My solution to an unruly twin screw waste gate actuator

[Midnightsun300c]

I thought I would share my DIY fix for an unruly waste gate vacuum actuator. I developed this to deal with the sudden transition into boost that my Harrop/Eaton factory vacuum actuator setup delivers. It is a very simple fix and it's like the difference between night and day for drivability. No more waiting for the hammer to drop while driving in traffic. It has allowed me to pull into traffic and accelerate up to speed without fear of lighting up all four tires and scaring the surrounding drivers to death. It also has made my daily driver much safer on winter roads.

All you need for supplies are two 1/8" flow control valves; three barbed fittings and some 1/8" vacuum line. Splice one of the valves in the vacuum line from the intake and top vacuum actuator nipple. The second valve goes on the end of a 1/8" line from the bottom nipple on the vacuum actuator.






I found the trick was in the setting of the two valves. The vacuum side valve is set with the engine at idle. Close it until you just start the waste gate closing. The ambient side valve is set with the engine off. Open the valve (this will allow air to be drawn into the bottom of the actuator); manually open the waste gate; close the valve completely (this traps pressurized air in the bottom of the actuator); finally slowly, very very slowly start to open the valve until the waste gate starts to close ever so slightly. The slower you can get the waste gate to close the smoother your transition into boost will be.

You can play with the valve settings to adjust the boost transition to your particular taste. The brass fittings that I used were just what was convenient at Ace Hardware but any flow control valve will do. I also adjusted the position of the waste gate actuator so that I was getting the waste gate completely open at full vacuum and it didn't hang at full close unlike the factory position. You might check yours as well.

I hope this helps some of you that are having the same problems I was having. Good luck.

[LoneStar]

Nice write up. Thanks for the info. This could save some a lot of trouble with the same issues you had.

[Sohfast94]

[Locadio]

Do you have a part number for the flow control valves?

Regards.
________
Fifth-Generation Mustang

[Midnightsun300c]

Do you have a part number for the flow control valves?

Regards.

The Ace Hardware that I got mine at didn't have them marked, they were just thrown in a bin. I believe they are just an Anderson Fittings Needle Valve. Here is a link...

http://andersonfittings.thomasnet.co...mpt?&forward=1

It is not imperative that you use this valve as any small flow control valve with barbed fittings will do.

I hope you get yours working. It really makes a huge difference. It will turn your otherwise scary daily driver into a drive like stock ride again. My boost gauge goes from 15" of vacuum to 15 lbs of boost in one continuous transition. No more jump from vacuum to 10 lbs of boost in an instant when you don't want it to.

[lafrad]

Nice fix!

[CrazySRT8]

I'm not mechanicly inclined, how hard is it to get it tuned in?

[DrMopar]

Is this at all related to the solution Tim @ Mr. Norm's has been referring to, in the thread below?

[Cam]

Man, what a simple kickass solution. Major props bud.

[Midnightsun300c]

Nice write up. Thanks for the info. This could save some a lot of trouble with the same issues you had.

Thank you. I believe this will really help anyone that has had the same issues as I've had.

Nice fix!

Thanks. Coming from someone as knowledgeable as you that is much appreciated

I'm not mechanicly inclined, how hard is it to get it tuned in?

No, it is very easy. If you follow my process you will only have to make one adjustment per valve. The valves are only finger tight so you can tweak them as often as you like with no tools required after the initial install.

Is this at all related to the solution Tim @ Mr. Norm's has been referring to, in the thread below?

This addresses the same issue I believe but in presumably a different way. I can only guess as to what Tim's design is but it should be much more complicated/comprehensive as he is seeking a patent and needs to manufacture parts.

Man, what a simple kickass solution. Major props bud.

Thanks for that, and thanks for the beans. This turns out to be a very simple solution to a problem that has perplexed me for over a year. I had already begun assembling a RC high torque servo as a control device when I noticed that my vacuum actuator linkage was binding and decided to start over from scratch.

[CrazySRT8]

is anyone that has more emechanical ability than me (which is none)going to test this? and, post what your experiences are?

[Tim@Mr.Norm's]

Great fix! I assume it will only work on a bypass that has a dual port setup? How would you make it work with only one vac/boost port on the bypass?

Your correct, my setup is alot different but similar. Kinda hard to explain.

I'll bet you were happy as hell when you came up with a solution, I know I was.

[Black08Chally]

Great fix! I assume it will only work on a bypass that has a dual port setup? How would you make it work with only one vac/boost port on the bypass?

Your correct, my setup is alot different but similar. Kinda hard to explain.

I'll bet you were happy as hell when you came up with a solution, I know I was.

Hmmm how to make this work for a single vacuum line set up......Could a T be put in the line so that there were two circuits parallel with a flow control on each leg and a check valve as well, could regulate the in flow and out flow for boost and vacuum as it would slow everything down.

engine---T---->--/----T---actuator
..............----<--/-----

[Black08Chally]

Well my lame sketch kinda worked LOL...... vacuum/boost comes from the engine and could split at a T, goes through the check valve (>) then the flow control (/) and into the actuator. Each side would control airflow in a different direction. I'm not a pneumatics expert but I think this works in my head LOL

[Tim@Mr.Norm's]

Hmmm how to make this work for a single vacuum line set up......Could a T be put in the line so that there were two circuits parallel with a flow control on each leg and a check valve as well, could regulate the in flow and out flow for boost and vacuum as it would slow everything down.

engine---T---->--/----T---actuator
..............----<--/-----

Dunno until its tested. Problem with a diaphram bypass like a KB's is it doesn't take very much pressure for it to close. I tried putting a restrictor inline on the vac line to the bypass and it didn't help @ all. The damn blower will make 10 psi when pullied for 15psi with the bypass wired open.

I like his idea, it actually gave me an idea on how to simplify my part and make it less expensive.