RJC boost control confusion..

[JayGord]

Just installed mine and not sure if working right.

From my understanding, you set your boost to your prefered setting and you dont see any boost untill it reaches that set amount , so if you set your boost at 15# of boost you will never see anything under that.. making your actuator not progressive anymore.

Now I took my car out for test drive, my boost is set at 10# and when i give the car 1/2 to 3/4 throttle my boost actually creeps to 5# then I give it full throttle and it goes the final 5 to get to 10#, which means it is still progressive??

 

[Grimster]

The way I understand it to work is, say you're set for max boost of 15, your wastegate actually starts opening up around like 10 or 11 psi and gradually opens up more as you get closer to your limit of 15. With this unit what happens (assuming I didn't misunderstand) is that no bleed off of boost happens until the max boost is reached, and then it opens up enough to keep the boost at max but not over, so you get no bleed off at all on lower boost levels. So your boost will still slowly build to your max, but once max is reached the extra boost is then bled off but no boost before the max.

Maybe someone can definitively answer that for us both

 

[Missouri T]

I have the same arrangement on my turbo dune buggy.
With the same valve ($8 Grainger air compressor valve, by the way), I can get 18 PSI boost (MUCH more is available!) on a factory wastegate actuator that's set for 10 (Garrett T25 turbo).
The ball and spring inside the boost controller is adjustable and does not release until the PSI you set it at is reached.
Thus allowing a LOT more boost than is attainable with a stock actuator.
I love it to death.
Dead-on boost and set-it-and-forget-it reliability.

How did I find out about this valve?
I did 2.2 Chrysler turbos YEARS ago and we used these valves for a myriad of turbo projects.

What am I using it on presently?
18PSI (by 4500 RPM) on 93 octane pump gas a 1600cc single-port VW air-cooled motor with a draw-through 390 CFM Holley 4 barrel in a 1220 lb. buggy white-knuckle ride.

 

[jpratt]

I have the same arrangement on my turbo dune buggy.
With the same valve ($8 Grainger air compressor valve, by the way), I can get 18 PSI boost (MUCH more is available!) on a factory wastegate actuator that's set for 10 (Garrett T25 turbo).
The ball and spring inside the boost controller is adjustable and does not release until the PSI you set it at is reached.
Thus allowing a LOT more boost than is attainable with a stock actuator.
I love it to death.
Dead-on boost and set-it-and-forget-it reliability.

How did I find out about this valve?
I did 2.2 Chrysler turbos YEARS ago and we used these valves for a myriad of turbo projects.

What am I using it on presently?
18PSI (by 4500 RPM) on 93 octane pump gas a 1600cc single-port VW air-cooled motor with a draw-through 390 CFM Holley 4 barrel in a 1220 lb. buggy white-knuckle ride.

Throw us a picture of the Grainger valve set up and of that buggy

 

[JayGord]

Missouri T - you said
"The ball and spring inside the boost controller is adjustable and does not release until the PSI you set it at is reached"

How come i'm set at 10# and i can still half throttle and hold at 5#?? Is this piece not working?

 

[Grimster]

Throw us a picture of the Grainger valve set up and of that buggy

A Grainger part # might not be a bad idea either I know I'm listening with open ears about this $8 boost controller!

 

[Missouri T]

Hi folks,

Okay, I know this isn't Buick but darn it, it's a blast to drive.

I grenaded the transaxle a month ago and JUST got it back this afternoon.
Tomorrow morning is a banzai install project to get it on the road again.
All told, it should take about an hour to get the motor/tranny in and running.

Here are the pics.

 

[Missouri T]

Here are instructions HOW to make one:
boostcontrol

Here is the Grainger site and part number:
Grainger Industrial Supply: Valve,Relief,1/4 In 5Z763

Sorry about the price, folks.
I forgot...I am able to buy it through my employer and must have gotten it at a lower price.
Less than $10 is nothing to sneeze at.
Do you have an employer who uses Grainger? If so, see if you're able to use their discount.

