Ha, sorry, my T3 is going on my Unimog at some point in the future...

Here's your trim formula expressed as it would be in a computer program:

T=((I**2)/(E**2))*100

Depending on the program, it may also be expressed like this:

T=((I^2)/(E^2))*100

Don't ask me why they square the figures...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Because it is a ratio of the AREA of the two wheel diameters and the formula for the area of a circle is pi x diameter squared. Since pi is in both the numerator and denominator of the equation it cancels out (pi/pi = 1) and you are left with the inducer diameter squared divided by the exducer diameter squared....

As close as I can measure it, this turbo has an inducer diameter right at 46mm and exducer just a hair under 60mm - that makes it a .60 trim. So it is a T3 with a 60 AR .60 trim cold side and a 63 AR hot side. Seems like the right one to me.

It turns out this unit came out of a 2.3L T-bird turbo coupe, not an SVO Mustang. I'm assuming that since the 4.3L will produce almost twice the exhaust volume of the 2.3L that this turbo - with an exhaust scroll sized for the 2.3L - ought to spool up at significantly lower RPMs on the 4.3L. I'm also thinking that the sligtly lower backpressure and EGTs of the .63 AR of the hot side and .60 AR of the cold side are also going to be good things - again, since I'll be pushing nearly twice the volume of exhaust gas through it than what it would normally see on a 2.3L

BTW, KarTek, did I interpret your axial versus radial play comments correctly?

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

Yes. Some radial play (perp. to axis) is OK. I have 2 other new turbos, the HX 40 and a Garrett that's stock replacement for my truck. Both have a teeny amount of radial play that's perceptible through wiggling by the fingers.

I also have a damaged cartridge from the truck that has about 1/8" of axial play. The impeller was impacting the compressor housing and oil was leaking from the exhaust side as a result.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Would that be me???

That is where this one is at. Shaft will move less than (eyeballing it) 1/16" off center in any direction (between 1/16" and 1/8" total)

I'm really starting to get excited about this project now!

I have run into one hitch though. I have discovered that the '85 body I was going to put it into would still have to pass emmissions ONE MORE TIME - so that's a non-starter. The good news is I have found two other possibilities.

One is an '85 - with the factory 2.1L Renault turbo diesel and an automatic tranny. Engine is toast but the body and interior look like they are 10x better than the one I have. It would still have to go through emmissions one more time, BUT, since it came from the factory with a diesel, that should be no problem. It probably has 3.73 axle gears, which would allow me to put at least 31" tires on it, and they're only asking $500 for it and I could probably talk them down from that. The only drawbacks are 1) it is a 4-door and I'd rather have a 2-door, and 2) it would have to be towed home - and its 250 miles away in Spokane, WA. A 500 mile round trip in my F250 will cost me about $200 and a whole L-O-N-G day of driving (5 hours over and 5 hours back). On the other hand, being a diesel would probably make the conversion a lot easier since it would have a tach I can probably hook up to the new engine, and have a fuel return line already in place, etc.

The other one is in some ways even more exciting. It is an '84, 2-door with a good running 2.5L 4cylinder gas engine and an automatic tranny. That means it for SURE has 4.10 axles, so I could probably even run 33" tires on it. The lady has had it for 14 years, and calls it "her baby" - so I'm sure it is in really good shape. She advertised it for $1000, and said she wouldn't take less than $700 for it, but it would be worth that to me to get the lower geared axles and a good straight clean body & interior. It is in Spokane too, but since it is a good runner, I could catch a $100 flight over there and drive it back. A lot cheaper than driving my truck over to tow the other one home.

Decisions, decisisons, decisions. I'm going for a camping vacation next week, and when I get back the decision may already be made for me - depending on whether one or both are still available. Guess we'll just have to wait and see...

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown