Turbochargers and Superchargers

[ephraim]

whats the difference? :D

[mbt]

both serve the same function -- essentially a turbine to cram more air/fuel mixture into the combustion chamber to increase power (otherwise achieved, conventionally, by enlarging the displacement of the cylinder) -- but the turbo is driven by exhaust gases, whereas the supercharger is driven by a belt driven by the crankshaft.

in other words, a supercharger uses a little bit of the engine's power (like an a/c does) to increase the total output, while a turbo doesn't. however, because the turbo is driven by exhaust gases, there is some lag before the turboed power comes along, a phenomenon called turbo lag. smaller turbos are generally less affected by turbo lag (some like the Supra use a sequential [smaller turbo is used at low rpm, then larger turbo at high rpm] twin-turbo arrangement).

there's a lot of resources about this on the net. try www.howstuffworks.com

[B16ba-type-RSiR]

Ang Supercharger is belt driven....ang Turbocharger depends on the vacuum created by the exhaust gases exiting thru the manifold...

[kevinp]

tawag diyan, forced induction. both super- and turbo-chargers increase the amount of air that enters the combustion chamber per stroke. more air = more fuel. more fuel = bigger explosion. bigger explosion = more power. kaya din may intercooler para malamig yung air na papasok sa combustion chamber ng engine. pag mas malamig, mas dense ang hangin hence more air (oxygen) molecules are able to enter the chamber for the same volume.

ot: may nabasa ako a few months back na sabi meron daw na-develop na turbo na walang lag. nilagyan nila ng small electrical motor ang turbine para mag-spin ito even at low revs. i think it's powered by a rechargeable battery that recharges during braking or pag naka-apak ka sa clutch kaya walang power cost sa makina.

may intercooler ba ang supercharged engines?

[logbook]

may intercooler ba ang supercharged engines?

good question...does anybody have a solid answer?

naisip ko kse wala e. kse pagkakaalam ko the extra power a supercharger brings doesn't neccesitate the use of an intercooler....o baka nagkakamali lang ako?:mrgreen:

[kevinp]

actually i think it would make sense for a supercharger to have an intercooler kasi ang function naman ng intercooler ay palamigin yung hangin na pumapasok sa combustion chamber. matanong nga si pareng Ace Vergel... :mrgreen:

[jackndabox29]

Anybody knows about an anti-lag systems for turbos? sometimes called ALS or "misfiring system" in initial D... alam ko lng po is sobra ingay kaya d pwede sa streets and madali raw maka cra ng exhaust... mron po bng nakaka-alam ng mechanics nto?

[SuperAE92]

may intercooler ba ang supercharged engines?

good question...does anybody have a solid answer?

naisip ko kse wala e. kse pagkakaalam ko the extra power a supercharger brings doesn't neccesitate the use of an intercooler....o baka nagkakamali lang ako?:mrgreen:

yes it still has... my corolla with a 4agze engine has one... :wink:

[splerdu]

Anti-Lag is used in WRC. Its done through the ECU program, basically when the drivers lifts off the throttle, the engine will overfuel the chamber and delay ignition so part of the combustion extends into the exhaust manifold. Burning fuel in the exhaust basically keeps the turbine spinning and kills lag during shifting and cornering.

Another form of Anti-Lag puts a dedicated injector and sparkplug in the manifold, so the turbine can be spun for even longer off-throttle periods. Problem with anti-lag is the wear on the turbine itself. You'll have to treat your car like WRC, and rebuild the turbine every 500-1000km.

kevinp,

That's very interesting. Do you remember the url? Or if not how did you come across the site?

[kevinp]

kevinp,

That's very interesting. Do you remember the url? Or if not how did you come across the site?

sorry bro, forgot na where i read about it.

[splerdu]

actually i think it would make sense for a supercharger to have an intercooler kasi ang function naman ng intercooler ay palamigin yung hangin na pumapasok sa combustion chamber. matanong nga si pareng Ace Vergel...

Supercharger doesn't need an intercooler.

As a simple analogy, the turbocharger uses hot exhaust to drive a turbine, so the air getting sucked in gets heated up. By putting in an intercooler, the compressed air is cooled using passing ambient air and gets closer to ambient temps.

The supercharger uses a belt to drive a turbine or screw. The air getting sucked in does not get heated up. Since an intercooler works with ambient temp, cooling air at ambient temp with external air at ambient temp obviously wont bring any benefit and will only make the intake tract more complicated, thus losing power.

Same principle for NA cars... Intercoolers are totally useless unless you find something else to cool the intake charge with. Having an air-to-coolant IC instead of air-to-air might be a good idea, but in most cases you'll need a large volume of coolant to offset heating up due to friction. Most likely its not worth it.

[kevinp]

di ba the cooler the air, the more dense it becomes kaya more air molecules ang magkakasya sa combustion chamber kung malamig ang hangin. if what you're saying is true, e di wala rin silbi ang mga cold air intakes?

[splerdu]

a lot of people do say that cai is useless.

i think cai helps a bit because it allows your car to take cooler air from outside, instead of from inside the engine bay which gets quite hot.

[Auto_Xer]

splerdu,

Any form of forced induction will benefit from an intercooler.
The heat mostly comes from the act of compressing the air itself not the radiated heat of the exhaust turbine.

A reason why most if not all aftermarket street roots type SC's don't have an IC is bec of cost, added complexity & bulk vs the relatively low efficiency.

In pro racing it's a different story, the technology & mods you see is only limited by depth of pockets & rules.

kevinp,

There has been a lot of research into how to make turbo's more responsive, most of them for one reason or another still aren't commercially viable yet.
Before the electro or magnacharger(i think this was what the system you just described was called) there's also the Hydracharger(uses a hydraulic pump to pressurize fluid & sends the fluid in regulated amounts to keep lag to a minimum) whose rights were bought by Garrett from the developer(but was eventually reverted back to him by Garrett), as well as the Aerocharger( a VATN turbo).

Only the Aerocharger is commercially available, Garrett has it's own version of the VATN which they added to their product line a few years ago.

It costs about 40-50% more than a standard turbo of the same size, iirc.

[Paul]

kevin, yes some superchargers have intercoolers, like the one in toyota's 4A-GZE

[Auto_Xer]

Found out an interesting & exciting tidbit of info over the weekend.

The new Nissan Patrol uses a VATN turbo.

[empy]

auto_xer said it...and actually some (semi) affordable street S/C applications now come with front-mounted intercooler (FMIC) options - ASA of Germany and Active Autowerke of Miami being two notable examples. Pretty decent claims of hp gains too.

IMO the only feasible way to minimize turbo lag currently is to use small turbos...the OEMs do this the best. I have driven the 993 model Porsche 911 Turbo and the Mark IV Toyota Supra (both stock) and neither of them have any turbo lag or non-linear power delivery that I could detect (but then again, I'm no expert).

Oh, and one more difference between the two - boost tuning is much easier with turbos...meaning with an electronic controller, you can control the level of boost (and resulting hp) from the cockpit as you please. As opposed to the S/C where a pulley change would be necessary.

[mbt]

Auto_Xer,

what is a VATN turbo?

[empy]

VATN - Variable Area Turbine something. Not sure how it works but supposedly this type of turbo allows smoother/more consistent power delivery from low to high RPM...

[pajerokid]

Is the VATN different from a VG Turbo like in the thai spec strada? (Variable Geometry)