Turbo vs Supercharger

MerelyKarma

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Oct 11, 2010
Location
Toronto, Onterrible
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Golf TDI 2005, Alfa Romeo 164L
So talking to some car guys over halloween, there was a lot of talk about how these guys loved the super chargers over turbos (a couple of them have cars that run high 8's). There was more hp in the driveway then on the rest of the block (3 x 600+hp diesel trucks for towing the drag cars. 1200ft-lbs in the one in front of me... needless to say i felt small).

I have read a bunch on them, but the only comparisons I could find were on websites for people who like superchargers/make them so they were always biased.

I was wondering, purely from an interest point of view, why do I never see any TDI's (SDI?) with a Supercharger? Would it be possible? Would the drag on the engine be too much of a power loss to over come with the supercharger?



Any thoughts? This is more of me trying to learn more, and pick the brains of the smart people that are on here. That and I think having a golf with a legitimate working hood scoop would make certain people on Vortex's heads explode
 

Ski in NC

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Wilmington, NC USA
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2001 Jetta ALH 5sp stock
Superchargers are good for generating maximum hp, and have zero lag when launching off the line. Good for drag racing.

Why you don't see them often on cars: The hp required to drive the supercharger comes from the crankshaft. And it is alot of hp. Not great if you are wanting efficiency (as in mileage).

Turbos use waste energy from the exhaust and have very little downside on efficiency, in fact may actually increase efficiency in some applications. Most modern engines where fuel efficiency is important use turbos.

Supercharger: Instant hp off the line. Not good for fuel economy.

Turbo: A little lag in hp (bad for drag race). Good for fuel economy.
 

GoFaster

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Location
Brampton, Ontario, Canada
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2006 Jetta TDI
There are plenty of turbo engines involved in drag-racing, too. Some of them have some rather unorthodox launch techniques to overcome the lag of the invariably very large and, strictly speaking, oversized turbochargers. In other cases, a little bit of lag can actually help, by not blowing the tires away right at the line.

Main reason you don't see more of them are (A) the rules for many classes don't allow turbochargers, and (B) it's not "traditional" and "old skool" - looks out of place on a '69 Chevelle.

Otherwise ... diesel engines are ordinarily designed for maximum efficiency, and turbochargers are a far better match than superchargers, for all the reasons described in the post above.
 

imo000

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Cambridge
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2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
Supercharger are also a lot easier to install. Fuel efficiency with the turbos is rescent. Materials came a long way in the last few years. In the past, turbo engines had to run rich to keep the impeller from melting. Exotic materials made this a non issue and now there are some gasoline turbo engines that are in the TDI teritory.
 

craig01b

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Mar 17, 2004
Location
Guelph, Ontario.
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None
Superchargers work in engines that need lots of power, with very little lag...or otherwise, things that run consistantly...cars do not fit that category.

Turbos cost little to run on the fuel side, since they extract their power from the exhaust side. Limitations...yes, but if you can control it, its wonderful. Much like out little cars.

I am happy to say, I have 2 turbos...nil super, and another that could go either way..depending on mom...

Night, and best of luck to you all!!!

Craig Bremner
 

Toronto_Vento

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Location
Richmond Hill, ON
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01 Baltic Green Bora
Mercedes had the Kompressor engines which were supercharged, but are switching to turbo slowly.
I thought I remember something about VW coming up with a combo unit. Small engine with a supercharger for lower the lower RPM zone (where turbo lag is of greater concern) and a turbo for the higher RPMs. Fuel economy was supposed to be nearing that of diesels.
 

diffas

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Jun 25, 2008
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vw used those on 1.4tsi engines. 1.4tsi up to 180hp output in Polo GTI.
 

Silver02TDI

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Toronto, Ottawa
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2012 Golf Wagon TDI Highline
I guess you don't see them here because our cars already have turbos, so it's easier to just put on a bigger turbo. Removing the turbo and adding a supercharger probably isn't feasible. Outside of diesels, the VR6 crowd use to love to supercharge because it was cheaper than turbo-ing their VR6's. But, a VR6T was everyone's dream (fuel efficiency aside)
 

imo000

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Cambridge
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2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
I have two turbos and a supercharged one. The SC is a homebuilt setup.
 

Ski in NC

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Location
Wilmington, NC USA
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2001 Jetta ALH 5sp stock
Superchargers can work in a normal (not race) car with clever plumbing and or clutching. So sc only comes on line when it is needed. Sure don't want any valve overlap, though!! Especially on a gasser with normal fuel injection.

Some marine engines (volvo KAMD series) use a sc with an electric clutch to force feed the turbo until the turbo takes over. Then clutch disengages and a bypass valve diverts turbo suction from compressor to air filter. Works well to get torque down low. Dang hard on the belts, though.

I like the old mad max cars with the clutched blowers. Fun!!
 

imo000

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Joined
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Location
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2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
.......I like the old mad max cars with the clutched blowers. Fun!!
You do realize that was all special effects, right? The SC clutch wasn't real, only movie magic.
There isn't strong enough of an electro magentic clutch, running on 12V, that can do that to a sueprcharger and last. Once you spin one by hand, you'll understnad why.

The first gen MR2 had one but their SC was very small.
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
You do realize that was all special effects, right? The SC clutch wasn't real, only movie magic.
There isn't strong enough of an electro magentic clutch, running on 12V, that can do that to a sueprcharger and last. Once you spin one by hand, you'll understnad why.
.
I know those were a prop. Well, actually I figured it out years later. Buzz kill, that!!!

It is doable, there are electro-mag clutches that can carry alot of torque. maybe not enough though. Heck, a clutch pack from a autobox would work, but that's alot of machining...

One can dream..

And they spin easy by hand, just hard when there is a delta p.
 

imo000

Top Post Dawg
Joined
Dec 13, 2005
Location
Cambridge
TDI
2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
I know those were a prop. Well, actually I figured it out years later. Buzz kill, that!!!

It is doable, there are electro-mag clutches that can carry alot of torque. maybe not enough though. Heck, a clutch pack from a autobox would work, but that's alot of machining...

One can dream..

And they spin easy by hand, just hard when there is a delta p.

Trust me, if this was possible, it would have been done by now. If for no other reason than becasue of Mad Max II. Every few months a newby ask this on the Porsche 928 forum and the asnwer is always the same. There are compact lectro magnetic clutches, that run on 12V, don't pull a ton of amps, are compact (like and AC clutch), can take the abuse of engaging at 7000rmps and will last 150K kms?

My Paxton GSS is no easy to spin at all, Vortechs are easier but when they all start to make boost, there is a huge hp demand to keep them spinning. That's the reason the SC belts are always tights as a drum. 2-3 times tighter than for a normal acessory and they wear/stretch fairly quickly.
 
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