Ruh roh!

[Anler]

How turbos can make more power

By: Kent Lester, Photo By: Mike Lester 
10/22/2018 

 

There's been so much feedback on the fact Ski-Doo’s new turbocharged G4s net out less power than Yamaha and Cat's Turbos, it puts a lot of focus on turbochargers in general. 

Here are a few points to consider: 

1. Turbochargers, which spin in the 100,000 RPM range, are actually air compressors that cram pressurized oxygen (air is mostly oxygen) into an engine's combustion chamber. Simply stated, the result is there's a lot more oxygen in the cylinder and when the spark plug lights it off in the presence of gasoline, it makes a bigger bang. 

2. This bigger bang effect mostly affects torque. There is a horsepower increase, but the most substantial benefit is that the torque generated by a turbocharged engine is higher than one that is naturally aspirated (carb or EFI). 

3. Not only is the amount of torque higher when a turbo is used but it stays relatively consistent across the whole power curve. Thus turbo engines deliiver more torque from just off idle right up to max RPM. This makes for some very interesting opportunities for clutching and gearing. 

 

4. In modern engines, turbo pressure, or boost, is regulated by a valve-like device called an electronic wastegate. This system stops the turbo pressure from getting too high – or too low. These electronic wastegates are the reason the newer turbocharged engines maintain such consistent torque as the engine spools up revs - the boost is close to the same all the time. 

Older turbo engines used to have mechanical wastegates to control boost, popping off pressure when it went beyond the regulated boost level. These were pretty inconsistent at operating across the full RPM range but did well at higher RPMs. 

5. Most snowmobile OEMs set turbo pressure at realistic (low) levels to conserve engine life. Even a 2-pound boost can completely change the way a turbo engine makes power. 

6. Usually, modifying the amount of boost a turbo engine makes requires a change to the engine's ECU (computer). There are aftermarket computer chips that mess with fuel flow, boost pressure and the wastegate and then adjust the engine’s timing to accommodate. 

These are actually pretty reliable (get references) and as long as you don't go too crazy with the boost, will not harm your engine. 

7. After making an ECU mod (new computer chip) you’ll likely need to modify your clutching - and maybe even your gearing - to get full benefit from the power increase. 

8. Have fun! 

[steve from amherst]

No clutching?

[Jimmy Snacks]

Well played! 

[Dave]

Kill yourself!!!!

[dz246]

 

[Zambroski]

[Mainecat]

WUT?

 

[ActionfigureJoe]

Of course new clutching will be required. What fucking moron says otherwise? 

[ArcticCrusher]

[Woodtick]

[f7ben]

12 minutes ago, ActionfigureJoe said:

Of course new clutching will be required. What fucking moron says otherwise? 

Good clutching on a turbo is good clutching. Little need to change it when adding power a lot of times

[DriftBusta]

  

[f7ben]

Fucking Lester's might as well just quote dripper as a source

[Woodtick]

1 minute ago, f7ben said:

Fucking Lester's might as well just quote dripper as a source

Enjoy your big tall glass of being owned this morning.

[ActionfigureJoe]

4 minutes ago, f7ben said:

Good clutching on a turbo is good clutching. Little need to change it when adding power a lot of times

Turbos lay down thick gobs of torque and horsepower throughout the power band. A turbocharged motor is no doubt more forgiving when it comes to clutching, but to get all those hard earned dollars to the track, a turbo motor ideally needs to be re-clutched. 

[f7ben]

4 minutes ago, ActionfigureJoe said:

Turbos lay down thick gobs of torque and horsepower throughout the power band. A turbocharged motor is no doubt more forgiving when it comes to clutching, but to get all those hard earned dollars to the track, a turbo motor ideally needs to be re-clutched. 

Your missing the most important part of the equation. With a turbo motor you are no longer constricted by an rpm peak. You can simply let the motor run 1000 rpm more and your clutching that was good at 8k will still be good at 9k with 100 more hp driving it

Edited March 3, 2019 by f7ben

[DriftBusta]

Start by adding more weight in the weights, from the heel to the tips.

[ActionfigureJoe]

Just now, f7ben said:

Your missing the most important part of the equation. With a turbo motor touch are no longer constricted by an rpm peak. You can simply let the motor run 1000 rpm more and your clutching that was good at 8k will still be good at 9k with 100 more hp driving it

That's what I just said. Stop being such a know it all.  

There's other issues that will show up. Like belt slippage, typically in the secondary, through the mid. Put a turbo moto vs a non-turbo motor on a track dyne and you'd see that. 

[f7ben]

Just now, ActionfigureJoe said:

That's what I just said. Stop being such a know it all.  

There's other issues that will show up. Like belt slippage, typically in the secondary, through the mid. Put a turbo moto vs a non-turbo motor on a track dyne and you'd see that. 

I'll take the pros word for it who rides the fastest and most expensive trail sled in the world.....sorry

[washedupmxer]

[BOHICA]

It says to get “full benefit”....  so you get 100% of the benefit of the mod vs 99% of the benefit you get by not messing with the clutching.  Nobody is going to mess with clutching based on power as it will vary through out the day.

Edited March 3, 2019 by BOHICA

[Dave]

[ActionfigureJoe]

6 minutes ago, BOHICA said:

It says to get “full benefit”....  so you get 100% of the benefit of the mod vs 99% of the benefit you get by not messing with the clutching.  Nobody is going to mess with clutching based on power as it will vary through outthe day.

 

[XC.Morrison]

The article is erroneous in point #1 when they state that air is mostly oxygen.  In truth, it’s 78% nitrogen and only 21% oxygen.  

[SSFB]

Somebody inform the author that air is not “mostly oxygen”.