Turbo Stators (warning: geek talk)

[VeeFource]

Morning All,

Recently bought a modern-ish turbo diesel and am a little disappointed with how quiet the turbo is compared to my old Leon Cupra Tdi. It got me reminiscing about the hobo mod I did to my Rover 420's turbo when I was younger and more naive about fluid dynamics. In those days I thought making my 'beast' whistle like an intercity would be dead cool, so set about making a stator to sit in the inlet of the turbo. Imagine a metal plate cut into a jumper sort of shape and bending the arms around to sit on the top outer lip of the inlet with a cutout in the crotch area to allow room for the spindle. So basically the bottom edges of the jumper shape now sit about 1mm from the inlet turbine blades.

Ok so a bit of a 'special' thing to do, but it was easy and actually worked quite well with no noticeable power losses. Wouldn't actually mind doing the same to my new purchase tbh but in these days of computer simulated, electronically controlled engines I can't help but think it might adversely affect the performance of the engine in some way unlike the more finger in the air engineering days of the old Rover diesels.

I'd have thought a stator could help to improve flow into a turbo given they're standard issue on jet engines but I imagine they're not used on turbos for the very reason I want to use one, as a loud whistle wouldn't be welcomed by you average Mr A-B. But then could it really be because stators only really come into their own when used within set airflow ranges whereas a turbo needs to be efficient through a large range of airflow conditions? If there are any gurus on the subject then feel free to advise your thoughts..

[anonymous-user]

I assume you are talking about a compressor inlet stator, and not a turbine inlet stator btw. Using a stator with a helix angle opposite to that of the compressor inlet face can help to widen the low mDot compressor map somewhat, but that then tends to act as a restriction at higher mass flows. Many ideas have been suggested for systems that use stators and bypass throttles to effectively add or remove the pre-compressor helix etc. Generally speaking, the benefit is not worth the cost.

[anonymous-user]

PS, they are used on "jet engines" because these are largely axial flow devices, and a lot of pressure recovery is lost if the exit air is spinning fast (they are much much more important on the exit side of the device). Automotive turbochargers are largely radial devices (well mixed flow really) and use a geometric system to aid pressure efficient recovery (the scroll)

[VeeFource]

Max_Torque said:

I assume you are talking about a compressor inlet stator, and not a turbine inlet stator btw. Using a stator with a helix angle opposite to that of the compressor inlet face can help to widen the low mDot compressor map somewhat, but that then tends to act as a restriction at higher mass flows. Many ideas have been suggested for systems that use stators and bypass throttles to effectively add or remove the pre-compressor helix etc. Generally speaking, the benefit is not worth the cost.

Yep, was indeed talking about the inlet stator, I was too fearful of doing anything on the turbine side of things in case it'd melt or become sooted up.

Hmmm, so would you say the effects on the pressure mapping from having a thin plate in the inlet of the turbo are probably negligible in which case? It would be nice to have a bit of whistle in my life!

[anonymous-user]

no, i said it "would tend to act as a restriction at high mass flows"



(how much power you'll loose is anyones guess, but i doubt you'd be able to feel it with just a "bumdyno".... ;-)

[VeeFource]

Max_Torque said:

no, i said it "would tend to act as a restriction at high mass flows"

(how much power you'll loose is anyones guess, but i doubt you'd be able to feel it with just a "bumdyno".... ;-)

Fair enough, I suspected as much. Ah well, much rather this engine than a whistley Rover unit!