jst read a post on which some commented about a turbo and suprcharged car.

just curious on how it works as i know the basics of how either work but not together???

Have a look here :) And click on the link in the blue box.

Link to VW Clip

Basically the super charger produces the power low down the rev range as is it powered by the engine and not by the exhaust. As the revs pick up and the more exhaust gas's flow the turbocharger kicks in and the super charger de-activates.

Mark

Edited 23 December, 200718 yr by max_crox

its just to stop that bastard called turbo lag.my freind feels it all the time in his evo

hence why people who own evos hate people that own scoobys

I think the TSI's pretty revolutionary. Plenty of tuning potential too!

^^ Eaton + Garrett GT28

Could that be combined with VVT to get a monster of an engine?

From: http://www.howstuffworks.com/question122.htm

"What is the difference between a turbocharger and a supercharger on a cars engine?

Let's start with the similarities. Both turbochargers and superchargers are called forced induction systems. They compress the air flowing into the engine (see How Car Engines Work for a description of airflow in a normal engine). The advantage of compressing the air is that it lets the engine stuff more air into a cylinder. More air means that more fuel can be stuffed in, too, so you get more power from each explosion in each cylinder. A turbo/supercharged engine produces more power overall than the same engine without the charging.

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine. Therefore, you would expect to get 50-percent more power. It's not perfectly efficient, though, so you might get a 30-percent to 40-percent improvement instead.

The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to run the air compressor. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does. A turbocharger, on the other hand, gets its power from the exhaust stream. The exhaust runs through a turbine, which in turn spins the compressor (see How Gas Turbine Engines Work for details).

There are tradeoffs in both systems. In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs. Superchargers are easier to install but tend to be more expensive."

evo owners hate scooby owners because the car is a direct rival, nothing to do with a turbo or the lag, both cars use turbochargers and produce lag

Edited 24 December, 200718 yr by shantybeater

evo owners hate scooby owners because the car is a direct rival, nothing to do with a turbo or the lag, both cars use turbochargers and produce lag

I thought that, you beat me to the reply, and its probably best you did as I'd have slaughtered any so called car enthusiast who didn't know that!

me 2, i was just bout to say it lol.

its just to stop that bastard called turbo lag.my freind feels it all the time in his evo

hence why people who own evos hate people that own scoobys

This is bullshit, unless we're talking about the latest gen's that I'm not familiar with because the Evo's have far better turbo resonse and mid-range torque than the Scoobies. Read one of the last two chapters of Forced Induction Performance Tuning by A.G.Bell for a side by side comparison of both of the cars abilities to get back on the power out of a corner.

And the sequential twin-turbo Subaru 22b engine is even worse than both of them with the handover between the two blowers causing a massive flatspot IIRC.

funnely enough my uncle rallys a impreza and an evo. he says basicly what you just said eeekie, evo has far less turbo lag and more torgue than the impreza. id have a evo over one all day long!

And the sequential twin-turbo Subaru 22b engine is even worse than both of them with the handover between the two blowers causing a massive flatspot IIRC.

That's an interesting point.. I thought Bi-turbos kicking in at different places in the rev range (due to their setup) sounded like a good way to solve the problem... if you didn't want to compound charge...

Lancia S4, compound charged:

1 Turbo with an intercooler + 1 Supercharger with an seperate intercooler. Read between 470 and 550bhp from a 1.8 litre engine. Supercharger takes care of low down boost and then bypasses at higher RPM and the turbo takes over. Design to eliminate lag...not such a problem these days with the modern Grp A. cars having anti-lag. http://en.wikipedia.org/wiki/Anti-lag

S4 engine layout:

And the sequential twin-turbo Subaru 22b engine is even worse than both of them with the handover between the two blowers causing a massive flatspot IIRC.

That's an interesting point.. I thought Bi-turbos kicking in at different places in the rev range (due to their setup) sounded like a good way to solve the problem... if you didn't want to compound charge...

I'm sure BMW have used the twin-turbo route to good effect?

The 22B though...has a single IHI-VF23...still only comes on boost at 3000rpm but has less lag than some other turbos fitted to Impreza's.

