"A turbo might still be in the cards. Small engine, good fuel economy. Lots of power when you want it. Perhaps they'll design one for Hero."
"There isn't a racing class in the world that would allow it to compete so what would be the point?"
To the best of my knowledge, Hero isn't in the business of producing motorcycles destined for the racetracks of the world. They build small displacement, economical street bikes.
There was a reason the turbo bikes only lasted a few years: They add expense and complexity for far less performance than you'd get from a simple displacement increase.
I wrote this up the other day, but I guess I forgot to press the "Post" button:
Unless you're building an aircraft engine or a diesel engine, a turbo charger is more "gimmick" than anything else. Case in point:
My first Subaru was a GL-Turbo wagon. It had a four cylinder, 1.8 liter turbo-charged engine with on-demand four wheel drive and a five speed manual transmission.
My current Subaru has a normally-aspirated six cylinder 3 liter engine with full time All Wheel Drive and a four speed automatic transmission.
The current car has far better low-end torque, much more peak horsepower AND gets the same gas mileage in the city and BETTER gas mileage on the highway.
The only thing the turbo gave me was a neat little light on the dashboard and a jet-engine like "whine" on full acceleration. In other words, it was a gimmick. All it did was add complexity for little real world benefit. Same goes DOUBLE for a motorcycle.
Jaimec take it from someone who works on airplanes with turbo chargers it is a gimmick in most of aviation too. Far as I am concerned all most turbos do as a practical function is to be a "separator". They separate the owner from his money.
Hmmmm, the turbo thing has been tickling me for some time, apart from motor cycles I've not owned anything non-turbo for many years, diesels it's true.
What you have to remember however is that the principles hold true, petrol or diesel.
The huge difference from the old turbo era to today is in materials & control systems. A small variable geometry turbo linked in to current injection technology would give you huge benefits, just look what Ford have done with the "ecoboost".
There really is no comparison to the old 80s turbo bikes.
I've been cogitating on getting hold of a Yam T-Max scooter & grafting on a wee turbo to give it some extra legs.
Jaimec, I'm not sure what you mean. Physics is physics when it comes to volumetric efficiency (is that the work I'm looking for?). You can't argue with the maths.
Like Mr. Grumpy sad, materials and control systems are leaps and bounds above what was around 30 years ago.
Turbo is not a gimmick. Just a different way of making power.
Jaimec, you're not comparing apples to apples. You need to compare two of the same engines, one with a proper turbo setup, and one without. Drive a 6.5 diesel without a turbo, then drive a 6.5 diesel with a turbo. Or hell, take the turbo off your 1.8 and then see how much power and economy it delivers! Or put a turbo on your 3 liter.
The problem with turbos is their added bulk (on a motorcycle), "lag" or "spool-up", and as was mentioned, the possibility of simply increasing displacement. But you have to increase displacement a lot (which typically decreases fuel economy, but there are a handful of variables there) in order to achieve the 50-300%+ increase in HP and TQ that a turbo is capable of delivering.
Turbos work fine, the failures of the '70s, with the long turbo lag times, and overheating issues are a thing of the past.
With modern closed loop fuel injection systems, electronic waste gates, and better understanding of the temps involved, a Turbo, or a mechanical supercharger are a good way to get performance out of a smaller, lighter engine, so, better economy and power.
Torquehd is right, an old turbo vs. a new engine is apples and pears.
Most modern diesels are built around the turbo, ditto with gas engines designed for them, just pulling the turbo off will give you a low performance low compression ratio engine that will disappoint.
Not saying that "no replacement for displacement" is invalid. When you burn the candle brighter, it melts faster. more power in a smaller package means more stress, and more heat. A 135 cu. inch turbo engine needs the same radiator/cooling power of a 350 ci. inch atmospheric engine of a bit more power.
Weighs less, a bit more complex, better mileage at cruise power. It's all a tradeoff.
Some dislike the lack of clear exhaust pulse noise they have come to expect from a high performance engine. The turbo mushes up the sound and adds it's whine. That turbo whine sounds like power to others.
