Re-Thinking the Boost Controller.

[Cowboy]

I have something against buying parts off the shelf...  So I came up with my own boost controller.  

 

What's wrong with the normal boost elbow?  It does work to increase the boost pressure, but It makes the wastegate opening curve even worse then it is stock.  With my stock 96, it makes about 22 psi with the stock wastegate and no boost elbow.  After some testing, I've found it to start opening around 10 psi.  So when we're at any boost pressure above 10 psi, the wastegate is already starting to open and bleeding drive pressure away from the turbine.  With this setup, you also have what's called 'Boost Creep' where the boost climbs as the RPM's go up.  This is because at 22psi, the wastegate isn't even half way open yet.   The boost elbow does not fix these problems, and neither does the ball and spring type boost controller.

 

After lots of complex designs involving a 3 way valve, I opted for a more simple approach.

 

I bought a $23 eBay fuel pressure regulator and modified it, which included replacing the diaphragm with a piece of tire tube (temporary), and changing the seat a bit.

 

 

 

Using an air compressor to mimic boost pressure.  The wastegate is fully closed with no pressure in it at 28 psi, and fully open at 32psi.  This means that the wastegate will do everything it can to keep us at/near our 30 psi setting.  This also means we can enlarge the wastegate port, without fear of it making the wastegate open prematurely.  Success!

[Mopar1973Man]

Can you post the parts you used and where you got them. Also show what you did to modify the regulator. I'm seriously curious about this one.

[Cowboy]

I need to get pictures tomorrow.  But the parts list includes, the regulator, a small screw head (cut the threads off), piece of tire tube, and some gasket maker...

[Mopar1973Man]

Seriously you might want to create a write up of this... I know it cost more than a boost elbow but to get on/off switching of the wastegate would bee awesome for anyone.

[Me78569]

Great work cowboy. Unneeded if you ever go with the vgt turbo (one for sale for 300 on cf by the way)

[Mopar1973Man]

Why no for sale here in the classified ads?

 

Well if you two would finish your VGT turbo controllers...

[Me78569]

I am calling mine done until I get it fully in the truck and start testing on the road.

[Cowboy]

I'll try and make a write up here in the next couple days.  It's been kinda crazy so I'm to tired to use my head now.  But here are some pics I was able to snap.

 

Grind the adjuster screw to a point for smoother adjustment.

 

 

Made a diaphragm out of farm tractor tire tube (thicker than your average tire tube).

 

Our Highly scientific bolt head... (next to a 1/4" nut and bolt for reference)

 

 

Location of the bolt head, Before.

 

 

After

 

Unscrew this part and put some gasket maker on the threads.  Otherwise you'll have a small boost leak.

 

 

And then lastly, take the bottom barb fitting out, remove all sealant, and reinstall so there is a small boost leak there.  It will only leak when the wastegate is open.  It's there to relieve the pressure from the wastegate once out boost pressure goes down and the regulator closes.

 

I have a feeling I'll be sticking with this HX35 for a while.  If not, then I can swap this setup onto a different truck.

 

Here's a video of it working, ignore the babbling idiot... life is better that way.

[Mopar1973Man]

Very impressive! Wow! You need to make that write up. I want to build one soon!

[CSM]

Neat

[Cowboy]

Took it for a drive today, it worked fairly well, boost isn't the smoothest, but I have a couple ideas I'll have to try to improve it a little.

 

Boost doesn't get to my set 22psi until 2100 RPM.  Though I know without a wastegate I can hit 30psi, so yes the wastegate is doing something lol.

 

Before (This is with my "upgraded" wastegate actuator, you can see it start to open at 17 psi, stock starts to open ~9-10 psi.)

 

After

[CSM]

I need more scales on your chart. Haha. Can you add boost to the right side? Where are you calling the open at 17psi?

[Cowboy]

OK try this, I'm not very good with charts.  It's the green line about the center.  Because my truck is stock, with the upgraded wastegate, and has a very inlarged wastegate port.  It's not as bad as it would otherwise be.

 

[joecool911]

Does this have any business on a stock truck with 50 hp injectors?

[Cowboy]

Does this have any business on a stock truck with 50 hp injectors?

 

 

That's a difficult question for me to answer.  Mostly because I don't want to sound like a salesman, or tell you that you should do everything the same way I did.  So I'll try my best to give you the pros, and the cons, and let you decide.

 

Cons:

More complicated, and more likely to break than other boost controller designs.

Cost double of what the more basic boost controllers do.

When the wastegate first opens, there is a little bit of fluctuation in boost pressure, as seen in the chart above.

