Why either Supercharging or Turbocharing?

[Trav]

Quote:
The engine still has to do work to force the turbine to spin and turn the compressor, as there's not free lunch when moving power.

True but the Turbo is a lot cheaper lunch by far. Parasitic drag is minimal with the turbo, the energy it uses in the form of exhaust gasses has already been used by the engine.
There maybe a slight increase in back pressure and additional heating of the oil requiring a higher viscosity of oil but that's about it.

 

[Spazdog]

Originally Posted By: 45ACP
Originally Posted By: Bamaro
Aren't turbochargers generally harder on the oil?


Yeah but so what! Just use Mobil 1 0W-40 or a dino 20W-50 like some do. (Make that 5W-50 if it were me.)


My turbo car is spec'd for 10W30

It hasn't had 10W30 in it since 5000 miles. It has been on exclusively 5W30 Synthetic. Not even premium "boutique syn". It was mostly Pennzoil Platinum until I ran across SM Quaker State QHorsepower at Autozone for $1.99 qt. I bought all they had and just used the last of it.

And it's not the low boost model either. It's 99% Neon SRT/4 under the hood.

 

[sciphi]

My Cruze specs dexos1. That's basically a fancier version of synthetic API SN 5w30. Nothing too exotic or pricey.

 

[HerrStig]

Diesels which have no throttle plate are a "natch" for turbos, and the power curves match well with torque converters. Piston aircraft engines, where the power settings are not constantly changing are as well. In WWII, (not that I am THAT old) the big and pretty crude radials in bombers and the P 47 fighter were turbocharged while the V12 Merlins in Hurricanes, Spitfires and P 51's were supercharged. It was a good thing the P 47 was a BIG airplane, the turbo installation took up a LOT of room and was mounted BEHIND the pilot with a bunch of duct work.
Turbos are a good way to get power, but perhaps not low end torque, out of a small engine, but you gotta keep up with the oil changes. If you consider what the operating conditions are for the exhaust side of a turbo, it's a wonder they last as long as they do. I wonder about the new Ford turbo gas pickups---they get good power from the smaller engine and I suppose the engine management system keeps them from being abused while towing, but small displacement and turbo doesn't seem to be truck material.

 

[Norm Olt]

Remember the Volvo and Saab Turbo's of the '80's?

Only remember one of my friends who bought one ever buying a second one...

Could it be more evidence that the car makers just want to make things so complex, so expen$ive, so difficult to repair (if even repairable at all!) that you'll just buy a new car (or start a new lease) rather than have to deal with any problems that may arise "post-warranty"?

 

[bruno]

Low end torque depends on the size of the turbo . My 99 Passat has a turbo engine that delivers max torque from 1700 rpm up to 4800 . The early turbo cars were set up for horsepower rather than torque .

 

[SteveSRT8]

Yes, no one should get the idea that turbos are only for high rpm gains.

One popular gas engine has peak torque at 1500 rpm!

 

[Kiwi_ME]

Volkswagen use turbos on their rest-of-the-world gasoline engines to get a good mixture of economy vs power. They have a 1.2 and 1.4 turbo, and a 1.4 turbo+SC amongst others. The 1.4 turbo-only for example reaches peak torque at 1600, is flat all the way to 4000 rpm and develops 120 hp peak. It has an air-to-liquid intercooler build into the intake manifold.

For diesel engines "supercharging" (either super- or turbo-) is essential these days to get enough excess air to meet even basic emissions. Power density can also be vastly improved.

In the end, what provides the most power in a petrol engine is only the volume of air and fuel contained in the combustion chamber at the maximum pressure that avoids pre-ignition. The engine bits beforehand provide the "compression" before combustion and the bits afterwards provide the "expansion" after combustion.

The trick is to optimize how those pressure ratio contributions are distributed among pistons, turbines, etc, such that the most net mechanical power can be derived via the piston and crank portion during expansion.

 

[sciphi]

My Cruze will make at least 4 PSI of boost at 1500 RPM or so if it's floored. It's enough to keep speed up a mild to moderate hill. Yeah, it's fun to rev it for peak torque. However, the drivability benefits of having some torque available down low are large. I like how it doesn't need the snot revved out of it to go up most hills.

 

[artificialist]

Originally Posted By: Norm Olt
Remember the Volvo and Saab Turbo's of the '80's?

Only remember one of my friends who bought one ever buying a second one...

Could it be more evidence that the car makers just want to make things so complex, so expen$ive, so difficult to repair (if even repairable at all!) that you'll just buy a new car (or start a new lease) rather than have to deal with any problems that may arise "post-warranty"?


The reason so many 80s turbo cars were a pain was because nobody was told to idle the engine for 2 minutes before shutdown, no engine specified synthetic oil, and turbochargers were only cooled by engine oil. This is why so many engines that were basically good were destroyed by sludge.

Volvo and SAAB turbo engines were actually better than most.

 

[Kiwi_ME]

I owned an '82 Saab 900 turbo as a hobby car, the first I understood to have electronic boost control. I can certainly see how the turbo could be damaged as mentioned if the driver was not aware of the precautions needed. I put a timer on the radiator fans so I could run them for a few minutes after stopping.

 

[Spazdog]

Originally Posted By: artificialist
Originally Posted By: Norm Olt
Remember the Volvo and Saab Turbo's of the '80's?

Only remember one of my friends who bought one ever buying a second one...

Could it be more evidence that the car makers just want to make things so complex, so expen$ive, so difficult to repair (if even repairable at all!) that you'll just buy a new car (or start a new lease) rather than have to deal with any problems that may arise "post-warranty"?


The reason so many 80s turbo cars were a pain was because nobody was told to idle the engine for 2 minutes before shutdown, no engine specified synthetic oil, and turbochargers were only cooled by engine oil. This is why so many engines that were basically good were destroyed by sludge.

