Why so few Turbo boosted bikes?

[BusterGonads]

It's a while since I had a car without a turbo on it. Even small runabouts have them so why so little use of turbos on motorcycles? The power difference available is remarkable. I was just looking on Google and the old CX500 did feature a turbo version.

CX500 - 50HP @9000 RMP
Turbo CX500 - 82HP @8000 RPM.

To the dabbler like me, it looks like a no-brainer that performance orientated motorcycling industry would use this obvious technology.

So what am I missing?
____________________
2016 Triumph Street Twin; 2000 Honda CG125; 1997 Honda Nighthawk CB250

[G]

[P.]

Because fuck those costs unless you really are racing on straights.

https://www.holeshotracing.online/pdf/turbo-pricelist/tbikesuzgsxr1000k5_L14_stage3_160402.pdf

I'd love 420RWHP, blaze it.

[RhynoCZ]

[Teflon-Mike]

Most Turbo's are fitted to Diesel cars. - There just aren't any diesel motorbikes!

Well... there's the Enfeild Robin powered by a cement mixer engine, and there was an American 'Battle-Field-Fuel' bike, based I think on an Armstrong and later a Kawasaki, maybe a few others; as a topic of academic interest go google, it does chuck up some interesting stuff out of the main stream.

But , the 'basic' answer why there are so few of them and so little has been successful is that a Deseasil engine burns diesel, and needs a very high compression ration to get it on fire, and then it burns rather slowly. The engine tends to be necessarily heavy to be strong enough to create and withstand the high compression, the slow burn then means that they generally aren't very powerful or responsive.

As a rough comparitor; a diesel car engine Needs to be around 25% bigger to have comparable power to a petrol car engine, and the 'performance' and responsiveness is still poor; Add a turbo, and they get more perverse.

A Diesel engine works because the fuel/air mixture self-ignites under the high compression; run an engine at part throttle... you 'choke' the supply of fuel/air into the engine; So if you have say a 500cc cylinder 50cc combustion chamber for a 10:1 compression, as a petrol / spark ignition engine; at 1/4 throttle you only actually 'suck' maybe 125cc of charge into the pot; the actual compression ratio is now only 3:1... fine as long as electric spark sets it on fire... not so great when you are relying on the heat and compression to make it go pop.... now a diesel engine may not even work, let alone work well or efficiently!

Adding a turbo, increases the amount of charge stuffed in the cylinder, and the effective compression ratio, because of the extra charge, and also aids ignition because the turbo tends to heat the charge before its crammed in the pot; Means that the engine might be made smaller and lighter to achieve the same power, but actually makes matters worse as far as maintaining the ignition causing actual compression ratio across a wide range of speeds and loads.

Fuel-Injection... curiosity of an oil burner, then is that they work 'best' from a full cylinder full, and don't work so well if at all, on a 'short fill' of charge; Consequently diesels are usually 'modulated' not like a petrol engine by a throttle choking the air-supply, to determine how much charge gets to the pot to go bang, but by letting them get an full or near full cylinder fill of air, on each cycle, and choking the supply of fuel at part throttle, so they get a 'weak' mixture. Weak mixture, in a petrol engine would likely cause 'knock' self igniting under Diesel principle ahead of spark, but on a diesel engine, that's exactly what you want. But, it means a more complicated regulated fuel supply, hence fuel injection, and it exacerbates the 'responsiveness' where on a petrol engine, the mixture strength and ignition timing are usually both controlled to get the best burn, for power and or economy.

Look at Diesel technology over the last 25 years as it has become the norm in cars; the 'high-speed' diesil engine still has a red line at around 6ooo rpm, where a similar petrol engine car engine probably has a red-line with a motor-bike like red-line around 9ooorpm.

The diesel has evolved a heck of a lot, BUT; still struggles to make the same amount of power, even with a blower and even with a cc advantage, and its still inordinately disadvantaged on 'responsiveness'.

OK, this is a bit out-of-date; but at Lucas we used to have a fleet of Rover 2 series (?) pool cars. I never opted for a company car, 'cos my lowly ranking in the hierarchy basically only qualified me for a Metro 1.1... and I'd have had to pay tax on its sow-room value! But the facilities manager was an old Cafe-Era biker...... had a JAP tattoo on his forearm, and he'd noted the bike I rode, and been a bit disparaging about this 'Jap-Crap' and when I spotted the tatoo quipped that it wasn't what (he thought) I thought it meant... as in Japanese.. and was rather taken aback that I DID.... and went on to loan me his copy of then discontinued, couldn't get hold of it for love-nor-money, Jupiter's Travels... but that's another tale! But he had to sort the pool car bookings, and managed some-how, to have sent them all out or not had them back, when I went to get the keys, and hand me the keys to a leather clad 218 one of the senior managers was trying to conserve for his own personal! Usual fare was a 214 base model petrol, that was about as inspiring as wet lettuce in a cauliflower cheese, so if he couldn't find reason to give me the 218, gave me one of the 216 desiesils.... and it was marked contrast to the 214... the 214 was gutless, but rev it hard enough it would, eventually move. 216Turblo.... floor it. gnash the steering wheel, it picked up rev counter started to move... slowly, and eventually it got a bit lively.... then bang! Rev limiter kicked in JUST as it came on the boost! Horrible horrible things!

