View Full Version : Why no production forced induction bikes?
Seems like you could make a super charged 600 that would be much lighter than the equivalent hp 1000cc bike, so why don't they make them? Can't be reliability as the Japanese firms would get it right if the wanted to.
In BIKE this month there is a supercharged Fazer 600 - at lowish boost its making 170hp at the wheel! :eek:
Jester666
07-08-07, 08:14 AM
Seems like you could make a super charged 600 that would be much lighter than the equivalent hp 1000cc bike, so why don't they make them? Can't be reliability as the Japanese firms would get it right if the wanted to.
Cost! :D
the_lone_wolf
07-08-07, 08:27 AM
what he said^^^
you can make huge horsepower, but try making it last 4000miles between services, that's got to be a big factor in the true cost of developing a road engine...
MiniMatt
07-08-07, 08:39 AM
Not sure if there's a size constraint too? An airbox can be pretty much any shape you want, can be moulded to fit round existing components whereas a turbo/supercharger is going to be a very definite shape which needs to find a hole someplace to sit.
That and as lone wolf says, cost of reliability. I had a rock solid reliable turbo charged MX-5 but that was only pumping about 150bhp out of a relatively massive 1.8 engine. Squeezing more power than that out of an engine a third the size that revs twice as high has to be an engineer's nightmare :D
In BIKE this month there is a supercharged Fazer 600 - at lowish boost its making 170hp at the wheel! :eek:
Exactly. Just thought that a well proportioned system would be reliable and wouldn't cost more than the equivalent thou. It would just be lighter.
gettin2dizzy
07-08-07, 09:07 AM
Because power isn't the issue with modern sportsbikes. they can have pretty much all they want - nobody is looking for a 50hp increase on the 600s
Because power isn't the issue with modern sportsbikes. they can have pretty much all they want - nobody is looking for a 50hp increase on the 600s
So why buy a 1000cc one then? It's not like they are more practical then the 600cc.
Alpinestarhero
07-08-07, 09:15 AM
So why buy a 1000cc one then? It's not like they are more practical then the 600cc.
Extension of ones penis, more bragging rights, lazier engine for long riding (that would be my reason for having one), ability to take it superstock racing!
Matt
Ceri JC
07-08-07, 09:15 AM
Exactly. Just thought that a well proportioned system would be reliable and wouldn't cost more than the equivalent thou. It would just be lighter.
Bear in mind a large part of the cost of litre bikes isn't just the increased cost of the engine, it's also the better suspension, brakes, stronger swingarm, etc. needed to deal with the power it makes, all of which you'd also have to pay for (as the bike would still make litre bike power), as well as the supercharger/turbo itself costing more than just a bigger lump would mean a greater cost overall IMO.
Still, as a 'special' it'd certainly be interesting. I read an interesting article on turbos in streetfighters the other day explaining that modern bike turbos have no real discernable lag the way car ones can.
arenalife
07-08-07, 09:15 AM
If they made a 600 that powerful, it would need stronger forks/brakes/swingarm/frame/components etc, it would end up just as big as a normally aspirated 1000 and less useable/more expensive.
gettin2dizzy
07-08-07, 09:27 AM
So why buy a 1000cc one then? It's not like they are more practical then the 600cc.
Sorry -point I was making was that it isn't worth turboing a 600, as the extra weight and cost assosciated puts it in 1000cc territory. Turboing a 1000cc engine puts you in busa territory, turboing a busa is bloody expensive! As much as people think that a busa turbo must be tiny you're actually looking at a turbo a v8 would be happy with. With that goes intercooler systems the space shuttle would be proud of and a swingarm that makes bear look small.
MeridiaNx
07-08-07, 09:46 AM
In BIKE this month there is a supercharged Fazer 600 - at lowish boost its making 170hp at the wheel! :eek:
Yeah and I think in the same article they also explained why manufacturers chose to make 1000s instead of supercharging/turbocharging 600s instead. Think it was to do with simplicity/cost, but can't be sure. Will check and post back.
Sid Squid
07-08-07, 11:42 AM
We've been here before. Factory turbos of the '80s:
Honda CX500/650 Turbo, (yes - really).
Kawasaki GPZ750 Turbo, (the best one).
Suzuki XN85, (looked good).
Yamaha XJ650 Turbo. (hmmmmmm...).
Pros:
Loadsa go, (ish).
Turbo stickers.
Performance of larger bike, (ish).
Ermmmm... that's it.
Cons:
Complexity, (see Honda above).
Fuel consumption of bigger bike, 100 horse costs 100 horse money - however you make it.
Consumables wear of bigger bike, 100 horse costs 100... etc etc.
