[wrighar]

1st, turbo theory...

turbo theory

2nd, TD04HL-15g efficiency map and explainations..

compressor map * details

3rd, some of the calcs needed.
here

Andrew

 

[cbullock]

Thanks Andrew I thought this was probably the most interesting piece of info:

Tin= 70 deg F + 460 = 530 deg R
Pin= -0.5 psig + 14.7 = 14.2 psia
Pout= 19 psig + 14.7 = 33.7 psia
Pout/Pin = 33.7/14.2 = 2.373 (this is the compression ratio)
Tout = 530 + 530 x (-1+2.3730.263 ) = 717.8 deg R - 460 = 257.8 deg F

Cant really add much to that

 

[wrighar]

Pout= 19 psig + 14.7 = 33.7 psia  [/b]

I think you'll find he got that bit wrong, he was talking 17psig but wrote 19 in the calc...

Andrew
Who's bee researcing what causes turbo surging tonight...

 

[cbullock]

Sorry Andrew but if you work through his extended calculation you will find it correct see below:

http://www.gnttype.org/techarea/turbo/turbocalcs.xls

Hope that helps

 

[California Saab Tuner]

That's a compressor map of the TD04H-15G, what about the TD04HL-15T? Anyone seen a compressor map for that?

 

[Alex_S]

The guy in the 2nd link has got his definitions wrong for points 5,6 and to an extent 7.

Adrian, I think a 15T and 15G have the same size compressor but a 15T has single height compressor blades, and the 15G has dual height. I believe the G type turbos are more efficient than the Ts.

 

[California Saab Tuner]

That makes sense. The g's being more efficient, but "perhaps" the T's have a higher surge limit to allow for boost at lower rpm. That would make sense for having more full length blades I think, and goes well with the Saab design philosophy about low end torque. Does anyone know what the flow limit is for a 15T though? If it's the same as the G or not? Just curious where it runs out of breath. Thanks bunches!

Yours Truly,
Addy