Hey guys,

Picked up a 2001 TT 225 hp a few months back. Its chipped. I always suspected the performance was a little low, so I finally installed a boost gauge.

when idle. 16 vacuum, wot never reaches over 10 psi boost.

heres what I did

- Cleared codes (via chips menu)
- Throttle Body Alignment (via chips menu).
- Ran for a few days. VagCom reports no errors
- Replaced the two braided vacuum lines (Made a slight improvement vac about 18)
- Replaced DV
- Checked all the other vac hoses, they all look to be in great shape, no tears, cracks, warespots..


So I am a little at a loss. If I got WOT the boost hits about 5psi untill about 3000rpm and then jumps to 10 really quickly (is that just typical boost lag?). if I come close to redline I could probably creep that upto 12. When I take me foot off the throttle the vac. will drop to 21-22 for a few seconds, and then go back to 16-17..

The car seems to idle fine for the most part. A little bit of idle hunt here and there.

Any suggestions for things to look at?

 

yes....but sounds like the chip is in stock mode ???

 

Hrmm.. pretty sure I switched it back. Several times. Besides, even in stock shouldent I be seeing a better vacuum and around 15 psi boost?

 

I should just put this in my sig I suggest it so much, but you should buy/build a pressure tester. Its easy to build, easy to use, and can save a lot of guessing.

www.modshack.info This guy sells one, easy to model your own after it, of if you're not inclined to do that much work, just buy the damn thing. 18-22 is about right on the vac side of things.

Theres so many places to develop a boost leak, and if hoses are separating under boost, you're gonna have a hell of a time finding them at idle.

 

vac should be around -20 , chipped boost should be around 22 and level off at 19-20 "thats what mine does". you can always get some soapy water and spray the vac/boost lines and see if theres a leak anywhere

 

yeah, but you're not gonna see bubbles if a vac leak sucks the soap IN, and you won't see bubbles for a boost leak w/o a pressure tester, because you CANT MAKE boost just revving at a standstill.

 

jack stands my friend !!!

 

I did note while changing the dv that I removed the two larger hoses first and pulled the valve out. The top little hose was still attached and the inside of the valve was held strong (sucked) to the top of the housing.

Does that help determine that there is not a leak upto that point, or is that just useless information.

Aside from the braided lines are there any particular lines to focus on, as all the rubber hoses look to be in great condition..

 

Sounds like you car isn't chipped. Keep in mind that stock boost on a 225 peaks at 14.7 psi but usually holds around 12psi. Chipped should hold 20 psi or above.

You need to pressure test... it's so easy to build it's rediculous.

 

Well.. i can bring up the chips modes using the cruise control stock.. so I think its in there.. I did notice it only has the stock and 93 octane modes.. but I am running 91..could that have anything to do with it.

I think there still is a vac leak because today I am seeing 14 -16 on the idle vacuum. sounds a little low..

regardless I will buy/build a pressure tester tomorrow. I am sure the procedures are well documented on google.. but any tips that are tt specific?