1st Gen R53 Cooper S Most liked posts in thread: Supercharged vs Turbo

The whine-rs a baby

 

Congrats, you are better than me? :thumbup:

 

Uh, no, didn't say that, was just kidding, hence the smilie at the end....

 

:cornut: Just me and I'm not an automotive engineer but the parasitic effect is only part of the story. The super charger's rpm/boost is dependent on the crank shaft's rpm(and the super charger pulley) there by making the boost finite as the highest(engine) rpm is reached. The turbo charger's rpm is dependent on the gas volume/pressure produced in the combustion chamber which continuously increases as increased boost puts more and more air/pressure/volume into the combustion chamber(and there for into the turbo charger) and is a some what more infinite situation. Higher pressure/volume would create more efficient combustion not nessasarily needing an increase in fuel to achieve more power. Tubo charger rpm is more infinite while super charger rpm is more finite. This also,to me, explains why the super charged engine's torque falls off more rapidly than does the torque produced by the turbo charged engine.
Any way, that's what comes into my puny mind to explain the differences.

Jason

 

The Turbo cars work best between 3,000 and 6,000 rpm. The SC cars work best between 3,500 and 7,000 rpm. The burn rate is higher at higher rpms, thus the reduced mileage at the track for the SC cars.

 

Stands to reason that if you are making more power at a higher RPM that you'll be burning more fuel.....

 

The 'power parasite' stuff is making it more complex than it is.

A supercharger is taking power from the engine, at all times, to turn the supercharger and compress the air passing through it.

A turbocharger is driven by energy in the exhaust gases which would otherwise by wasted out the tailpipe - so the energy to run the turbocharger and compress the air passing through it, is got for free.

That is a bit simplistic, but basically true. As with everything there are additional complications, but the fundamental difference in economy is down to how the intake air gets compressed.

 

That's pretty much what the websites discussing the pros and cons of SC vs. Turbo have also said.

Also, BMW and VW all do Turbo and not SC, even on the most costly models. They have figured out the software to control the infinite potential of Turbo which could destroy an engine if not properly controlled.

However, I am impressed with what has been said about the Sprintex SC, which apparently improves on the efficiency and reduces parasitic losses somewhat.

So, my goal is to continue driving the 1st Gen MCS, and try to mod it into the perfect street machine with maximum power without sacrificing smooth linear power and economy, while preserving sharp handling and special characteristics of the 1st Gen. Maybe down the road, a Sprintex will replace the M-45 Eaton with a good custom tune.

 

ask yourself how a twinscrew which is COMPRESSING air ALL THE TIME is more efficient than an eaton which isn't when they both are just cruising down the freeway? Which do you think is going to burn more fuel?

 

I've lost a little mpg with my everyday, just around town driving, I'm only getting 26.5 compared to the 27.8 I was seeing with my JCW/M45 combo, I haven't really road tripped with this pulley yet, but with the 69mm on the MOTD drive this year, it wasn't really that much different, I was getting between 30.5 & 31 if I stayed under 70mph, and 29 to 29.5 if I cruised between 70 & 75, so probably a loss of .5 to 1 mpg.

 

Our tiny turbocharger spools up so fast, you don't notice any lag. What many people think is turbo lag is the dead spot at the beginning the drive by wire throttle pedal's travel.

Dave

 

The 6200 rpm redline is what really stinks. I would love to have 8200-8500rpm redline on my car :biggrin5:

 

^ Couldn't that red-line be changed by a tuner?

The turbo on the prince engine doesn't seem to have lag to me. Not like the one on our Subaru did. The small turbo spools fast, but seems to run out of breath at higher rpm. Just my .02. I'd be glad to do more in depth testing if someone would loan me their R56 turbo for a couple of weeks. :wink:

 

This is why I went with a track tested and proven CNC BVH. All of these things have been thought of and addressed.

 

Whatsa CNC BVH?

Dave

 

Computer numerical control (CNC) machine tools have revolutionized the machining processes and they are used to make Big Valve cylinder Heads by some vendors.

(cough RMW cough) This means quality control is very high and every unit, in this case big valve cylinder head is milled to the same spec time after time.

Other hand made heads can not touch the quality of a CNC machined head.

 

:cornut: Thanks mrntd. This is why I love MA. I learn something new every day in an informative and polite manner. Again,thanks. If I had a 'whine' badge, I'd send it to you.

Jason

 

:cornut: So...............for my little pea brain...............one needs multiple Turbo Chargers in series to equal a single(large I suppose) Super Charger or is it more complicated then that? This is very interesting to me, more more please.

Jason

 

^^^Great information. SCs don't have to have parasitic losses. The one that use to on the Thunderbird had a bypass system that allowed the intake air to go around the SC. This relieved the the pressure and dropped the power consumption. I think there was even a test version that had a clutch on the pulley (like in Mad Max).

The only problem with all of it is cost. Turbos are cheaper that is why there used more than SCs. Too bad.

 

:cornut: Thanks Paul(I'm Jason Paul by the way). So what about 'twin Scroll' turbo (that MINI loudly proclaimed on 07-09 R56) and 'over boost'(taking high rpm torque from 172 to 192 ft/lbs)? Did this level the playing field any or was it MINI hype?

Jason

Great Article @.................modified.com/tech/modp-0906-twin-scroll-turbo-system..........(answered my own question)