BUT, and this is the salient point; in a car the weight holds back the acceleration; with a turbo desiesil, that weight does a lot to damp the turbo lag, and put the motor under load and give the blower a chance to start doing its thing, whilst it has a chance to make a difference.

Stick one in a truck, and with 7 and a half tons or more, that weight will do a lot to help hold back the motor, whilst the blower spools up, and it sort of works. Stick on in a mid-sized saloon.... and no... by the time the blower catches up, its all over!

Which sort of gives clue to why diesels worked reasonably well in heavy trucks, and bigger heavier cars... but really didn't suit a lighter car... and they have done an awful lot in the last quarter century to make a 2.0l turbo deseasil 'almost' as powerful and responsive as a 1500 normally aspirated petrol engine!

Try stick one in an even lighter motorbike.... that phenomena is only going to be even more amplified, and when you have a bike that probably weighs something ion the order or 175Kg rather than 750Kg for a mid sized saloon, the power delivery is going to be even more unsuitable.

Yes I am still talking Desiesels not Turbo's! Bear with me!

Oh-Kay.... mentioned how you can make a petrol engine that bit more responsive with a carburetor adjusting the mixture strength through the range of load and speeds of the operating range, more still, using a distributor that has a mechanical advance to adjust the spark timing according to engine revs, and a vacuum advance mechanism to adjust it more for the throttle position/load on the engine.

On a motorbike..... forget the C15!!! They tend NOT to have a distributor. Timing is set 'static' and is fixed, a compromise between best economy and best power, usually as its the more pertinent to a biker, set closer to best power, where it will help acceleration response a bit. There's no bob-weight system to adjust the advance according to engine revs (So WHY on earth did a C15 have one!!!Lol) and no vacuum advance mechanism to adjust it for engine load and throttle opening.

In later years 'electronic' CDi ignition systems evolved to give an advance curve via the 'advance by retard method'... and this is what your CG has.... basically the static advance was set for maximum revs, but the little black box, 'retarded' spark timing the slower the crank turned not actually 'electronically' but 'electrically' utilizing the inherent 'lag' between input and out-put on an AC system caused by capacitors and conductors... BUT, although I have come across one or two systems that had a rheostat on a plunger worked by manifold vacuum to offer some 'load' adjustment to the curve, I don't think that any made it to production motorcycles that still made do with essentially a 'fixed' ignition system.

Now lets look at the 'Factory Turbo' bikes.... you have mentioned the CX500/650 Turbo Maggot (I actually 'almost' bought one of them in 1987... pretty glad I didn't now, even though they are worth pretty respectable money on the collectors market!) This was, and Honda even admitted such, pretty much a corporate thumbing the nose to the world to prove they could! It was an astounding feat of engineering, making a turbo work on a V-Twin with asymmetric exhaust pulses, which was mainly why they did it; but it wasn't a great bike.

The CX to start with was an anomaly.... Sochiro Honda had been wowed by Moto-Guzzi when he visited in the late 50's, and it's been said that the Honda wings are a homage to his enthusiasm for that marque; BUT, the CX500 was Honda's 'Techno V50'.

Leon Tonti is the father of Guzzi V-twins; in the mid 60's he was given a very luke warm amber light to make a 'big' bike, and no money to develop it, told to use as many existing catalogue Guzzi parts as possible. The original 750 V-Twin was then taken from the catalog, and was mostly used as a field-generator engine on air-fields and as a pump-motor for fire fighting equipment, a-n-d the only 'self propelled' vehicle it actually powered was a little tracked 'gun tractor' used for hauling cannons around and moving aeroplanes. (HENCE it's not so much a derogation, as homily, when I reffer to err nibs 'Bludi-Guzzi as an 'Italian Tractor'! That's what they were evolved from! That's my excuse and I am sticking to it! lol) Anyway, Tonti built the original 'biog-block' Guzzis using that plant engine, to make something in the 650+ 'Big-Bike' world, and when the battle cry of the day was "Export of die!" created the Moto-Guzzi 'America; indicating where they were determined to export them. Fantastic bit of engineering given what he had to start with, and based on its success, he was given a green light to develop a completely 'new' small V-Twin for the domestic and Eurpoean market, and with De-Tomaso money when they were amalgumated with Benelli, the V50 stormed ahead, the bike Tontio had imagined.

