I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
Why supercharged 4 cyl is not popular
- Thread starter vulture
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I thought superchargers had more parasitic loss than turbochargers, especially on the low end.
I know the Mini Cooper S's new turbocharged engine is a LOT better than the old supercharged one with the same displacement, but that could be due to many things...
I know the Mini Cooper S's new turbocharged engine is a LOT better than the old supercharged one with the same displacement, but that could be due to many things...
Supercharged, turbo or mechanically driven, gasoline engines are best suited for intermittent high power output. They work well in lightweight and performance cars, in heavier cars where they are on boost much of the time, engine life suffers.
Diesels do much better at sustained boost because their excess combustion air flow keeps internal temperatures down and the combustion profile is different.
Diesels do much better at sustained boost because their excess combustion air flow keeps internal temperatures down and the combustion profile is different.
Offhand I can think of 2 reasons.
1) Superchargers cost more than a turbo. Typically, a lot more.
2) Superchargers are driven off the motor, robbing the engine of 10 - 20 HP. Most 4 cyl engines need every pony they make just to perform halfway decent.
1) Superchargers cost more than a turbo. Typically, a lot more.
2) Superchargers are driven off the motor, robbing the engine of 10 - 20 HP. Most 4 cyl engines need every pony they make just to perform halfway decent.
Originally Posted By: eljefino
Maybe the low compression they need to avoid detonation on boost is a bummer for MPG off boost.
Plus you always have to be feeding 'em high-test.
That's the flip side of what I said. That's how you make them survive under stressful circumstances.
Maybe the low compression they need to avoid detonation on boost is a bummer for MPG off boost.
Plus you always have to be feeding 'em high-test.
That's the flip side of what I said. That's how you make them survive under stressful circumstances.
Spot on guys.
We live near an intersection with a give way sign.
On hot summer's days, you hear prolly 10-20% of the 4 bangers rattle their way off from a standing start (detonation), which you never hear with a six or 8.
The 4 spends more time at a higher percentage load.
We live near an intersection with a give way sign.
On hot summer's days, you hear prolly 10-20% of the 4 bangers rattle their way off from a standing start (detonation), which you never hear with a six or 8.
The 4 spends more time at a higher percentage load.
Originally Posted By: XS650
Supercharged, turbo or mechanically driven, gasoline engines are best suited for intermittent high power output. They work well in lightweight and performance cars, in heavier cars where they are on boost much of the time, engine life suffers.
Diesels do much better at sustained boost because their excess combustion air flow keeps internal temperatures down and the combustion profile is different.
I agree with that somewhat when it comes to daily drivers.
On the flip side, for a daily driver/weekend warrior, there's nothing that's going to get you reliability, power, and streetability all in one package as well as a properly setup turbo car.
I do find it weird that some of these 4 cylinders run around in boost just to get moving from a redlight. For fun, I ran the wastegate open and raced my friend's SOHC 4.0 explorer with no boost. It was too close to call but needless to say I don't need boost just to get the car moving.
Supercharged, turbo or mechanically driven, gasoline engines are best suited for intermittent high power output. They work well in lightweight and performance cars, in heavier cars where they are on boost much of the time, engine life suffers.
Diesels do much better at sustained boost because their excess combustion air flow keeps internal temperatures down and the combustion profile is different.
I agree with that somewhat when it comes to daily drivers.
On the flip side, for a daily driver/weekend warrior, there's nothing that's going to get you reliability, power, and streetability all in one package as well as a properly setup turbo car.
I do find it weird that some of these 4 cylinders run around in boost just to get moving from a redlight. For fun, I ran the wastegate open and raced my friend's SOHC 4.0 explorer with no boost. It was too close to call but needless to say I don't need boost just to get the car moving.
My turbo 4 cyl benchmark car was the VW Passat 1.8 T. Same torque, same HP, same 0-90 kph acceleration with my 2.8 v6. My car slightly heavier and have only 3 sp AT. and considerably more economical. Well, it is also carburated.
We miss that 6 cyl is also one costly technological advance.
We miss that 6 cyl is also one costly technological advance.
Originally Posted By: BuickGN
I do find it weird that some of these 4 cylinders run around in boost just to get moving from a redlight.
They may have taller gearing. My Saab 93 2.0T has tall gearing for the displacement of the engine. Even so, it still has to limit boost in 1st and 2nd gears to maintain traction.
I do find it weird that some of these 4 cylinders run around in boost just to get moving from a redlight.
They may have taller gearing. My Saab 93 2.0T has tall gearing for the displacement of the engine. Even so, it still has to limit boost in 1st and 2nd gears to maintain traction.
Originally Posted By: vulture
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
Originally Posted By: rg200amp
Originally Posted By: vulture
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
I would think the move to a turbo would be more for fuel economy rather than emissions. If anything the turbo zaps a little heat from the exhaust pre-cat.
Originally Posted By: vulture
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
I would think the move to a turbo would be more for fuel economy rather than emissions. If anything the turbo zaps a little heat from the exhaust pre-cat.
Originally Posted By: BuickGN
Originally Posted By: rg200amp
Originally Posted By: vulture
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
I would think the move to a turbo would be more for fuel economy rather than emissions. If anything the turbo zaps a little heat from the exhaust pre-cat.
I read it in an artical on the SS. I can't put my finger on it right now. But it said inorder to meet a new emmissions standard coming in 2010(I believe) they had to axe the supercharger and go with the turbo.
Originally Posted By: rg200amp
Originally Posted By: vulture
I always wonder why automaker don't widely use supercharged 4 cyl, (like the one in Cobalt SS) in compact and intermediate sedan. IMHO, it is the best blend of economy, performance and reliability. You can get 4 cyl gas efficiency if you are easy on gas pedal during city driving. And the power is there when you need it. Also it is easy to maintain compared with a six cylinder and turbo charged 4 cyl.
