I'm pretty sure the problem is limited to the turbine housing used on the GT2560r, I don't ever recall this same "unmanageable" problem on any other turbo. Differently specced turbos are going to have differently specced castings, it just seems like many Miatas running the GT2560r are seeing turbine/compressor efficiencies that exceed what Garrett's engineers thought were possible, so much so that we're having to improve the efficiency of the wastegate to correct the nearsightedness of those engineers. After telling the engineers they screwed up, we continue to have to port wastegates in new turbochargers to correct the thickheadeness of those engineers.

Nice, thanks for the update.

I don't have my 2560 installed yet, but this is one of those "well, I can do it now and be more sure of what to expect, or rip shit apart later and deal with it again shit I have this issue." How prevalent is this issue in all reality? Obviously we can site a bunch of examples here in this thread, but would this be considered systemic?

Edit: Let me put it this way... if you had to build a Miata w/2560 today, would you port as a preventative measure or not?

built? as in built engine?

heck no.

otherwise yes, definitely. esp in CA where temperatures swing 20-30* from day to night sometimes.

Built as in "started over and built a whole another Miata"

But yeah, your reasoning is exactly along the lines of what I've been thinking about. Plus I've got all this awesome chilly coastal air to pack away :party:

Bouncing off the boost cut on a cold night in a higher gear blows.
And disabling or raising boost cut means venting the block.

So you either build the engine and enjoy the boost creep, or you eliminate the boost creep

If your exhaust is going to be any more "free flowing" than a 2.5" full length with stock cat, then port the wastegate. BEGi does every single 2560 they sell as a matter of doing business because they know the problem isn't just limited to "special circumstances". Half or more of the active 2560s on this board are probably ported. The other half are either running small exhausts or they manage to keep their cars out of "boost cut" with throttle modulation.

The 2560r I have came from an older FM2 so Im assuming its not ported and to confirm I never noticed boost creep with a stock exhaust and test pipe. Looks like it only started when I went 2.5 all the way back from the turbo. I'd rather port it at this point the response I get with the 2.5 inch straight is much better.

Also, let it be known that FM's "fix" for this is to put a restrictor plate in the exhaust, or run a cat. Which is why i'm guessing they don't sell a test pipe.

I noticed that. Looks like I'm calling BEGI for some portage.

Thanks gays for the discussion, I love how productive this community can be when motivated. :makeout:

I'm kinda shocked you didn't get blasted to "search noob", because this topic is brought up somewhat Often.

Though.
I do think i made a thread exactly like this maybe 2 years ago and didn't get blasted.

Meh, not my thread. Believe it or not I have searched previously, but all I really found was a series of isolated reports rather than a thread like this one with actual feedback from multiple people who had done the deed. So... :party:

THIS ^ THIS ^ and THIS ^ I originally searched my ass off and it kept coming back to

1)Vacuum Leak
2)Bad Wastegate Actuator
3)Vacuum Leak
4)Bro is your turbo bad
5)Too much preload
6)Its a vacuum leak jackass are you a troll

None of which till now could I find about the turbo porting. Thanks for the help from everyone and pics.

You searched "boost creep" and got those answers? I find that hard to believe

I feel like "Boost Creep" should be someones title, like Concealer :giggle:

Scotty: Want to sell me that FM WGA if you decide to stick with the Kinugawa?

Yeah Ill sell it to you now. Do you have the FM Bracket already? I have this

https://www.miataturbo.net/attachmen...ine=1387398027


But not this

https://www.miataturbo.net/attachmen...1&d=1387397986

PM me if your interested with a zip and an offer

No I searched "overboost"

BTW off topic the Kinugawa piece is very nice for 100 bucks shipped.

Yup, I haz that brackety thing.

I actually looked at the Kinugawa and the one from Turbosmart because I want an adjustable. I didn't notice anyone running either one so I kinda went "meh." Lots of posts asking about the turbos, but nothing about the adjustable WGA. There is a huge dent in my 2560 can so I don't exactly trust it, but do I trust Kinugawa more? :giggle:

Kinugawa, while a knockoff ching-ching ebay distributor, actually tends to put out decent products. I've not been disappointed yet and I've used at least a handful of parts from them.

Like a WGA? ;)