The only other items you will have to buy are two brass fittings (hdwe. or auto parts store) to convert to barb nipples on either end. Common stuff.

 

[jpratt]

Here are instructions HOW to make one:
boostcontrol

Here is the Grainger site and part number:
Grainger Industrial Supply: Valve,Relief,1/4 In 5Z763

Sorry about the price, folks.
I forgot...I am able to buy it through my employer and must have gotten it at a lower price.
Less than $10 is nothing to sneeze at.
Do you have an employer who uses Grainger? If so, see if you're able to use their discount.

The only other items you will have to buy are two brass fittings (hdwe. or auto parts store) to convert to barb nipples on either end. Common stuff.

Is that the one you use? Says up to 20PSI. WHat about guys running higher pressure?

 

[Missouri T]

Whew...over 20PSI?
Not sure.
Do some research on the Grainger site.
I THINK they may have one with a higher PSI rating.

18 is as high as I could go with pump gas and the timing control I have (MSD 6BTM) so I never had a reason to venture that high.

Personally, if I was going THAT high, I'd rely on something a little more substantial than a little brass valve to control my boost.
And the subsequent BIG-$$$ carnage that would result from failure of a $10 part.

 

[BlackMetal]

How come i'm set at 10# and i can still half throttle and hold at 5#?? Is this piece not working?

You still have the wrong idea. Setting the controller at 15psi doesn't mean you're going to see no boost, no boost, no boost, and then WHAM suddenly 15psi.

"Dixiesys" explained it correctly. The RJC Bleeder Valve simply holds in boost pressure until you hit your MAX setting, and then allows the wastegate to open to stop you from overboosting. On the stock wastegate/actuator setup, as you near your max boost, the wastegate slowly starts to open a few PSI early and bleeds off some of the boost pressure.

Basically, the turbo creates a lot of boost pressure, the wastegate is there to open and stop boost from increasing past a certain point. Think of it like a faucet, on a stock setup the wastegate slowly drips boost pressure out as you near max boost and then holds you at your max boost, with the bleeder valve, the pressure is held in the entire time until you hit max boost, then the faucet turned on full blast to release extra boost pressure. The stock setup starts releasing some of your boost pressure at say 12 or 13 psi and then hold you at your max, the RJC valve will keep the wastegate closed until the very second that you hit max boost. It puts 100% of your boost pressure to use instead of gradually leaking it out, until the boost pressure overcomes the spring pressure (which you adjust), and only then allows the wastegate to open.

So if you have the valve set for 15psi it's still normal to see 5psi at part throttle.

 

[Missouri T]

Turbo6Chicago hit the nail on the head.
GREAT explanation.

My buggy will start showing some boost at 2000-2500 rpm and have the full 18PSI at 4500.

 

[jpratt]

Whew...over 20PSI?
Not sure.
Do some research on the Grainger site.
I THINK they may have one with a higher PSI rating.

18 is as high as I could go with pump gas and the timing control I have (MSD 6BTM) so I never had a reason to venture that high.

Personally, if I was going THAT high, I'd rely on something a little more substantial than a little brass valve to control my boost.
And the subsequent BIG-$$$ carnage that would result from failure of a $10 part.

We have a little in common, you and I. Dieckman worked on my car a few years back and the other guy caused me 2 engine failures. Forget about that though. Add alky control to the mix and you can increase boost to 23+. I am currently running 23lbs and looking for more. Do you go to the St Lousi GSCA meeting?

 

[Roc87]

Hey Missouri T, that buggy looks almost identical to what I've got in the back yard! I'll have to post pix Wish it was turbo'ed, I can't even keep it running as it is though.....

As for higher boost with the RJC/Grainger valve, just pull it apart and stretch the spring just a little. I'm running almost 28# with that valve, and having trouble getting it lower...