Larger and bulkier than most other boost controllers.

 

Pros:

The wastegate stays closed until the pressure you have it set for, so you can spool faster and cleaner.

Because the wastegate no longer starts to open at 10 psi, if you're climbing a grade, or your pressure is above 10 psi,  the wastegate won't be bleeding away pressure.

There is no boost creep, so the boost will stay close to your set pressure throughout the RPM range. 

Unlike the boost elbow, There is no boost leak until after the wastegate starts to open, in which case you have to much boost anyway.

 

Hopefully that's a complete enough list.

On the boost fluctuations,  I need to make a couple more mods, and "tune" the regulator a little bit.  But I don't think others will see that much fluctuation because my system has everything going against it:

 

My wastegate actuator is 3" in diameter, meaning there is a large amount of volume that has to be filled, and bled to adjust the wastegate actuator, meaning it takes longer, so more fluctuation.

 

My wastegate port is almost twice the size as stock, meaning that a little bit of movement bleeds off a lot of drive pressure.  So it's easier to "Overshoot".

 

My truck is basically stock, meaning the wastegate hardly has to relieve any extra pressure, so it's even easier to overshoot, because the first little bit of opening, is going to have the greatest effect on flow going through the wastegate port.

 

According to some data I have about my wastegate.  At 2400 RPM, it takes .05" of wastegate movement to regulate my boost to 19 psi.

[CSM]

I would be interested to see how it reacts with steady load and enough fuel to ride the 22psi boost you have set.  I am betting it either works well or it will oscillate a little bit.  

[AH64ID]

Very interesting. Seems like a cheaper version of what Cummins used on the 04.5-07 5.9's.

Maybe it's how I am reading it but I am not sure you are using the term boost creep correctly. If your stock WG is set to peak at 22 psi and it gets boost creep then this setup would as well. Boost creep is a function if the wastegste port and not the actuator.

The benefit to the standard adjustable elbow is a smoother limit to boost, where this setup (like the 04.5-07 5.9) can be jumpy at peak boost and even cause rapid drops/peaks. But like you said you aren't bleeding any air to the atmosphere.

I am curious, why port the wastegste on a stock truck?

[Cowboy]

You are right, I'm not using the term correctly.  What I'm incorrectly calling boost creep, is when your pressure keeps rising above your set boost pressure as RPM's go up.  Technically that is boost creep, but only when it's happening while the wastegate is all the way open (thank you google).

 

The stock wastegate is all the way open at 32 psi.  Even though people run 35 psi, due to the way a boost elbow functions, it doesn't reach 32 psi, and won't open all the way.  

 

Yes, a boost elbow is a proven design, and works well.  I just didn't like how the design looked in my head and wanted to do something different.  I also heard a couple people trying to decide between running a boost elbow, or disconnecting the wastegate because they liked how the turbo spooled with the wastegate disconnected, but didn't like having to watch the boost gauge like a hawk.

 

Why port the wastegate on a stock truck? well, after I get the gauges working like they should, and have a base line, I'd like to change the 'stock' factor.  Also,  I just like fiddling, I actually screwed up and went to far, so I had to make a new wastegate flapper with an old exhaust valve.

 

Thank you for pointing out my mis-verbiage.

[AH64ID]

If your boost is rising with a partially opened WG to above your desired point the WG needs to start opening sooner, and could be why it starts to crack at 10 psi stock for 22 peak.

Have you tried varying the length of the rod?

You may need a different WG actuator with the enlarged wastegste port as the drive pressure now has a much bigger area to force the WG open with.

I have always liked the idea of spring WG's that work purely off of drive pressure.

[Cowboy]

That is exactly the reason I wanted to make my own boost controller.  I didn't want it to start opening until a couple PSI before my max boost pressure.  And that way I can maintain a certain boost pressure throughout the RPM range.  Though that didn't come without some fallbacks.  Really though, my wastegate actuator was working plenty well, but I never have liked the idea of how a boost elbow worked, so have been trying to think of a better design for a couple months now, so when I realized what I was trying to design was a slightly modified fuel pressure regulator, I had to try it out.

 

Before making this boost controller, yes, adjusting the rod was my main way to adjust the pressure.  A while back I was playing around with the idea of making my own "big head" wastegate actuator, or going with a spring gate.  I decided to make my own actuator, as I couldn't picture the spring gate working as well, and my welding skills could use a project.  I would still like to make a spring gate and see how well it works.

 

Here is a chart  I made for the amount of actuator movement / pressure.  Red is the one I made, Blue is stock.  Left is 1/10 of an inch movement, bottom is psi.