Porting internal wastegate/turbine on Stock IHI, need direction...
 

Hey, Thanks to this site I found a good deal on a Stock Mazdaspeed miata IHI turbo with the compressor upgrade, and was wondering if anyone has some experience with mild port working on turbos. Deadbolt wants about 350 plus shipping, and I'd rather do it myself... I have asked a few MSM guys on our forum, but there is far more experience here, and many more tuners. Well, basically I'd like to smooth out the exhaust side and clean up the wg where the downpipe bolts up, on the IHI it apparently flows horribly. Any tips? also, I have a die grinder and a lot of bits/paper to use. anyway, thanks a lot!

Don't just clean up the wastegate, port it out as much as possible while maintaining enough sealing surface for the flapper to move around on.
Do a search on the forum for wastegate port and you should get a few threads.

any specific number/measurement/figure for the flapper-to-port overlap?

I could ramble off numbers but its much easier to just look at the shadow and machined surface for the flapper then actually measure anything.
Here are some threads about it.

https://www.miataturbo.net/forum/sho...ting+wastegate
https://www.miataturbo.net/forum/sho...ting+wastegate
https://www.miataturbo.net/forum/sho...ting+wastegate
https://www.miataturbo.net/forum/sho...ting+wastegate

You're awesome. Thanks man. I'll get to this on Thursday.

Definitely some mixed theory behind the porting. I didn't consider the line bore from the turbine entry to the wg port, but it makes some sense. I wonder how much that disrupts flow (hurts efficiency) to the turbine wheel. :dunno:

Corky at BEGi would also do it for you....most likely at a much better price than Deadbolt, and since deadbolt is a deadbeat, you'll get your turbo back and not get screwed...

http://www.boostedmiata.com/turbo/wa...e/CIMG1365.JPG