Why turbos instead of superchargers?

Kain · 12th October 2010, 15:27

I don't know all that much about this but isn't the main downside of turbocharging the lag while the main advantage of supercharging is no lag? Why are most car companies that are using FI using turbos instead of superchargers?

imsaid · 12th October 2010, 18:18

Turbos are more efficient because they use the exhaust to spin the compressor wheel while superchargers compressor spins via a belt connected to crankshaft which consumes some of the engine's HP.

Kain · 13th October 2010, 09:41

Even if turbos are more efficient, isn't the supercharger's consumption of some of the engine's power an "acceptable" trade-off for a lag-less engine response?

imsaid · 13th October 2010, 09:54

With the new technology turbo lag is almost not noticable by most drivers, also turbos consume less fuel which is the main reason companies are switching to turbo charging from NA.

Even Mercedes dumped SC and witched to Turbos with their AMG55 engine.

blackxs · 16th October 2010, 22:43

With a supercharger you may not notice any perceptible lag, but you will not be able to achieve the power you want as easily. Superchargers sap power from the engine unlike turbos that use "free" power from the exhaust to feed the engine.

Especially with the reverse-flow architecture of BMW's turbo V engines, turbo lag is essentially something of the past. You feel the throttle response as fast as you would with an N/A and the engine will start making power almost immediately after. This isnt like old times where turbo lag was a fact of life - you would floor it, have a coffee, wait for your turbo to spool, watch a movie, then your turbo is spooled and you are off. With modern technology we have created turbos and engine designs that give you no perceptible turbo lag or throttle delay.

So essentially it comes down to using a S/C which saps power from the engine or a turbo which gets more power and isnt extra load on the engine.

AFC1 · 17th October 2010, 04:44

I believe BMW is using turbos in the next M5 purely because of fuel economy reasons. Besides returning better gas mileage, turbos have the disadvantage of turbo lag (still noticeable to me even in modern cars...drive a 335i and E46 M3 back to back and you will see what I mean). Also, turbo engines cannot rev anywhere near as high, while current supercharged M cars (ESS E90 M3 for example) retain their 8400 rpm redlines with the superchargers.

Sure, you can often get more power from an engine by turbocharging it as opposed to supercharging it, but I believe the urge BMW has to use turbos is purely from a fuel economy perspective.

afc1

digger · 24th October 2010, 04:04

Quote:

Originally Posted by AFC1

I believe BMW is using turbos in the next M5 purely because of fuel economy reasons. Besides returning better gas mileage, turbos have the disadvantage of turbo lag (still noticeable to me even in modern cars...drive a 335i and E46 M3 back to back and you will see what I mean). Also, turbo engines cannot rev anywhere near as high, while current supercharged M cars (ESS E90 M3 for example) retain their 8400 rpm redlines with the superchargers.

Sure, you can often get more power from an engine by turbocharging it as opposed to supercharging it, but I believe the urge BMW has to use turbos is purely from a fuel economy perspective.

afc1

turbos are more efficient and will make more power and torque.
Its rubbish that turbo engines can't rev as high. The reason they generally don't is that they don't need to rev high in order to make the power level they need.

HeroSina · 25th October 2010, 17:58

i agree BMW is using turbos in the next M5 because of economy game,but you will get more power with turbo compared to supercharger.i also should admit turbochargers are not 100% "free" power because turbocharger itself is a obstacle for exhaust gas so engine should work harder to send the gas out of the pipes.

blackxs · 25th October 2010, 23:57

Quote:

Originally Posted by HeroSina

i agree BMW is using turbos in the next M5 because of economy game,but you will get more power with turbo compared to supercharger.i also should admit turbochargers are not 100% "free" power because turbocharger itself is a obstacle for exhaust gas so engine should work harder to send the gas out of the pipes.

The engine isnt really working any harder to get rid of the exhaust gas.

Superchargers can not even be compared to turbos in the vein of economy. S/C will drain power from all revs, sapping HP making you get worse MPG. Turbos can sit there not spooled, not being an additional burden on the engine - helping the car seem like a smaller-engined vehicle until you need the power

And seriously, BMW M is not the ones who wanted to go to the TTV8. They were forced to by emissions laws the world over. Dont blame BMW, blame the stupid "Green" activists.

HeroSina · 26th October 2010, 16:05

Quote:

Originally Posted by blackxs

The engine isnt really working any harder to get rid of the exhaust gas.

Superchargers can not even be compared to turbos in the vein of economy. S/C will drain power from all revs, sapping HP making you get worse MPG. Turbos can sit there not spooled, not being an additional burden on the engine - helping the car seem like a smaller-engined vehicle until you need the power

And seriously, BMW M is not the ones who wanted to go to the TTV8. They were forced to by emissions laws the world over. Dont blame BMW, blame the stupid "Green" activists.

i didn't say Supercharger is better but i still insist on my opinion that MPG gets worse when you force an engine with turbo.for example BMW N53 powerplant uses less gas compared to N55 which has Turbo , and N55 is more advanced.