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Old 01-08-2008, 10:19 PM   #2
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What I Drive: MINI Cooper S TURBO

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Now we look at what form of FI...

There are two choices Turbo and Super Charger, both have good points and bad points. There are also MYTHS that we will look at.

Lets start with SuperChargers


Roots Style

Roots style superchargers are positive displacement, which means they flow the same amount EVERY rotation. This is why they have a little more bottom end but usually start starving at higher rpms.

Jackson Racing JRSC

A good entry level power adder, great for daily driving but are on the small side. You can get around 220whp(SVT) or a little more but since the JRSC has NO way to cool the boost you just start creating heat and as heat increases efficiency goes out the window.

Do NOT expect to go out and beat on Vettes... you'll get your feeling hurt. BUT the JRSC make both the Zetec and SVT funner to drive.


A great setup, PW took it one step farther than JRSC by using a water to air cooler for their boost... which allows you to run more boost safely. As an added bonus they opted to use a larger blower so you get more power and its makes power longer. I have seen a couple of PWSC in the 280-290whp range. But as with ALL superchargers it takes power to make power... which relates to roughly a 20% (or more) loss in power .. since the faster you turn the PWSC the more power it takes TO turn it.


Both are Centrifugal SC's... basically a belt driven turbo.. but they dont hit like a turbo. Both of the SC's make less low end than the roots blowers but they also are capable of making MORE power.. where they flow more air the faster you turn them (unlike roots style blower)

Vortec uses an air to water intercooler that depends on an electrical pump to circulate the cooling water... if it quites you dont cool.

ProCharger uses air to air but its mounted UNDER the car instead of up front like a turbo.

BOTH systems can be fitted with front mount intercoolers, which is the best way to cooler your boost.

Both Vortec and Procharger will perform about the same, both have good top end and are very linear (as are roots superchargers) when it comes to making power.


All turbo's act the same, so I'm going to lump them all together.

A properly sized turbo is a beautiful thing on a car, fast spooling and making big power at lower rpms (since they are not belt driven they make there power sooner) turbo's by far make more power than the available superchargers on the market.

A turbo is also easier to upgrade the boost on, instead of changing a pully and belt like a SC you can normally just turn a knob on your boost controller.

Turbo LAG... modern turbos do not have turbo lag, older ones did the newer ones do not. What alot of people PERCIEVE as lag is the way a turbo comes on, as soon as you hit the throttle you can see boost on the boost gauge so that alone tells you there is no lag.. BUT turbos hit so hard they feel like it all comes at once and most people dont even notice that the boost starts building immediatly.

Turbos are easier on the motor in some ways but harder in others.

The easier ways are they dont put excess stress on the motor since they are turned by the exhaust gases instead of a belt.

The harder is they hit full boost sooner than a SC so you are putting more stress on the system sooner instead of coming on throughout the whole rpm range like a SC.

ALWAYS REMEMBER you need to choose your SC/Turbo depending on your goals

You can go to and use their formula's to figure out what size turbo you need, and you can learn how to read compressore maps.

I HIGHLY recommend that EVERYONE read their turbo tech parts 1,2 and 3.


For off the line... Roots SC's are a little quicker (unless you master pre-loading the turbo like I have) Since they move the same volume with every rotaion they will always make the most low end power.. but this also limits the top end performance.

You have 2 SVT's a PWSC and a Turbo car (GT28Rs) running the same boost level.... the PWSC car takes off and will pull the turbo car at first, but the turbo car will pass it ... how you ask?? Where the PWSC car wont make peak boost until close to redline the turbo car will hit peak boost around 3k rpms... a full 4k rpms sooner. Boost will also cause your motor to rev FASTER... so not only will the turbo car benefit from full boost sooner it will also rev faster for the entire 4krpms.

Centrifical SC's dont have the advantage of the bigger bottom end like the Roots do, simply due to their design. They are designed to flow more air up top, hence giving them the capability of 300whp and more. Their down fall is the lack of bottom end power.. low flow at low rpms because of being belt driving, bu they usually make up for it on top.

ALL FI can be used the same way... you just have to learn how to drive it.

Example Autocross... A turbo car can be just as competitive as a SC car, you just have to learn how to take turns and adjust you full throttle points.

BUT when it comes to drag racing.. especially 1/4 mile the turbo will rule... see earlier example about boost and spool time.


This one is so easy... the bigger the better. Your engine is basically an air pump the faster it goes in and comes out the better it will perform. Usually 3" exhaust is the way to go.. since its hard to put anything much bigger under a Focus.

There are 2 things you can do to help your exhaust flow better.

1) Ceramic coating... its pretty, its expensive and it does help keep the exhaust gases flowing. It also will bake off if its not properly done and it scratches easily.

2) Header wrap... this is by far the best method. Its cheap, looks tough and insulates the exhaust piping way better than ceramic ever thought about doing. If you "PROPERLY" install header wrap it will last for years. I generaly soak mine for 10 minutes prior to install AND I stretch it as I install it while using a 50% overlap.


two headers 1 ceramic coated and one wrapped, you touch the ceramic header and you loose skin and hear bacon frying... then you touch the wrapped one.. you can leave you finger there quite a bit longer AND you dont loose any skin in the process.... why??? INSULATION.. the header wrap just far out performs the ceramic coating when it comes to holding in heat... and hot gases flow faster.. faster gases mean better scavaging which in return ends up making more power.


You can either try to tune it yourself with something like the SCT ProRacer, Sniper's SST, or eventually DiabloSports upcoming tuning software.

Or you can take it somewhere to have it tuned... take it somewhere that they have done Focus's before.... the Focus is ... different that tuning a Mustang.

If you feel comfortable with yourself... you should try tuning it yourself, its a great learning experience and there are plenty people on the forum that will help you.

Well that covers the BASICS... feel free to add "HELPFUL" information... if you start a pissing match you will have your posts deleted and I will see you get at a minimum of an infraction.

This is a "HELP" thread, not a debate.
[B]1951 McCormick FARMALL M
2007 MINI Cooper S Turbo... new project car
1998 Chevy 3500 Ext cab, long bed, 4x4, duelly, turbo diesel
2004 Harley V-Rod.... sex on wheels
2011 Harley Electra Glide Ultra Limited

Last edited by 03OrangeSVT; 01-09-2008 at 01:11 AM.
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