.  I guess it is odd to be talking cars in the 2-wheeler section, but my old bones probably not up to the rigors of biking the Himalayas or dealing with the damp of the NE states, so future bike trips will probably be in Goa and neighbouring states.

[Yogesh Sarkar]

Hippie at Heart, on May 25 2006, 02:10 PM, said:

Yogesh, Dark Sun. ditto for no filter policy, if there is any filter its an impediment, if there is performance there is a price to pay for it, no lunch is free up there. With bikes or any engine capable of kinetic energy there is an inherent element of best working compromise between various things, if one feels there is no need to improve upon a mediocre aspect or to pay any price, the safety cocoon can go only as far as existing dynamics will allow it go.

Some believe that motorcycles are a “tool” for touring, while others like me believe motorcycles are our travel partners. I refer to my motorcycle as my kid, having said that I still believe I would be better off getting 5-10kmph less top end, than to remove the air filter and reduce the engine life by 10-15%.

In any case in motorcycle touring saddle time matters more then riding fast.

Edited by Yogesh Sarkar, 26 May 2006 - 05:02 AM.

[Hippie at Heart]

Yogesh Sarkar, on May 26 2006, 05:00 AM, said:

In any case in motorcycle touring saddle time matters more then riding fast.

I am never in favour of reckless and fast driving, but I like an engine performing to its optimum best under given conditions..... anyway if you feel your setup is best for you... plz feel free to stick, just don't post comments in such a way that it might give impression to first timers that a P180 can do 60-70 kmph in 3rd gear climbing tanglung la and when p180 cant do such speeds its because of rider trying to fend off AMS... raw enthusiasm cant match facts and natures might.

Edited by Hippie at Heart, 26 May 2006 - 12:51 PM.

[Hippie at Heart]

Mike, I don’t know if they are going to put in diesel versions on road in swift within this year or not, but the fact remains, most car manufacturers are shy of making cars that are inherently powerful. We never had a racing legacy nor there is any in development, most people are ignorant and kept ignorant driving mediocre cars and bikes with no understanding and wherewithal to improve or experiment upon the seedy old trashed models discarded by rest of the world. So our highest selling cars are sub 1000 CC category, a sub 200 CC bike is touted and sold as road tourer, what can you expect?
And high price for things against an almost abysmal earning index makes things only worse for any new development efforts or to sustain a moment.
But I hope by the time you come around to buy there will be other options available to you then swift. Have you seen the car in real? To me it look like a design rip off from Audi TT 600, but the original look far far better then copy cat, esp her broad rear view is so ungainly. But the due must be given to what she is worth for. Suzuki usually slowest to catch up with innovations but whenever they do find a niche to market, they do a good job of it backed up by engines that are average performers but simple in construction and utterly reliable. If you are not going to drive around as much, then don’t you think petrol version would sit you just as fine? Beside you can order for a CNG variant which works out very economical for local runs.
Right now there are few diesel turbo in market, but they are not true blooded ‘turbo’ as you might used to seeing them over there. Mahendra Scorpio is one such, more then turbo it’s the comman rail driven ignition (CDRi) that’s making all the power, they are likely to pass engine refinements as ‘turbos’ the only real turbo on diesel in cars I hv seen is on Octavia 1.9 ltr, at nearly 12 lakh this is not a cheap car for hicky like me.
My fav would be Fiat Palio 1.9, Fiat still makes cars that think safety first and mileage later. mileage is so crucial factor in India auto market… but we Indians really push things without a care for safety, I suspect swift will still weight lighter then Fiat, at the trade off of few extra Kms run per ltr…… my only deterrent not to buy fiat would be scarcity of parts and exorbitant costs when you finally get them.

[-m2-]

From what I've read, the Palio is well-regarded as a solid and nice driving car and is one I will probably consider as well -- the poor service network is also cited as a problem with Fiat but that might improve now that they are planning joint dealerships with Telco.  Depreciation is also rather fierce, but that might make a recent model a pretty good deal.  

