Boost Control

[IATurboBuick]

I have been working on this project for awhile now. You can see my mods in my signature of my 86. I have a TIAL MVI2.5 adjustable spring wastegate actuator. Actuator rod is short as possible which gives 1/16 preload onto by puck arm in the downpipe. When I follow the spring rating Tial recommends I have way too much boost through the sweep of 0-100% TPS. for instance, the blue spring is 23 PSI at 40% throttle input. The softest spring pressure will not hold the gate and it basically bypasses. With a Green Spring I have solid throttle response and I can get 60% TPS input at 25PSI. What options or experience with internal gates does anyone have for me. Thanks in advance.

I have a Mac Valve controller from Bob Bailey, but he wants my mechanical portion refined before we use the boost duty table to 1-2 actual Boost.

 

[Pronto]

What downpipe are you running? Have you ported the turbo exhaust housing?

 

[IATurboBuick]

What downpipe are you running? Have you ported the turbo exhaust housing?

TA 3" interbal gate, yes on porting. Its a new Work 6262

 

[BEATAV8]

I'll check and see what we used on a couple of internal gate cars with full flex fuel. The cars have turbosmart internal gates with 4 port mac valves. At 0% duty they can run low boost, and with higher duty 30-34psi is no problem. From memory, we used relatively low pressure springs. 7psi maybe. The 4 port plumbing uses both sides of the diaphragm where it can apply pressure to close side. This makes it very sensitive to duty.

Keeping it simpler with a 3 port mac I'd say pick the spring combo that gets you 5 or 10psi below your intended target at WOT and 0% duty, and from there apply duty to increase it.

turbosmart gate with 4 port mac:
0% duty 12psi

and with 74% duty 28psi

 

[Pronto]

What are you using to control the MAC valve? I've been looking at the AEM Truboost X since I don't anyone that has successfully controlled boost with XFI. I currently have a Grimm manual boost controller that works good but not sure how it will do with the new Next Gen turbos.

 

[Mr.Spool]

I've used the turbosmart internal gate with manifold pressure in the past.
It can be hit or miss based on the amount of backpressure the turbo system has and what boost ranges the user wants.

 

[Mr.Spool]

I would recommend starting spring pressures the get you lower boost levels on your system at wot
So you dont encounter an overboost situation where you go lean and hurt things.