Volvo and SAAB turbo engines were actually better than most.


Nobody told us then

Credit where credit is due to SAAB for making the Triumph Dolomite Sprint/TR7 motor resemble something reliable. Especially with a turbocharger.

'80s turbocharged cars also had some design faults. Notably the 4G54 Mitsubishi with MCA Jet valves. The ROTW got the 4G63. I read somewhere Canadian Starion/Conquests were MCA Jet delete heads. But the USA got the bad heads. Go fast, car goes boom and issues white cloud worthy of 3-Mile Island, replace head, repeat.

The Pontiac Sunbird GT/Skyhawk T-Type seemed to be short lived engines too. The regular 2 liter OHC engine would destroy cylinder heads prematurely and it doesn't appear that GM made any improvements to the head when they turbocharged it. But it did make more horsepower than a TurboI Chrysler....for a short time until it handgrenaded it's head.

Same thing with the Isuzu Impulse.

I don't know if the Thunderbird Turbo Coupe was better built than the later Super Coupe. I dislike the Essex 3.8 V6 from that era so my opinion is it is better built. All I know is that I still see Turbo Coupes. I seldom see Super Coupes. In fact, if I see a 10th gen T-bird, it's probably a 4.6.

The F2-T Mazda MX-6/Probe seemed to be pretty well sorted. CA18T Nissan too.

 

[ls1mike]

My turbo Dodges were all pretty good. If I got them with the Mitsubishi Turbo, I swapped them out to the Garrett. They had their problems, but I beat them, they were all fairly reliable and I had a few that saw over 200,000 miles on the original turbo. They were easy to modify and cheap to fix.
I never idled any of those cars. They were water cooled and had a pretty good size oil feed line. The earliest turbo failure I had was a Mitsubishi unit that failed at about 96,000 miles in an 88 Daytona Pacifica. It received a Garrett after that.

I have also have had a few Supercharged cars, both my Buick and the previous Grand Prix were modified. It seems to me the supercharged cars require a bit less under hood maintenance. Infact I rarely have to open the hood on the Buick.

 

[Scott_Tucker]

Thought you guys who like turbos would like to see the latest project I'm tuning.

Bugatti EB110
3.5L V12, 4 turbos, 550 HP

 

[SteveSRT8]

Originally Posted By: sciphi
My Cruze will make at least 4 PSI of boost at 1500 RPM or so if it's floored. It's enough to keep speed up a mild to moderate hill. Yeah, it's fun to rev it for peak torque. However, the drivability benefits of having some torque available down low are large. I like how it doesn't need the snot revved out of it to go up most hills.


That's an awesome thing to say about a tiny 1.4 liter motor in a big car!

And to Scott, AWESOME!

 

[artificialist]

Originally Posted By: Spazdog
Originally Posted By: artificialist
Originally Posted By: Norm Olt
Remember the Volvo and Saab Turbo's of the '80's?

Only remember one of my friends who bought one ever buying a second one...

Could it be more evidence that the car makers just want to make things so complex, so expen$ive, so difficult to repair (if even repairable at all!) that you'll just buy a new car (or start a new lease) rather than have to deal with any problems that may arise "post-warranty"?


The reason so many 80s turbo cars were a pain was because nobody was told to idle the engine for 2 minutes before shutdown, no engine specified synthetic oil, and turbochargers were only cooled by engine oil. This is why so many engines that were basically good were destroyed by sludge.

Volvo and SAAB turbo engines were actually better than most.


Nobody told us then

Credit where credit is due to SAAB for making the Triumph Dolomite Sprint/TR7 motor resemble something reliable. Especially with a turbocharger.

'80s turbocharged cars also had some design faults. Notably the 4G54 Mitsubishi with MCA Jet valves. The ROTW got the 4G63. I read somewhere Canadian Starion/Conquests were MCA Jet delete heads. But the USA got the bad heads. Go fast, car goes boom and issues white cloud worthy of 3-Mile Island, replace head, repeat.

The Pontiac Sunbird GT/Skyhawk T-Type seemed to be short lived engines too. The regular 2 liter OHC engine would destroy cylinder heads prematurely and it doesn't appear that GM made any improvements to the head when they turbocharged it. But it did make more horsepower than a TurboI Chrysler....for a short time until it handgrenaded it's head.

Same thing with the Isuzu Impulse.

I don't know if the Thunderbird Turbo Coupe was better built than the later Super Coupe. I dislike the Essex 3.8 V6 from that era so my opinion is it is better built. All I know is that I still see Turbo Coupes. I seldom see Super Coupes. In fact, if I see a 10th gen T-bird, it's probably a 4.6.

The F2-T Mazda MX-6/Probe seemed to be pretty well sorted. CA18T Nissan too.

I think the reason the USA got MCA-jet cylinder heads is because our smog tests are harder to pass, so some of the cars we ended up with had extra gadgetry attached to them.

 

[rpn453]

Originally Posted By: Scott_Tucker
Thought you guys who like turbos would like to see the latest project I'm tuning.


I wish I had something like that in my garage to look at!

 

[MrHorspwer]

Originally Posted By: Spazdog
The Pontiac Sunbird GT/Skyhawk T-Type seemed to be short lived engines too. The regular 2 liter OHC engine would destroy cylinder heads prematurely and it doesn't appear that GM made any improvements to the head when they turbocharged it. But it did make more horsepower than a TurboI Chrysler....for a short time until it handgrenaded it's head.


Two blown head gaskets, one leaky turbo, one cracked exhaust manifold, and one wasted head. This was my brother's T-Type Skyhawk. All in less than 30,000 miles.

Fun car when it ran. That is, if you like on-boost torque steer that was constantly trying to drive you into the curb.