They were rubbish, the best one, the GPZ750T, had the performance of a GPZ900R, which was cheaper to buy and run.
gettin2dizzy
07-08-07, 11:49 AM
although we all know theres no reaosn for one...I bet if they made one it would sell like hot turbine blades!
Sorry -point I was making was that it isn't worth turboing a 600, as the extra weight and cost assosciated puts it in 1000cc territory. Turboing a 1000cc engine puts you in busa territory, turboing a busa is bloody expensive! As much as people think that a busa turbo must be tiny you're actually looking at a turbo a v8 would be happy with. With that goes intercooler systems the space shuttle would be proud of and a swingarm that makes bear look small.
Nahhhhhh not quite.....
Drag Hyabusa Turbo, your not really going to go any bigger than this, and it'll be an all out specc'd engine.
http://images20.fotki.com/v355/photos/4/48802/4234192/DSC02060-vi.jpg
Compared with Ghost Riders Turbo which is tiny in comparison.
http://images19.fotki.com/v33/photos/4/48802/4234192/GhostRidersTurbo-vi.jpg
And some med/large sized turbos on cars.... They can get MUCH bgger
http://img.photobucket.com/albums/v481/TWINSEDAN/gatebil/gatebiljuly07081.jpg
http://img.photobucket.com/albums/v481/TWINSEDAN/gatebil/gatebiljuly07156.jpg
http://img.photobucket.com/albums/v481/TWINSEDAN/gatebil/gatebiljuly07203.jpg
http://img.photobucket.com/albums/v481/TWINSEDAN/gatebil/gatebiljuly07226.jpg
Squid, don't forget how a turbo spools as well. Bit like an IL4's powerband, but the difference when it spools up will tend to just raise the nose into the air.
It'll be "quick" but will it be "rideable" on the road, or the track? Lag lag lag POWER POWER. The idea of bikes is to keep the throttle nice and smooth.
TBH, i would be interested to see a Supercharger on an IL4 machine. You'll have the instant power of a Vee Twin (as SC work off the engine hence power available straight away), but still have the powerband of an IL4 at top revs where a twin will fade.
But its location and cost. Locating a SC that has to be run off an engine (opposed to a turbo working off exhaust gasses for those that arn't sure) makes it quite hard to safely locate.
I've got it, replace the 250cc 2 stokes in motoGP (theres talk) with 250cc 4 stroke SC or Turbo'd engines :lol:
It'll be "quick" but will it be "rideable" on the road, or the track? Lag lag lag POWER POWER. The idea of bikes is to keep the throttle nice and smooth.
Cant remember the science but apparently bike turbos dont work like that - they are much more linear...
gettin2dizzy
07-08-07, 12:37 PM
Bikes are high revving so the turbo is practically spooled at all times.
Daimo - a 500hp turbo is a 500hp turbo whether attached to a busa or a 5l v8. It needs to provide enough airflow to generate that power - regardless of engine size. The reason they are difficult to install is that they are so bulky - and when they look as neat as that they really are a work of art!
Bikes are high revving so the turbo is practically spooled at all times.
Daimo - a 500hp turbo is a 500hp turbo whether attached to a busa or a 5l v8. It needs to provide enough airflow to generate that power - regardless of engine size. The reason they are difficult to install is that they are so bulky - and when they look as neat as that they really are a work of art!
that'll be the maximum flow rate...
I.E, on our astra, its happy at 237, once remapped yadder blah, the turbo peaks at aroudn 300bhp, after that, the turbo simply can't flow any more power. You need a larger spec turbo that can chuck more air through.
Something like a Garrett T2 or T25 would be fine on a bike. Not much lag as its a low boost turbo so will spool up faster, but provide less peak power (around 250 on a T2, more on a T25).
I think most turbo bike tuners just mount them on the front behined the front wheel just off the downpipes.
Cant remember the science but apparently bike turbos dont work like that - they are much more linear...
A few things make a difference to this, ultimately you want a short distance between the bike' exhaust ports and the turbine, and a turbine that is small enough to spin up quickly. If you run a big turbine you get more boost but it can lead to sharp power delivery as mentioned above.
Long distances from the header pipes to the turbines lead to delay in spinning up as well IIRC (Generally people tend to stick to turbo charging IL4s because the pipe routing is so much simpler)
A lot of turbo setups from the 80s ran "suck through" turbos with 1 big carb. The mix was then compressed and forced into all cylinders by a manifold. Today, blow through systems which pressurise, cool, then force the air through individual Throttle Bodies / Carbs which add fuel are more common. These require lower boost pressure for the same power (as I understand it) so are more reliable and better behaved.
