gtred

Track day tomorrow and out of the blue the car is not boosting fully... only 10lbs instead of a target of16lbs. I suspect that it's the mbc. It's been sitting all winter and the mbc/regulator might have just frozen up. I've ordered a new Westgate actuator, replacing the old 7-11 lb actuator with a 12-15lb actuator. I'd like to just set it at 15lbs and just forget about the mbc. I'm not sure how to properly set this though. Another difficulty is that it gets boost creep at levels above 16lbs... so I'll want to make sure that the waste gate will fully open. Anyone with advice on a Garrett 2860?

Chiburbian

iTrader: (1)

Without an MBC, the only method is to play with pre-load. Go out and do a pull and check the log in 5th gear. Did you hit your target? If so, you are fine, If not, turn the wastegate actuator end a full turn. Repeat until you hit your target. If you overshoot, come back a half turn.

Using wastegate to get your turbo to spool is a less than optimal way of making power though. You are much better off with an EBC hooked up to your ECU. You will get to your target faster.

sixshooter

iTrader: (12)

EBC will get you there. Wherever there is.

andyfloyd

EBC for sure, itll hold the wg closed which will improve spoolup. Using only the wg can to control boost will result in slower spool due to the flapper blowing open earlier.

gtred

Im a little frustrated at all of the I.T. gremlins that have been unleashed since i modified this msm away from stock. Sure it's way faster now... but routinely has issues that send me packing up early. Sometimes simple gets you to the finish line. I'm currently using a MBC because it seemed more "bulletproof" when compared to an EBC. And 2 days before the event, it still went south. Thinking about just using a 15lbs spring and doing away with the MBC all together. Am I wrong about this? Are you of the opinion that an EBC is a more reliable way to go?

sixshooter

iTrader: (12)

If you go that route why don't you just weld the flapper shut.

Instead buy a greddy profec b and be done with it. Reliable, adjustable, worth it.

I don't try to make the MS EBC control work because it's more trouble than I want. I went with proven.

DNMakinson

iTrader: (3)

Actuator is the simplest, most reliable method for a single boost target. You are on the right track. Especially since you already ordered it.

Put the spring in you want. Adjust 1/16” to 3/16”’preload. So gate does not open prematurely.

Does the actuator have any other adjustments? Possibly washers? If so, that can be a fine tune for final pressure.

nitrodann

Additional preload due to washers or a threaded actuator rod.

Dann

Schroedinger

There is a pretty good range of adjustment available with WG preload. Just adjust in fine increments, log and compare.

I’m curious how your MBC failed... they are pretty simple devices. Have you taken it apart to see what’s going on inside? I run a Hallman MBC and it works perfectly. I’ve seen no real need to jump to EBC.

curly

iTrader: (25)

Chiburbian

iTrader: (1)

100X this... That is a really good point Curly.

curly

iTrader: (25)

My only thought is that it could only be the vacuum line from MBC to turbo, right? If it was a charge pipe coupler, you'd get the same boost but the turbo would have to work harder. I guess that could happen if it wasn't able to spin faster. Sorry Craig, I don't remember what turbo you have and how hard we're pushing it.

If it was the vacuum line post MBC, you'd have an overboost issue. Feel free to check my logic y'all.

Savington

iTrader: (31)

There is pretty much no way the MBC failed in the open position unless the spring broke inside it. Curly is probably onto something.

gtred

Yes Curly... I didn't recieve the new waste gate actuator until late... the plan was to tech the car and fix it at the track. Interestingly, as I was going thru tech, I leaned on the boost hoses when putting up the hood prop... and noticed that the diverter valve hose pulled away from the throttle body inlet tube... then slipped right back in place when I released tension on it. It seems that the factory spring clip was not up to the task, allowing for a a large boost leak. Luckily, Dan from AR automotive was the tech stewart and had brought a trailer full of parts. A new hose clamp and the car ran like a champ!

In fact with the new motor ... and your tune, the car ran faster than it's ever run. Thank you!

curly

iTrader: (25)

Called it! Good to hear it's running better now.