Nutty idea???

[Jonny Hotnuts]

Lets say you mount a turbo on a NA engine.
On this engine you remove the compressor side of the turbo.
On the shaft to the remaining turbine you connected a drive mechanism (belt, gear or other) that would mechanically drive the turbine faster than it would spin with the exhaust flow spinning it with 100% efficiency.

I would think that you could (especially with proper cam timing) be able to gain motor efficiency by reducing pumping losses (and even go into positive numbers) to increase HP on any NA motor without calling it supercharged. I am not sure but I could also see that with cam timing overlap you could also begin bringing in air/fuel into the cylinder.


I am not suggesting I am going to try this.....
I am only bringing this concept up for discussion on the viability of the concept.

BTW:
If anyone sets a record using this....remember where you heard of it and make sure to call it the "hotnuts suck charger".

~JH


 

 

[McRat]

Sounds like a really cool experient.   

For LSR, first problem would be convincing someone it was not "turbo-compounding" which I guess is illegal.  It would look just like it.

Creating a partial vacuum at the exhaust port during the exhaust cycle is normally done by the design of the exhaust header.  You might even make things worse by trying to scavenge with a pump. 

[Rex Schimmer]

JHN,
How fast do you think the turbo on you motor turns? Probably over 100,000 rpm at big boost so to get the compressor driven up to this speed you would need to have probably a 10:1 ratio between the engine crank and the compressor snout. That will typically require at least a pulley ratio and one gear set that will give you the 10:1 ratio. And if you look at it this is exactly what people like Pro-Charger are doing.

I have proposed several times on this forum that you need to mount a Pro-Charger on your engine and then the hot side of a turbo, and make it BIG, then connect a shaft between the turbine and the Pro-Charger with a sprag type over riding clutch. So the engine drives the blower but when the exhaust driven tubine gets up to speed it will start driving the blower and if it is really large it will also start driving the engine thru the blower's drive system. This is a compound engine. And remember at 60,000 rpm it only takes an additional 100 inch- pounds of torque from the turbine to make 100 hps being added to the engine crank. Now this would be efficient as you are using heat from the exhaust, which is approx 35% of the total power made by the engine, to drive both the compressor but also the engine.

Only time and money prevent me from doing this!!!
Mostly money!!

Rex

[Stan Back]

I'd think that if you hooked a supercharger or turbocharger to the intake or exhaust and were driving it -- it would be supercharged to the SCTA.

Stan

[Jonny Hotnuts]

I'd think that if you hooked a supercharger or turbocharger to the intake or exhaust and were driving it -- it would be supercharged to the SCTA.

Stan

Stan, I hear ya.

But every definition of "supercharger" states that it is a device to force air "INTO" a motor. I could see an argument for saying that there is nothing about a vacuum device to suck air out.

If I were a SCTA official....I would have a problem with it!

JHN,
How fast do you think the turbo on you motor turns? Probably over 100,000 rpm at big boost so to get the compressor driven up to this speed you would need to have probably a 10:1 ratio between the engine crank and the compressor snout. That will typically require at least a pulley ratio and one gear set that will give you the 10:1 ratio. And if you look at it this is exactly what people like Pro-Charger are doing.

Pro-Charger, Vortex, Paxton....these are all models of how I thought the experiment unit could be driven....that and a larger than needed turbine section if it was used as a traditional turbo on that engine.  Maybe something off a big diesel truck? 

[Peter Jack]

My thought is that you'd get the mixture through faster, but it's on the wrong side so wouldn't be able to compress any air in the cylinder once the exhaust valve had closed. I think the boost would be minimal and you'd still have the parasitic drive using up power. Might be a loss rather than a gain.

Just my thoughts.

Pete

[RichFox]

If you really want to do this i have a Mack turbocharger that is pretty big or one off of an 8:92 Detriot that I could donate to the effort.

[joea]

....pushing it in, or pulling it in  is still creating a super-charge.........

and definately not normally aspirated...

[Peter Jack]

I'm just saying that the effect is on the wrong side of the valve so that you'd get a vacuum after the valve rather than a compression before it. I doubt that there would be very much benefit if at all.

Pete

[McRat]

I doubt it could beat tuned-length headers.  Still sounds fun though.

And yes, you'd have to use the compressor side of the turbo.  Hay goes in the other end of the horse.

[HotRodV8]

My thought is that you'd get the mixture through faster, but it's on the wrong side so wouldn't be able to compress any air in the cylinder once the exhaust valve had closed. I think the boost would be minimal and you'd still have the parasitic drive using up power. Might be a loss rather than a gain.

Just my thoughts.

Pete

To compress any more air in the cylinder you would have to rethink all intake manifolds that work with a "vacuum exhaust system." Meaning, some type of NA intake system such as those Ram-Air manifolds on Dodges and Plymouths back in the mid 1960's to take advantage of the exhaust suction. No? Perhaps a gain of power then.

[Dean Los Angeles]

Joe hit it on the head. "Normally aspirated" are the words that kill this idea.

You can word it and re-tinker it any way you want, it won't pass in unblown class.

If you say "why?" the gods of SCTA say "because I said so."

[MattS]

Page 46 of the 2009 rulebook.

4.FF

Nope.


Matt

[Milwaukee Midget]

Jonny, I got to hand it to you - I'll be thinking this one over for a couple of days.

The question is if you could really get the converted compressor/vacuum-extractor turning fast enough to completely evacuate the cylinder of any remaining exhaust, and thus completely fill the cylinder with a clean charge.  A full, clean cylinder charge would be an advantage. 

The problem I see is that you'd be trying to extract a gas that's still expanding as it leaves the exhaust port, and thus, as both RPM and heat increase, so does the need for the vacuum extractor to turn proportionally faster to draw higher vacuum than the approaching exhaust.

It might fatten up a torque curve at low RPM and make your cam sound less lumpy, but I suspect the advantage would fall off at high RPM's.

[robfrey]

I agree with Pete.