Boost Trouble and Tranny Stall HELP!!

**00s4slvr** · 11-02-2008 09:44 PM

hey guys so today i partcipated in the black forest run meet. It was a blast and i was the only audi there (some of you guys should have came :P) anyways... i am having some concerns/ issues with the S. Its a Tiptronic and im wondering if maybe im just worrying to much so here it goes...

Problem #1: I have a giac x ecu on pump performance and if im just cruising along the highway and punch the gas (to kick down mode) my boost seems to go to about (14-16) PSI and then when it shifts it spikes to 17-18 and then back down 12-13 and then back up to 14-16 PSI again. Also i noticed when i was in tip mode and shifting manually the boost would be around 14-15 and when i shift spike up to 17 then go back to 14-15 again. Do i possibly have a boost leak/ problems with boost??? Or is this just normal??

Problem #2: I was trying to take the S to 160MPH today and when i have the giac ecu on Pump performance mode and im going about 135 getting ready to manually shift into 5th gear the tranny gets stuck between 4th and 5th and would downshift and upshift like 5-6 times until i ease off the gas a bit and then it would shift into 5th and then i can continue going just not flooring the car. Is this normal??

**InLoveWithMyS4** · 11-02-2008 10:28 PM

Problem 1: Don't quite understand your problem. Are you saying that boost peaks in between shifts?

Problem 2: Not 100% sure, but I think top speed is achieved in 4th, so I think you were trying to do something it was not wanting to do, ie, be in 5th while at that speed/throttle position.

**00s4slvr** · 11-03-2008 06:17 AM

For problem 1, im saying that when i use the car in drive and it shifts it will peak in between shifts and then drop down to 12-13 which is low for giac and then go back up to 14-15. But if i use the Tip mode it will peak up to 17 then back down to 14-15. is this normal?? Also what should the giac x boost be at?

Problem 2: Are you sure cause i think i remember at around 135 the car was redlining and trying to shift into 5th but the tranny like got stuck and would go back down to 4th then up to 5th then back down to 4th and up to 5th about 5-6 times until i let off the throttle a little bit... Is that normal?

**00s4slvr** · 11-03-2008 01:26 PM

i was thinking maybe a bad n75 valve???

**4RingsCircus** · 11-03-2008 06:36 PM

It's the kick down. My stage 3 acts worse, unless I stay in auto after 1st gear. It will stumble at 4500- 5000 in every gear, and not want to shift as cleanly.

You could get a custom tranny chip through VAST that would fix most of these woes. Just don't use a post-6800 RPM rev limiter on your ECU. It will put the tranny in limp mode easily in 1st gear.

Also:
If you don't have downpipes, you should get piggies from VAST now, not later. Your turbos are frying in that pressure range with pre-cats.

**00s4slvr** · 11-04-2008 06:54 AM

oh i didnt know that thanks for all that info. As far as the piggie pipes i have the ecu on the stock setting and i barely put it on pump performance because im low on money right now. But i will definantly be getting piggie pipes asap then.

As for problem 1: Everyone i spoke with told me my boost on pump performance should be around 15-16 and spike to 17-18 then go back down to 15-16. When i was in Drive and use kick down the boost will go to 14-15 spike up to 17 then back down to 12-13 then back up to 14-15. If im in the tip mode it will just go from 14-15psi spike up to 17 then back down to 14-15.

Is this normal??

**1997gtx** · 11-04-2008 09:03 AM

When does the car "go down" to 12-13psi? Don't forget that the tiny K03's can't handle 16-17psi all the way to red-line, and they will trail off to 12-13psi once you hit the highest RPM range.

"Normal" would be a spike at 17psi, holding steady at 16psi and trailing off to 12-13psi by redline. If you have a lot of deviation while accelerating, it could be a small boost leak or a bad N75.
--Adam

**00s4slvr** · 11-04-2008 11:44 AM

It drops down only when the car is shifting. It will spike to 17 then down to 12-13 then back up to steady 15.

**00s4slvr** · 11-04-2008 11:44 AM

im getting 14-15 more towards 15 psi steady.

**1997gtx** · 11-04-2008 12:34 PM

^ Sounds normal to me. When you shift, of course the boost will drop off for a split second.
--Adam

**00s4slvr** · 11-04-2008 02:52 PM

so i was doing some runs today on stock mode and my boost is going nuts. Im in second going 40 and punch it and then when the rpms get to about 5000-redline the boost like drops from 9-10 to about 6-7... and stays there until i shift to 3rd and so on. THen i did another run and the boost was fine and stayed at 9-10 then dropped a little to 8-9 when i was at 5000-redine then back to 9-10 when 3rd gear kicked in...

Any explanations... i have no idea how to find a boost leak... and if its a small tiny one would my boost be affected??