Working out ideal turbine housing

[Danm54]

In the process of ordering parts for my turbo rebuild and as I need a new turbine housing I'm wondering if I should stick with a replacement or go a little smaller.

 

Currently got a T3/4 with a .48 turbine housing and a .42 compressor housing.

 

I can get a smaller .36 turbine housing but how do I work out the characteristics of each and decided which is best?

 

Thanks

[Arttu]

By this far I haven't found any good way to calculate turbine sizing. For compressor it's much easier. For turbine side there are more unknown or hard to get variables like total exhaust gas flow, flow through wastegate etc. And turbine flow data for different turbos is quite scarce too.

So I think you would first need data from some turbine option on your engine (or something similar), how quickly it spools, what is the exhaust pressure or whatever you can get. Then you can try to estimate if you want to go bigger or smaller. Bigger will result less exhaust back pressure and therefore more power at same boost, especially at top end. As downside it will build boost later and slower. Smaller one would be opposite, naturally. 

 

[vizman]

try dave @ FBM 07581304745 or universal turbos 01425656900 advice is free.

[Danm54]

Thanks Viz, I'll give a call when I get 5 mins. I could do with knowing the oil pressure and flow requirements for the turbo as well.

Ordered a .48 first thing this morning as I found a little info on a couple of people using that size for a 1k gsxr.

No real info on how and when it boosted but I guess I'll go with this and find out, its been mapped using a .48 with a loose fitting turbine wheel and a cracked housing so it can only be better.

 

@Arttu I've not found any turbine data, I've just been led to compressor maps.

I'll get it back running with the .48 and see how it spools and when boost comes in.

 

Cheers