Turbo Chargering

[GSJimbo]

Thinking about putting a Turbo Charger on mt 1100 GS any input would be great, Ideas etc............Thanks

 

[lecroy]

I'm not sure what you want to know.
Do you want to try and make your own setup?

 

[GSJimbo]

No I have a chance to buy a whole set up and was wondering how much of a deal to set it up and keep it running right, drag race only......

 

[lecroy]

What kind of setup? If it's used, what do you know about the history?

 

[Nerobro]

If it were me, I wouldl find the smallest turbocharger that could supply the needed air. Smaller turbos spool faster, but won't give you the same top end power due to higer exhaust restriction, and or a compressor that can only supply X cfm.

At least if you plan on driving the bike on the street.

Right off the bat, I would investigate the warner IHI rhb3. It's really tiny, and should be a good start.

 

[Anonymous]

Turbos'

Turbos'

There is a full kit from MR Turbo that has a full bolt-on kit which will get you 150-250 HP,($3695) depending on octane & your nerves(will she hold together). The real weak link will be your 'unwelded' crankshaft.
The key to turboing our bikes is the turbo needs to be of the self-lubricating type, not an engine oil supplied type. Using a high pressure externally supplied oil type (As is common with most all cars & trucks) will not work on our bikes as they run on very low oil pressure. They just can't supply the required oil pressure nor volume.
Look up Mrturbo.com
___________________________Rick......

 

[earlfor]

Due to complexity, weight, and tuning difficulties, I would forget using a turbocharger. I believe a direct supercharger is the better choice.
Here are some comments from supercharger online.

FEATURES :: SUPERCHARGER TECH
Turbo vs. Supercharger
4/3/2002 11:31:00 PM

It's one of the most common questions we are asked - the answer to which is almost impossible to find
"What is better - a supercharger or a turbo?"

We only wish the answer were that simple, but unfortunately it is not. The simple answer is:
"It depends."
But don't worry, we'll go into more depth than that here. Both superchargers and turbos have distinct advantages and disadvantages. Selecting the right kind of forced induction for your vehicle will depend upon your particular vehicle, your driving habits, your power preferences, and your needs.

Clearing Up Confusion

According to Merriam-Webster's dictionary, a supercharger is defined as:
"a device (as a blower or compressor) for pressurizing the cabin of an airplane or for increasing the volume air charge of an internal combustion engine over that which would normally be drawn in through the pumping action of the pistons".
A turbocharger is defined as:
"a centrifugal blower driven by exhaust gas turbines and used to supercharge an engine".

According to Webster's, a turbocharger is included in the definition for superchargers - it is in fact a very specific type of supercharger - one that is driven by exhaust gasses. Other superchargers that do not fall into this category - the kind that we are all used to hearing about - are normally driven directly from the engine's crankshaft via a crank pulley. So in reality, it is not fair to compare all superchargers to turbochargers, because all turbochargers are also superchargers. For the purpose of this discussion, however, a supercharger will be considered all superchargers that are are not driven directly by the engine, while turbochargers will be considered all superchargers that are driven by engine exhaust gasses.

Similarities

Both superchargers and turbochargers are forced induction systems and thus have the same objective - to compress air and force more air molecules into the engine's combustion chambers than would normally be allowed at atmospheric pressure here on Earth (14.7 psi at sea level). The benefit of forcing more air molecules into the combustion chambers is that it allows your engine to burn more fuel per power stroke. With an internal combustion engine, burning more fuel means that you convert more fuel into energy and power. For this reason, supercharged and turbocharged engines normally produce 40% to 100%+ more power (depending on the amount of boost - check out our horespower calculator) than normally aspirated engines.

How They Work

A supercharger is mounted to the engine and is driven by a pulley that is inline with the crank (or accessory) belt. Air is drawn into the supercharger and compressed by either an impeller (centrifugal-style supercharger), twin rotating screws (screw-type supercharger), or counter-rotating rotors (roots-type supercharger). The air is then discharged into the engine's intake. Faster crank speed (more engine rpm) spins the supercharger faster and allows the supercharger to produce more boost (normally 6 to 9 psi for a street vehicle). Typical peak operating speeds for a supercharger are around 15,000 rpm (screw-type and roots style superchargers) and 40,000 rpm (centrifugal-style superchargers).

