BY ACCIDENT!!! I have been running 13.5psi since I built this kit without a hiccup. I have the small Precision wastegate with the 9lb spring under the turbo on a homemade log. On the way to work friday morning I pass a few cars and notice the truck wanting to break lose on the 2nd to 3rd upshift,I'm thinking man this thing loves this cold air. So I decide to glance at the boost gauge and its on 20psi...Oh ****!! I have it tuned rich after 14lbs and didnt hurt anything but what gives? Hole in the wastegate diaphragm or a stuck gate.

 

that could of turned out badly!!

 

Lol good on you for tuning it rich up top...saves potential headaches. I do the same thing. Just lean it out as I start tuning for higher boost.

Check all the vacuum lines, gate movement, etc...the simple stuff.

 

I am glad the walbro 255 was able to keep up...she still give me a 10.4afr , I had to get in it again slowly to see if it was a fluke. Vacuum lines are good so Im thinking the gate. Damn thing is 20 days out of the 1yr warranty.

 

Wow butthole pucker moment !

Quote of the day. " she loves cold air " LMFAO !

Gotta love 2bar SD

 

Your boost gauge must be wrong. A 255 lph fuel pump won't support 20 psi on a 5.3. Going from 13.5 to 20 psi would run lean. You can't run rich enough at 13.5 to be safe at 20 psi.

 

I thought the same thing.

OP, I bet it felt good while it lasted. Let us know what you find and I would be pissed if the manufacturer of the wastegate wouldn't fix the issue 20 days out of warranty. GL

 

Maybe he's shifting at 4000rpms

 

I hope it's just the boost gauge,that would be an easier fix. I cant believe the 255 supported 13.5psi let alone 20. The mp70 would just be blowin hot air at that pressure anyways. My hardrive crashed last month and I havent looked at the tune in several months so no data logs. Boy will I feel like a dumbass if it's just the friggin gauge.

 

Ok so I went out to the shop to pull the gate off and this is what I found!! I have a 1.5'' flex pipe between the downpipe and wategate the flex liner collapsed resulting in a 3/4'' diameter hole for the gate to dump through.Solid liners are a must on any part of the hot pipes even the gate dump. 20psi with a walbro 255 I wont try it again.pics to come!