SO! taking deep breath... the V50 was Tontis master-piece. An air-cooled twin, making 50bhp from 500cc, with push-rods?!? its quite remarkable that that motor is still with us today (Give or take crisis at Mandello!) In things like the Breva. It was much like the CG, a remarkeable rejection of contemprary technology, when the Japanese and even a lot of the Italian's were utilising over-head cams, and water-cooling, was being used on the track and not far off for the road. To my mind, rather like an air-cooled two-stroke single, it is a very 'cool' as in Miles Davis 'cool' bit of engineering, minimum technology for maximum motion. And put to market in approx 1976, was a pretty remarkeable motorcycle. Made in the new Benelli plant, they got economic of scale and made lots of them; the push-rod motor was a mechanics dream, they really are 'nice' to work on; yet it was a 'quick' bike for its day, depsite what looked like pretty medoicre specs; it was light, and it handled and although it didn't make 'big' power, it was respectable, and it made far more 'useable' power than the stats suggested. When the first Yamaha RD350LC was launched, in 1980, with as much power and less weight, a V50 could still show one a clean pair of mazzocchi's round a race track given the chance, and often humbled them on the road.

THAT though was the inspiration for the Honda CX500.... and talk about missing the bludy point! Light tight and simple... no! Lets make this thing water cooled! But even though they'd made a techno BMW in the gold-wing and gone over-head cam... lets keep the push-rods?!?!?

Much loved NOW, because the things were pretty economical, and they were comfy, the maggot was in its day the favorite tool of the dispatcher.... and whilst they had some virtues... they were never a particularly wonderful bike... and bore little or no comparison the the V50 that inspired them.....

BUT, lacking any sort of reputation for 'exiting' and such a technical non-starter for Turbo-charging.... that's what Honda picked... essentially to shop they world they could!!!!

Moving on to the other factory turbo's.....

Suzuki, with the XN850 turbo, was possibly the most engineered of the factory bikes; they had caught a cold so badly it almost froze them in the RE5 wankel. And thier 'Not a Kawasaki' GS accross the frame fours were built like a brick out-house, mostly because it was thier first real four-stroke, but also because of the reputation of the RE5 and two-strokes. The turbo, really failed.. it's styling was just plain wiered to start with, and it didn't really know if it was a sports bike or a tourer, and it was neither particularly fast or ecconomical.

The Yamha XJ650? Again boasted pretty wired styling, but the blower failed to do much to make its performance particularly remarkeable.

Probably most successful of the blower bikes, (and another I 'almost' convinced myself to hand over cash money for!) Was the Kawasaki GPz750 Turbo.... curious given that Kawasaki Heavy Industries could call on all its ship-building engineering resources, and had, particularly with the Z1 almost done a 'money-no-object' exercise to make thier big accross the frame four, the GPz Turbo was the least funded and lest developed of the 'factory' trubo's! It was essentially an over the counter GPz750 'uni track'.. with an after-market 'MrTurbo' kit slapped on.. and a neat LCD boost gauge...

In a performance orientated market, particularly the US, though, whilst it did come closest to the hype that the Turbo's aught make for a bike that made big-bike power yet retained small bike handling... it probably didn't! It was a 750 to start with, it did NOT have small bike handling! Handled better than the behemouth 1100 superbikes of the era, but it was not a bike you could chuck around like a 400/4! Add turbo-lag, it was one you probably wouldn't want to even try! And ultimately it was only just about as fast as Kawasaki's own GPz1100, and rather more fragile.

Water-cooled and far more thoroughly engineered the Turbo-Maggot, I think lived longest in the brochures, and was probably by sales the most successful of the factory turbo's...

And its a point debated to death WHY the factory turbo's died?

There's probably a lot of reasons, and the fact that the factory turbos were based on air-cooled engines, apart from the CX is a good one.

More revealing though is that it to delivered about 115bhp... honda at the time said that it was almost impossible to make more than 100bhp 'reliably' from a 750 motor without going water-cooled... which is mutable, but that is about the best they ever achieved from the CBX750 motor. And I shall try and avoid mention of the VF 'concept'!! But Kawasaki showed them the error of thier ways with the GPZ600R that without a blower, and down 150cc to the 750, managed to produce 85bhp, almost as much as the normally aspirated 750; the 900R managed to make 115bhp.. and it came far closer to realising the ambition of big-bike power and small bike handling than any of the turbo's did... and did it without turbo lag, or turbo fuel consumption, or the complexity and unreliability of them having habbit of eating thier own turbine shafts!

