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Thread: Mini build

  1. #1
    Join Date
    May 2009
    Location
    Indiana
    Posts
    34
    My Cars
    88 635csi-M

    Mini build

    Been considering doing a Mini build. Will likely buy a salvaged Mini (body work only and/or minor engine work depending) and do a build on it.

    Want to get the drop top cooper, having trouble deciding engine/years/etc. to work with.

    I would like to do standard suspension build (antiroll bars, springs & shocks, poly bushings where usable, strut brace), standard brake stuff (slotted rotors bbk available?, stainless brake lines), put it on a diet (no back seats, ditch the spare), but add some other things.

    Want to add a turbo (Mitsubishi td04hl-13t is one in mind) and then fabricate the exhaust (magna cat, magna muffler, 3" to the back). Would have to add an IC not sure which to go with/size necessary for the mini.

    Here are the questions I have now:
    - what turbos are most people dropping in? (garrets is was it looks like)
    - what are the differences I need to be aware of between the S cooper and regular Cooper? (compression could effect which turbo and boost I shoot for, are there rod differences/trans differences, etc.)
    - What tuners are recommended for a custom map like this?
    - how much BHP can the transmission handle?
    - will loosing weight make me loose the back end?

  2. #2
    Join Date
    Aug 2008
    Location
    Delta, BC, Canada
    Posts
    118
    My Cars
    2006 BMW 525i, 2005 MINI Cooper S
    If you are looking for a convertible, then unless you buy a new car, you are looking at R53/R50 cars (previous gen) as the latest update to the convertible was just a few months ago. The R53 used a supercharged engine which also drives the waterpump so you can't simply sub in another supercharger. However, some have tried and been successful but with a lot of effort. There are also twin charge kits available. You might check with Alta Performance

    RMW or Mynes seem to be the two highest regarded companies that can custom map your ECU for you. They do it on a dyno so it's not a canned mapping.

    The Cooper engine is the same block as the Cooper S but is higher compression so uses different pistons and maybe head. I find it revs more freely than the supercharged engine, though the supercharged engine makes more torque and power.

    The R53 6 speed manual transmission has proven to be very robust and can handle race prepared engines without any mods. However, you may consider upgrading the dual-mass flywheel and clutch if you are planning on going over 250 or so horsepower.

    Losing weight will actually make your car go faster and handle better. If you leave your car relatively stock, but upgrade to the JCW suspension, MINI actually checks your vehicle's VIN to see what options you had on the car and match the springs to the weight of the car when it left the factory.

    If you decide to build an 07 or newer coupe (R56) or 09 convertible (R57?), I have not seen anybody successfully remap the ECU yet to gain a lot of horsepower. BMW seems to have locked that down pretty good. However, there are a number of pretty good MINI tuners that have done great things with the already pretty good suspension. It would depend on where you are.

    Good luck to you on your project.

    2006 525i, 2005 MINI Cooper S

  3. #3
    Join Date
    May 2009
    Location
    Indiana
    Posts
    34
    My Cars
    88 635csi-M
    I've been thinking 250bhp so flywheel & clutch upgrades look like a must have.

    I don't want to do the supercharger. I want to pop in a turbo instead. I've read that some of the later series coupe S-series were turbocharged rather than using a super. Are the mani and downpipe a direct bolt on to the older series Minis?

    I was assuming to go all aftermarket for the suspension rather than deal with the JCW pricetag.

    I have turbocharged N/A engines before and seen some good results due to the higher compression. Can the stock Mini engine handle 250bhp albeit around 15psi without melting rods? I haven't found any aftermarket rods available yet for the mini, which could make the decision of whether to get the S-series or not. I'd prefer to avoid due to the significantly higher cost (even of a salvaged vehicle!)
    88 635sci project car

  4. #4
    Join Date
    Aug 2008
    Location
    Delta, BC, Canada
    Posts
    118
    My Cars
    2006 BMW 525i, 2005 MINI Cooper S
    The 2007 and on Cooper S cars are turbo-charged. But the convertible was not until 2009 (just recently actually). The entire exhaust, actually even the engines between the Supercharged and the Turbocharged engines are different. Certainly the Turbocharged motors are faster and appear to have better midrange torque. The factory mapping also has about a 10 second overboost on hard acceleration. I suspect 250hp should be easily achievable with available aftermarket bolt on parts.

    The turbo charger sits right in front center of the engine bay so if you plan on bolting on a larger turbo, you should make sure heat shielding is adequate. I have seen some slightly melted (warped) hood scoop assemblies.

    I'm hardly knowlegdeable on anything about the turbo'd engine as I own an R53 (supercharged engine). But a quick look at the list of usual suspects of MINI Vendors and I don't see anything real major mods that would give the turbo'd MINI engine much more than what is already there.

    Cold air intakes and exhaust systems seem to be the major way of gaining more horsepower.

    2006 525i, 2005 MINI Cooper S

  5. #5
    Join Date
    May 2009
    Location
    Indiana
    Posts
    34
    My Cars
    88 635csi-M
    Thanks for the good information. Apologize if some of these are stock questions but this is my first bimmer.

    I think i need to pull the trigger and engineer as I go.
    88 635sci project car

  6. #6
    Join Date
    Feb 2007
    Location
    Atlanta,GA
    Posts
    132
    My Cars
    6 MINI's, 1 '95 318
    Way Motor Works in Atlanta has a slightly damaged MINI for sale you could use for your project. It's not a convertible, but the price is right.

    Also Way does Custom tunes like RMW/Mynes, but doesn't fly around the country doing them so he doesn't get the PR like they do. But gauranteed quality tuning.

    They are right there in Atlanta so it should be super easy for you.

  7. #7
    Join Date
    Aug 2008
    Location
    Delta, BC, Canada
    Posts
    118
    My Cars
    2006 BMW 525i, 2005 MINI Cooper S
    Quote Originally Posted by MINIGURU View Post
    Way Motor Works in Atlanta has a slightly damaged MINI for sale you could use for your project. It's not a convertible, but the price is right.

    Also Way does Custom tunes like RMW/Mynes, but doesn't fly around the country doing them so he doesn't get the PR like they do. But gauranteed quality tuning.

    They are right there in Atlanta so it should be super easy for you.
    Actually, I've heard good things about Way also. But I'm clear on the other side of the country...actually in another country.

    Good of guys to chime in here.

    2006 525i, 2005 MINI Cooper S

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