True ^. I'm only looking at doing a restrictor plate cut out of scrap aluminum bolted in as a temp gasket at downpipe to exhaust flange. Figure if a little restriction cures the issue then it is WG porting time. No funds for EWG.

Read- https://www.miataturbo.net/showthrea...ht=boost+creep

Disconnect the damn flapper. Know this- when the wastegate opens the flappen, the range it opens is not as much as you would think. I used a small air compressor to actuate the assembly and was surprised how little it moved. Also, exhaust gas takes the path of least resistance. If it's easy to get through the turbine, it won't want to go through the wastegate.

^Thanks. That thread describes what is going on with mine to the T. Even just had the CHRA rebuilt recently. Just called Begi and they'll be getting my housing after the new year. Still going to do a wastegate wired open pull, later tho, my back is killing me. Just for funsies.

On a note: It seems like a ton of people need to port the turbine side. Why not just cast this in from the get go? I know I'm pissing in the wind. Just needed to say it, no need to flame me.

I tried putting a simple restrictor plate in the exhaust system as a temporary solution. Not only did it NOT fix the boost creep problem, but it also significantly increased the boost threshold.

Effectively, my boost came on later, and still creeped to boost cut well before redline.

You really have 2 options, as far as I can tell:
1. Send turbine housing to BEGi and have them port it for the cost of shipping.
2. Buy an EWG setup.

Edit:
Shit, you beat me by 5 minutes

It seems Corky contacted Garrett about the problem to ask them to change the casting, and Garrett basically told him,

"We've never experienced the problem before, you are obviously doing something wrong"

Apparently, we're running a much more efficient setup than garrett has ever experienced...

Begi is only charging me the hour of labor. So for less than $100 it should be fixed. An I agree a exhaust restriction is a bad idea.

Dopp: thanks for the link For some reason didn't come up in my searchs

It is now.
Look at Borgwarner EFR turbo line.

Haha yeah. If I had the money in a heart beat. Need to rebuild the motor soon. Actually what I'm trying to do is make sure everything works right while I save up funds for the motor. No point on putting in a built motor attached to non working parts. Then it's wheels and a call to ARTech. Unless I find wheels for cheap. '97 has a pair of slightly tweaked ugly ones and the '99 has the ugliest 16's ever made that came with the car. Waiting for 949's new style to come out.

Look closelys. It's almost as if someone at BW put some actual thought into the IWG design. :giggle:

Note the angle of the wastegate port and the cavity behind the flapper - the cavity is of particular interest, since the flow off the turbine wheel should create a significant low-pressure zone to promote wastegate flow.

https://www.miataturbo.net/attachmen...ine=1324522040

Here's a less sexy photo of the WG inlet:

https://www.miataturbo.net/attachmen...ine=1324522040

For comparison's sake, here's my old ported 2554R with a much, much sharper transition into the wastegate:

https://www.miataturbo.net/attachmen...ine=1324522040

Can't resist, this pic is too sexy. Our new product photo guy is phenomenal.

https://www.miataturbo.net/attachmen...ine=1324522216

Does this mean we all need to start saving up for a group buy....

No group buy - they will definitely go into production. We may offer a small discount for certain early adopters with certain cars, though.

They'll be priced competitively, but our goal isn't to compete on price - our kit will be a big departure from the status-quo in lots of ways.

No problem Sir.

The hotside I got back from BEGi had a much deeper channel cut into it, interesting. Did that posting fix any issue you were having before, Sav?

Very simple and common issue. Boost creep happens when the wastegate doesn't flow enough which is made worse when your DP back has very low back pressure. Most internal wastegates would creep if you were to run an open turbo blowing hot air on the fire wall (don't try this at home - only mentioned for perspective). Adding backpressure like a restriction or cat as a means to control creep makes as little sense as putting in a smaller turbo that flows less as a means to control creep.

Apples to oranges, but I finally got my 16g upgraded MSM turbo to stay somewhat under control by putting in a wastegate can with a longer throw. The stock can would only crack the wastegate a small amount. I found a can that would swing the flapper open until it hit the back wall of the DP and it helped. Pressurize the WG can with the turbo off the car if you can and observe what the flapper is doing. Don't forget to check how the inside of the DP might be inhibiting the opening. If none of that helps, build the engine, tune to 20psi and hold on!

I guess for others and their searches I should call this issue fixed for now. I wound up porting the turbo. I only had a couple drives with it together before I found out the 2 middle cylinders are F---ed. I will admit I didn't go rape it to truly test the boost stability, however what romping on it I did do it held the pressure I had set it at. Well actually I was messing with a new MBC so don't "know" what I set it at, but it would hit 8psi on wastegate can only and stay there. Couple clicks on the MBC and it would hold 9psi, then clicks and 10psi. So as far as I can tell porting the hot side fixed my issue.