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I did a preliminary test and there's barely any change from previous turbo. I want to get the boost pressure profile to match a bit more closely with previous results before I post a comparison. It's been pretty hectic, but this is definitely still on the to-do list.
For every 1mm of compressor inducer diameter - 100rpm slower spool
For each step in turbine AR (0.63 to 0.82) - 250rpm slower spoll
Single scroll vs twin scroll - 500rpm slower spool
My manifold twinscroll vs single - approx. 300rpm
Bottom is the GT3582 wheel that came with the turbo . Top is a GTX3576 copy that I bought off ebay .
My frankenturbo will now have Garrett housings , Kinugawa turbine, Onehunglo bearings and Mambatek compressor.
So we are up and running again .
The good news :
*more power right through the rev range (due to going back to 1.01AR ) . Losing traction again in 2nd now.
*Pulled 460g/s .....highest i've ever seen !
*exhaust actually sounds better .... lost most of that pulsing it had when the 2nd stage kicked in.
The bad :
spoolup is freakin identical !!!! FFS WTF !!!!!Borrowing Jimmy's parrot here ...............
Before anyone says it's due to the larger AR turbine housing . Spool was the same as this with old wheel and 1.01 as well .
I'm thinking it's a housing clearance issue . This wheel had much larger clearances than the other one .
Clearance is around 0.8mm which seems like too much to me . The old wheel was 0.45mm which seems normal.
So I have zero experience with turbos but I do work in aerospace and most of the compressor aero guys I work with would sell their souls to get clearances .35 mm tighter. Granted that's on engines for commercial aircraft. But unless it needs the more open clearance to keep the wheel from rubbing the housing, seems like some performance is being left on the table.
So I have zero experience with turbos but I do work in aerospace and most of the compressor aero guys I work with would sell their souls to get clearances .35 mm tighter. Granted that's on engines for commercial aircraft. But unless it needs the more open clearance to keep the wheel from rubbing the housing, seems like some performance is being left on the table.
Agree 100% . I actually emailed the suppliers and they told me they allow extra clearance on non standard covers to be on the safe side. So I wont be doing it that way again !
Running out of places to do a 3rd gear log ..... here is one in 2nd . Doesn't seem that wonderful ....but I've never seen such a good result in 2nd before.
07-18-2016, 09:58 PM
