Hi all,

Just recently did a single turbo conversion with a Garrett T04z 1.32.

I found this set up to be laggy with full boost coming on around 5200 rpm. I didnt think much at the time that anything was wrong.

I then went to a 1.00 rear housing and expected boost to be somewhere between 4000-4500 rpm. To my surprise full boost came on later at 5500 rpm.

At first we thought there was no valve seat for the wastegate but when i jacked up the car today it was all there.

Any ideas on what the issue can be?

 

Is the motor ported?

Somethings not right, are you doing your boost runs on just the wg spring? whats your "full boost" PSI?

I see full boost (22psi) at about 4800rpm on a to4s (non bb like your Z) and with a 1.15 hotside

 

Is your engine ported? What are you using for boost control? Have you verified no exhaust leaks? Have you pressure tested for boost leaks? What manifold are you using? Is it divided or undivided?

 

the motor is street ported.

im using a greddy e01 to control the boost

how do i verify no exhaust leak or boost leaks?

its a custom manifold

 

Greddy electronics... FTL. Hate them. Disconnect that boost controller and run off the wastegate spring to see what happens.

Is it building boost through the pull or is it full boost or nothing? Controller might be opening the w/g early not allowing it to make boost.

 

Get a PVC cap from the hardware store that will fit in the coupler at your compressor inlet and drill and tap it for an air fitting or a valve stem. Connect an air compressor to it and pressure your whole intake to around your full boost psi, spray soapy water on all your couplers, vac lines, block off plates, tb and uim/lim flanges, every possible leak point, look for bubbles and listen for leaks.

 

Its building boost but very slowly. i get about 5 psi at 5000 rpm with the 1.00 rear housing.

 

5psi at 5000rpm is definitely sign that something's wrong. On my T04R (same as T04Z but not ball bearing) with large street port, divided 1.00 turbine housing and Feed stainless manifold I see 15psi at about 5000rpm.