Manual Boost Controller Recommendations?

TXSpeedDemon

I've never had great results with a MBC. I've run 3-4 different set ups on my turbo mazda, all had a little boost creep and boost spikes.

I decided to go electronic and went with this:
HDi

it's a dual stage EBC that runs about $100 more than a good quality MBC. I think I got mine for like $150-200. Pretty easy to install. Unit is pretty small and will fit in most discreet locations. It allows you to switch between two different boost settings with just a push of a button.

Adjusting the boost for each setting is a simple as turning a knob, then pushing the knob back in to lock it in place. It can be done on the fly - makes it much easier to adjust as weather temps change - here in Dallas we've had a 25 degree temp shift this week.

There are individual knobs for the two different settings. The low boost knob allows for a lot of turning without much adjustment. The high boost knob is exactly the opposite, little turns make a big difference.

On the low boost setting I'm seeing about a quick 1-2lb boost spike on initial full throttle. Spikes at about 11psi and settles in at 9-10lbs. Boost creep is pretty minimal. Seems to hold the set psi no matter which gear I'm in.

On the high boost setting I'm seeing a 2-4lb boost spike on initial full throttle. Spikes at about 14-15lbs and settles in at 10-12lbs. Creep is a little more on this setting. 2nd gear seems to hold at about 9si while 4th gear will be the desired 11-12lbs.

All in all I'm pretty happy with it. I run the low boost setting most of the time, and just push the button when I need to make a statement.

If it were me though I would probably opt for a better EBC for the Z and stay away from a MBC all together. A 4psi spike isn't so bad on a T25 turbo in a car making maybe 250 WPH. A 4 psi spike on a car making closer to 500 WHP might be a bit too much to handle. For me the Z is worth the added security.

You could also think about changing out your waste gates. If you only want to run 1 set level of boost all the time this is probably the best way to ensure you don't ever overboost.