Disclaimer: First off, I know you guys are gonna flame me hard like CNN roast the President, but just want to get some advice and opinions, a lot has changed since 2009 when I last had a miata.

So, How much boost can I safety make on a stock IHI Turbo. And are impeller upgrades (in example Blouch) still available? What’s the track record on BNR, and are there any reputable tuners in North Alabama that can work with FM221 ECU. (I know, I am an idiot for buying this, because Megasquirt is the Alpha and the Omega, the Beginning and the End.).

So I have a 1999 10th Anniversary, damn near literally looks just like a Mazdaspeed Miata, same suspension, 2001 headlights, same same sway bars, same wheels, same body kit and 2001 front bumper, same wheel liners, belly pan, same MSM exhaust system from downpipe to tail-pipe (a bolt on affair) same turbocharger assembly, charge pipes, everything down to the tower brace with the crappy catch can that is even plumbed to the oil pan, so I had to put the fm check valve in it because hard driving was sucking up oil. Oh and MSM motor mounts which WOW what a difference that made considering 8 psi and 10,000 miles of spirited driving will ruin oem mounts fast, they were separating when I replaced them!

Engine management is currently voodoo card with 2004 msm purple top injectors and a torque killing six degrees of static retard, NGK-bkr7e11’s, with a boost gauge and a wide band oxygen sensor, running straight wastegate pressure 7.5-8 lbs of boost, depending on temp. Dynoed around 155 rwhp from what I recalled.

So I got 60,000 miles on the car, runs like a top runs decent afr’s around 12:1.

Lovely car, All that being said, ready to upgrade and just ordered FM little enchilada, FM221 stand-alone (I will never hear the end of “why didn’t you get a megasquirt” I know it’s coming) and 550cc injectors. That out of the way, what boost level can this little IHI safely put out. I’m not looking for maximum boost as much as I am efficiency. What psi should we be aiming for to push the most air efficiently without churning a lot of hot air; consequently, wearing this little turbo out? Torque, drivability, and reliability is more important to me than peak power numbers...

So 10 psi, 12 psi, 14 psi? I need some advice and experience, and yes I know what people are gonna say, “why didn’t you just rip that IHI turbo out and go with a Garrett’s T2560. My answer, “because that makes way too much sense.”

Also, I used to recall years ago that people were changing the compressor wheel impellers on these things and porting the waste gate, are those options available still?

What about the BNR? Any good track records on that?

Obviously, I am running this BP4W stock internals and it runs like a champ, so I am not interested in pushing the car anywhere over 250 lb-ft of torque. That seems to be the point of diminishing returns on a stock motor and rewarded my last miata with considerable engine wear. (Piston rings and eventually rod knock, well tuned, but 14 psi on a 2860RS was just too much.)

As far as your questioning goes, I would find the efficiency range on that turbo simply by googling it, and base your boost numbers off of that.

Good to see you too!Maybe I need to just go back to the old folks home known as Miata.net

Well, this is news to me, and the first I have heard of it. Please understand that I have not participated in this forum since 2010, and in my earlier post, I wasn’t implying or asking for indept and specific tuning advice, just general questions and a idea of a safe range of what MSM owners generally set their boost at without grenading their turbo. At least I know where the general consensus on this forum stands with Flyin’ Miata.