Compressor surging

[S475_12V]

My s475 will surge like a ***** in overdrive when at low rpms. I know it does it from lack of drive pressure, when I run out 3rd to about 4300+ then hit OD it is fine but if not it surges something awful.

It's a bullseye power turbo .89 exh housing. 7x17 injectors. What can I do to help this?

 

[LReiff]

Put a 68mm comp wheel in the charger and an external gate for the upper rpm.

 

[S475_12V]

I'm worried a 68 comp. wheel will be too smokey. It's already pretty dirty with the 75 in it.

 

[LReiff]

So how exactly will a turbo that surges less and spools up faster will be more smokey?

 

[JQmile]

My s475 will surge like a ***** in overdrive when at low rpms. I know it does it from lack of drive pressure, when I run out 3rd to about 4300+ then hit OD it is fine but if not it surges something awful.

It's a bullseye power turbo .89 exh housing. 7x17 injectors. What can I do to help this?

Sort of the nature of the beast. You can improve airflow through the engine through camshaft selection, lowering compression, head porting, intercooling, etc, or you can just shift at high rpm.

 

[S475_12V]

I haven't seen the flow charts on a 468 but I would imagine they are less than the 475. I can light the turbo at about 21-2200 rpm and hold a steady 70psi of boost if I run it out.

Jq that's what I was figuring as of now the cam and head is stock. That's actually the winter project shaving the intake and working the head over. I have a Maxspool cam to go in at the same time. Just wasn't sure if I could fiddle with some stuff to alleviate the surging a bit for the time being.
Thanks