A turbocharger operates in much the same way as a centrifugal (internal impeller) supercharger, except it is not driven by pulleys and belts attached to the engine's crank. A turbo is instead driven by exhaust gasses that have been expelled by the engine and are travelling through the exhaust manifold. The exhaust gas flows through one half of the turbocharger's turbine, which drives the impeller that compresses the air. Typical operating speeds of a turbocharger are between 75,000 and 150,000 rpm.

Head to Head Comparison

Now it's time to evaluate the turbocharger versus the supercharger according to several important factors.

Cost
The cost of supercharger and a turbocharger systems for the same engine are approximately the same, so cost is generally not a factor.

Lag
This is perhaps the biggest advantage that the supercharger enjoys over the tubo. Because a turbocharger is driven by exhaust gasses, the turbocharger's turbine must first spool up before it even begins to turn the compressor's impeller. This results in lag time which is the time needed for the turbine to reach its full throttle from an intermediate rotational speed state. During this lag time, the turbocharger is creating little to no boost, which means little to no power gains during this time. Smaller turbos spool up quicker, which eliminates some of this lag. Turbochargers thus utilize a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses boost pressure, and if it gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down..
A Supercharger, on the other hand, is connected directly to the crank, so there is no "lag". Superchargers are able to produce boost at a very low rpm, especially screw-type and roots type blowers.

Efficiency
This is the turbo's biggest advantage. The turbocharger is generally more economical to operate as it as it is driven primarily by potential energy in the exhaust gasses that would otherwise be lost out the exhaust, whereas a supercharger draws power from the crank, which can be used to turn the wheels. The turbocharger's impeller is also powered only under boost conditions, so there is less parasitic drag while the impeller is not spinning. The turbocharger, however, is not free of inefficiency as it does create additional exhaust backpressure and exhaust flow interruption.

Heat
Because the turbocharger is mounted to the exhaust manifold (which is very hot), turbocharger boost is subject to additional heating via the turbo's hot casing. Because hot air expands (the opposite goal of a turbo or supercharger), an intercooler becomes necessary on almost all turbocharged applications to cool the air charge before it is released into the engine. This increases the complexity of the installation. A centrifugal supercharger on the other hand creates a cooler air discharge, so an intercooler is often not necessary at boost levels below 10psi. That said, some superchargers (especially roots-type superchargers) create hotter discharge temperatures, which also make an intecooler necessary even on fairly low-boost applications.

Surge
Because a turbocharger first spools up before the boost is delivered to the engine, there is a surge of power that is delivered immediately when the wastegate opens (around 3000 rpm). This surge can be damaging to the engine and drivetrain, and can make the vehicle difficult to drive or lose traction.

Back Pressure
Because the supercharger eliminates the need to deal with the exhaust gas interruption created by inserting a turbocharger turbine into the exhaust flow, the supercharger creates no additional exhaust backpressure. The amount of power that is lost by a turbo's turbine reduces it's overall efficiency.

Noise
The turbocharger is generally quiter than the supercharger. Because the turbo's turbine is in the exhaust, the turbo can substantially reduce exhaust noise, making the engine run quieter. Some centrifugal superchargers are known to be noisy and whistley which, annoys some drivers (we, however, love it!)

Reliability
In general, superchargers enjoy a substantial reliability advantage over the turbocharger. When a a turbo is shut off (i.e. when the engine is turned off), residual oil inside the turbo's bearings can be baked by stored engine heat. This, combined with the turbo's extremely high rpms (up to 150,000rpm) can cause problems with the turbo's internal bearings and can shorten the life of the turbocharger. In addition, many turbos require aftermarket exhaust manifolds, which are often far less reliable than stock manifolds.

Ease of Installation
Superchargers are substantially easier to install than a turbos because they have far fewer components and simpler devices. Turbos are complex and require manifold and exhaust modifications, intercoolers, extra oil lines, etc. - most of which is not needed with most superchargers. A novice home mechanic can easily install most supercharger systems, while a turbo installation should be left to a turbo expert.

Maximum Power Output
Turbos are known for their unique ability to spin to incredibly high rpms and make outrages peak boost figures (25psi+). While operating a turbocharger at very high levels of boost requires major modifications to the rest of the engine, the turbo is capable of producing more peak power than superchargers.

