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couple of questions on going turbo.

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    couple of questions on going turbo.

    The time has come to turbo my m30 but I have a couple of questions. I am only planning on 8-10 psi wont go further not looking for massive power. want modest power and reliability
    1. wasted spark is it a must? or will the stock ignition system with maybe an upgraded coil be sufficient for my goals?
    2. Should I use a boost controller or just use the waste gate spring I know you can get a spring for my psi goal
    3. Should I go ARP studs? and could I do them one by one so I don't need to remove the head?

    Info on the setup it Is an m30b34 stock bottom end with a semi built head, mild port job with a 284 cam and upgraded rockers and retainers. Custom euro m10 flywheel and an M5 clutch. fuel system and ignition system are stock but new. Also turbo is a precision 6262 journal bearing has a .63 ar housing likely going to bump that up and G&T turbo manifold tial 44mm waste gate. vibrant intercooler wanna say its 22 inches long, 8 inches tall and 2.5 thick

    1989 325is l 1984 euro 320i l 1970 2002 Racecar
    1991 318i 4dr slick top

    Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
    Vintage race car revival (2002 content)
    Mtech 2 turbo restoration
    Brilliantrot slick top "build"

    Figuring the Big Six is comparable to the Baby Six, I suspect the ignition system will be just fine for you boost goals. It seems the general consensus on M20 spark blowout with the cap and rotor is about 15-17 psi. A set of colder plugs and I'll bet you're good to go.

    You don't need a boost controller, but adding one will enhance boost response and drivability. Here is some good info on the benefits on boost control and how to set it up on your car:

    Here is a commonly used boost controller:

    Regarding the ARP studs, again at your boost goals the stock studs will probably be fine but it's cheap insurance to upgrade the studs. Replacing the studs one at a time without removing the head is a common way to handle it, I haven't seen or heard of any ill effects going this route.

    Good luck!! I'm rounding the corner on turbo dreams soon, at least I can thank quarantine for the extra wrenching time


      Don't know much about the m30 but I know they are similar to the m20. I would say as stated above the stock ignition will be fine. For the headstuds I believe people have replaced them one at a time so they don't have to remove the head. I'm not sure your injectors will be enough though also might want to consider a larger fuel pump. Don't want a fuel failure and a lean condition will definitely melt the cast pistons. Sent from my SM-G973U using Tapatalk


        Stock bolts will handle that 10psi ez. They're non stretch and huge.
        I think i tq mine to 75lb.
        You should test the stretch on an old bolt i think they started to stretch at 80lb.
        Maxed out a 60mil hx40 for years until the turbo over-spun finally. never lifted the head. stock bolts.

        MBC makes the turbo hit harder so use one of those.

        If you have megasquirt use the EBC because you can keep the torque flatter and rev it out alittle more.
        or u can back off boost at lower revs to save the clutch.

        Stock ignition is fine of 10psi if not there's always msd box those things sell for cheap but it's a crap way to do things.

        wish i saw this thread before i sent u that thing because i have a walbro i'll never use. probably a good idea to get bigger pump.
        but test out the stock pump it might be good
        Last edited by LowR3V'in; 05-09-2020, 11:04 PM.


          I am running a stock fuel pump with 60lb injectors and haven't had any fueling issues.

          I am also on a new factory ignition system and everything is good up until 13psi. Right around 13-14psi i start to get a little bit on blow-out with a colder plug. I believe it's a 7 series NGK? I don't quite remember. I set the boost cut at 12 and managed it all with an 8lb spring and EBC. The boost controller is super easy to setup and will make your car a lot more fun for the streets.

          This is all on an m20, but I am sure the M30 is just as capable.

          A stock motor should be be able to handle 8-10psi and 250hp/tq no problem, but studs and the boost controller are little things that will add some longevity to your build.