Stock Turbo information for what it's worth

[Houdini]

Copied from Upgrades:

"Well I took the stock turbo apart after posting here this morning and I was pleasantly suprised. Although a direct match wasn't found it did seem to fall between 2 different turbos on the compressor side. I took the larger turbo for comparison and it looks like it could fall into the range of 200 to 215 HP assuming the wheel aero is similar which can't be validated. Maybe 225 is obtainable but it didn't look promising."

To add to that post the compressor looked to be approx. .48 Trim with an approx. .45 A/R. I had a harder time measuring the turbine but the trim looked like .47 and the A/R looked like .43. The A/R's are very difficult to guess/calculate with precision unless you were to reverse engineer the housing.

[F1 LOTUS]

Seems to fit with what LEC members are achieving, nice to verify stuff like this before changing things willy-nilly
Now, from what you've measured of the stock turbo, can you identify stuff that is causing avoidable (with a newer design) lag besides it not being a ball- bearing design, and any inefficiencies that lead to higher intake temperatures etc?
Interesting stuff

[Houdini]

Brian,

Turbo actually looks very nice, they did an excellent job as they still do today. Not really anyhting that sticks out for improvement. What is holding it back is the flow capacity and that's it. The cure is a larger turbo plain and simple. Turbo could be from any manufacture actually, IHI and Garrett are the obvious choices, but Borg Warner may get into the performance scene shortly.

[Doug]

Can you post how you figure out the HP range of the turbo? Is it by max sustainable boost pressure in certain displacement engine--I've often wondered what goes into the equation to get a bunk little HP answer ? ? ?

[Houdini]

Doug,

What I did was alot of guess work based on the information I already new, and the history of how IHI turbos test in the lab.

In the real world it's a combination of several things. Know aerodynamics of wheels and volutes, material properties, simulation software, gas stand testing, engine stand testing, and on vehicle testing by us and the the end customer. All the major turbo manufactures are designing to specific application for the most part. Alot of our aftermarket turbos are hybrids of different applications, but quite a few have been used in production vehicles. We have some very fancy propietary software that allows us to combine different wheels, housings, etc and simulate performance before actually building the turbo and test it.

So I guess there is no short easy answer to your question. Now if you want to size a turbo and use known maps you can go to our web site and see some manual calculations that you can play around with and some general theory as well.

Cheers!

[F1 LOTUS]

Found some more info that I believe is relevent to the stock turbo?
[url]

General IHI turbo Info:

Here is some info revealed about turbine casting numbers:
2
k
oD
52k
20R5
I don't know if the 2, K or OD mean anything but 52 means a 5200 wheel the 20 is the a/r and R5 is the

material which is D5-niresist or high temp material for gasoline(not diesel). The 5200 wheel is 52mm

(52.5mm to be exact per sixsick6) wide at the inducer tip. The inner diameter of the VJ11 turbine is

42.40mm (again from Sick: http://www.mx6.com/forums/showthread.ph ... 920&page=1 )

For IHI, the A/R(Pxx) is in mm2/mm. It can be converted and compared to other turbines, which are more

typically in2/in. [example: Just divide it by 25.4 to get the "real" A/R, for example, if you have a p20 it's what

Garrett would call a 0.78 A/R housing.]


More good info about IHI turbos and their names/spec #'s:

The VI-34 (Isuzu Impulse turbo) number is called a short spec. V=Vehicle I=Isuzu (don't know about our "J"

or "F") 34=the first 2 numbers in the long spec. The long spec is actually the part number on the IHI bill of

materials or the list of parts that make up the turbo right down to the snap rings, nuts and bolts. RHB5 is

typically called the frame size. RH=Right Hand(the direction the wheel rotates) B=Generation( IHI is now on

F in 2005) 5=size range(5 is approximately 80hp to 250hp) Within a frame size things like shaft diameter

and bearings are common.

