In my years of research on here and working on these cars, I have in my head that EA82s have a VF-7 and EA81s have a VF-4 then early Leggys get a VF-11. If that is wrong we can end the discussion. It is also my understanding that the EA81T VF-4 was oil-cooled only.

Well, I pulled the turbo from my 88 RX. The unit is clearly marked as VF-4, and it is water-cooled. I'm pretty sure that it is the same turbo that came in the RX with ~120k miles. The previous owner had it for a couple years and thought that it was an original motor. It could be from a different EA82, or maybe bonus junk from another car purchase, but I'm pretty sure it was my first one and daily driver.

Could it be a rebuilt VF-7 with a VF-4 compressor housing (where the marking are)? One of my motors is one of the JDM imports, could it be a JDM-only legit water-cooled VF-4?

 

I remember reading that the ea81t's had either a tsb or recall to install a water cooled turbo.  Its quite possible the replacement units were the same as early ea82 turbos

That turbo is an EA82 turbo and is both oil and water cooled.

That turbo is an EA82 turbo and is both oil and water cooled.

So do EA82s normally get a VF-4?

IHI RHB5 from what i have seen

There are dozens of different RHB5s.

RHB5 is a IHI frame size that was used in many turbos:

The RHB52w is found in our Mx6/Probe's with the VJ11 from 89-91. A
Warner Ishi RHB52w was also used in the TBird from 87-88 (VC32M -for
manual trans and (VC32A) for auto) *(NOT a VJ17 which are from the non-U.S 323 GTX)*.
Other RBH52w's include: 85-90 Isuzu I-Mark (VI-55), 84-87 Isuzu
Impulse(Piazza)(VI-34), 90-94 Subaru Legacy (VF-11) and all 1.8L T
subarus from 86-91. The VJ20 is in the 1.8L Mazda GTX the 88-98 1.6L 323
had a VJ-14 and the 86-87 2.0L 626 had a VJ-5.



The RHB52 was used in the 84-86 turbo Escorts(VC-31), the 88-89
Chevy Spectrum (VI-55), 91-94 Ford Laser-Capri (VJ-14), 84-95 Mercury
Lynx (VC-31), Ferrari 208, and Bugatti EB110(x4). Fiat used them and
it's a popular turbo for motorcycles. It was also going to be used in a
TT version of the DeLorean, but the company supplying the parts went out
of business before they could build them.

The RHB51w is found in the 84-91 Maserati BiTurbo(VM-3 and VM-4)

Some known RHB52 part numbers:

subaru turbos:

VF10 - RHB52XW - 5200 2 P15NR BRXLL4225CFZ 39.5mm/56mm

VF11 - RHB52XW - 5200 2X P15NR BRLL4016EZ 37.5mm/52.5mm

VF8 - RHB52XW - 10000 3X P20NR BRXLL4625CFZ 43.5mm/56mm

VF12 - RHB52XW - 10000 3X P20NR BRXLL4726CFZ 45mm/56mm
 

Isuzu turbos:

VI34 - RHB52A-10000 3 P25NR BRL3911EZ

VI37 - RHB52W-10000 3 P25NR5 BRL3911EZ

VI23 - RHB52A-10000 3 P25NR BRL3911EZ
 

and the mazda turbos:

VJ11 - RHB52KW - 5200 2K P20NR5 BRL3911EZ 38mm/52.2mm

VJ14 - RHB52MW - 5200 2M P12NR5 BRKL3711EZ

VJ16 - RHB52MW - 5200 2M P15NR5 BRKL3911EZ

VJ17 - RHB52BW - 10000 3B P25NR5 BRL4016EZ

VJ20 - RHB52UW - 5200 2U P15NR5 BRUL3911EZ 36.5/52.5mm
 

Here's a TON more I found:
www.turbomaster.info

More RHB5 compressor/turbine dimensions:
turbointernational.com

^^^ from http://www.angelfire.com/extreme4/mattmouth182_rag/mx6/page.html

In my years of research on here and working on these cars, I have in my head that EA82s have a VF-7 and EA81s have a VF-4 then early Leggys get a VF-11. If that is wrong we can end the discussion. It is also my understanding that the EA81T VF-4 was oil-cooled only.

Well, I pulled the turbo from my 88 RX. The unit is clearly marked as VF-4, and it is water-cooled. I'm pretty sure that it is the same turbo that came in the RX with ~120k miles. The previous owner had it for a couple years and thought that it was an original motor. It could be from a different EA82, or maybe bonus junk from another car purchase, but I'm pretty sure it was my first one and daily driver.

Could it be a rebuilt VF-7 with a VF-4 compressor housing (where the marking are)? One of my motors is one of the JDM imports, could it be a JDM-only legit water-cooled VF-4?

 

That is wrong.

The strictly oil cooled EA-81Ts were VF1s.

 

Early EA-82s were VF2s.

I pulled a VF2 from an 85/86, IIRC.

 

VF4s and VF7s followed in later years.

 

The VF1 has noticeably smaller wheels.

The VF2,4,and 7 are almost indistigushible.

 

They are all RHB5s.

RHB52s are a slightly different breed.