turbo or super

[Irace86.2.0]

Originally Posted by FR-S2GT86

I've been pondering this for quite a while now, but thinking of the positive displacement supercharger set ups that are available for the twins:

What if one could reduce the parasitic load on the engine that the supercharger draws, to almost nothing as engine RPM's increase, by installing an exhaust-driven turbine in addition to the supercharger, which spins a gearbox, which then spins a pulley to drive a belt that spins an overrunning clutch pulley, which is mounted to the supercharger's drive pulley?

In theory, at low engine RPM's, the supercharger would be providing the immediate low-end boost and as the RPM's increase, the turbine gradually spins up and takes over the torque demand of the supercharger.

The key part would be the overrunning clutch pulley to allow the engine driven belt for the supercharger to initially spin the supercharger's drive shaft, and then as the turbine and its gearbox gradually takes over, the turbine assembly's belt would take over, spinning the supercharger's drive shaft, but just BARELY faster than the engine's serpentine belt would at top RPM.

Something like this:

which can be found here:

https://www.hilliardcorp.com/overrunning-clutches/

This set up could again, in theory, eliminate the parasitic draw of the supercharger, increasing available torque to the drive train.

Basically, this is a turbine-driven, positive displacement (this could even be applied to a centrifugal) supercharger with little to no parasitic loss to the engine, combining the two best advantages of both a supercharger 1) immediate low-end boost from the engine, and a turbocharger 2) free horsepower and torque from the exhaust gasses.

This is not twincharging, as the intake air is not compressed in two separate stages.

The only disadvantages of this set up that I can think of would be 1) slightly more weight, which would be immediately negated by greater available drive train torque, 2) higher under-hood temperatures, which can be dealt with as one would normally do with a turbo set up, and 3) a slightly more complex set up.

I think this is totally do-able with the right parts, which are already available, and by a persistent and innovative individual (with obviously deep pockets).

When you say it could be added to a centrifugal supercharger, well, then isn't that just a turbocharger that is more complex and inherently less efficient? Most manufactures would probably just add an electric supercharger or mild-hybrid system with a belt alternator starter (BAS) to torque fill down low and then use a traditional turbocharger for up high. This is what multiple manufactures are doing.

https://www.greencarcongress.com/201...180411-a6.html

I think the best, simplest and most elegant supercharger solution that was already mentioned is the electronically-controlled, variable-geometry pulley, which can essentially create a small-pulley high-boost-map for more power down low, and it can taper off boost by creating a large-pulley low-boost-map for less power up high. This means the supercharger never has to over-spin or bleed boost.

[FR-S2GT86]

Originally Posted by Irace86.2.0

When you say it could be added to a centrifugal supercharger, well, then isn't that just a turbocharger that is more complex and inherently less efficient? Most manufactures would probably just add an electric supercharger or mild-hybrid system with a belt alternator starter (BAS) to torque fill down low and then use a traditional turbocharger for up high. This is what multiple manufactures are doing.

https://www.greencarcongress.com/201...180411-a6.html

I think the best, simplest and most elegant supercharger solution that was already mentioned is the electronically-controlled, variable-geometry pulley, which can essentially create a small-pulley high-boost-map for more power down low, and it can taper off boost by creating a large-pulley low-boost-map for less power up high. This means the supercharger never has to over-spin or bleed boost.

I'm speaking of what we as consumers can do to improve our EXISTING FI systems. With what I am describing, there are no electronics, no electrical connections and no batteries involved. It's purely mechanical. This would be something a home mechanic would be able to piece together with existing parts that are already out on the market.

You're talking about something that would have to be mass-produced by a vehicle manufacturer that adds electric motors, additional batteries and a redesigned charging system. Why turn mechanical energy into electrical energy just to turn it back to mechanical energy, when the first two steps can be eliminated?

The first video you posted above is addressing turbo lag, I'm addressing supercharger parasitic load of an already existing and installed supercharger unit which eliminates the lag in the first place.

The second video seems to be focusing mostly on fuel efficiency and regenerative electrical production, I'm addressing performance by freeing up the power and torque at high RPM's which would normally be needed of your engine by the supercharger and that you are already producing anyways, to make it available to the drive train instead. (Besides, would you really ever want anything designed by Chrysler/Fiat to be bolted up to your engine?)

[86TOYO2k17]

Originally Posted by FR-S2GT86

I'm speaking of what we as consumers can do to improve our EXISTING FI systems. With what I am describing, there are no electronics, no electrical connections and no batteries involved. It's purely mechanical. This would be something a home mechanic would be able to piece together with existing parts that are already out on the market.