TTS and BigCC racing (both in the UK) make a living turbo charging production and drag bikes.
No practical experience of turbos but I spent a little time reading up on them.
Edit:
I think one main point was raised when the Suzuki B-king came out. The press asked one of the developers why the road bike would not be supercharged like the concept. He shrugged and said "Because it makes more than enough power already". When you can get a light, compact, normally aspirated engine to punt out over 160BHP, forced induction isn't something the general public are crying out for.
northwind
07-08-07, 02:44 PM
If they made a 600 that powerful, it would need stronger forks/brakes/swingarm/frame/components etc, it would end up just as big as a normally aspirated 1000 and less useable/more expensive.
Nah... The suspension found on sports 600s is pretty much identical to the thous- in fact, in the case of the GSXRs it's inexplicably better. They wouldn't try costcutting like with the B-model 636s, but then they souldn't have done that for a 600 either, they just knew they could get away with it. Brakes are generally identical, certainly interchangable (except for the R1, which gets the tarty 6-pots, but doesn't need them). Swingarms if not the same are similiar. Frames, yep, those tend to be different but "just as big"? They're similiarly sized now, size isn't much of a factor in strength for bike frames these days.
The hp numbers aren't that interesting, but how about economy? Power characteristics? Turbos have the potential for lag, but superchargers don't (though they're a bit harder to locate).
Nodding back to the old turbo'd bikes doesn't make an awful lot of sense to me, they were crude affairs from the dawn of time :) Forced induction technology's moved on a bit. Look at the new VW TSI 1.4- It replaced the 2 litre FSI engine, makes better power, better torque and midrange, and chopped about 10% off consumption. Not suggesting that dual charger is the way to go for bikes o'course, but that's an idea of what's being done now- it used to be you'd plaster a turbo'd car with TURBO logos, stick the motor in your fastest hot hatch, and people would avoid it or flock to it. Now you pop it in a warm hatch, and people don't notice it's turbocharged.
But first, I want my diesel bikes ;)
Ceri JC
07-08-07, 02:47 PM
When you can get a light, compact, normally aspirated engine to punt out over 160BHP in a naked street-oriented bike, for heaven's sake, forced induction isn't something the general public are crying out for.
I can see the 'point' of a turbo 'busa. I can't really see the point in a turbo GSX-1400, or similar. I think a large part of the appeal is the look/status symbol, rather than any practical use.
Oh, 1 more thing about the turbos......
As said, I've always thought you want as small a distance from the top of the manifolds to reduce lag..
But not too long ago an American company designed a turbo system (same turbos etc) where the turbos were mounted behined the rear wheels just before the rear silences. They suffered no lag issues and made a hefty gain in BHP..
Its on one of the video sites, i'll have to have a nose later to search (or just search "Rear turbos" or something).
I can see the 'point' of a turbo 'busa. I can't really see the point in a turbo GSX-1400, or similar. I think a large part of the appeal is the look/status symbol, rather than any practical use.
Its for the wannabies who can wheelie in front of crowds and go in a straight line, but can't go round bends ;)
To change the subject slightly, referring to quick power boosts, on the way to my license training a geezer on a lovely big naked something or other with a nitro bottle strapped on came right up the outside of my van as I was indicating to turn right into the training place. Turned out he was the instructor! (but not mine) What a ****ing pillock?! I could've easily had him off but to be honest I wouldn't have been too bothered unless he was hurt.
Sorry but I haven't really got a point other than you might get power hungry silly Billys getting into bikes buying them when they can't ride to save their lives (almost literally-instructor???!!!!).
To totally derail this, my instructor was a bit of a moron cos he kept on about keeping near the kerb? Nowadays I own my space on the road and am not giving anyone the temptation to scrape past me in a kind of aggressive/defensive way. Can I have a hell yeah?!
Stella is my friend.
:drunken: :D
P.S. I've actually thought before can there not be a different type of forced induction like an electrical fan system which could be light and placed more remotely or would that simply be too puny? Peugeot made a supercharged scooter a few years back.
P.S. I've actually thought before can there not be a different type of forced induction like an electrical fan system which could be light and placed more remotely or would that simply be too puny? Peugeot made a supercharged scooter a few years back.
Yes there actually is electric superchargers. they use them in twin turbo cars as a cushion in between. They don't make too much psi. Google electric superchargers and you'll learn more.
I think a supercharged 250cc light bike would be ace fun, and low to insure.
Supercharging is better than turbo as it's on all the time so you don't get upset whilst going round a turn when the turbo kicks in.
Hey, I'm a Yank. My father was born in London.
Thinking of buying a SV 650 to turbo charge.
