When should the Alpha 3071's with all the supporting mods be spooling? Why I ask is that mine are starting to spool at 4100.
Also do you think having 47.5 m headers are cause the turbo lag?

Thanks,

i see mine full boost at about 3200-3600. i have stock headers though and marki's 2.5 inch pipings to the turbo.

That is a huge difference!! Mine full boosts at over 4400

i also still have stock intercooler hoses and y pipe so i'm not sure if that's where the difference is

If you swap out those restricted parts shouldn't you have an even quicker spool?

It should help a lot if you run bigger ducts to the inlets of the turbo. I have some 2.5" hose if you are interested PM me. My alpha 3076s spool the same as my 24/18Gs did!

Thanks mang but I have all the supporting mods. I'm putting smaller headers on this weekend 44.5 and see what happens to the boost response

4400 seems late. have you tested for leaks?

I did a smoke test and tightened a few areas but nothing dramatic.

this

something is holding you back - 3076's are at full boost around 4K

Agreed. The boost response was the main reason why I went with Alpha's.

Can having bigger diameter 47.5 headers cause this much of a difference?

eh maybe. bigger diameter primaries - slower velocity of air traveling through, given that the volume of air is constant. blow in a straw and then in a bigger straw with the same intensity...

R911 997TT hits 800awtq (ft/lbs) at 4400rpm, ramping in the boost.Turbos we run are custom 30's.

Neil at what boost LOL

Another thing to check for is your wastegate preload on each turbo. I found that Tial does not set these from the factory. On the dyno we found one set at a crack point of 12 psi and the other at 15 psi. My turbos spooled up a few hundred RPMs quicker when we found this out.