GM droped the Supercharger and now uses a Turbo on the Cobalt SS for improved Emmissions. Personally, I feel a turbo would be better.
The few reason car makers do not use them on all cars is
-) price
-) Reliability issues/Warranty
I would think the move to a turbo would be more for fuel economy rather than emissions. If anything the turbo zaps a little heat from the exhaust pre-cat.
I read it in an artical on the SS. I can't put my finger on it right now. But it said inorder to meet a new emmissions standard coming in 2010(I believe) they had to axe the supercharger and go with the turbo.
Hi,
vulture - Just another viewpoint to consider - as always it is a case of engineering practice and applicability. Mercedes Benz introduced the first supercharged cars for sale in the 1930s
In the late 1990s MB introduced a small displacement 4 cylinder supercharged engine for the "C" Class cars. They were very good and MB produced 2.5 million of them!
In 2000 MB decided to upgrade that family of engines into a new one called the M271 - it was and is available as in two forms, DI and port injected. It has Lanchester shafts and is still a very advanced and very durable engine family. They have been produced in many millions too
Superchargers are now easier to manange via a "complex" ECM and the M271 runs a master and slave and computer system. Combined with inlet and exhaust valve timing controls the ECM has indeed tamed the supercharger
I have owned a number of these engines and they are very easy on fuel and have good torque charactistics (engine tuned to the intended application of course)
Turbochargers have many application difficulties from a design perspective - superchargers can now be managed very well indeed. As always it is a cost effectiveness question too!
vulture - Just another viewpoint to consider - as always it is a case of engineering practice and applicability. Mercedes Benz introduced the first supercharged cars for sale in the 1930s
In the late 1990s MB introduced a small displacement 4 cylinder supercharged engine for the "C" Class cars. They were very good and MB produced 2.5 million of them!
In 2000 MB decided to upgrade that family of engines into a new one called the M271 - it was and is available as in two forms, DI and port injected. It has Lanchester shafts and is still a very advanced and very durable engine family. They have been produced in many millions too
Superchargers are now easier to manange via a "complex" ECM and the M271 runs a master and slave and computer system. Combined with inlet and exhaust valve timing controls the ECM has indeed tamed the supercharger
I have owned a number of these engines and they are very easy on fuel and have good torque charactistics (engine tuned to the intended application of course)
Turbochargers have many application difficulties from a design perspective - superchargers can now be managed very well indeed. As always it is a cost effectiveness question too!
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It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Originally Posted By: jldcol
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
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Worlds fastest 10.5 inch tired car. Single turbocharged. It has no exhaust!
http://www.youtube.com/watch?v=JKxyHycSEjQ
http://www.youtube.com/watch?v=JKxyHycSEjQ
And a 6 cylinder single turbo addition. I run mine around with no exhaust all the time. It's not *that* loud with the turbo acting as a muffler.
http://www.youtube.com/watch?v=8K15ANt28Gk
I could swear this car has broken 200mph now but I can't find it.
http://www.youtube.com/watch?v=8K15ANt28Gk
I could swear this car has broken 200mph now but I can't find it.
Originally Posted By: Drew99GT
Originally Posted By: jldcol
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
The reason turbos aren't used in Top Fuel is beause the rules won't let them. I know they experimented years ago and had promising results but it would've taken years to fine tune the new combos.
What I find funny is when the centrifugal blower guys talk about turbo lag when in essence they have "lag" all the way to redline.
Originally Posted By: jldcol
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
The reason turbos aren't used in Top Fuel is beause the rules won't let them. I know they experimented years ago and had promising results but it would've taken years to fine tune the new combos.
What I find funny is when the centrifugal blower guys talk about turbo lag when in essence they have "lag" all the way to redline.
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Originally Posted By: BuickGN
Originally Posted By: Drew99GT
Originally Posted By: jldcol
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
The reason turbos aren't used in Top Fuel is beause the rules won't let them. I know they experimented years ago and had promising results but it would've taken years to fine tune the new combos.
What I find funny is when the centrifugal blower guys talk about turbo lag when in essence they have "lag" all the way to redline.
Same with EFI. All rules. I believe the same goes for NASCAR with injection.
Originally Posted By: Drew99GT
Originally Posted By: jldcol
It,s probably more cost effective to do turbo over super-charging especially at the low boost pressures passenger cars use.Supercharges are better at making more pressure than turbo's because if you take to much out of the exhaust stream backpressure on the combustion lowers efficency. Turbo's are more thermodynamically efficent more power for unit fuel burned. Comment's about intermitten power seem correct ie dragsters use blowers and race cars use turbos.
Totally disagree. An exhaust driven centrifugal compressor is much better at making more pressure. And with a turbocharged engine, you want less back pressure! When you install a 2.5 inch or 3 inch mandrel bent exhaust on a factory turbocharged car, you can easily get 5 to 10% more hp.
With any kind of supercharger, the maximum speed of the compressor/rotors is dependent on maximum engine rpm. With a turbocharger, it's not.
Roots type positive displacement blowers are used on top fuel cars a) because they always have, and 2) nitro methane would be hard on a turbocharger.
But the fastest cars in NMCA racing, NMRA, and any class that allows any kind of power adder (short of top fuel) running gasoline (not alcohol) in drag racing all use turbochargers for the most part.
The reason turbos aren't used in Top Fuel is beause the rules won't let them. I know they experimented years ago and had promising results but it would've taken years to fine tune the new combos.
What I find funny is when the centrifugal blower guys talk about turbo lag when in essence they have "lag" all the way to redline.
Same with EFI. All rules. I believe the same goes for NASCAR with injection.
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