Turbine housing A/R

[howboycat]

I'm looking for a good source of info on how to properly choose turbine housing sizes for turbos.
I feel pretty confident in selecting properly sized compressors, But there seems to be a void in everything I read on the exhaust side. Not looking for some one to do it for me just looking for a really good source for this info.
I've been through Corky Bell's book "Maximum Boost" and the Garrett Turbos website is really good. I just need more.

 

[j79guy]

cyclecyko: Have you tried the guys at

http://www.rbr-racing.com

?
Their website has a lot of useful information, and I'm sure if you talk to the owner, he can at least point you in the right direction.

j79guy

 

[ivymike]

the only "professionals" I know who pick turbos do so based on a combination of experience, simulation results, and test cell results. Software-wise Ricardo's Wave and GT Power's Boost are very popular.

 

[Lou Scannon]

I second ivymike. If you don't have access to the turbine maps and/or similation software, your best bet is find out what others with your engine application are using for power levels similar similar to your goals. Be prepared to iterate to find the optimum match.
Another good text is "Turbochargers" by Hugh MacInnis.

 

[howboycat]

If I get this engine running minus the turbo, is there a way to measure the ehxaust gas volume and speed, or perhaps I can fabricate a short exhaust pipe with the same rate of taper as the turbine housing, and size the exit according to the turbo's A/R.

If done on a chassis dyno under load and at full throttle, I think theoreticaly one could find the exhaust gas pressure and velocity at the point in the rpm range just before your desired time to boost. of course I'd have an egt sensor to refrence as well.

I think I might be well out in left field on this but some constructive critisism may do me good.

 

[Lou Scannon]

The exhaust flow can be calculated, base on air and fuel flow, and exhaust pressure and temperature. Don't get too wrapped up in the volume and velocity. It is the turbocharger's job to convert exhaust energy to shaft energy, and that is what turbine maps are for. The mass flow and temperature can be estimated based on data, and that is all you need to start with for the turbine map.
The engine running minus the turbo won't be a very good source of data for the engine running with the turbo.
I still recommend the advice in my previous post.

 

[turbomotor]

cyclecyko,

What you need is a turbine performance map (which includes a flow curve), a just a little background into how to interpret the data.

Hugh MacInnes' book on turbocharging, albeit somewhat dated now, still is the best treatise on turbocharging for the performance enthusiast (sorry, Corky). The book will help you understand the different ways the manufacturers map the performance of the turbine stage.

That's the easy part.

The tough part is actually getting your hands on turbine map data.

A/R is just a proxy for nozzle size, and is based on the principle of conservation of angular momentum of the inlet gas (the tangential component of the velocity).

But get and read MacInnes booklet, as he has explained much better than I can in this short note.

 

[Lou Scannon]

I agree with turbomotor, MacInnis is much better technically than Corky Bell.

 

[howboycat]

Thanks for the advise guys, I ordered MacInnes book.

Never stop learning !