what is stock boost for a 951? i was told 11psi. i just hooked up a aftermarket gauge and the max boost i have shown was 7 psi in 2nd near redline. i just changed to LR boost lines hoping to see a difference and nothing it sits at 6psi. the vac is at 18 solid at idle where it was at 12 before the new lines.

would it be a bad idea to connect a MBC and turn the boost up to 11psi if that is stock?

 

How old is your cat? I was only boosting about 7 psi until I got rid of a clogged cat. Stock boost is ~11.5psi.

 

75,000 on factory cat...

 

That's about the exact mileage I had. One thing I noticed was a lot of heat in the cabin area coming form the torque tube tunnel through the shift lever area. Once I replaced the cat with a test pipe I was achieving stock boost and the excess heat was gone.

Other possibilities include an exhaust leak, a collapsed down pipe or cross over pipe. Or a boost leak that seals when running in vacuum.

 

one thing is when the 02 goes, the car usually runs rich them clogs the cat. Could also be several other things keeping boost from being max.

 

well i think my x-over pipe is leaking... so that might be it? and i did a pull in 4th gear and i hit 8 psi ~ 4500 rpm but then leaked down to 6psi. and that would be a wastegate problem right?

 

Not necessarily. If your cross over is leaking I'd fix that first. But as long as you are that far into the exhaust you might as well update your wastegate. You could shim the stock gate or upgrade to a Lindsey or Tial.

 

so fix the leak at the x-over then see what i hit? then look at removing the cat?


wont removing the cat give extra power also?

 

If your cat is clogged and preventing max boost then you will see a lot of "new" power but probably not a huge amount over stock. But yeah, fix the leak first. And if you wanted to do some WG upgrades you might as well do it when you have everything apart.