RS2 Turbo hot side

[orsum]

I have an original RS2 middle and cold section bolted to a standard K26 #6 it’s a hybrid that I would like to get back to completely RS2 original specification.

I also have an original RS2 turbine shaft and wheel and the dimensions are not the same as the K26 turbine wheel. So I can confidently say the hot side is the odd piece on the turbo.

I read the comments by Scott Justasson about the RS2 "Comp" turbo and the way I read it he talks about the cold side (compressor) being larger. I am quite sure I know what I have and it’s just a standard RS2 with a modified hot side because the original owner could not get an original RS2 turbine housing to replace the one that was damaged.

UrS4boy I may be going at my problem the wrong and confusing and concerning myself for nothing.

Below are the measurements of the turbine wheels. As you can see the K26 is larger in diameter and the wheel is wider thus I think will result in more lag. And also is of concern to the person doing the map for the car.

To reduce lag and reduce possible issues with software surging etc because of the mismatched turbocharger components I would like to fit a replacement turbine housing and fit my RS2 turbine wheel effectively retuning the turbo back to a standard RS2 turbocharger.

This is the only way I know to get the Turbo back to standard without thrown the turbo I have away and starting all over again?

Turbine wheel presently fitted to the turbo
All size in mm
A 54.5 Small diameter
B 64.3 Large diameter
C 10 The width of the flat part across the top of the wheel
F 24 Total width of wheel
G 12 Number of blades

RS2 Turbine wheel I have wrapped up in a box
All size in mm
A 52.8 Small diameter
B 58.9 Large diameter
C 10 The width of the flat part across the top of the wheel
F 20 Total width of wheel
G 12 Number of blades

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[orsum]

Sorry I did not mean to imply it was a tuning problem but it was issues that could arise from matching the K26 #6 to the RS2 cold side. Which I understood may not allow the software to be perfect without tuning the software live on the car.

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[Quattronaut]

I think you´re doing it right, going back to normal RS2 turbo. As the RS2 hotside (wheel and therefore housing) is a very special part and used ONLY in the RS2, I think KKK only sold the parts to Audi and to aftermarkets, not to private people. Thats why it is so expensive also.

For me, you have 4 possibilities:
Wait for an RS2 hotside housing sold on ebay or in a forum.
Buy another, complete RS2 turbo (new or used one) and sell your hybrid.
Accept the laggy hotside as a compromise, install turbo and drive.
Take the turbo, change the compressor wheel and have a turbo capable of 420-450hp. In that power range, the lag is quite normal, because much power needs big turbo, big turbo has lag.

[orsum]

I will most likly do one of the following.

Wait for an RS2 hotside housing sold on ebay or in a forum.
Buy another, complete RS2 turbo (new or used one) and sell your hybrid.

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[Billman]

cant you just machine a k24-7000 turbine housing to take the rs2 turbine impeller. both turbos have same flange and same neck volute #6.

[orsum]

It sounds like a good idea not sure if it would be the same

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[Billman]

I believe appart from the wheel diameter the rest is the same. Wait till more input comes in.

[Quattronaut]

Yes, housings are identical. I forgot that :-) K24/7000 can be machined out to K24/7200. You just need someone who can do it...
To be honest: When you brake the turbo apart, and fit a hotside housing that has to be machined- it will be overhault surely. Then you should add a few more bucks, and change the comp wheel. Then you have up to 420hp woth stock RS2 hotside.