wastegate signal line relocation = MORE BOOST

[THE REAL BORIS]

Has anyone out there been watching this thread at Mazdaspeed over the last eight/ten weeks?

It explains a lot of strange things that have happened when other alterations have been made.

Has anyone here tried it yet or am I behind the times?

[THE REAL BORIS]

42 reviews and no replies!
"I had a dream...." It was last night and it said, VACUUM TO THE WASTEGATE ON CLOSED THROTTLE (NOW THAT THE SENSING POINT HAS BEEN RELOCATED AFTER THE THROTTLE BODY) WILL MEAN THAT THE WASTEGATE WILL ONLY EVER OPEN ON A FULL THROTTLE?
So, more boost (about 1 1/2 to 2 psi) but the blow off valve will be working overtime during vacuum conditions????????

[Babalouie]

You haven't linked to the thread mate

[PT]

I think he's talking about this one:

http://mazda-speed.com/forum2/index.php?topic=2896.0

[Sean]

Why not just put a simple bleeder vcalve in if you want more boost?

[Woo]

Aren't you robbing vacuum/boost by using a bleeder valve? They bleed to atmosphere.
Your better off adjusting the wastegate linkage..... it enables you to attain another 1.5-2 psi without loss. Only hassle is if the dodgies have had a go at the linkage there often isn't the throw to keep the WG closed at low boost levels while gaining the extra up top.

Boris, you'll need to be really careful of your EGT and AF if you hold the WG closed at high revs man. One reason why the WG is there is to lower crown temperatures to avoid melting pots or burning valves.
Additionally, the highest vacuum will be in the TB due to the venturi effect.

Wòó

[Benny]

On my SP, I've re-located the vaccum/boost line from the exhaust maifold to the inlet manifold so that it reads boost after the intercooler instead of before the intercooler.
It does seem to have a little more low down boost, but the top end stays about the same, although my boost gauge does indicate I'm getting an extra half a pound boost.
The wastegate is now louder, for some reason, and throttle has become jerky when declerating while under boost.

In the end, I think it drove beeter with the line in it's original position, but there may be a smidgen more power the new way.

[THE REAL BORIS]

Benny,

If you look at the original thread (actually started from a quote from Flyin' Miata, regarding their metal throttle inlet elbow, which has no wastgate tapping) they suggested the inlet manifold OR at the turbo were the preferred locations. The suggestion was, as you say, smoother off the exhaust tapping and at the same time, more responsive.

This seems to be the reason why plenty of people that have replaced the rubber elbow have recorded extra boost. Probably not all the new plumbing, but rather the tapping point location for the wastegate signal. The vacuum line to the BOV was also used, briefly, at 12 psi!

I wonder if it is safe after the throttle body, many say YES, Woo sas NO, and I am on the fence erring toward Woo.

Benny, thanks for trying this already.

[Sean]

Aren't you robbing vacuum/boost by using a bleeder valve? They bleed to atmosphere.

No because you will be increasing boost. the bleeder bleeds air out of the line that signal the actuator to open, which resuls in the actuator opening later.

Yes you will lose a small amount of air (less than 1.4 cfm) but the extra boost will make it unnoticeable. Even at the same boost you will make the same power. AT vacuum no air will be gained or lost.

[THE REAL BORIS]

I tried this mod. a couple of weeks ago, with no effect! (My boost pressure gauge still agreed with the dyno results that I got from Chiptorque last year).

I have since replaced my factory bypass valve with a GFB plumbed-back. It has taken out the boost drop off that I had between 4,000 rpm and 5,500rpm.

The wastegate signal line has now been moved again (back to the brake boost hose) and the gauge is showing an extra 1 psi of boost; maintained through to the engine red line. Worth keeping.