You're talking about something that would have to be mass-produced by a vehicle manufacturer that adds electric motors, additional batteries and a redesigned charging system. Why turn mechanical energy into electrical energy just to turn it back to mechanical energy, when the first two steps can be eliminated?

The first video you posted above is addressing turbo lag, I'm addressing supercharger parasitic load of an already existing and installed supercharger unit which eliminates the lag in the first place.

The second video seems to be focusing mostly on fuel efficiency and regenerative electrical production, I'm addressing performance by freeing up the power and torque at high RPM's which would normally be needed of your engine by the supercharger and that you are already producing anyways, to make it available to the drive train instead. (Besides, would you really ever want anything designed by Chrysler/Fiat to be bolted up to your engine?)

Subscribing if you actually do this.

[FR-S2GT86]

Originally Posted by 86TOYO2k17

Subscribing if you actually do this.

I'm just throwing the idea out there. If I had deep enough pockets and a big enough shop with a dyno, as well as all the time that would be needed, I would do this. But as things are right now, I'm just slowly getting my car built little by little.

[Irace86.2.0]

Originally Posted by FR-S2GT86

I'm speaking of what we as consumers can do to improve our EXISTING FI systems. With what I am describing, there are no electronics, no electrical connections and no batteries involved. It's purely mechanical. This would be something a home mechanic would be able to piece together with existing parts that are already out on the market.

You're talking about something that would have to be mass-produced by a vehicle manufacturer that adds electric motors, additional batteries and a redesigned charging system. Why turn mechanical energy into electrical energy just to turn it back to mechanical energy, when the first two steps can be eliminated?

The first video you posted above is addressing turbo lag, I'm addressing supercharger parasitic load of an already existing and installed supercharger unit which eliminates the lag in the first place.

The second video seems to be focusing mostly on fuel efficiency and regenerative electrical production, I'm addressing performance by freeing up the power and torque at high RPM's which would normally be needed of your engine by the supercharger and that you are already producing anyways, to make it available to the drive train instead. (Besides, would you really ever want anything designed by Chrysler/Fiat to be bolted up to your engine?)

What you’re proposing would require a lot of customization and cost for little gain, which is why I mentioned manufacturers. They care more about 3 mpg loss or gain in fuel economy (hypothetical) or the warranty of a supercharger or managing excess heat, while keeping costs and packaging manageable. Most people would rather add more cooling capacity and call it a day or switch to a turbo system than retrofit a custom exhaust manifold, custom half a turbo with output shaft, gear and belt and everything else. I get the idea of using wasted exhaust gasses to help spin a belt, so the parasitic energy from the supercharger is balanced out, but your setup is so close to a turbocharged setup that dual charging seems easier and cheaper to do for the lay person, and it would probably outperform your setup in other aspects. For instance, that same exhaust energy could generate boost and thus horsepower probably more efficiently than it could assisting with driving a belt.

Also the point was to mention inherent benefits and drawbacks to each system. I wasn’t quantifying the impact of any of these things.

The cheapest supercharger solution would be to buy a variable pulley supercharger like in the video above and build custom brackets since no one is offering an off-the-shelf kit for the 86. I posted a video from Torotrak, but Procharger also has a CVT-like supercharger:

https://www.enginelabs.com/news/insi...ng-technology/

Just FYI, many other manufacturers are using BAS setups like Audi. Obviously, such systems could be custom added to any vehicle, but these are more for OEMs, which again, is what I assumed you were referring to in a hypothetical situation; I didn’t think you were thinking someone would actually build something one-off for their setup in a cost-beneficial way.

[FR-S2GT86]

Originally Posted by Irace86.2.0

What you’re proposing would require a lot of customization and cost for little gain, which is why I mentioned manufacturers. They care more about 3 mpg loss or gain in fuel economy (hypothetical) or the warranty of a supercharger or managing excess heat, while keeping costs and packaging manageable. Most people would rather add more cooling capacity and call it a day or switch to a turbo system than retrofit a custom exhaust manifold, custom half a turbo with output shaft, gear and belt and everything else. I get the idea of using wasted exhaust gasses to help spin a belt, so the parasitic energy from the supercharger is balanced out, but your setup is so close to a turbocharged setup that dual charging seems easier and cheaper to do for the lay person, and it would probably outperform your setup in other aspects. For instance, that same exhaust energy could generate boost and thus horsepower probably more efficiently than it could assisting with driving a belt.

