I shoved a big ol turbo in, but I still want more
 

I spent about every free moment of my life for the last two months working on sticking a big ass turbo on my MSM. I made a custom tubular manifold, a full 2.5" exhaust, its got a 38mm Tial waste gate with screamer pipe, nicely routed intercooler piping, bosch EV14 750cc injectors, Megasquirt 3 pro and a bunch of other stuff I had to make.

The turbo is a Chinese thing that I brazed the waste gate hole shut on and then brazed a Vband straight onto the exhaust housing. The specs are as follows: T3 with a 50.5/76mm Compressor and a 65.5/55.9mm Turbine .63 AR. Yes it is too big, but I already had it laying around and I kinda like the insane torque curve that a big turbo makes.

After a bit of tuning, I was able to get everything running nicely, but the giant ass turbo doesn't make full boost (15 PSI) until about 5,800 RPM. It isn't that insane when you consider the stupidly low gearing of this thing, but still, I've got a slightly smaller turbo with a .48AR turbine housing I'm going to stick in there to see if that makes me happier.

But basically, I'm at a limit here. I like the ~250 Horsepower it makes, I like the 4.5ish second 0-60, I especially like the turbo noises, however, I want more.

My question is what should I do next? I either build this engine to be able to handle the 300+ WHP that I want, or swap in a 2.2 ecotec and either modify the cobalt SS supercharger to fit on there or slap a big ol turbo on that. I'm open to ideas, and other swaps that could get me where I want to be.

While cost really isn't a big deal, time is a factor since I'm fabricating just about everything myself.

Either way, Thanks for just helping me brainstorm ideas.
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What type of turbo? I'd prefer to not spend $1300 on a turbo, but I haven't seen any with technology better than China for under that amount.

And what's wrong with a custom fabbed 2.5" exhaust? I've got vibrant mufflers and everything

You want to spend massive money on a swap, but you won't invest in a decent turbo on your current setup?

Yes. My priorities are messed up.

I just haven't experienced a $1300 turbo so I don't see how that Garrett can be 13 times better than the $100 Chinese turd.

A properly sized turbo and a properly sized exhaust will be much better than improperly sized ones. Even if it's a properly sized churbo, and not name brand.

Curly, I'm not as interested in extreme boost response so I'm looking at turbos around the 2860R size. Plus low end torque isn't great for rods and all that.

I'll have to look into remaking my exhaust in 3" for better power and response though.

What? Its making 230tq and 250hp now. I want more than that.

I found a Garret GT2860rs with a VBand housing and I think with a 3" exhaust, that'll get me where I need to be.

A 2560r will make all the power a stock motor will handle, and do it across a wider range than any other turbos you're talking about. Why would you want to make less power with a bigger turbo?

Got a dyno chart of that? Interested how you're making that much torque with a turbo that doesn't spool until 5800rpm...

A three inch exhaust will help whatever turbo you are running on a Miata.

Adding forged rods will allow you to turn up the boost on the system you have or any other system so it makes good sense. Forged rods and low compression forged pistons would let you go to 350 or more horsepower. You will have to make some other supporting modifications but forged motor is the best investment no matter what.

He didn't say it didn't spool until 5800. He says he hit his limit of 15 psi there. I bet his torque peak is above 5252 RPM. The stock motor does a torque plateau due to the cams and intake runners being maximized between 4500 and 5500, and he's hitting 15psi right close to that.

That said, it sounds really peaky.

https://docs.google.com/spreadsheets...6bI/edit#gid=0

This may help. Figure out some specs, find a turbo that fits what you want from a name brand, then find a churbo knock off of said brand.

There are non-Chinese options for half that number new. They aren't EFRs but they are turbos. Spend a minute searching and they pop up everywhere.

Name Brand Turbos Sale

http://spsdiesel-com.3dcartstores.co...0HP_p_423.html

https://www.full-race.com/store/borg...m-s200sx-7070/

https://www.full-race.com/store/prec...831-cea-turbo/

https://www.full-race.com/store/garr...3t04e-turbo-2/

*Some of these may not be exactly what you need but they are examples to prove a point. You should research before buying to determine proper whatever and stuff.