I've had big bores and I've had small bores and I like the power of the big bores but the handling of the small bores. I want a bike to accelerate with anything but I also want it to corner with anything. I wan't to be able to throw it into a corner, slide it, and generally make the wheels walk. I'm not THAT good on a big bore - especially at sane speeds. The big bikes will do it, you can push the front/push the back/slide it - it's just that you have to be going psycho speeds to do it predictably. A powerful small bike can do it more easily/predictably at lower speeds. It has to do with the ratio of my weight to the bike's weight. The center of gravity of the bike has a lot to do with it too. The multi cylinder 4s just have too much weight up too high.
Anyway, that's why I think a turbo SV 650 is good idea - power with agility.
Maybe with the rise of diesels we will see, eventually, a return to two strokes - high pressure injection/cylinder injected two strokes.
Alpinestarhero
03-09-07, 07:47 PM
Hey, I'm a Yank. My father was born in London.
Thinking of buying a SV 650 to turbo charge.
I've had big bores and Iv've had small bores and I like the power of the big bores but the handling of the small bores. I want a bike to accelerate with anything but I also want to corner with anything. I wan't to be able to throw it into a corner, slide it, and generally make the wheels walk. I'm not THAT good on a big bore - especially at sane speeds. The big bikes will do it, you can push the front/push the back/slide it - it's just that you have to be going psycho speeds to do it predictably. A powerful small bike can do it more easily/predictably at lower speeds. It has to do with the ratio of my weight to the bike's weight. The center of gravity of the bike has a lot to do with it too. The multi cylinder 4s just have too much weight up too high.
Anyway, that's why I think a turbo SV 650 is good idea - power with agility.
Maybe with the rise of diesels we will see, eventually, a return to two strokes - high pressure injection/cylinder injected two strokes.
Question: all that power - will the chassis cope?
You could be better off turbo'ing a gsxr750 or something. Much better standard chassis and runing gear, more able to cope with power increase.
Anyway, I'm sure if you're skilled you can slide an SV without the need to increase its power?
Matt
Well, yes, the SV650 is renowned for its handling - they are a favorite mount for club racers here in California - just not powerful enough.
Two ratios matter - Power:Weight and Traction:Weight
Recipe - Take a good handling bike and add power without adding weight, add chassis upgrades to suit your taste.
northwind
03-09-07, 08:50 PM
Yep, with a front end swap or AKs in the stock front, and something like a Penske dual in the back, the SV will handle rather nicely indeed.
What it won't do is survive significant boost for very long, though :( You'd need to do a lot of work to make much more than 90bhp long term survivable, especially in hard use. On the plus side, if you wanted to drop the compression, then turbo Busa pistons will fit with a slight hone.
You can make an SV motor unstable with NA, so there's not an awful lot of benefit to turbos IMO.
I'm_a_Newbie
03-09-07, 11:09 PM
Seems like you could make a super charged 600 that would be much lighter than the equivalent hp 1000cc bike, so why don't they make them? Can't be reliability as the Japanese firms would get it right if the wanted to.
I read somwhere that the Bugatti Veyron needs 120bhp just to run it's supercharger :smt118
Yep, with a front end swap or AKs in the stock front, and something like a Penske dual in the back, the SV will handle rather nicely indeed.
What it won't do is survive significant boost for very long, though :( You'd need to do a lot of work to make much more than 90bhp long term survivable, especially in hard use. On the plus side, if you wanted to drop the compression, then turbo Busa pistons will fit with a slight hone.
You can make an SV motor unstable with NA, so there's not an awful lot of benefit to turbos IMO.
Yes they are unstable. Why? IMO it is NOT because of the power level but because of the overspinning that is necessary to get to the power.
The SV's reputation for breaking cranks likely comes from over revving, especially on downshifts.
I'm into turbo mopars and they can use stock forged rods in 450+ horse engines while a naturally aspirated version of the same engine - because it makes power by way of higher engine speeds - instead of boost - demands a forged H beam rod at far lower power outputs. One theory for why this is so - the boost "cushions" the rod and piston as it comes up on TDC.
Yes, Busa turbo pistons - 1100cc lower compression forged turbo pistons.
Magnaflux the crank. Boost it - don't spin it - to get to 100 HP?
northwind
04-09-07, 12:22 AM
Mmm, not sure I'd agree with that, most hard-tuned SV engines don't chase high revs as a rule. Obviously the stresses are highest at peak but I don't think it's accurate to say that this is the only reason they break. You don't need to overspin an SV engine to get to the power, particularily with big bores, because the standard tune is conservative you can gian power without chasing it upwards.
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