Difference between supercharge and turbocharge

[Genie47]

Nope. I will post another picture to show you the complexity of its piping.

[Genie47]

Here it is:

 

 

 

A clear view of the SC and TC. Quite obvious where they sit.

 

 

A beautiful shot of the S4. I would love to get into this car and give those with their WRXs and Evos a scare in their rearview mirror.

 

 

If you are interested in a new S4 Stradale, Walkers Garage refurbishes and sells them. http://www.walkersgarage.co.uk/s4_new.htm

 

See the evil in its ass.

 

[Elfenstar]

And heres a small writeup to compliment genie's pic from the ask sarah section of www.nissanpaerformancemag.com

 

Ace I was asking where you read the article on the golf.

 

Known as twinchargers, the Lancia rally cars employed both a turbo and a supercharger. HKS even offered an upgrade for the Toyota MR2 with a supercharger-into-turbo kit. Nissan introduced a twincharged car, the front wheel drive March. The March (Nissan Micra in Europe) was originally offered in 1982 and is still around today in Japan and Europe, where there is also a Nismo version with intake, exhaust, suspension, and Rays rims (they get all the tasty cars). A turbo model was introduced in 1985, but the twincharged version was available from 1989-1992 and only sold in Japan and Malaysia. The March Super Turbo version had an inline 4 electronically fuel-injected 930cc single overhead cam turbo and supercharged engine, the MA09ERT. Only 110 hp at stock 0.7 bars of boost (about 10.3 psi), it was still practical to almost double the boost to get an extra 20-30 hp. At only 1700 pounds, the Super Turbo was capable of 0-60 in only 7.5 seconds. Is twincharging possible? Yes. Likely to see on a production car or cost effective? Not usually. It's hard enough trying to fit one forced induction system in an engine bay that trying to get two in a car already on the market would probably take some Crisco, a sledge hammer, and some funky body work. You can produce a kit where the turbo output powers the supercharger or vice versa. Powering a supercharger into a turbo takes advantage of low end spool since the supercharger is powered off the crank and doesn't have as much lag as larger turbos typically do. The supercharger blows air facing the turbo. However at high rpm, the turbo will be flowing too much air and there is a lot of backpressure, creating a vacuum. You would either have to disengage the supercharger as the turbo spooled up or add an outside source of air to power the turbo. Roots blowers, although not too efficient at high rpm, are cheaper and work well at low rpm, making it a most cost effective option. A variable speed centrifugal supercharger is a slightly pricier option as well. Use a higher boost setting in the low end and a low boost setting on the top end to let the turbo take over. Powering a turbo into a supercharger fools the turbo into thinking the engine is a greater displacement, but power is consumed by the spooled up supercharger and SC's are usually less efficient compressors than turbos. One easier option (both mechanically and on your wallet) is to use nitrous oxide to power a large, laggy turbo in the bottom end.

[BMW320i]

Your da man.

 

How is the efficiency in comparison with Sequential Turbos or twin scroll ?

[Elfenstar]

Isn't twin scroll just a "door" to control the exhaust gas flow to the turbo. At lower RPM's the door is closed and causes the exhaust gases to flow through one path at a higher velocity and shaper angle to spool the turbo up faster then as the boost pressure rises the door opens allowing the turbo to run to its max potential? Mazda stopped it because they found a more efficent turbocaharger system that didn't need it.

 

Sequential... well thats something i'm looking into

 

Edit: Ah crap as for comparison, the sequential system is ver similar to the super-turbo setup.

Edited September 5, 2005 by Elfenstar

[Dtvox]

The good old 'Killer Bs'....

[Astrid]

I prefer supercharging. Runs less hot (at least the compressor) and has almost no lag. But latched-on compressor carries additional weight and belt driving compressor pulleys takes up some power losses from engine. May not be great for small engines (e.g. 1.6L or below) ... otherwise the initial drag will be too much for the engine to pull (before the SC is clutched in at typically >2000 rpm).

 

Turbocharging runs very hot at the turbine and require intercoolers. Intercooler oil will coke up and plug up with time, even with a turbo timer. Too high boost pressure will also result in significant lag. TC turbine generally small / light, compared to SC compressor. Less load and exhaust gases driving turbine does not sap engine of its baseload power. Better for smaller-engined cars, but turbo lag will be there.

 

So VW is right to combine both SC and TC for their new 1.4L engine. Best of both worlds for a small engine setup.

[Genie47]

You still need an intercooler for supercharging setup. The air is still compressed and you still get heat from adiabatic compression. Look at the backside of the S4 above. You see two intercoolers, no? One is for the turbocharger, the other is for the supercharger.

 

Unless your boost levels are low like around 5-6psi, there is no need for intercoolers. Same applies to supercharger setups.

[Acemundo]

sat's Today papers.

 

usually they have some short write ups on new cars or stuff.

[Acemundo]

ah ha, get a better idea. in terms of physics or engineering, why does sc excel in low end but tc excel in high end?

 

also look at the sc, with its filter like gadgetry, does it also suck/blow air to work?

[Genie47]

Both SC and TC suck and then blast it in. The reason why SC excels in the low end and in a way have little or no lag is due to the fact that a belt drives the compressor. In a TC setup, the exhausts need to flow really fast to effect the forced induction. That is why in a TC setup, bigger turbo = more lag.

[Acemundo]

quite a good writeup.

 

now my next question is how do explain why sc is better at low end while tc better at high end?

[Acemundo]

think i get wat u mean

[Acemundo]

well if it reaches sg shores, i will be most interested to sit in it as someone drives

[Elfenstar]

Genie already explain mah no need for me to repeat.

 

Just to add in to what Genie said abt intercooling... air gets hotter as it gets compressed (regardless of TC or SC). As such an intercooler is needed to bring the intake temps down. However the need for one is also affected by the fuel grade, compression ratio, engine componenet strength, etc. (i.e. why some cars can use a smaller intercooler at higher boost than other cars).

Edited September 5, 2005 by Elfenstar

[Acemundo]

hehe..yeah i posted before genie replied

 

but i tot from astrid's post intercoolers are more needed for tc?

Edited September 5, 2005 by Acemundo

[Elfenstar]

not exactly... lots of factors... basically air gets hotter as it gets compressed. Intercoolers are there to bring these temps down because under compression a hotter air-fuel mixture will be more likely to pre-ignite. However a higher octane rating will mean lower chances of this, as will a lower compression ratio, and lower boost levels. Simply put the need for an intercooler will rely on these factors and not the method of obtaining boost.

[Acemundo]

http://www.mycarforum.com/forum/gforum.cgi...1021646#1021646

 

check this out. i think this was the golf the sat's today papers referring to. argh, i thrown it away. otherwise can scan the article to u.