Edited 24 December, 200718 yr by Tav

Mk4 Supra twin turbos use sequential turbocharging, and they are constantly on boost from literally a throttle tap above idle right up to the limiter. Floor it in 6th at 70, and the boost gauge rises straight away, no lag at all. Do the same in 4th and you get pushed back into your seat instantly Never driven one of these but I bet it would be an expereince, even in a standard 320ish bhp model.

The Mk3 UK spec Supra Turbo uses a similar bottom end and 24v head to the Mk4, and the lag is silly, foot down, wait, wait, wait, 3000 rpm, boost, OH SHIT! I have driven one of these, an auto one in fact, and it builds boost up, then kicks down a gear - scary stuff, especially when it's slightly damp, LSD sends you all over the place...

Edited 24 December, 200718 yr by tobyk

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine.

Right I know this is from a website but is this statement correct?

AFAIK 14.7 psi is more pressure than 8 psi. So how is getting 8 psi from a supercharger double if the air coming in from the atmosphere is at 14.7psi?

I know I'm probably reading this well wrong but an explaination into this statement would be most appreciated :)

Perhaps it was not the 22B then, and yeah the point of sequential charging is just that. A small turbo to reduce lag and build up enough exhaust gas to get an otherwise laggy bigger efficient turbo spooled. The Subaru Bell mentions in his book fails miserably at it though as it hasn't been done properly.

Wasn't the 22B:

The Twin-Turbo EJ20 Appears

In late 1993, Subaru split its turbocharged EJ20 into two distinctly different versions – the single turbo version would continue in the Impreza WRX while a new twin-turbo version was introduced to the updated BD/BG-series Legacy GT/RS.

The single turbo EJ20 engine always had poor bottom-end performance so, to remedy the situation, Subaru developed a sequential twin-turbo arrangement to improve the driveability of the high-performance Legacy (which is considerably heavier than the Impreza). Using a relatively complex control system, the EJ20 TT employs two small capacity turbochargers – the primary turbocharger boosts low rpm torque while the secondary turbocharger chimes in to increase performance at high rpm. The secondary turbo transition (the point where the secondary turbo begins to add intake airflow) is around 4000 – 4500 rpm.

From what I remember the Mitsubishi wins on mid-range through a longer stroke, and less lag by being able to position the turbo nearer the exhaust ports which is harder to do on a flat-4 engine.

Edited 24 December, 200718 yr by EeekiE

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine.

Right I know this is from a website but is this statement correct?

AFAIK 14.7 psi is more pressure than 8 psi. So how is getting 8 psi from a supercharger double if the air coming in from the atmosphere is at 14.7psi?

I know I'm probably reading this well wrong but an explaination into this statement would be most appreciated :)

6 to 8 PSI above atmospheric pressure

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine.

Right I know this is from a website but is this statement correct?

AFAIK 14.7 psi is more pressure than 8 psi. So how is getting 8 psi from a supercharger double if the air coming in from the atmosphere is at 14.7psi?

I know I'm probably reading this well wrong but an explaination into this statement would be most appreciated :)

6 to 8 PSI above atmospheric pressure

Ah right ok cheers, sorry for being extremely dumb then. I know nothing about turbos/superchargers.

youd think a two stage turbo would be cheaper, more reliable and easier to set up...

There a lot of VNTs around now, probably for that reason

evo owners hate scooby owners because the car is a direct rival, nothing to do with a turbo or the lag, both cars use turbochargers and produce lag

it's more to do with the fact scoobys are a direct rival but can be picked up for a lot less, plus most evo drivers seem to suffer from badge snobbery of the highest level, kinda like a lot of vw owners

You can't get a Subaru that is as good as an Evo for similar money. If you want a good Impreza you need to go and get something properly meaty....like and STi Typre-R...none of this watered down WRX rubbish.

I'd have either....but whilst I'd settle for an Evo 7, I'd be looking for an imported Impreza with 3 doors and some factory fancy light weight bits.

I think there's more Imprezas because the service intervals on the EVO's are ridiculous. Every 5-10k I think it was...

uncles evo 8 tuned to 440bhp with a remap, 5k service and does 12mpg combined, 4 when ragged.

an awesome car, he wouldnt get rid of it for love nor money!

but it is awesome! i still cant get over turbo lag though, after driving mine for so long with instant mental boost response going in a turbo is like whats going on!