Waste gate vacuum line size

[meanchicken]

See if this makes sense.
Can a smaller inner diameter vacuum line running from the turbo inlet to the actuator actually impact how soon the actuator opens? can a smaller diameter line cause the actuator to open sooner (i.e. at 11 lbs vs 14 lbs)?
Or could a longer than normal, smaller diameter line do this?

The reason I'm asking is because...
In my quest to eliminate KR until my Alky kit arrives and is installed, I have removed my RJC boost controller and adjustable WG actuator and reinsatalled my factory vacuum line arrangement (sort of) and WG actuator. I did things one step at a time. I was having that boost spike and creep issue described in my seperate post and have not opened up the puck hole yet cuz I know and accept that making my car higher boost capable before I add alky is a recipe for BOOM on 91 octane.

I couldn't get less than 16 lb of boost (with a spike to 18 at WOT) with the RJC controller and adj actuator
So first I pulled off the adj actuator.

Still couldn't get lower than 16lbs so I pulled off the RJC and installed the hoses per the factory arrangement, but I used longer and smaller diameter (what I had readily available) vacuum hoses and routed over the top of the turbo so that I didn't have to turn the fitting on my inlet bell back around.

The result is that I max out at 11 lbs of boost and wouldn't you know it....0 KR no matter how hard I try.

Should be able to hit 14...right? That's where I was before I added the RJC and adj actuator.

...now the car can barely get out of the way of a peppy soccer moms SUV...
So just for fun, I'll be trying some larger diameter hoses to see if I can "hose tune" the car for a couple more lbs without returning to KR issues.

...but does this make sense???

 

[meanchicken]

OK....I know you guys think this is crackers...so do I.... but something is up.

I went ahead and put the adjustable WG actuator back on with these longer, smaller diameter vacuum lines, and no change.

The adj actuator was at the stock length. The boost started at about 10 lbs. Since then I've cranked it in 4 full turns and the best I've got is 12 lbs of boost.

I had to come in to put the kids to bed, so I'll try some more adjustment tomorrow, then I'll start trying to swap vacuum lines.

Could that little Y fitting between the turbo, the actuator and the solenoid have gone bad some how and be causing this?
How about the solenoid?

 

[turbojd]

You do have the "Y" hose hooked up correctly don't you? If it's hooked up wrong it will cause low boost.

 

[meanchicken]

You do have the "Y" hose hooked up correctly don't you? If it's hooked up wrong it will cause low boost.

I...Think...I do.
Straight end goes to compressor housing and the Y end goes to the actuator...correct?

 

[Lee Thompson]

Y fitting

The Y fitting has 2 straight ends. 1 has a restrictor in it. The restrictor end must go to turbo port.

 

[Hedge]

Had time to fiddle with this again yet? I'm curious to see your results as I am having a similar low boost issue after I got the car back from the mechanic.

 

[meanchicken]

The Y fitting has 2 straight ends. 1 has a restrictor in it. The restrictor end must go to turbo port.

I'll check this when I get home tonight. Possibly I've installed the Y 180deg out and have the straight ends going in the wrong direction. It's the only thing that makes any sense.

 

[meanchicken]

Had time to fiddle with this again yet? I'm curious to see your results as I am having a similar low boost issue after I got the car back from the mechanic.

Er...um...if your mechanic was futzin' around with the vac lines at your turbo, and if he's anywhere near as creative a thinker as I am....check the orientation of your Y fitting.

He might have installed it bass ackwards.

 

[bsdlinux]

Er...um...if your mechanic was futzin' around with the vac lines at your turbo, and if he's anywhere near as creative a thinker as I am....check the orientation of your Y fitting.

He might have installed it bass ackwards.

And in your case "YOUR" mechanic was "YOU" ??? LOL

YEAH check that fitting or go tuner style get rid of it and be done with i t:biggrin:

 

[turbojd]

The restricted side of the "y" hose goes to the compressor port on the turbo. this would be the "straight" vacuum hose, the other end to the wastegate actuator, and the small 5/32 hose to the wastegate solenoid.

 

[salvageV6]

With anything in the normal range for hoses, 1/16" to 1/4", and within 3 feet in length I doubt you will see any more than milliseconds in delays to react to pressure differences.

Shouldn't affect the actuator time wise, operating wise I doubt either if the hoses are in the ball park in diameter.

I did some impulse timing testing going from 0 to 25psi. or so pressure with a scope, different hoses and materials.

 

[meanchicken]

We have a winner.

My....mechanic ....had installed the Y fitting 180 deg out.

Once I corrected his mistake, things are as they should be and I can again adjust my boost higher than 12 lbs.:tongue:

Yes, I was ...er...smart enough to lengthen the actuator rod to just a tad longer than stock before I tried testing the correctly installed Y fitting, and was able to turn it another turn to 14 lbs which is safe and knock free for my current set up.

My RJC Boost controller will stay in the tool chest until the alky kit and new chip arrive. I just couldn't set it any lower than 16 with the RJC controller on there.