TA49 WG Hole Diameter ???

[Twil]

Please help.

I just bought a TA49 and a 3" THDP. After installing (along with other mods - see below) I now get very bad over boosting. Initially, I had over 25 lbs of Boost and excessive KR. I have adjusted my Actuator Rod out all of the way and that has helped. My chip is a 17lbs Joe Lubrant (93 Oct). As of last night's testing, the lowest boost I can get is about 16 lbs, which seem ok (Only 2 - 4 degrees of KR max)

My Puck is 1 3/8" (Seems large - From my 3" THDP)
My hole is only 15/16" (Seems too small to me- TA49)

Should I have had the WG hole increased to 1" or more ???
What is the correct size for my mods???

TA49, Mark Jackson "Stretch" IC, Blue Tops, Adjust. Fuel Reg (46 Lbs), 3.5" MAF w/ Translator Plus, Power Plate, Big Mouth Ram-Air, Kenne Bell Plenum, 3" THDP, 3" Cat, Hooker 2 1/2" Exh, DynoMax Ultra Flow SS Mufflers, Kirban Valve Spring Upgrade kit, 307 Walbro FP, Joe Lubrant & Extender chip.

Brandon

 

[TRBON8R]

Brandon,

Been there and done this before. Since you're running a TA49, I'd bet the wastegate hole has probably already been enlarged. I'm pretty sure most of the vendors out there like PT&E or John Craig already open up the wastegate hole in the housing as a matter of course.

Are you sure that you have the Y hoses leading to the turbo hooked up correctly? If so I'd suggest unplugging the boost solenoid, and then taking the car for a drive. The hardware on the car has a baseline setting that should be right at about 13 pounds of boost with the solenoid unplugged. The check engine light should come on when boosting the car. If boost holds steady at approximately 13 psi you've found your problem, it's probably the solenoid. At least this way you can narrow down whether you are dealing with an electrical problem or a problem with the hardware. Good luck.

 

[Twil]

The Y hoses leading to the turbo is hooked up correctly and I just replaced it and the boost solenoid with new ones from Poston.

I have a TA49 Precession Turbo (Via Kirban) and I measured the hole before install and it was a hair under 1" (15/16" to be exact).

I will try your suggestion today or tomorrow.

Thanks alot.

 

[TRBON8R]

Brandon,

You say you replaced the y-hose with a new part. You could also have a problem with the y-hose. It seems that GM had some problems with some of the y fittings having holes that were drilled out of spec. Hopefully you have your old y-hose assembly so you could swap it out if need be for some trouble shooting. Like I said though, try the solenoid first. It's the easiest thing to try first. Just because yours is new don't assume it's good.

You'll get this thing solved. I went through exactly the same deal and know how frustrating it can be not having confidence that you can get into the throttle without overboosting.