Thirty years on.... its intriguing that Kawasaki returned to forced induction with the H2... but using an engine driven 'super-charger' rather than exhaust driven turbo... phenomenal stats in the specs, the thing offers 300bhp from just 1000cc... but its NOT a turbo.

Probably the most revealing thing to look at though is bike weights.....

1982 GPz750, normally aspirated, had a brochure weight of 215Kg; about as heavy as any-one would tolerate for a 'sporting' motorcycle. Mkst bikes were smaller and significantly lighter, like the V50, that had a brochure sped of around 150Kg in that era. Look at the brochures now, though and there are 125's that pork in that heavy, and the 250Kg motorcycle is more often the norm than the exception.

This does suggest that with a heavier vehicle to shift, they may respond 'better' to turbo-charging... but they are still a long way off the mass of even a light car!! And when you can get the sort of 'big' power you might from a turbo, with a bigger water-cooled engine, far more easily and with far fewer technical hitches to deal with, why go there?

Probably the most significant though, is that unlike thirty years ago when the Japanese marketed their machines on this years tecno-marvel they had managed to pack into a proddy bike... these days, extra performance is in such abundance, and so often NOT the buyers most significant criteria, whats the 'need' to tackle these technological challenges... and more importantly who will pay for it?

Look at Hardley Davidson.... they lumbered on through the era of Japanese techno marvels making things that owed more to the stone age than the space age, with air-cooling and push rods, getting an even then 'barely' adequate level of performance from them just making them bigger, and their biggest technological innovation of that whole era was aluminium cylinders!

So, ultimately the answer is mostly 'Marketing'; with modern suspension and more significantly modern radial tyres, there's little or no reason to try make a motor with big power from small cc's and low weight.

In a market where if 'economic' is the main facet of design it can most easily be obtained with a low-cost, low-tech deign utilizing a low cc engine, like a CG or C90, customers aren't going to pay the big money to buy a turbo-tiddler.

If they want big power and big performance, well, how much can you or your wallet handle? The Kawasaki ZZR1100 offered 200mph threatening top speed way back as early as 1990, the Bird and Busa more still, and there aren't many who ever max one out on the public road.... if the customer wants handling? Well, you probably doint need to look much further than the Yamaha FZR1000 dating back to '87, barely three years after the hight of the factory turbo's, that like the GPZ900 showed you could make a big bike handle almost as well as a smaller one; and by '98 that evolved into the immortal R1 that achieved far more by way of making a bike that handled like a middle-weight, but went like a heavyweight.... and did it without a blower or the niggles associated with them, and more and better...

Back to cars vs bikes..... the answer then is that they are apples and oranges, and what's important in a car isn't necessarily whats important in a bike, and despite the convergence of technology since the original Honda CB750 with a four cylinder engine and electric start, and weights heading upwards on both bikes and cars.. bikes have not made a hole in the market as a general purpose every day means of transport, falling into the specialist niches either end either as economy vehicles or outright performance toys...

Back to diesel vs petrol.... there are no commonly available diesil powered bikes; and whilst they have done a lot to make diesel powered cars more exiting and promoted them as a viable performance alternative, the higher performance car is still petrol powered.... and of those.... how many sport turbo's?

Even in the domain of cars where they have a better chance to 'work'.. they don't tend to work SO well they have become common let alone ubiquitous.. except on diesels... where thier use is still somewhat questionable, but they are more eminently suited to being used to 'help' with that format of engines fundamental drawbacks.

Interesting aside, is to observe the rise of the diesel mostly in Europe, where it was mainly popular because of its adoption for heavy good vehicles, and as a 'by-product' of petrol manufacture was sold at a significant discount at the pumps.. an advantage that it might still have, were it not for the inordinate high 'fuel taxes' now levied not only by European governments, but in the US, where they rue the dollar gallon, let alone the £1 per liter!

Interesting argument, slightly relevant to the topic; I ran a 3.9l V8 Range Rover... as my mother described it "A conic Gas-Guzzler"... which I smiled and nodded at, cos I ran it on LPG gas! True, the Range-Rover claimed a mere 15mpg in the brochure, but on LPG at around 1/2 the pump price of 2-Star, it gave a £-Per-Mile equivalent of 30.. mother ran a 2.2L turbo Diesel, from which she struggled to achieve much over 25mpg despite book suggestion it could do 30, making the 'gas-guzzler' actually the more 'economical'.. and I got that lovely V8 sound track when I wound down the window!

