I have me a bleeder valve I need to adjust. What's the best method of checking max boost? WOT throttle runs or laying into the throttle at ...say 50 or 55 mph?

I would start with a roll on at about 70 or so(were ever it wont downshift in 5th) Start rolling into her watching your boost. Then try again pretty much punching it in 5th. Then use it as a good excuse to do a WOT pass through the gears:ro)

JMO as the safest. Remember to roll out if you get too high boost! Dont just lift hard and quick!

Thanks. I have done a few, no ...actually a lot of WOT runs thinking that was the way to go ...then realized it wasn't ...but I was having to much fun so I made about 8 WOT passes on a lonely country road. After about 8th run I noticed my tranny was just over 200 :( so I tucked my tail between the legs and headed to the barn. If it goes past 32 don't I just let her keep going up to see where the boost will stop? :) :joke:

Here's my bleeder valve I'm experimenting with ...pretty cool. Has vent hole on bottom and you set bleed off with allen screw.

Here's my bleeder valve I'm experimenting with ...pretty cool. Has vent hole on bottom and you set bleed off with allen screw.
You can purchase adjustable valves that will be a little more user friendly.
Keep an eye on the boost guage though.

I used to run the bleeder valves on my Turbo Buick. I would set the boost where I wanted with the wastegate and splice a rubber hose between the wastegate and turbo. Run this line inside the car and connect to a bleeder valve. Place another rubber hose at the outlet end of the bleeder valve. You now have the poor mans 2-step boost controller by opening the valve and placing your finger over the end of the hose. Bleed depends on size of hoses and valve. I was getting an instant 2 + - lbs of boost which in my case was substanial. I could get by for a short spike like this say near the end of a run and not hurt the engine. Won a few races that way. :D
For the record I graduated to an Inovative boost controller later in life. That was $$$$

All this may not apply to the diesel though

I did mine on a load cell dyno.:D However you can accomplish the same thing with WOT runs, careful to observe the boost at the top of each gear and then right after the shift.

Well I'm baffled. Just got back from some test runs ...did about 10 runs starting around 60 mpg to WOT ensuring the tranny didn't kick down to 4th. No matter how far in I go on this set screw my boost pegs at 28 psi. I got down to only 1/4 turn out with the same results and didn't want to go any further as others running this same bleeder valve are about 1 turn out and running 32 psi. The only difference is I am still running the OEM air cleaner. That wouldn't be the culprit would it? I don't think I have an air leak anywhere ...and doesn't make sense that my boost stops at 28 psi before/after I installed the bleeder fitting. Stumped.

On my gas car I found out that the size of tubing feeding the bleeder valve makes a hugh difference on boost control. Too small a line will diminish the bleeder valve effects. Sounds to me like the feed line and/or the bleeder valve is too small in your case.

It's spliced inline with the wastegate line so the diameter of line is whatever the wastegate is ... 1/4" or 3/8" I think. I also have a 'T' inline that goes to my boost gauge. The bleeder valve has the same inside diameter where the orfice is limited by screwing in the hex nut. I guess I'll go in further on the hex screw even though I'm only about 1/4 turn to the hex screw being fully seated.

Make sure the guy that gave you the instructions on how to install it has his head pulled out of his ass :iamwithst

Make sure the guy that gave you the instructions on how to install it has his head pulled out of his ass :iamwithst:lol: Thanks. I got this idea this afternoon of turning it around the other direction and see if it works :)

I've never seen any mention of this type of a deal before. What gives? I'm curious...

It's spliced inline with the wastegate line so the diameter of line is whatever the wastegate is ... 1/4" or 3/8" I think. I also have a 'T' inline that goes to my boost gauge.

IF YOURE FOOLING THE WASTEGATE AND TAKING A READING FROM THE SAME LINE AS YOURE FOOLING IT, THEN IT WONT BE A CORRECT MEASURE OF THE ACTUAL BOOST :)

IF YOURE FOOLING THE WASTEGATE AND TAKING A READING FROM THE SAME LINE AS YOURE FOOLING IT, THEN IT WONT BE A CORRECT MEASURE OF THE ACTUAL BOOST :)
I don't follow. Several others have the boost gauge in the wastegate line with a bleeder valve. The way I have it connected is:

Looking at the engine it looks like:

WasteGate ======== Bleeder Valve ======= Boost Gauge T =========


This won't read correct boost?

