Question for 617 turbo gearheads
 

I am in the middle of upgrading a number of things on my '84 300D and first on the list is rebuilding the turbo. I finally got the turbo out of the car and dismantled see photo
https://picasaweb.google.com/lh/photo/smFILkZxVtBea0tisRZ12NMTjNZETYmyPJy0liipFm0?feat=directlink
The turbo looks to be in excellent shape with some evidence of oil seeping past the seal on the exhaust side with some carbon buildup under the heat shield.

I bought an "upgrade" Stage I turbine wheel that has the exact same dimensions as the stock wheel, except for the inducer (major) diameter. The inducer on the stock turbine is roughly 2.5" and the inducer on my new wheel is 2.3" , see photo:
https://picasaweb.google.com/lh/photo/8Ep2AbbvsH8Dz-uVx0-9tNMTjNZETYmyPJy0liipFm0?feat=directlink

So my question is this:
All other things being the same, will an exhaust turbine wheel with a smaller inducer (major) diameter give faster spool-up but lower max boost?:confused:

Bigger exhaust will give you quicker spoil up is what I understand.

I hope you don`t mind if I copy and past the pictures, case you deleate them.

Can`t help on the Turbo rebuild.




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https://lh4.googleusercontent.com/-s...2010.43.59.jpg




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Charlie

I wouldn’t be too concerned with max boost on the turbo. Its possible w/o a wastegate to push over 20 PSI with a stock turbo. That is about 7 psi over what you could ever hope to accomplish when using an unmodified injection pump. Gaining a faster spool is a definite plus.

Thanks, Charlie.
I don't know why, but the discussion board software does not let met copy and paste images into my posts.

I totally agree, W123love.

My plan is to install a 2.65 rear diff, and by rebuilding the turbo, replacing the compression wheel with a new one, and upgrading the exhaust turbine, I hope to get a little bit faster spool up and maybe a bit more boost down low, say 8-10 psi around 1500 to 2000 rpm under a moderate load. I am hoping to find an oem t3 garrett stage II turbine, which will require machining the exhaust housing to accommodate the larger exducer, but I think it would be worth the trouble.

Don`t want to get the thread off track, but what did you get the 2:65 from? I know the W116 6.9 used this Diff, and has the Clutches.


Charlie