Mostly I agree that a turbo on a motorcycle is not-optimum. An exception to that, funny enough, are tube frame Buells that can stuff far more power into the frame with a well designed turbo motor, ( like from RB racing ) than can fit with simple displacement techniques. ( because the frame design limits cylinder height )
You can order an engine for your X1 etc. built with aftermarket, stronger cases, rods, etc. both with and without turbosupercharging. The difference will be the exterior plumbing and the pistons. ( and possibly the porting ) Either engine will be more than a rational human needs. Either one will have enough power to flip the short wheelbase bike like a poker chip, and either one will make one of us lunatics happy. ( except for the wallet ) The turbo will have more power. It will also cost more.
Can you even use 150-200hp in a bike? Sure! How well is a matter of talent. For me, being practical, either of the built engines is a waste of money. But to quote the Sec. State, "What difference does it make?"
There's ego involved. I find a Rolex a waste as well. YMMV, and love what you love.
Mr. Grumpy is right about the Ford "ecoboost" and like him my Diesel car has a turbo. It'd be pretty castrated without one.
In airplanes, turbocharged engines are not usually for more speed ( as such ) but to maintain power at altitude.
The higher you go the lower the drag ( overall, there's a tradeoff, profile drag goes down, induced drag goes up ) but the engine power output drops. Pump the engine and rate of climb & cruise speed rise.
Turboprops are usually optimized for altitude, and they are, after all, superchargers at heart.
Yes, the Reno air racers pump up the low altitude power with blowers, but those are race engines, and remember, burning bright!
Spot on. Eventually, I'll get around to taking off the little turbo "silencer" on my duramax. the 07 and later trucks sound like they have no balls compared to the others.
i love it when you hear a truck with an aftermarket turbo, it just screams, "AMERICAN HORSEPOWER"!!!
No, you didn't see my original post. It is far easier and more efficient to simply build a bigger engine than to add the complexity and issues you get with a turbo-charger. THAT was my point.
Considering how uncomfortably HOT those Harley lumps got, try to imagine a red hot turbocharger next to your leg in addition.
Get ready for more and more turbo'd auto engines. Ford, BMW, Mercedes and eventually all the others are replacing their larger engines with smaller, turbo-charged units. You can achieve similar results with a larger engine and cylinder deactivation too.
Not sure what that means for motorcycle engines though (you can get all the power you'll ever need from normally aspirated 1000 - 1300 cc's) My brother had a '94 Dyna with an Aerocharger kit. That thing was a hoot. Boost (adjustable too) only came on when the engine was under load. Otherwise it was transparent.
I;m shocked and totally disgusted,unshaven,tattooed,non stich riding hippies on a BMW,what is this world coming to, there wasn't even a schuberth in sight.
......It is far easier and more efficient to simply build a bigger engine ......
I agree, all things being equal. No replacement for displacement. And total agreement on the simplicity front. I agree Bikes are most likely to be "better" normally aspirated. Lighter, simpler, less heat to dispose of..
For a fuel economy standpoint, however, the complexity of pumping a smaller engine makes sense.
You pay for cubic inches all the time in efficiency. If you assume some arbitrary HP for cruise, ( say, 60 hp @ 60mph ) a smaller engine will give better mpg than a larger one. The smaller one will not have as much excess power available to accelerate, or hold the vehicle against a higher speed air drag. Unless you "boost" it somehow.
The efficiency cost of the complex plumbing and cooling systems can be smaller than the loss to hauling around a bigger engine.
Or not, depending on a raft of other factors. It makes enormous sense in a small diesel. They're all about Compression.
I'm actually surprised more work hasn't gone into "performance" engines designed for e-85. I guess that the wide range of alcohol and octane rating make it difficult to choose the right compression ratios... where a turbo would be great.
But. Everything in it's place, and while I occasionally consider spending too much money to put a turbocharged monster engine in my Cyclone, ( all it takes is cash ) I doubt I'll ever do it. Too much bother for silly power. Port work, someday, sure.
Truth to tell, I Like them. But I'm unlikely to buy the new BMW "café" bike. A used Bimmer? sure.
That XB12 turbo is the one of cleanest turbo install on a bike I have ever seen. the under hung turbo is a very cool idea. Those blue line torque numbers are insane
(Message edited by aaron thomas on October 29, 2013)
The one thing about a turbo in a performance application is that with the adjustable waste gate the boost can be set to different stages for various situations.versus building a beast of an engine that once built is a beast all the time. Read the dyno charts on the link posted above about the turbo XB
