Older IHI Turbos revisited .

discopotato03 · Post by **discopotato03** » Mon Apr 06, 2009 10:33 am

Hi all , a few people are telling me that rebuild kits for the earlier IHI RHB52 turbos are not unobtanium afterall so I've been researching the ones used on early EJ turbo engines with a view to making something up for my EA82T .

I should have my hands on a JDM VF8 from an early Legacy RS RA spec and a VF10 which I think was also JDM .

With a flange change a VF10 is probably not a bad place to start with standard turbos .
The "other" spec (see real XT4 WSM's) have a 15R turbine housing and the same turbine in their EA82T VF6's where all other USDM/ADM cars got the smaller 12R one .
With slightly better cams they made an extra 30 Hp when new .
Grafting on a VF10 gives you best factory spec turbo hot side and a better compressor end which takes a bit of explaining .

With RHB52's there were large and small turbine sizes and a similar deal on the compressor side .
The large turbine size is not much larger on the major (inducer) diameter but a fair bit larger on the outlet (exducer) diameter .
The turbine housing is also noticeably larger in its volute passage and has the 20R size cast into it .
The usual give away of a VF8 or VF12 is the large 10 bladed turbine and the 20R turbine housing .

The smaller series 9 bladed turbines were used in VF2/3/4/6 Turbos on EA82T engines and some early Turbo EJ's .
As I said most EA82T's had the small 12R turbine housing but a few were sold in Europe with slightly bigger 15R ones . These with the better cams and Spider inlet manifolds cranked out an extra 30 horses over our spec EA82Ts ie 135 vs 105 .
The USDM Legacy Turbos had a unique VF11 turbo which is basically an EA82 turbo with a slightly different compressor and an EJ flanged 15R turbine housing .

Compressor wheel wise two basic sizes were used in Subarus , the 52mm major diameter ones and the 56mm major diameter ones .
The 52mm ones are in all EA82 turbos and the US spec Legacys VF11 .
The inducer size of the EA's turbo compressor is ~ 39mm and the US VF11 is slightly larger but not sure by how much .
With these smaller compressor spec turbos IHI used a smaller compressor housing and you can ID this by the external lip or flange with "eyes" where the clamp bolts screw in .
The real give away of the larger 56mm compressor versions is the larger housing that blends into its backplate . You find them on VF10s 8s and 12s because they all use 56mm major diameter compressor wheels .
Where a lot of confusion occurs is because people look at a turbocharger and try to guess its power (airflow) potential based on how big the compressor wheel "looks" when looking through or measuring the size of the hole in the snout of the compressor housing . Failed concept .
The inlet or inducer size of a compressor wheel won't tell you what the major diameter of the wheel actually is and you can't see that with the compressor housing in place .
To look at a VF10 has pretty much the same inducer/inlet size as an EA82's turbo but the major diameter is 56mm not 52mm and that makes quite a difference .
The VF8 and 12 also use 56mm OD comp wheels but the trim is slightly larger on the VF12 which is the only significant difference between an 8 and a 12 .
I don't yet know what the exact inducers sizes are but I think its in the 46-48mm range with the 12 being supposedly 1mm larger .

In laymans terms smallest to largest power wise .

EA82 turbo = small hot side + small cold side , 12R or 15R turbine housing .
VF11 turbo = small hot side + small cold side , 15R turbine housing .
VF10 turbo = smal hot side + large cold side , 15R turbine housing.
VF 8 turbo = large hot side + large cold side , 20R turbine housing .
VF12 turbo = large hot side + large cold side , 20R turbine housing .

Note the VF10 is small on the hot side and large on the cold side , its the small inducer size or trim that prevents it being a real laggy dog .
It also means ratbags like me can hybrid the larger diameter but smaller trim VF10 compressor and its housing on to the larger hot side VF8 or 12 which get s you low exhaust restriction and better response from the less loaded smaller trim compressor wheel .

Gee tells me that someone here before I came on the scene had a souped up RX L sedan in QLD which used custom cams and a std VF8 , supposedly made 200+ ponies at the treads with no intercooler and aftermarket computer and injectors .
If anyone knows where in the archives any of this info is please let me know .

Hmm , 200+ at the deck in an 1120 kg AWD L sedan could redden a few faces if it looked and sounded insignificant . Rubs hands together , must dig up a pair of later MPFI NA cams ...
Seriously though 140 odd Kw (approx early RS Lib engine power) would be exciting enough in an L series sedan given that they are about 220 Kg lighter overall . Have to be nice to the gearbox .

A .

Late Edit :

A bit more info to hand , I found some part numbers for the compressor wheels in some of the above mentioned turbochargers .

1) 3911EZ 52.2 x 38.53mm so 54 trim .
2) 4016EZ 52.53 x 39.42 so 56 trim .
3) 4225CFZ .
4) 4625CFZ .
5) 4726CFZ .

It was mentioned on another board that the first two numbers to the nearest upper mm represents the compressors inducer or inlet diameter .
It could be a fluke but it runs very close to being right .
The LHS numbers represent the compressor sections of VF2-6 , VF11 , VF10 , VF8 and VF12 .

I really need to pull the comp housing off that VF10 and measure its compressor when it arrives .

brumbyrunner · Post by **brumbyrunner** » Mon Apr 06, 2009 11:18 am

Original owners username was QikRX or something and the car was sold to a miner in Gladstone I think. He bought it for his wife to go shopping in as he had a GTR. Last I heard it had been painted prodrive blue and the 15" Superlites swapped for some 13"s.

steptoe · Post by **steptoe** » Mon Apr 06, 2009 12:00 pm

and QikRX was last in here in Jan this year

discopotato03 · Post by **discopotato03** » Mon Apr 06, 2009 12:18 pm

LOL , Mrs rev head in the "shopping trolley" .
Doesn't bear think about does it ? Road rage anyone ?

Cheers A .

Ben · Post by **Ben** » Mon Apr 06, 2009 5:25 pm

discopotato03 wrote: Seriously though 140 odd Kw (approx early RS Lib engine power) would be exciting enough in an L series sedan given that they are about 220 Kg lighter overall . Have to be nice to the gearbox .

A .

I had a 185kw L series sedan and yes it was 'exciting'

Gannon · Post by **Gannon** » Mon Apr 06, 2009 5:51 pm

Ben wrote:I had a 185kw L series sedan and yes it was 'exciting'

Yeah but that was with an EJ20T?

QikRX sold his >>>QikRX's RX Leone <<< to ORX-18

Apparently it made 260HP and over 400NM on 18psi and a VF-10

Ben · Post by **Ben** » Mon Apr 06, 2009 6:53 pm

Suparoo wrote:Yeah but that was with an EJ20T?

Yeah, the sensible method for big power in an L

It's easy - bolt in, go fast

steptoe · Post by **steptoe** » Mon Apr 06, 2009 10:40 pm

he may have been the one using 1983 model 300ZX injectors on his EA82

discopotato03 · Post by **discopotato03** » Mon Apr 06, 2009 11:55 pm

Yes I understand that one of the Nissan L28 sixes , possibly the L28ET which we didn't get used reasonably sized hose tail style injectors .
I still have a set of FJ20ET injectors which are same or slightly larger - in the 280-330cc range .

A .