Also the point was to mention inherent benefits and drawbacks to each system. I wasn’t quantifying the impact of any of these things.

The cheapest supercharger solution would be to buy a variable pulley supercharger like in the video above and build custom brackets since no one is offering an off-the-shelf kit for the 86. I posted a video from Torotrak, but Procharger also has a CVT-like supercharger:

https://www.enginelabs.com/news/insi...ng-technology/

Just FYI, many other manufacturers are using BAS setups like Audi. Obviously, such systems could be custom added to any vehicle, but these are more for OEMs, which again, is what I assumed you were referring to in a hypothetical situation; I didn’t think you were thinking someone would actually build something one-off for their setup in a cost-beneficial way.

Although the variable pulley supercharger is an interesting design, seeing the technology already being used in vehicle transmissions with somewhat iffy reliability results, (I'm thinking Jatco CVT's in Nissan vehicles) I would have serious doubts about the overall reliability of that particular technology within the Procharger over an extended period of time. But time will surely tell once they are out on the market. Maybe they'll be more reliable than the Edelbrock kits, maybe they'll be worse. I can almost guarantee you that they won't be as reliable as our Harrop kits. One thing for certain is that they WILL cost even more than their standard supercharger as the rep stated in the video you provided.

Another thing I see about the variable pulley supercharger, is that whenever boost is needed, and wherever in the RPM band, parasitic draw on the engine will still always exist. Low demand for boost, like in a standard fixed pulley supercharger, will mean a low draw, and high demand for boost will mean a high draw. What I'm proposing would reduce the draw on the engine completely (ideally) at high demand. This would have the added benefit of less strain on the engine internals.

You are correct in pointing out the higher cost, which I pointed out already, but the two combined technologies I'm proposing are already tried and true and have been for decades. There is already an understanding of both out in the field of how they work and what things to expect to have to deal with when using them, with the exception of mounting a drive pulley to the gearbox instead of a compressor, but I would think that would simplify the build somewhat. And with the higher cost will come higher reliability, not only of the engine, but the bolt-ons as well.

I seriously think my idea would be much more reliable in the long term than any type of electronically-controlled variable pulley drive system, as long at it is designed properly. I doubt those rollers or electronic actuators inside the Procharger will hold up to years of even just normal wear and tear.

The good thing is, the standard Procharger supercharger is a tried, tested and reliable design, and its gearbox would be a good candidate to modify in the set up that I'm describing. The desired final supercharger drive shaft speed could be as simple as experimenting with different combinations of gearbox, pulley size, belt size and possibly overrunning clutch pulley size. It will certainly take time in developing, but what good product doesn't?

[Irace86.2.0]

Originally Posted by FR-S2GT86

Although the variable pulley supercharger is an interesting design, seeing the technology already being used in vehicle transmissions with somewhat iffy reliability results, (I'm thinking Jatco CVT's in Nissan vehicles) I would have serious doubts about the overall reliability of that particular technology within the Procharger over an extended period of time. But time will surely tell once they are out on the market. Maybe they'll be more reliable than the Edelbrock kits, maybe they'll be worse. I can almost guarantee you that they won't be as reliable as our Harrop kits. One thing for certain is that they WILL cost even more than their standard supercharger as the rep stated in the video you provided.

Another thing I see about the variable pulley supercharger, is that whenever boost is needed, and wherever in the RPM band, parasitic draw on the engine will still always exist. Low demand for boost, like in a standard fixed pulley supercharger, will mean a low draw, and high demand for boost will mean a high draw. What I'm proposing would reduce the draw on the engine completely (ideally) at high demand. This would have the added benefit of less strain on the engine internals.

You are correct in pointing out the higher cost, which I pointed out already, but the two combined technologies I'm proposing are already tried and true and have been for decades. There is already an understanding of both out in the field of how they work and what things to expect to have to deal with when using them, with the exception of mounting a drive pulley to the gearbox instead of a compressor, but I would think that would simplify the build somewhat. And with the higher cost will come higher reliability, not only of the engine, but the bolt-ons as well.

I seriously think my idea would be much more reliable in the long term than any type of electronically-controlled variable pulley drive system, as long at it is designed properly. I doubt those rollers or electronic actuators inside the Procharger will hold up to years of even just normal wear and tear.

