Boost Over Shoot with a Manual Boost Controller

[Speed_Dreamin']

How much over shoot are you guys seeing with your manual boost controller and what controller are you using? I run a Turbo XS piece. I bought it from the local speed shop who cater to imports - I was being impatient and didn't want to wait for a mail ordered one. This thing overshoots about 4 psi. Seems like alot.

 

[Speed_Dreamin']

Any one?

 

[scottyb]

Do you mean spike? As in you set it for ~17 lbs, and it jumps to 21 before settling back down to 17.

 

[Speed_Dreamin']

Do you mean spike? As in you set it for ~17 lbs, and it jumps to 21 before settling back down to 17.

Yes. Mine does exactly that. Overshoots to 21, then settles on 17. Seems like a pressure spike of 21 psi could be dangerous. I currently run straight 94 octane, but I haven't seen any knock. Isn't the sampling rate of the Scan Master pretty slow? Could I be getting knock during the pressure spike or over shoot but the SM is not recording it?

 

[scottyb]

Is the car basically stock - stock turbo and converter?
What type of controller? Relief valve?

 

[Speed_Dreamin']

Is the car basically stock - stock turbo and converter?
What type of controller? Relief valve?

TA-49. Stock converter. Turbo XS under hood manual boost controller. What's a relief valve? I don't have a blow off valve if that's what you're reffering to.

 

[scottyb]

TA-49. Stock converter. Turbo XS under hood manual boost controller. What's a relief valve? I don't have a blow off valve if that's what you're reffering to.

A relief valve is a ball-and-spring valve. It runs in-line from the turbo to the WG actuator, and is adjustable. The more you tighten it the more compression you put on the spring, therefore the more pressure it takes to move the ball, and let pressure pass to the actuator. I just looked at the turboXS site, and those appear to be adjustable relief valves.

I had issues with bad spike as well with the stock turbo and converter, and still do with the TA49. Frankly, I feel that this type of valve is more useful for those who have big turbos and loose converters. I tried everything under the sun, relief valves, bleeder valves, and then finally the boost command electronic controller.

There are several thoughts to consider that seemed to help me, but not 100%:
-port/open the wastegate hole so there is better flow when the WG opens
-minimize the length of the control hoses. This will put the controller in "knuckle burning" area, but it minimizes the area to pressurize
- adjust the actuator arm so it's not tight. The tighter you make the arm, the less reliable it's control is.

Eventually I went to the boost commander, and I was happy. Now that I installed the TA49, I have small spike again. I haven't had time to really adjust and play, nor have I had tome to port the WG hole.

 

[QUIP'6']

i have an rjc bleeder and mine spikes to 30 then settles at 26 in a second i think it comes on so fast that it cant control itself

 

[VadersV6]

Are you still using the factory Y fitting? There is an orifice in there which limits the flow rate into the wastegate diaphragm. Its designed around stock turbo and stock boost. After increasing the turbo size and the boost and doing other things which increase the airflow rate, the orifice will cause the wastegate to fill and pressurize slower than the actual turbo does. So what happens is at the moment the manifold sees say, 20psi, the wastegate diaphragm may only have 15 in it, so it hasnt actuated the puck arm all the way to where its set. Give it another second or whatever, and now the wastegate has 20psi in it and now it actuates the puck arm all the way and now the boost drops to where it is set. Garrett engineers knew what they were doing when they decided on a wastegate vent diameter. Drilling it out is a band-aid approach that can cause the turbo to decelerate too quickly and cause a shutter that can hurt the turbo over time. The correct cure is to fill the wastegate at the same rate the turbo pressurizes the intake. You need to drill the orifice in the Y fitting out slightly, like .003" Just buy a reamer from mcmaster.com in the right size. I think the stock size is .047"...at least thats what mine measured with a pin gauge. Go to .050 and see if it helps. The controller you're using cant really divert the volume of air quick enough and that can also contribute. Its too small. I use a special needle valve for air cylinders. Just adjust the wastegate so you have to pull it about 1/8" to get it on the puck lever, set up the whole hose system like stock with the Y fitting and everything, then just pull the hose off the factory solenoid and stick it on this needle valve. Stick it in the threaded hole showing in the picture. You'll need to get a barbed 1/4" NPT fitting for it, and just tell them what the inside diameter of your hose is so you can get the right one. Or just go to mcmaster and order it there. Hell, home depot probably has it. I can adjust boost in tiny increments and it spools really quick. Ive tried a million different things and this worked the best. Im an automation builder so I had this on the shelf here and it worked great. Its got a knurled knob. Doesnt require any tools and is incredibly stable. try this before drilling your orifice out. trust me everyone should be using this thing. Plus it can handle the volume of air the turbo produces, so it has very stable control over the air. Use this one. The FBC, not the FC model.