More revealing was the fact that mother 'convinced' of how economical her aga engine was, never thought twice about jumping in the thing to pop to the shops, or traveling 50miles to have a chat with her friend rather than using the 'phone.... which rather dented any notion of ecconomy before she started... and flooring the dang thing every where she went, got appalling fuel consumption from the thing, doing all the extra miles she needn't.. and convinced it was more ecconomical to use low revs and high gears, even more inefficiency never getting the blower spooled up! and this sort of 'use' is incredibly common, and 'economical' vehicles often aren't purely because their owners simply drive to the limit of their wallet!

Yet, the marketing men still flog dirty desiesels on the notion that they are 'ecconomical' even despite the fact that pump prices on the stuff are now higher than for petrol, on the 'ecological' benefits suggested, I really am unconvinced by, and the presumed 'efficiency' they really dont have, and the idea that a 'modern' diesel can be as fast and exiting as a petrol engine, cos they got the RAC to let them race the Skoda in touring car!!!

So ultimately there's lots and lots and LOTS of reasons that turbo's aren't common on bikes, and I dont believe that any of the mass manufacturers offer a factory turbo any-more. Whilst its refutable that they are 'that' common on cars, where the only place they are that common is on Diesel engined cars, not all cars, and still the marketing men and bureaucrats are more of an influence than the engineers as to why.
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[P.]

What the actual fuck ^

[G]

Indeed.

[kgm]

I think we need a character limit introduced.

[MCN]

[Evil Hans]

[Fisty]

[The Shaggy D.A.]

[BusterGonads]

Come on lads - be fair. I asked the question and he gave his answer and he didn't stint on it, did he. Not like the rest of you tight B'stards... )

I'm going to read it later because I am cooking my dinner now and I only have twenty minutes before the cooking will be finished. I will be reading it though. First thing I noticed was about diesels..... I'd have thought there are plenty of petrol cars with turbos - most probably. It has obvious advantages not only in power, but also in economy. You can use a smaller economical engine and get the power when you want it of a much bigger engine. Best of both worlds I would have thought and they don't add that much complexity really. Not as much as adding two cylinders for example by going from two to four.

Anyway - back to the stove for now. Thanks.
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2016 Triumph Street Twin; 2000 Honda CG125; 1997 Honda Nighthawk CB250

[MCN]

Primary reason to turbo charge is to have lots of power from small engine.

Other primary reason is to compensate for altitude.

Any combination of the above is possible for whatever purpose you like.

Bikes do not like turbos because the power delivery can affect handling.
Modern turbo design and engine mapping has reduced this effect.
Like was said no need to boost a small engine that revs it's head off to get BHPs.
Bigger engines can't rev so fast or they pull them selves apart due to forces and stuff.

Stop laying Tef-bait you.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[stevo as b4]

Fuck me, I'd never know where to start in picking apart the vast number of inaccuracies and errors in post thats sprouted so many random off topics that it's incompressible!

Oh and Tef, I'm sure I'm not the only one that's noticed your forgetfulness, lies or miss quoting of dates or things you did when you said you did them etc?
For someone that bought a new AR125 in 1990, how the utter fuck could you have been considering buying a CX500 turbo in 1987?

OP, don't overthink it all, as others have said taxation and emissions standards for bikes in a world apart from cars legislation. And remember also how much smaller they can make a litre bike now compared to a 2003 ish era 600 Sportsbike. There's no need for turbos to sell bikes, and no one would buy say an Aprilia RSV1000R V4 if to have a turbo fitted it would end up the size of a ZX6R from 15years ago.

[The Shaggy D.A.]

[Teflon-Mike]

[Ste]

There is a character limit per post but I can't find my posts where I figured out what the limit is.

[G]

[The Shaggy D.A.]

[BusterGonads]

Ha ha ha - I REALLY did NOT set out to create annoyance here......

Thanks for the replies which answered my question.

Well, I never suggested or even considered making diesel motor bikes, but that aside, either I have misunderstood him or Mr Tefflon has a strange idea about how sporty and good to drive modern diesel cars are, but I'll leave it there and also a whole lot of other things he said.

Take a look at this >

https://www.youtube.com/watch?v=9ncuy-TBCvM

Audi won Le Mans 24 Hr time and time again with TDI cars nothing touched them while they were in it until they pulled the plug around 2016.
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2016 Triumph Street Twin; 2000 Honda CG125; 1997 Honda Nighthawk CB250

[Ste]

[Courier265]

[Nobby the Bastard]

[arry]