Maruti seems to be taking a new direction with the Swift as in most respects it is an up-to-date design with the world market in mind.  Still a small car in length but taller, wider, and more heavily built than most but probably somewhat underpowered with the 1.3 petrol engine.  I like the looks, but would concede that the visibility to the rear is not helped by the high belt-line and large rear quarter pillars.  For me, ease of entry and driving ergonomics is very important and the swift passes that test ok but I haven't actually driven one yet.  The reviews are mainly positive, including one for the  european-spec turbodiesel model -- Maruti will be building the same engine in India but they haven't announced when it will be available in the swift.  It has less hp, but around 50% more torque and 30% better fuel economy than the petrol models, so it will likely become the engine of choice for many unless it is priced too high.   While owning a car would open up some interesting travel opportunities, it would really be an extravagance rather than a necessity, so looking into it may be more of a tire-kicking exercise.  Have to see how the project in Goa works out first, I guess.

thanks for comments!

mike

[Yogesh Sarkar]

Hippie at Heart, on May 26 2006, 12:47 PM, said:

I am never in favour of reckless and fast driving, but I like an engine performing to its optimum best under given conditions..... anyway if you feel your setup is best for you... plz feel free to stick, just don't post comments in such a way that it might give impression to first timers that a P180 can do 60-70 kmph in 3rd gear climbing tanglung la and when p180 cant do such speeds its because of rider trying to fend off AMS... raw enthusiasm cant match facts and natures might.

Does any one who tours long distance on a motorcycle ride at 7000+rpm when the max bhp is produced at 8000???

From reading the above lines I guess so.

Does removing the air filter at high altitudes increases the performance?

YES

Does removing the air filter lets in dust and shortens the life of engine?

YES

Do you really need your bike performing 100% so you can ride at speeds which are neither safe, nor doable if your suffering sever headache and nausea?

No for most, yes for super humans who can ride at optimum level even when suffering from AMS.

Does sever headache and nausea hampers ones ability to do the things at the same speed he/she might have been doing in normal case?

I guess I am an exception here, because I can’t seem to control my motorcycle in the normal manner when I have sever headache and nausea which on occasions forced me to sit beside the road holding my head.

Will removing the air filter make the bike perform on the same level as it would while in plains?

No way!

Making hard and fast rules about anything is neither good for the motorcycle, nor good for the rider. Sure removing the air filter would let the maximum amount of air in, but at the same time it will also damage the engine. Better option would be if the bike is not performing up to the level you want it to, first try to retune the mixture. If that fails only then remove the air filter.

Posting comments which leads a newbie to believe that he needs to remove the air filter no matter what, will not be beneficial to him, it will also shorten his bikes life.

Remember removing the air filter may cause water to enter into the engine in case of riding in rain. Also the entering dust can clog up the carburetor in case too much dust enters, which can happen in worlds highest and coldest desert.

Edited by Yogesh Sarkar, 28 May 2006 - 10:32 AM.

[Hippie at Heart]

Yogesh, I can somewhat understand your limitation about not being able to fully grasp the situation; however I feel I should make one last attempt to explain things again in a purposeful context and not lumping facts together for heck of it.

“Does any one who tours long distance on a motorcycle ride at 7000+rpm when the max bhp is produced at 8000???  From reading the above lines I guess so.”

It is very much possible to tour long distance on a motorbike, not only at 7000+ rpm but in excess of even 11,000 or until rave limiter kicks in, however this will happen somewhere on GT Road, wherein this thread have a specific purpose I guess, I could not find any direct reference to 8000 Rpm while riding in high mountains, am sorry you could understood an illustration only as far you managed to think.

“Does removing the air filter at high altitudes increases the performance?

YES” That is the idea indeed.

“Does removing the air filter lets in dust and shortens the life of engine?

YES” I have already said so; it may shorten the engine life however it does not so drastically shorten the life span of engine that it may warrant an immediate re-bore as soon as one is back in plains. Ok well I have to admit - those who think they have no business opening up the innards of a bike till its really due for a re-bore simply overlook what I posted, I am not from that school of thought and its absolutely important for me to do a physical inspection of an open engine every 15,000 Kms. Unfortunately I have been mixing with bad boys of circuit who would open up a brand new Gypsy engine so they can hand shine the Camshaft. My apologies in advance – I don’t want another rant about money issues on that.

