why does the ST model have a built in dump valve and the BT doesnt? you would logically think it would be the other way around, as the BT flows more air thus would need a bov as standard.

 

My big turbo has 1 fitted as standard?

 

cahzz T-34 was homologated rally turbo - it needn't it and the car was homologation speical so it had added diverter valve for road use but it's needed it not in rally use with was much more important for people designing it (If I am right they designed rallycar first). ST wasmore civilised version for road use as big turbo was considered very bad as standard and as such it got new turbo with unique cold side It think with this build in diverter (recirculatory) valve.

 

The T34 has one to stop the noise it makes without one.

The T28 has one because it is mass airflow managed and NEEDS one.

 

the small turbo one is supposed to be more effective as it dumps the air straight onto the compressor blades for maximum response

 

Didn't know that Stu,

You learn summat every day

 

What noise does it make without one? Can you run a standard T34 without a DV, or does this damage turbo?

 

It makes the noise that people normally refer to as 'chatter' or compressor surge

 

i was acually thinking the ST one is a very good design looking at it, is the BT built in on the comp housing? or is it like the rs500 unit, stand alone?

 

BT is stand alone, black Bosch valve I think.