Trying to get all the Force Induction experts opinion. If you have the means to install Force induction on your bike. Which one will it be? Super charge or Turbo. I decided instead of piecing my engine together to have available power any given time I decided to go the force induction route. But which one.

 

there is a 20 - 30 hit thread on this in the engine section--it got kinda heated but very interesting reading

 

If money and available parts were no problem, turbo is the best way to go. More power all the way around with a turbo. You get full boost much earlier and carry it all the way to redline. Superchargers are rpm dependant. You only see full boost at max rpm's.

 

In addition to what 05LowRider said is it takes HP to make HP with a SC. Turbos produce free HP.

 

i installed the procharger w/intercooler. i have approx 5000 miles on it and no major issues. i completed the whole job myself in 6 hrs. no exhaust changes. i had someone else tune it. 154 hp. i don't know much about turbos, but the supercharger was a job i could do mostly myself. call frank @ draggosbikeworks, he does both. good luck

 

With all due respect that is a myth! For a turbo to function properly the engine has to be tuned to generate enough surplus energy in the exhaust to drive it. You cannot add a turbo to a stock engine and get much out of it. Much the same applies to a supercharger, that to work well it also needs the engine to be tuned to suit. There is no such thing as a free lunch!

A supercharger works all the time and will give improved performance from idle, but tends to be limited at higher engine speeds. A turbo gives best performance when spinning fast, so the improved performance tends to be further up the rev range. Volkswagon have recently introduced a car engine that has both! If I was fitting one I would choose a supercharger, for its increased torque off the line and accelerating at normal road speeds.

If you are going to buy an add-on kit, you need to read through the advertising hype and see what improvements they each give and what changes you have to make to your motor to fit them.

Have you found any kits that take your eye?

 

Your comments about superchargers apply to positive displacement type superchargers. Centrifugal superchargers behave more like turbos, making more boost as revs climb. I am pretty sure the procharger is a centrifugal supercharger.

Your comments on turbos arent necessarily true either. The turbo doesnt know how fast the engine is spinning. It sits totally separate, spun by the exhaust gas passing thru the turbine nozzle and wheel. Nozzle / wheel size selection determines when the turbo is active. You can size a turbine housing to give you boost at very low revs if you want, and use a wastegate to stop the turbo overreving, it may hold the engine back right up at high revs but it can be done. Volvo did it with their engines a few years back, sized the turbo to give high boost from 1200 -5000 rpm.

Turbos can produce "free" power, but it is very hard to acheive on an engine with a wide rev range. The nozzle of the turbine housing accelerates the gas and squirts it onto the turbine wheel. This acceleration results in back pressure on the exhaust manifold which robs power. As the gas drives the turbine it expands (due to the design of the wheel) and cools (slightly). The energy of the high speed gas combined with the expansion drives the wheel. The way to get free power is to use a large nozzle (for low backpressure) and let the expansion of the gas thru the turbine drive the compressor. that way the resistance to exhaust gas flow is as low as possible. This is only partially acheived in large relitavely fixed rpm motors like generators.

You can add a turbo to a stock motor, I have done it to cars, its less than optimal without turbo cams but its doable. Also you risk excessively straining internals if you run too much boost / not enough fuel (done that too - cracked piston, melted a piston, welded a valve into a head...)

When it comes to bikes you are dealing with multiple issues, the biggest one being lag in my opinion. Riding a laggy turbo bike thru a set of corners must be a total nightmare, opening the throttle, waiting for boost and then when it comes on strong having the bike react badly would test the most skilled rider.

If you are building a drag bike this is irrelevant, but IMHO I would go for supercharging. The compressor is always at the operating speed and so the throttle should be more or less proportional. My bike only has about 123 hp and it tears strips off the rear dunlop on the way out of 2nd and 3rd gear corners. Trying to keep the back wheel from spinning up with a laggy turbo and avioding a highside would be beyond me.

The biggest downside with supercharging is that for most of the time you are wasting fuel driving a supercharger that you arent using. In street use you might spend 2% or less at full throttle, the rest of the time the supercharger is spinning away producing boost that you are destroying with the throttle butterfly. This is why mercedes fit a clutch to the supercharger and a bypass system so that it isnt wasting fuel when cruising.

I would steer you towards a big cube build, personally, but whatever floats your boat. just be sure to post lots of pics for us to check out, and write a bit of a review about what its like to ride when the boost comes on strong.

 

A wise suggestion!

It is easy to be lured into thinking that because a supercharger is driven by the engine (belt or chain or whatever) and a turbo is not, that the turbo gives 'free' performance. It is every bit as dependent on the engine as a supercharger is - they are both parasitic.

 

I considered this route once.When factoring in beefing up bottom end it did not make sense to me.A big inch machine gives you all you want and then some.Whatever floats your boat,good luck

 

Hot Bike fitted a Pro-Charger kit to a TC88 and increased power from 61HP to 106HP, with only a small torque increase low down. There are several tuning shops on HDF who can supply engine upgrades that will match or better that!

Kit seems to cost around $5k plus fitting, so it is certainly worth considering other options.