 

[Missouri T]

Hey Missouri T, that buggy looks almost identical to what I've got in the back yard! I'll have to post pix Wish it was turbo'ed, I can't even keep it running as it is though.....

As for higher boost with the RJC/Grainger valve, just pull it apart and stretch the spring just a little. I'm running almost 28# with that valve, and having trouble getting it lower...

Hey Roc87!

That's a great idea on the spring. Simple but effective.

 

[RUQWKNF]

I have been running one of these valves on my current car since I got her back in Jan. I have run it with a standard spring actuator and heavy duty spring actuator. With boost levels from 16psi all the way up to 30psi. I have not modified my RJC valve at all. With my current PT6776RHP turbo with a properly ported wastegate hole and a heavy duty wastegate actuator, I have boost control from 18psi, all the way up to 35psi. I have not run it up past 26psi as of yet, but the adjustment procedure I follow is this,

With the RJC valve adjusted so that it is barely held together by 1 full thread, I set my boost with my adjustable wastegate actuator. Once I get to a comfortable level with the wastegate actuator, then I start to adjust the RJC valve to raise the boost even higher.

Here's an example.
At Bowling Green this year, I had my actuator set to 21psi with the RJC valve barely threaded together. Then from there, I simply tightened up the RJC valve and was able to get the boost up to 30psi without any problems.
A lot of people make the mistake of only adjusting the RJC valve, and never touching the wastegate actuator and they run out of adjustments on the valve. It is recommended to set your main boost level with the wastegate actuator first, and then fine tune the higher boost levels with the RJC valve.
HTH

Patrick

 

[Underboost]

I have been running one of these valves on my current car since I got her back in Jan. I have run it with a standard spring actuator and heavy duty spring actuator. With boost levels from 16psi all the way up to 30psi. I have not modified my RJC valve at all. With my current PT6776RHP turbo with a properly ported wastegate hole and a heavy duty wastegate actuator, I have boost control from 18psi, all the way up to 35psi. I have not run it up past 26psi as of yet, but the adjustment procedure I follow is this,

With the RJC valve adjusted so that it is barely held together by 1 full thread, I set my boost with my adjustable wastegate actuator. Once I get to a comfortable level with the wastegate actuator, then I start to adjust the RJC valve to raise the boost even higher.

Here's an example.
At Bowling Green this year, I had my actuator set to 21psi with the RJC valve barely threaded together. Then from there, I simply tightened up the RJC valve and was able to get the boost up to 30psi without any problems.
A lot of people make the mistake of only adjusting the RJC valve, and never touching the wastegate actuator and they run out of adjustments on the valve. It is recommended to set your main boost level with the wastegate actuator first, and then fine tune the higher boost levels with the RJC valve.
HTH

Patrick

That's how mine is set.

 

[Missouri T]

I threaded and added and adjuster sleeve to the wastegate actuator on the T25 on my turbo buggy.
It's set at very little preload.
My boost control valve ("RJC valve" is where I do my adjusting) makes for a VERY fast boost rise and very accurate peak boost control.

It starts boosting around 2500 and I have full 18PSI BY 5000 rpm.
Dependent on the weather primarily.
Hot days have a profound affect on peak boost numbers.

The Grainger valve (RJC) is a Godsend for my combo.

My Regal uses an external TIAL wastegate that works outstanding.
I haven't entertained the idea of using the Grainger on it yet.

 

[workingdan]

Ok I just made a grainger (rjc) boost control valve. My ? is what is the .020 hole for?

 

[Missouri T]

Here's what I understand the hole to do:
It's somewhere for the residual boost pressure to go.
When the Grainger ball and spring release, they send airflow to the wastegate actuator to open the wastegate.
When the ball and spring reseat, there is still air in between the valve and the actuator that has to go somewhere, thus the tiny hole.

I imagine there is an explanation of the theory of the hole in the link in my post above.