I at least partly wished I hadn't bothered as I have an aversion to spanners and hard work

 

I have a bunch of logs where I'm hitting 22-23 psi at 6000 rpm and tapering to 21-21.5 psi at 7000 rpm in 3rd/4th gear. I think that was the max possible boost that could be wrung out of the turbo. It worked ok in the winter months, but as the weather started warming, I started seeing spikes in the knock counts and had to pull back to boost. I'm now doing about 21 psi at 6k and 20 psi at 7k. Mods listed below. Running 92 octane.

 

I hit 30psi @ 4200 rpm, holds 30 until about 5200, drops to 28psi until 6k then tapers off to 22psi @ 7600. This is with the megan O2 housing and AVC-R.

 

Your bhp, is it wheel or flywheel?

 

If you're asking me, then those numbers are at the wheels.

 

Thanks mrfred, those levels seem sensible on pump.

Thanks mixmastermatt, nice result on Dynodynamics. What is your actuator setup?

 

I'm using the stock actuator, haven't adjusted the loading on it at all.

I have the AVC-R set to 90% duty cycle and 1.95kg/cm2 @ 3500-4500rpm. This allows boost to build very quickly and spike to 30 psi. As rpm increases, I increase the target boost pressure to get as much out of the stock turbo as possible. I've turned it all the way up to 3.kg/cm2 @ 6k and above, but it can't go over 24psi.

 

When I had my EBAY O2 housing I had boost creep soo bad that I removed the darn thing and sold it. It was fine for race gas or alchy but on straight pump my 4th gear would climb to nearly 25psi. Mine was ported and I had the tension turned down on the actuator.

 

Thanks Jeff.

So mixmastermatt, do you know what your boost curve does with the AVC-R off or at 0% duty?

 

Excellent

What boost are you running and and what rpm (if you don't mind )

Hoping to make those numbers with an evogreen

 

For some reason the WG door is more resistant to open. Perhaps you've changed the path of exhaust to where it's forcing the door closed at higher loads.

This sucks because in order to get the door open in time at high loads to reduce spike will actually make it want to crack open (taper) at high volume/rpm.

How far is the tubing from your WG solenoid to WGA? Reducing this length will reduce the "open" signal lag time

 

"The day I log 2 byte load is the day I give up heroin" - well have that and 2 byte airflow on me - see other threads.

Having loosened it off a lot I now need to ramp up the top end duty to hold the boost I want, I think I can now start to go a bit tighter to try to flatten the duty cycle curve a bit. There are no spikes, controls just as well as before the O2 housing now the actuator preload and the AVC-R settings are near.

 

slowly but surely. I bet in the end it will not all be a waste of effort! And you'll look back with no regrets! The joys of tuning!!!

Good Luck!

 

I followed a 575M whilst setting up my AVC-R, I suppose I got it dialled in quicker than usual. No horseplay though

 

With my VIII turbo, it doesnt matter if it's set to 26psi or 22 psi at 7000 rpm it is always 21.5 psi (3rd).

I bet if I removed the WGA hose it would hit 28 psi and taper to 21.5 psi at 7000RPM.

Since your compressor moves more volume and has a different map perhaps 22.5 psi at 7000RPM sounds like a possible target, what is your goal (in psi)?

Perhaps the variable intake cam also allows more air consumption used for power resulting in less pressure too