Compressors: EX. stock compressor - VJ11 (spec: BRL3911) 39=39mm inlet, 11=???, BRL=Back Rake

large (BRLL - very large). Back rake is how much the exducer tips of the compressor lean back. The more

back rake the wider the map and the less pressure ratio.

Turbine wheels: 5200II=52mm inducer tip width. II=revision 2. I think all RHB5 turbines are 60mm in major

diameter and 52 or 54 at the minor outlet diameter. You can stick a 5200II turbine wheel in a

P9,P12,P15,P20 or P25 A/R turbine housing. Each increase in A/R shift the turbine hook to the right a little

on the compressor map. In engine terms the larger the a/r the more lag and more top end.


RHB5 is a IHI frame size that was used in many turbos:
The RHB52w is found in Mx6/Probe's with the VJ11 from 89-91. The RHB52w was also used in the

TBird from 87-88(VJ17)[some sources say VC32M -for manual trans and (VC32A) for auto], 85-90 Isuzu

I-Mark (VI-55), 84-87 Isuzu Impulse(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)

RHB51 hold compressors up a BRL348
RHB52 holds all compressors up to the BRLL4625 (VF8 compressor).
A "W" on the end means it is a water-cooled center section.

My Elan Turbo identification numbers: -
On compressor
TURBO SPEC VI77 9009
SERIAL No RHB5 25 374A
PARTS No 894 3373502

On turbine housing
S1
06
52-
15-R
5


http://www.mx6.com/forums/showthread.php?t=140946
http://www.angelfire.com/extreme4/mattm ... /page.html
http://www.gnttype.org/techarea/turbo/turboflow.html[/url]

[Houdini]

Cool - Let me look at this for a day or 2

[joeisuzu]

So if we make a the tbird hybrid turbo, does the lag increase much if at all? My car starts to boost right around 3000 to 3200 RPM, but its an impulse... Does the Elan have a different turbo? I would think not much difference besides the intake side being rotated...

[Dave M]

I can't speak to the lag issue with the T-Bird turbo, but I do know that the turbos are the same in both the Elan and the Impluse RS.

[Doc Fizzix]

So if we make a the tbird hybrid turbo, does the lag increase much if at all? My car starts to boost right around 3000 to 3200 RPM, but its an impulse... Does the Elan have a different turbo? I would think not much difference besides the intake side being rotated...

I have heard that there is a small increase in the lag and that would only make sense since the T-bird has a larger intake wheel and translates into a greater rotational inertia.

[joeisuzu]

I was thinking of doing making a tbird hybrid out o fmy parts turbo, but I can barely stand the amount of lag my impulse gets as it is, does the engine in you elan spool the turbo around 3K RPM? I know there are SOME differences between the engines, one being the exhuast cam timing being different, didn't know how much this effects lag...

I couldn't stand the stock cams in my impulse and installed some from an 89 imark, they made my turbo Geo FLY, so I'll see how it goes in the impulse, as I just got all the bits I need to remake the oil feed line to the turbo!

[Doc Fizzix]

does the engine in you Elan spool the turbo around 3K RPM?

In my oppinion, I think the lag very low. I havehad several different turbo powered cars and the Elan is one fastest spooling turbos and it should be due to its low inertia

I know there are SOME differences between the engines, one being the exhuast cam timing being different, didn't know how much this effects lag...

Not many differences, only the lifters, cams, and cam gear timming marks. Other than that they are the same motor.

[joeisuzu]

I'm trying to find some of those hydrolic lifters from a 92 geo like the elans have, my solids are SO noisy with the higher lift cams in!

[Doc Fizzix]

I'm trying to find some of those hydrolic lifters from a 92 geo like the elans have, my solids are SO noisy with the higher lift cams in!

I might be willing to sell my spare set as long as you only want the lifters, I am keeping the cams. If you are interested send me a PM and I will also think about it, I am not 100% sure yet but if you make me a good offer then now is a good time for me. I do not really need them because I was going to start rebuilding my original Elan motor after the first of the year and I was going to order all new buckets (at $39.00 each )