I've never seen any mention of this type of a deal before. What gives? I'm curious...
It's the poor man's way of getting more boost without buying a Banks Bighead wastegate. Do a search on 'bleeder valve' or 'boost' and you'll find some posts that explains how it works much better then I could explain. Several other guys are using a bleeder/needle valve with a round knob to adjust the boost.

NO it won't..


your boost line should tap in after the intercooler before the air enters the engine. some put it in a super diesel manifold (collar). mine is tapped right where the blue tubing meets the intake plenum (next to the oem boost sensor).

i have seen one truck where no matter how much we bled it with 1/4 line (even no needle valve, and tried w/ line disconnected) it wouldn't go over 28. new actuator fixed that problem.

I don't follow. Several others have the boost gauge in the wastegate line with a bleeder valve. The way I have it connected is:

Looking at the engine it looks like:

WasteGate ======== Bleeder Valve ======= Boost Gauge T =========




This won't read correct boost?

NO it won't..


your boost line should tap in after the intercooler before the air enters the engine. some put it in a super diesel manifold (collar). mine is tapped right where the blue tubing meets the intake plenum (next to the oem boost sensor).

i have seen one truck where no matter how much we bled it with 1/4 line (even no needle valve, and tried w/ line disconnected) it wouldn't go over 28. new actuator fixed that problem.
Thanks. I'm just trying to understand the whole boost deal. Why do so many people splice their boost gauge into the WG line? Is this a valid location when a bleeder valve is NOT used? Or is it not an good location to get boost from regardless?

Thanks for the info--I guess it's just an LB7 mod in that case, as the LLYs have no wastegate per say.

Look At It This Way, Youre Manipulating The Boost Pressure That Is Pushing On The Diaphram In The Wastgate Controller. If You Take A Reading From The Same Area, Youre Also Manipulating The Pressure That Your Guage Is Reading.

You are not taking a reading from the bleed area. You are taking the boost reading before the restriction in the line (set screw), and after that restriction is the bleed orifice. You are measuring pre-cac boost, which will be higher than post-cac.... The point here is know what the turbo is doing, to prevent damage.

Your gauge must be upstream of the boost fooler.

measuring from the WG line is fine. Much easier to install is the reason people do it.

Max Payne, so the bleeder valve we are using (not sure if it functions differently then other types of bleeders others are using) isolates the bleed area (from bleeder valve to the WG) from the boost T? This is how I "thought" it worked ... I know you are running it with good results (32 psi) with your boost T in the WG line before bleeder valve.

If I understand what you are saying is the boost T does not see the "fooled pressure" from the bleeder valve to the WG ...where pressure at the boost T could be 32 psi and pressure at the WG could be 28 psi?

Is that set up with a allen plug creating more of a restriction in the line and a bleed behind the plug to lett off a bit of presure?

thats the idea

Your gauge must be upstream of the boost fooler.
I believe the below layout would be considered "Upstream" (I.e. Before) ?


WG<<<<--------BleederValve<<<<-----------BoostTee/Gauge<<<<-------------

Exactly. This isn't a valve you buy at HomeDepot ...they are made by a reputable diesel performance shop in NY.



Is that set up with a allen plug creating more of a restriction in the line and a bleed behind the plug to lett off a bit of presure?

thats the idea

Yes, the restriction is there to lower the pressure on the WG side, and the bleed is to keep it lower on the WG side.Max Payne, so the bleeder valve we are using (not sure if it functions differently then other types of bleeders others are using) isolates the bleed area (from bleeder valve to the WG) from the boost T? This is how I "thought" it worked ... I know you are running it with good results (32 psi) with your boost T in the WG line before bleeder valve.

If I understand what you are saying is the boost T does not see the "fooled pressure" from the bleeder valve to the WG ...where pressure at the boost T could be 32 psi and pressure at the WG could be 28 psi?

Even if you do get it to show 32 psi in this area, it will still be lower post CAC at the intake manifold due to psi drop across the intercooler. I still have that SD manifold for you!

Even if you do get it to show 32 psi in this area, it will still be lower post CAC at the intake manifold due to psi drop across the intercooler. I still have that SD manifold for you!
If I understand what you are saying wouldn't reading boost pressure post-CAC read lower boost then what the turbo is actually seeing due to the pressure drop across the CAC? ...which means if you adjust a bleeder valve in the WG line to read 32 psi post-CAC actual boost pressure at the turbo would even higher?