Boost

[trading t/a]

I am having trouble with attaining boost. I've posted about it in other threads. Today I decided to do the wrong thing and hope it didn't blow anything in the process. So I couldn't get anymore than 13 psi. I checked the wastegate rod(plunger moves in and out), checked the vaccum lines(all good), checked the puck(moves freely), so I decided to take the vaccum line off of the wastegate plugged it with a screw(for now) and did a run. Spooled a little quicker this time,got a good hazing of the tires on the 1-2 upshift, hit third got 8.0* of knock at 14 close to 15 psi. Pulled some timing out with the trans+ and did another. Same thing almost 15 psi(14.? close to 15 on the gauge) with 1.2* knock @660mv.

Now my question is, isn't it supposed to overboost? Without the wastegate relieving the pressure I thought it would go sky high! I maxed it out to about 110mph and couldn't build anymore than that. Any suggestions? It runs like a rocket from idle to max boost but I cant get anymore out of it.

Still kinda choppy at idle and blms are low but it's coming along.
Thanx for any replies.

Pete

 

[UR50SLO]

660mv?

Your O2 is reading 660mv? at WOT???? You better get some more fuel to it before worring about more boost! Move Fuel presure up 4lbs and see what the O2's look like.
I'd like to see AT LEAST 770mv or so and tune from there. That would be a safe setting to begin with.
If your putting a screw in the side where it comes out of the actuator then your relying on the actuator tension only. If your realy wanting to make more boost then get a HD actuator and you'll get the boost your wanting..
~Scott

 

[trading t/a]

No the only line i plugged came off of the T. The actuator didn't have a vaccum source at all. My main question is why wouldn't it overboost? I would've gotten out of the throttle alot sooner if I sensed it was spooling better, but it didn't. So now I'm back to trying to figure it out. I think the exhaust or plugged cat is keeping it from boosting this Friday I will open the cutout turn the trans+ all the way up for fuel and down for spark and see if it boosts any higher. If not I dont know where to look next.

Pete

 

[mrtransam3]

If your header or crossover pipe have a exhuast leak in them you will not be able to build good boost either. I have a stock turbo on my TTA and have no problem getting 22-25 lbs of boost with cam 2 and reds race chip in. All I do is adjust my actuator rod. It could also be the actuator or the boost control solenoid.

 

[tta583]

When you say "off of the WG" do you mean the actuator bolted under the tubo or the solinoid on the pass. valve cover? A lot of folks pull the line from the solinoid and plug it. The only effective connections are at the pressure side of the turbo and the actuator. The spring in the actuator holds the gate closed on the hot side of the turbo until the boost comes up enough to overpower the spring, thus allowing the actuator rod to extend and open the gate. If you pulled the line from the actuator itself I would guess the thing would boot to the moon as there would be no assistenace from boost to push past the spring tension.

Brent

 

[trading t/a]

That's what I did. Figuring it shoulg go through the roof. Well it didn't and it only built 14 psi.

 

[Quick6'n'-K.C.]

im going to try as much as possible here-

are you relying on the stock DASH Boost gauge??
if so, dont trust it!
get a aftermarket pillar mount

does your turbo have an adjustable wastegate rod???
turn it in for more boost!!

why is your car KNOCKING at 15psi of boost when it goes into 3rd gear?? 8* already???
DONT TURN UP THE BOOST

does it still have a catalytic convertor?? if so, it could be plugged

is the T fitting FACING the correct way???

actually it is a Y FITTING, picture the fitting as a lower case y the fitting goes straight from the turbo compressor houseing to the electric wastegate solenoid located on the pass side valve cover, and THE ODD part of the y DOGLEGS down to the WASTEGATE DIAPRAGM

does the y fitting have the correct orafice in it?? .040 ??

is the wastegate PUCK sealing completely?? what downpipe do you have? if the PUCK isnt sealing correctly then the pressure is bleed off-

all these are possible things that can cause low boost-

here is what i would do-

check the Y fitting for proper arrangement
check intercooler hoses for tightness

to get more boost, you need to TAKE AWAY pressure to the wastegate diapragm, so if you are BLOCKING the hose that leads to the ELECTRIC solenoid on the valve cover, that is why you DONT get any more boost!!

plug your vacuum hose back to the electric solenoid, and put a BLEEDER inline from the y fitting to the solenoid, bleeds off air to the wastegate diapragm= more boost

 

[tta583]

What I ended up doing was going with a manual boost controller and ditching the factory solenoid all together. I would not go that far right now, you have something else wrong. I agree, check the "y" in the line to make sure it is right. If the car ever boosted correctly and you have not touched the "y" then I would still double check it and move on. Does the actuator rod pull out easily by hand? The actuator may be messed up so that no matter how short the rod is it is easily overcome by boost pressure through the diaphram or exhaust pressure in the hot side of the turbo. I think I would look at the exhaust next if those pan out. Pull the converter and run it uncaped for a test. It will be loud as hell but it will tell you if the converter is junk. Just make sure to support the rest of the exhaust. You may also want to look at the puck as suggested above. Pull the turbo shield, get the motor warm, then remove the exhaust housing. I say get it warm so you have less trouble breaking the bolts free and less chance of breaking a bolt. Look at where the puck seals against the housing, clean it up for a good seal.

Checking the lines and "y" and the rod for strenght will be like 5 minutes. I think I would pull the converter next. The ones on the TR just bolt in, right? I would save the puck for last but I would still do it just becasue.

BTW, if you go with a manual boost controller down the road you eliminate the "y" and the factory solenoid. Everyone I have ever seen acts as a bleeder, like the solenoid, and a restrictor, like the "y".

Brent

 

[trading t/a]

Well after checking the above mentioned areas I'm pretty sure it's gotta be the exhaust stifling the turbo. I will open the cut out and turn the rod back out and see what kinds boost it has(whuile richening up the top end. Thanx for the suggestions


Pete