“Do you really need your bike performing 100% so you can ride at speeds which are neither safe, nor doable if your suffering sever headache and nausea?”
No for most, yes for super humans who can ride at optimum level even when suffering from AMS.”

Yes I want my bike to perform her 100% so that am able to ride at safe speed, and have better drivability, a bike that may suddenly lurch and die on those Gata loops is the last thing I want to happen to me. You are mixing better drivability with speed which I have never advocated. To drive and control a bike that still can do more does not mean one have to drive recklessly, emotional bonding with bike is fine too, but for all practical purpose it is a tool that facilitates you from point A to point B, perhaps I am more sensitive then many to sense the metal fatigue before anyone can, but I wont mind flogging her a bit more only if she is healthy enough to take it.

“Does sever headache and nausea hampers ones ability to do the things at the same speed he/she might have been doing in normal case?”
I guess I am an exception here, because I can’t seem to control my motorcycle in the normal manner when I have sever headache and nausea which on occasions forced me to sit beside the road holding my head.”

Strangely in spite of being a regular bloke on road, I have always found that it is prudent not to fight AMS but make friends with it, and being aware of things usually help then rushing headlong into it. Somewhere in 2 wheeler section other Titan Vistet has given a very fine explanation about AMS. I suggest you a read that.

“Will removing the air filter make the bike perform on the same level as it would while in plains? No way!”

Please read the whole thread again I have not said anywhere that she will fly as in plains after removing air filter. If you think its ‘No way’, well … its your horse, your saddle time, not mine.

“Making hard and fast rules about anything is neither good for the motorcycle, nor good for the rider. Sure removing the air filter would let the maximum amount of air in, but at the same time it will also damage the engine. Better option would be if the bike is not performing up to the level you want it to, first try to retune the mixture. If that fails only then remove the air filter.”

We are back to the basics as far as carburetion is concerned, I will try again some other day to explain, maybe this time I will try to incorporate economics principal of demand and supply. But what gave you an idea more air will damage the engine? Perhaps you meant dust will enter in copious amounts as well. Some 12 year back we measured the bore wear before and after the ride of a Yamaha RX100, in all the filter was removed for about 1000 Km and total ride back to del was of 3500 Km, we suffer a loss of about 5000th micron, which roughly meant that if a STD RX bore was to last 40,000 Km under optimum riding in plains it will last for 38,000 Kms if we make 2 trips of 3500 Km each. I think it was a very marginal situation and worth granting space.

“Posting comments which leads a newbie to believe that he needs to remove the air filter no matter what, will not be beneficial to him, it will also shorten his bikes life.”

If the newbie is from a school of thought that bore barrel is made of butter, one should not touch engine without a reason, there is no need to be inquisitive because mediocre is best, one sheep must follow other sheep, engine tuning is a black art, riding is about twisting throttle only, am sorry that I even posted anything about an engine performing to its best. I can perhaps go page after page about tech issues, but this is not a right forum for that. Brevity of words sometime is a fine idea but if you are not able to comprehend an issue, don’t lump few words and throw at us without linking your thoughts behind them.

“Remember removing the air filter may cause water to enter into the engine in case of riding in rain. Also the entering dust can clog up the carburetor in case too much dust enters, which can happen in worlds highest and coldest desert.”

This is the last straw really, to know that there is plenty of water all around in cold desert, I assume it’s the rain water which may get sucked up in carbs; but a very unlikely possibly to happen in an area that is known as a cold desert, even considering water running off at road bends is so static to do any thing other then just get splashed around for no more then 2 feet before splattering down to level. Infect that is something I miss more every time I go there, every latest visit mean I’d have to cross few water obstacles because of better roads and their management. Even way back in 1989 when things were relatively wild, I did not suffer more then wet CB points of an old Jawa. For the dust issues refer above.

I was about to add comments on sprocketing, but I think am done with this issue.

Edited by Hippie at Heart, 29 May 2006 - 01:37 AM.