Hey i have a stock s5 t2, and i thought s5 stock boost was something like 8psi? because this is what happens for me: (according to my defi boost gauge)

1st gear : no boost, hits about 0psi
2nd gear: max around 5psi
3rd / 4th / 5th: around 6 or 7psi

is this normal? this is also my first turbo, and i also dont floor the pedal or anything, i take very much care of my car, i just like it to go fast

sometimes when i hit boost in second, i can hear it spool, but i really dont 'feel' it like i think i should... is it just me?

my only mods are a ssqv and a boost gauge. oh and dont forget the k&n drop-in

thanks guys

oh also im around 3k into a rotary ressurection rebuild

 

I'm not sure what's wrong with your car, but I just bought my TII and the boost stays at 8psi once I get to about 3500 rpms in any gear. It kicks in fairly hard at that point even at only 1/2 throttle. This is just my opinion though since all I've driven before is a bunch of N/A cars. It was just rebuilt along with the turbo too.

 

Yeah, something weird is going on, not allowing your turbo to spool correctly. You should check to make sure your WG is not disconnected.

 

how /where would i check that? anyone have a picture? the fsm isnt helping me much there :/

 

also ive been searching, and people ask these questions in threads about this so ill answer now:

at idle im pulling about -20 vacuum.
my idle is solid.
when boosting, i can hear it 'whoosh' (stock airbox and piping)

i dunno what the problem is :/

 

anyone? id like to start on this when i get home

 

check all your intercooler piping and couplings and hoses for leaks..could have one big boost leak somewhere but with your syptoms i would think ur vac or idle would show signs of this....

do like one dude said and check you wastegate.. make sure the hose is connected to it ...it could be stuck open or somehting...

 

I'm trying to use the fsm to do this but its hard to picture everything from the exploded views... Anyone have a pic of what I'm checking, on the car?

 

the wastegate??? its the little thing on the turbo (usually gold or bronze colored..kinsa circular) that hads a rod that goes to the o2 housing. it should have a valcum line hooked to it..

 

So I'm going to check both ends of that vac line, and I check to see if I can move the actuator rod by hand? If its stuck is pb blaster ok on it?

 

how many km's on this motor and turbo? fresh?

have you checked the shaft play on the blowdryer?

what do you have for exhaust?

 

i've never been able to move the rod by hand, and if you can i'd suspect a problem. i noticed you said you don't floor it, try flooring it, if that doesn't work, come back and let us know, cause cars only reach full boost at high throttle openings(i.e. flooring it). so pretty much, floor it, it's not going to hurt the car, and if it does, something else is wrong

 

did anyone else miss the part where he says he doesn't floor it?

 

Stock exhaust. Approx 3000 miles on fresh engine. Turbo is in good condition.

I'm going with a racing beat exhaust soon, but I want to fix this before I go adding parts.

I'm checking the wastegate when I get home, last night I checked all my ic piping and couplers and it was all fine. Plus I'm seeing ~-20 vac at idle so its really not a boost leak, I'm guessing it has to be the wastegate :/

 

Yea I tried flooring it on the way to work, maxed at about 6psi in 3rd, 2nd saw around 4 , 1st saw -5 max

 

compression check

 

Last compression check ran 106/107 both rotors. Engine shows no trouble or signs of engine trouble, idle is rock hard at 800, no smoke, no coolant loss, no hesitation or sputtering

I am convinced it has to be the wastegate stuck open, but I don't know how to check this. I can check the vac. Line to the actuator but I don't know what else to do.

Its not a boost leak (I think) because of the strong vacuum, and the nice idle.

Anyone encounter this before?

 

you can disconnect the w/g line ... add presure to it for a second (air comp nozzle or something) ... listen to the manifold area you should hear the w/g open then close ... if not the actuator diaphragm could be shot ... or perhaps just your bov is leaking boost ...

 

Ill check it out when I get home... Feel free to give more theories so I have more chance of finding the problem... Thanks guys

 

Check your vacuum lines for a leak. If all checks out check the continuity on your boost pressure sensor. If that is good, it is probably your gauge gone bad.

 

so THATS what boost feels like!

the problem: my upper intercooler hose (the 90 degree one coming off the intercooler) wasnt all the way on. one half of one side was 'ovaled out' and the hose clamp wasnt around the whole thing.

i turned it around so the 'bad' side was accessable, and made sure it was clamped down and then went through all the other piping.

drove the car, hit boost in every gear, and pedal down was around 9psi. nice and freaking fast! the car felt like my n/a before i fixed this hose problem!

thanks guys, for continuously yelling at me to check my hoses even though i kept saying they were fine

and thanks Ruffryfer for serving. you're making us proud man.