Tunability
Turbochargers, because they are so complex and rely on exhaust pressure, are notoriously difficult to tune. Superchargers, on the other hand, require few fuel and ignition upgrades and normally require little or no engine tuning.

Earl

 

[earlfor]

I forgot to add that for each pound of boost, you will need to flow about
6.8 % more fuel. If you stay at 5 lbs of boost or less, you can use normal 92 octane pump gas and no ignition timing changes (retardation) will be necessary.

Earl

 

[lecroy]

Earl,

They make some good points, but I disagree with most of them when it comes to use on a drag bike.

I agree that lag is the big difference, but I can make pressure without having any load on the engine.

I would rather adjust a wastegate set screw than have to purchase 5 sets of pulleys to get the pressure I want. A modern system would be all computer controlled with EFI.

I would say the overall operating cost for a drag bike is going to be higher for the blower. You need to consider the pulleys, belts, etc.

Because the blower is direct drive, you need to get that drive from somewhere. The turbo is just a lot of plumbing. I would rather install a turbo.

Surge
Because a turbocharger first spools up before the boost is delivered to the engine, there is a surge of power that is delivered immediately when the wastegate opens (around 3000 rpm). This surge can be damaging to the engine and drivetrain, and can make the vehicle difficult to drive or lose traction.

Both of my wastegates are normally closed and open to vent air to regulate pressure. How the boost comes depends on the system. It could be a function of a computer controlling a VGT. For drag use who cares, we want pressure from start to the end. That surge feels so damn good!!

residual oil inside the turbo's bearings can be baked by stored engine heat. This, combined with the turbo's extremely high rpms (up to 150,000rpm) can cause problems with the turbo's internal bearings and can shorten the life of the turbocharger.

Yea, it's a problem. One way around this on a drag bike is an electric pump, accumulator, or just don't shut the engine off right away. I do the last and have had little problems. I still run the old oil bearings and I'm sure the newer ceramic bearings are far better.

But let's face it. A drag engine is not going to last for very many miles anyway. I spoke with a guy not too long ago that made it five seasons on his engine. Let's say he runs every sunday and makes 20 passes at a mile a pass. Let's make it an even 1000 miles a year. It's just not many miles. Rare to hear of one running for five years unless it's a slow bike.

Now, let's get to the real point. Which one looks cooler? I give that to the blower every time!!

A better system is to spray. Simple to install. Low cost. No maintaince. Can be computer controlled. No lag.

I really have never had any oil problems with the drag bike.

 

[earlfor]

I just thought I would post a few points from the other side of the coin, so to speak. They both have their merits. I think youre right in that for a dedicated drag bike, a turbo is the way to go. For a street bike/daily rider and occasional weekend drag bike, I think a supercharger is the better choice.

For the strip, nitrous injection is fine, but I find it lacking in street application where one would want "unlimited always" capability.

Earl

Earl,

They make some good points, but I disagree with most of them when it comes to use on a drag bike.

 

[Nerobro]

If it were me... I would supercharge a motorcycle.

Drag bikes, lag can be your friend. Helping the launch, and helping you maintain control.

Now, allow me to pose a situation to you.

You are just finishing braking for a turn, you just leaned the bike over and you are rolling onto the throttle. You crack the throttle a little, the bike doesn;t seem to respond. As you open the throttle further you get enough air moving through the engine to bring the turbo up to speed, building more boost, and feeding into itself. The bike suddenly is generating 80% more horsepower than it was.

I will let you do the math on what happens after that. It is an extreme case... say a drag turbo on a streetbike. Not a well matched or undersized turbo like I was pointing at in my first post.

With a small enough turbo, lag is nonexistant. (at least in relation to how fast you can move your hand around the throttle)

With a supercharger. Lag is nonexistant. However, depending on the type of supercharger you can be in for a wild ride. Positive displacement blowers would be my boost provider of choice on a bike. They make the same amount of boost, no matter what rpm the engine is spinning. This leads to an easily controled throttle. A positive displacement supercharger works out to being the equivalant of adding cubic inches to the engine.