The good thing is, the standard Procharger supercharger is a tried, tested and reliable design, and its gearbox would be a good candidate to modify in the set up that I'm describing. The desired final supercharger drive shaft speed could be as simple as experimenting with different combinations of gearbox, pulley size, belt size and possibly overrunning clutch pulley size. It will certainly take time in developing, but what good product doesn't?

Maybe you didn’t notice, but that video is 7 years old. They have been on the market. They do cost more, but they do more, so it is what it is. It allows for more boost down low with a flatter torque curve up high for people who have a fuel/boost/block-strength limit all while being more efficient and while generating less heat and this reducing the chance of knock.

I think the biggest obstacle for your design would be mounting the exhaust turbine to an exhaust manifold with good tolerances and then having that interface with a pulley in a good packaging situation. I don’t know if you were thinking that there would be a custom output shaft mounted at a distance to a gearbox or if it would be mounted to the turbine like a centrifugal supercharger, but if it is the latter then there may be heat concerns for the components. It is an interesting idea.

[Jaden]

Originally Posted by Irace86.2.0

Also, do a turbo if you want to do boost-by-gear, boost-by-rpm, multiple boost maps, etc. It is also easier to run a turbo with FlexFuel/E85, especially when E85 is not always available; I would need to swap pulleys if I couldn't get E85 or drive around without going into boost or something, but a turbocharged car could just do boost-by-fuel by either limiting boost or just running a completely separate map. Finally, you can always swap to a different sized turbo or vary exhaust and compressor sizes if you are not happy with your turbo profile. You can swap superchargers too, but it isn't always as easy or an option. The JRSC has the C30 and C38, but the Edelbrock kit doesn't offer a different sized blower. It is typically much easier to option a turbocharger of your desire during an initial purchase, and it is easier to make a swap later--typically.

For flex fuel on a supercharger, you can just drop the timing and you should be fine unless you're running a tiny pulley and immense boost...

Jaden

[Irace86.2.0]

Originally Posted by Jaden

For flex fuel on a supercharger, you can just drop the timing and you should be fine unless you're running a tiny pulley and immense boost...

Jaden

Oh, of course, but that isn't as good as swapping to a lower boost level like on a turbo. My car wasn't too happy with 91 pump gas at 85mm (11.5 psi) pulley, especially on hot days or when pushed. It would break up some up top. I have never driven it on 91 with the 75mm (14.5 psi) pulley. I definitely wouldn't feel comfortable driving aggressively like that on 91, so a turbo would definitely be better because I wouldn't have to change my driving like I mentioned.

Also, when not on E85 with advanced timing and high boost, pulling timing with high boost might result in the same power or knock resistance as advanced timing on low boost, but the lower boost level will have better EGTs, less heat and less cylinder pressure for the same horsepower. It will have better fuel economy too, so while it may be done on a supercharger, the turbo would be better with flex fuel.

[DarkPira7e]

I think after this, OP will be buying a canoe to simplify his life

[x808drifter]

Originally Posted by DarkPira7e

I think after this, OP will be buying a canoe to simplify his life

Wood or Carbon paddle?

[DarkPira7e]

Originally Posted by x808drifter

Wood or Carbon paddle?

We need to know OPs demographic and how harsh the waters are I think. Also, if they wear gloves or bareback the paddle. And if they have a dog(s). I give up, life is too complicated

[Jaden]

Originally Posted by Irace86.2.0

Oh, of course, but that isn't as good as swapping to a lower boost level like on a turbo. My car wasn't too happy with 91 pump gas at 85mm (11.5 psi) pulley, especially on hot days or when pushed. It would break up some up top. I have never driven it on 91 with the 75mm (14.5 psi) pulley. I definitely wouldn't feel comfortable driving aggressively like that on 91, so a turbo would definitely be better because I wouldn't have to change my driving like I mentioned.

Also, when not on E85 with advanced timing and high boost, pulling timing with high boost might result in the same power or knock resistance as advanced timing on low boost, but the lower boost level will have better EGTs, less heat and less cylinder pressure for the same horsepower. It will have better fuel economy too, so while it may be done on a supercharger, the turbo would be better with flex fuel.

Except I'm finishing up a flex fuel supercharger with a total cost of around $500, try that with a turbo...lol

Jaden

BTW, the $500 includes the $156 it cost me to add flex fuel already.

[Irace86.2.0]

Originally Posted by Jaden

Except I'm finishing up a flex fuel supercharger with a total cost of around $500, try that with a turbo...lol

Jaden

BTW, the $500 includes the $156 it cost me to add flex fuel already.

How would a turbo be different?