Fabco-Air Online Store: Super-Vee™ Needle Valve, Super-Vee™

 

[Speed_Dreamin']

Very cool stuff here. I am not running the factory restrictor orifice with the manual boost controller. I was told that the orifice was redundant with the controller and not needed. Is this not correct?

 

[scottyb]

Very cool stuff here. I am not running the factory restrictor orifice with the manual boost controller. I was told that the orifice was redundant with the controller and not needed. Is this not correct?

That's correct. You have it hooked up:
compressor -> adjustable controller -> actuator
and removed the solenoid plumbing
right?

 

[BlackBandit]

FWIW I ran a stock turbo/converter with a MBC from dawes devices (now 3 Bar Racing---Home Page) for years and NEVER had any boost spike. No ported wastegate puck, no nothing. All stock stuff (with alky) and I ran my boost as high as 27 pounds with ZERO boost spike. Maybe you just got a POS controller. The good ones like the one 3barracing sells have a ceramic ball I believe along with a few other features that allow it to react extremely fast. I would guess your local import shop is selling crap to honda guys with turbos that spool so slow it doesn't matter. That's my 2 cents. james

EDIT: Also, if you're using a MBC with the spring and check ball you should eliminate the "Y" connection and the boost solinoid. Just run it inline between the vacuum/boost source and the wastegate. Trying to include parts of the stock system seems like a bad idea as that "Y" is designed to work in conjunction with a bleeder that is adjusted at a set rate by the ECM based on several factors. These types of boost controllers are designed to stand alone or work with a constant bleed. Unless your an engineer or equivalent with something to prove don't waste your time trying to get the two systems to work together.

 

[Speed_Dreamin']

That's correct. You have it hooked up:
compressor -> adjustable controller -> actuator
and removed the solenoid plumbing
right?

Yes this is how I have mine set up. Looking on the Turbo XS website, the controller I have is a bleed type. Bummer. Guess thats what you get for purchasing something on a whim.

VadersV6 - is your needle valve more or less a bleeder valve that you can adjust the bleed pressure on? What are the approx. dimensions of the valve you are showing?

Black Bandit - The 3 bar racing piece looks like the RJC boost controller. Are they the same? What I don't like about that piece is that you have to disconnect the hose to make adjustments. I like the idea of just turning a knob.

 

[VadersV6]

VadersV6 - is your needle valve more or less a bleeder valve that you can adjust the bleed pressure on? What are the approx. dimensions of the valve you are showing?