A centrifugal supercharger. Like you find in many car supecharging kits, are non linear in their responce. They make no boost untill their rotor reaches a certian speed, and the level of boost goes up exponentially with rpm untill you reach the compressors stall rpm. This, I think, would be like riding an old school 2 stroke. I am not sure I would like that.... But at least it would be consistant.

Earlfor: what you posted about supercharging and turbocharging has some pretty big errors. it completely skips over the MAIN reason why intercoolers are used, and trys to explain them away as a byproduct of the compression method used. Not the real reason that a given volume of air has a given amount of heat in it. Compress it to 50% of it's original volume and it will be twice as hot. No matter what compressor you use. It also neglects to mention the reason roots compressors are in disfavor is that they are painfully inefficant. While a good turbocharger setup can return 95% of the energy it uses, a roots style supercharger is somewhere on the order of 45-55% Therefore the huge level of heating that the incoming air charge sees.

The "surge" explantion is completely off it's rocker. And from what I can see about what is being written there is really just lag. It sounds like the author is only familliar with poorly matched turbo setups.

The author also mentions back pressure. While a turbocharged engine looses some horsepower to driving the turbo, so do supercharged engines. That is where the efficancy percentage comes from. In therory if you doubble the air going into an engine, you should get twice the horsepower. This isn;t how it really works out though. With a reasonably matched turbocharger you can expect 75-85% efficancy. With the best centrifugal superchargers you are looking at 70%.

Ease of instalation is questionable as well. But that's a matter of debate. Especially when it comes to motorcycles. (just think about how easy it is to get a new exhaust manifold made, versus cutting a hole in the side cover, attaching a crank extention, building a drive setup, and a bracket to mount the supercharger on....)

 

[LarryT]

GSJimbo Put that turbo on the bike I have been running a turbo for 15 years with no fancy oil pumps.No problems .Only one bearing replaced and no engine problems@27lb boost Very controlable power Most of what has been written in this forum'in my oppinion is just untrue, misinformed ,misleading and probably few have experienced Larry

 

[LarryT]

You are just finishing braking for a turn, you just leaned the bike over and you are rolling onto the throttle. You crack the throttle a little, the bike doesn;t seem to respond. As you open the throttle further you get enough air moving through the engine to bring the turbo up to speed, building more boost, and feeding into itself. The bike suddenly is generating 80% more horsepower than it was.
You would have to have the throttle wide open for this to happen.

 

[lecroy]

27lb boost

8O 8O On gasoline? Water injection or what? Or is that 2 - 7lb boost?

 

[LarryT]

I did use VP C-16 but i didnt make the power(et) i thought it should so i mix VP C-16 with pump gas = 4/10s / 10 mph,5.50 TO 5.10 in the 1/8 mile T he engine and turbo was in a drag chassis. When riding on the street i use pump gas I read about mixing the gas in a motorcycle drag paper

 

[LarryT]

26 degrees timing

 

[Nerobro]

You would have to have the throttle wide open for this to happen.

I was describing turbo lag. Yes it happens at less than full throttle. And yes my description was of an extreme case. On a properly matched engine and turbo combination it really is a non issue. I was just posing an example. 80% more horsepower was what I said. Yes that number was pulled out of my butt but it does not seem unreasonable that a bike that makes 20hp off boost, would be producing 36hp on boost at the same throttle setting.

 

[LarryT]

OK I dont think,I mean i know it wouldnt happen so fast you could lose control. Maybe in some loose gravel

 

[Robert Corrie]

I used to have a cougar thet was turbo-charged,it took a while to get used to where and and when the power would come in after the lag. By "where" I mean what gear. Second gear would put you back in the seat real nice. Third would let you know the boost was there. Fourth and fifth really didn't give you that rush.It took a while to learn how to push the car hard in the twisties, once I got used to it; FUN CITY !! I found out after I got rid of it how early I was on the gas coming out of corners when the new car just wanted to NOT go through corners because I was on the gas WAY to early.One way to help keep it under you is to install a mercury switch that won't let the boost come in if you are leaned over beyond a certain point.

 

[Nerobro]

A mercury or pendulum switch wouldn't do it. From the riders point of view, gravity is always in the direction the tires are. You would need a gyroscope, which doesn't rely on gravity to determin orientation.