Guys

Normally I dont post many tech questions, but an issue thats recently developed has me scratchin my head a little.....

Preface: Car ran great just a week ago. I pulled it in the garage on Monday evening to perform an exedy twin install.

Install went fine, no real major issues, just a PITA like any clutch job on these cars is.

Now onto the issue.

I went out and drove the car, and immediately noticed it felt a little sluggish. I put my foot into 2nd gear gear and something definitely wasnt right. After checking the vitals on the dash once again, I noticed the car was hardly making any boost.

I came back to the garage and did a quick boost check up to 15psi.......passed with no problem.

Checked the inlet pipe, there are no obstructions

I removed the MBC just to make sure that wasnt the issue. The car is now on the w-gate spring which is 25 preset from FP

I also put shop air to the actuator to verify its opening/closing the flapper, the travel seems to be fine. Later today I'm going to disconnect the arm from the wastegate to verify the flapper isnt hanging open a little.

I havent checked the validity of the tune, but I havent ever seen a tune dissapear due to disconnecting the battery.

There are no exhaust leaks.

Anyone got any suggestions?

I'm mostly stumped, because I cant wrap my head around why anything would be affected by what I did, considering the only things having to do with the engine/turbo that I touched during the clutch job were the UICP, inlet tube, downpipe, and BOV (which are pretty damn simple)

 

Check the hoses and connections on the back to the intake manifold, you may have broken one of the plastic connectors for the EGR/FPR/EVAP system, and thus you do have a boost leak...

 

Not disagreeing, however I have blown just about each and every one of those off at some point, and the car will still make 35+lbs of boost when it happens.

The car is struggling to even make 15psi and it comes on slow as hell. It was like 5psi @ 4k rpm last night when I went out and tested it

 

I forgot to mention that the driveability of the car is the same as it used to be. It idles fine, and cruises fine. The vacuum is exactly where it was at previously as well.....

 

Check the turbo out...

 

As a safety precaution, I always check for shaft play with the inlet pipe is off, and it was tight and spun freely as of a day ago...

 

Boost controller?

 

I eliminated the boost controller as one of the initial tests, just running the vacuum line straight to the wastegate.

However, the issue IS resolved.....and it just happened to be a freak occurence.....nothing related to the clutch job, but happening at the exact same time

I had a feeling the issue had something to do with the wastegate, being the car could build *some* boost, just not enough. Last night while looking at the car, it appeared the flapper was completely shut, but today on lunch I disconnected the wastegate arm from the flapper, and noticed I could get the flapper to close completely. After looking around at it for a bit, I finally discovered that the bottom most bolt that holds the wastegate/bracket onto the turbo, had fallen out. The upper most bolt was still intact, but loose. This allowed the bracket to swing slightly away from the flapper, thus opening the flapper slightly. I was unable to see the bottom bolt missing due to the fact that its burried way down there between the turbo and the radiator.

After installing a new bolt, applying threadlocker to both bolts, and getting the arm set back on the flapper, the car is now normal again.

 

What was your target boost level?

 

I reread your opening post and see where your turbo is set to boost to 26#, right?

 

My advice is to bypass the MBC and try getting the turbo uo to your peak boost level of 26# by rotating the turnbuckle on the end of the threaded acutuator rod inward clockwise.

So, disconnect the MBC and plug the two hoses that were connected to it with golf T'ees, etc. Next run a new and separate length of hose directly from the WGA nipple to the compressor discharge tube nipple.

Remove the cotter pin that holds the turnbuckle onto the flapper valve's pivot arm. Pop the actuator rod off at the front with a flat blade screwdriver. Loosen the turnbuckle's backup nut. Crank the turnbuckle in a couple of complete 360* rotations. This will shorten the overall length of the actuator rod and thus increase spring pressure and boost level. Now take the car out for a spin and see if the boost has gone up and how much.

I think that for your boost level of 36# you'll want to increase the WG spring pressure on that 25# actuator up to about 30-32#. At least that is what I would shoot for. GL.

 

No offense, but im not sure where you're going with these suggestions.

The issue has been corrected, and it was all due to the flapper being held open slightly due to the missing bolt on the wastegate can bracket. All is normal now....

In regards to desired boost levels, etc, the turbo has a preset 25# w-gate on it.....for mid 30's boost, its just a few turns on the MBC

 

It's good that you got it fixed. So, I take it that you are running the WGA w/o any additional preload? This makes for a slower spooling beast.

 

Why would it be slower?

As long as the flapper is shut 100%, the turbo is going to spool as fast as it can (up to the setpoint)

The wastegate is setup from FP preloaded to 25#

 

Similar issue with my stock IX, when I first purchased it only boosted a little past 10lbs..as a quick fix I put a MBC and cranked it up to stock. Still Not sure what ths issue is