It basically replaces the factory solenoid. It bleeds off pressure. Alot of bleeders cant handle the flow rate of the turbo so you run into problems. The ball bearing style, which is a flow controller, not a "snap open or snap closed" valve like many of them claim it is. The ball bearing vibrates and the spring pressure determines how high the ball bounces off its seat and allows flow to pass, and it cycles extremely fast. It buzzes. The ball doesnt wear out, but the brass seat does and so does the spring. Plus it gets sticky and jams and usually isnt that reliable. Ive tried about 8 different bleeder setups and this one is awesome. I can adjust boost 1psi per turn and I dont even have to lock the knob down. Doesnt take a wrench to adjust. You can run it into the car if you like. Its about 3" by 2" and maybe 1/2" thick. I tapped one of the holes the same thread as the stud that mounts the factory solenoid, and just spun the fabco on the stud and its locked on just like the factory one. Just set everything up like stock, unplug and remove the factory solenoid, and plug the air hose up to the fabco and you're good to go. Not a shred of boost spike or creep and no ball bearings to get sticky, springs to wear out, rubber diaphragms to go bad...its a teflon shaft with a triangle shaped groove, and has a steel triangle cut shaft that slides in this groove at an angle. So the more the steel shaft moves in or out, the more it moves sideways and covers/uncovers more of the air path. Its a design that will never wear out or clog or go bad. It has no moving parts other than the obvious.

 

[TurboMonte 2]

Installed a Q-Boost controller & eliminated my 3# boost spike. Got the optional bleed valve & hose for fine tuning in-car. Thought perhaps my WG solenoid was funky--so it's now removed from system & on my workbench--next to stock Y-hose w/ orifice.:smile:

 

[BlackBandit]

The ball doesnt wear out, but the brass seat does and so does the spring. Plus it gets sticky and jams and usually isnt that reliable.

I ran one of those MBC's for years and never had a problem. Nothing ever wore out and it never messed up. Not once. As far as I know it's still performing at that level for a friend several years after I gave it to him. Plus, no simple bleeder can match the spool characteristics of a MBC.

Edit: Vader, if I can ever make one of the socal meetups maybe we could get together and I could hassle my friend to see if he'd let me borrow it back for a day. You seem to have had bad experiences with them so I'd be interested to see what you think about the one I used. Just a thought. james

 

[VadersV6]

I ran one of those MBC's for years and never had a problem. Nothing ever wore out and it never messed up. Not once. As far as I know it's still performing at that level for a friend several years after I gave it to him. Plus, no simple bleeder can match the spool characteristics of a MBC.

Edit: Vader, if I can ever make one of the socal meetups maybe we could get together and I could hassle my friend to see if he'd let me borrow it back for a day. You seem to have had bad experiences with them so I'd be interested to see what you think about the one I used. Just a thought. james

Unfortunately I never make any of the social things myself...
Ive heard several people complain about their boost acting funny, and they'll call the manufacturer and they will tell the customer to spray wd-40 in it, blow it out, readjust...all this constant crap...and then a month later its acting up again. It takes the slightest tiny particle to screw up the seal between the ball and seat. Thing is that all those are, are flow controllers. We use them every day in the automation world. SMC, Fabco...you name it, all make flow controllers with a little knob on it, and they do a better job than these homemade brass fitting/spring/ball bearing things. An actual system that truly stays closed until a set boost, then slams open...I have yet to see a system that actually, truly does this. Its marketing hype and isnt true. The ball just vibrates and limits the flow rate to the wastegate. I could actually make a system that does this, but it would be alot of money. It would take valves and pressure switches and alot of work. But it could be done in 10 stages if desired. Each valve will open at a set point and you'd have total control of the boost curve...not just 2 stages like many others out there.

 

[bison]

For internally gated cars i open the wastegate hole to its max. I use the appropriate actuator for the intended boost and back the arm off till it slides over the swing valve arm with minimal tension. Then i back off the controller knob till there is minimal tension on the ball. From there i check the spool and see if it over shoots. If it doesnt which it usually wont at that setting i continue cranking the knob down until the boost is where i want it. I will then play with the actuator rod length and the controller knob until i get a 1 psi overshoot. Usually have to back off the knob a turn or 2 and then add 1 or 2 turns past the minimal rod length setting.

 

[tb3]

I installed high pressure rubber fuel injection hose (that has the liner on the inside) in place of the vacuum hose and that fixed the 2 psi spike on my adjustable boost controller. hth. remember to use zip ties

 

[Hot Air]

Cool. Food for thought!
Conrad