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Discussion Starter · #1 ·
Looking through the build threads and what pre made turbo kits have to offer for turbochargers its a prety wide variety. Anything from a garrett t25, mitsubishi td04, possibly ihi rf3, mhi t025 from the 1 5 civic si turbo (really small turbine wheel and housing) , ko3 or ko4.

Then you have the borg warner efr6258.

Obviously with these stock bottom end engines we cant boost over 10 psi safely. 8 psi seems to be the common safe number. 9 psi pushing it and 10 psi your waiting for the boom. We cant make too much torque at low rpms as the rods will exit the block. So need to keep full spool around 3000 rpm?

The question and with real world experiance what is a good matched turbo that does well on low boost, satisfies our 3000 rpm 8 psi full boost, and is in about the 200-220hp range efgiciently. Also one that doesnt have a tiny turbine wheel and housing and cause lots of drive pressure. Excess drive pressure just as bad as a plugged cat and negates putting boost to the engine. From prior experiance most hondas are able to run slightly larger turbochargers than other engines of similar size. But thats from b,h,k,f series engines that have good geometry and good flowing heads.

Ive had my fare share of modified and fast high hp hondas. I know what the crz is and fine with the reasonable power that can be added. Not looking for racecar but a fun daily. Also since messing with such a small displacement engine and low power levels this will be interesting and fun. Im strongly considering the borg warner efr6258. Its ball bearing. Internal wastegate, stainless steel turbine housing with v band inlet/outlet, aluminum center section optional, compressor cover with 90* outlet nice and compact. I think it will fit well. Only problem hard to stomach a 2k$ turbo for just 8 psi and not even for 200hp.

I currently have 2013 crz ex, k tuner, ge8 cam and intake. Will be using rdx 410cc injectors. Will be fabricating the turbo setup and using a air/water intercooler setup.
 

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the only widely available kit that I know of for the CR-Z used the Greddy TD04H-15G turbo which I think is a 32mm turbo. That's the size class I'd be sticking to.

There's a couple people that have done their own turbo kits. I wanna say someone went up to 12 or 13 psi, but I don't know for sure, and I certainly wouldn't say it's safe. Honda warrantied the HPD supercharger kit at about 9psi, so figuring a 20% margin 11psi is the most I'd really push comfortably.
 

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Discussion Starter · #5 ·
Seing how the borg efr6258 is going to be a wzit time to get. Looking at other options. Thoughts on the gt2554r, gt2560? The 1.6l miata guys use this turbo a lot and with good results. Its the smallest garret turbo offered in ball bearing. Has standard t25 inlet and outlet. Very similar to the stock sr20 t25 but in ball bearing.

The next turbo choice is the garrett g25-550
Dual ball bearing, water cooled center section. Stainless steel turbine housing, t25 and v band inlet options, internally wastegated, billet compressor wheel. Only downside its another 1800-2000$ turbo.

Been poking around also looking at existing manifolds instead of having to fabricate one or have one metal 3d printed. Im not a fan of china or this company or fact its cast iron not stainless steel. But it is an option that would get a t25 turbine housing based turbo on to a l15a cylinder head.

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Discussion Starter · #6 ·
The other option is the stock 1.5l si MHI t025 turbocharger that im not really a fan of. Would require an adapter manifold, would require a custom downpipe, and an adapter plate to run a boost referenced wastegate actuator. No one is really sure on the drive pressure because of the very small exhaust housing size. Or if it can flow enough out the rediculously small turbine. Or if the wastegate is open a lot. Also if the turbo would be efficient at lower boost levels. Stock si runs 17 psi.
 
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