1st Gen R53 Cooper S Supercharged vs Turbo

That is what I like about the Supercharged MINI. The power and torque is linear from 2000-2500 all the way to redline. Despite the powersitic loss the power comes on immediately and doesn't have to wait for the turbo to spool up, the Supercharger comes on immediately as the R.P.M. increases in a linear fashion. In the old world of high H.P. Drag racers the Supercharger on that American V8 at the Drag strip is still King. How many Turbocharged Funny Cars are there in the winners circle?

 

The Forge POV and a CAI fix a lot of those peaks and the fall off of torque. I was pretty surprised how much they helped, actually.

 

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:

 

not going to happen without some major help with the valve train

 

Redline is dictated by, among other items, valve inertia. In order to increase redline you need to reduce reciprocating valve train mass...springs, valves... etc. This is necessary to reduce valve float. And it's not simply a matter of increasing the stiffness of the valve springs. Increasing the spring rate has the downside of increasing cam wear.

 

On my old rally car we used valve float as a rev-limiter. Worked well too. :smilewinkgrin:

 

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.

 

Not true.....CNC allows consistency not necessarily quality.

 

A CNC is only as good as the programer and operator, however that equipment if used properly will give repeatable results time after time. And a beter quality in the long run, I ran a CNC when I was making aircraft alternators with Bishop Aviation.

 

Like any tool, it depends on who is using it.

 

^^^ You've got that right.

 

Understood. I don't think the Prince cylinder head components are up to the task for the redline I would like. Besides the cylinder head components need to be entirely reworked for a higher max engine speed, the next obstacle would be the restriction of the small turbo past 6K rpm. I just don't have thousands to blow on experimenting with crap like this. That is a true test, tune, and burn up cash task.

I can say that I had the chance to compare my R56 experience to the R53 at Grattan Raceway last year. I got a ride in my buddy Roger's '04 R53 JCW and absolutely envied how he could wring the engine out and not have to shift as much. My tuned R56 had great gusto out of the corners but I had to shift from 3rd-4th on almost all my accelerations to the next corner where he could just hold that baby out in the same gear. A little more footwork on my part is no problem, but I think a driver that isn't good at heel-toe can get irritated with. Oh yea, that supercharger whine at 8200rpm is FANTASTIMUNDO!!!!

 

CBS, keep in mind that the '04 transmission had a long second gear where your R56 doesn't. That may be some of the difference. Just sayin....

 

Turbos aren't infinite because to get the fast spool up you have a low volume (small) turbo. At higher rpms the turbo can't handle the volume of air and the rest gets shoved through the bypass valve. That's all the mfgs have been and are working on variable volume turbos. The twin scroll is one good simple method. Honda has a nice one that uses a flap that allows more volume as the rpms go up. Chrysler had vanes that moved changing the volume in the 80s.

Now after that I have to say I have been driving a 320hp turbo car for the last 7 years and drove the R56. But after driving my new R53....OMG:drool:crazy:. The power right at throttle tip in is unbelievable.

Now where is my "WHINE is better than whoosh" badge? I'm sold

 

: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

 

Many auto makers have looked into using multiple small turbos so that spool up is fast and yet by using twin or triple turbos you don't run out of volume. In fact the turbos can be staggered so as to provide a very wide operating range.

Many manufacturers have dabbled with variable vane or variable wall devices to accomplish the wide operate range in a single design. I'm actually a centrifugal compressor designer and have developed a few VGD's (variable geometry diffuser) for specifically that purpose.
I am by no means an expert but Porsche and Mercedes have both referenced one of my patents. So when it comes positive displacement (superchargers) or centrifugal designs....I must admit to being a bit biased.