Boost Gauge Reading??

[A3 T]

As some of you know I've been trying to work out how i was going to fit my boost gauge without damaging the pillar and today i managed to fit it



Just a couple of questions........



I'm not sure what the readings should be.....lol


This is what it shows on idle from cold:

And this is it after idling for a few minutes:

Also should the pressure be consistent throughout the gears?



The reason i ask is because in 1st the needle goes to just over the 0 mark, while in 3rd it goes to around the 10 mark.

 

[AGU-TURBO]

yes 10 psi is 0.7 bar and that is what these are stock. how did you end up doing the pod then

 

[AGU-TURBO]

you carn't be hiting max boost in first

 

[A3 T]

So it being around the 0 in first is normal (thank god....lol)?


I ended up using elastic in the end.....lol

 

[A3tell]

really, you should see around 8-10 psi in ALL gears!! not just 1st, do you have it connected to the correct vac pipe??

 

[sportstractor]

You wont be getting full boost as there isnt the demand because the engine load is minimal. Looks like you are getting enough to just overcome the engine vacuum, but I would of presumed you would of got a bit more than that?

That pod looks really smart, got any links from where you got it?

 

[EDY S3]

i get 10psi in 1st and 12/13psi in 3rd with no map just decat and air kit

 

[AGU-TURBO]

i get 10psi in 1st and 12/13psi in 3rd with no map just decat and air kit

is you'rs a s3 or a3

 

[quattro1]

i get 22psi in all 5 gears and that vac on idle seems about right, 0 in first is deffo not right though! where have you got it plumbed in to?

 

[A3 T]

well guys......


I took the car out for a good run today and it seems that its only first that's giving the inconsistent readings.



For example, sometimes i can get it to read 10 in first while other times it only goes to 0. I suppose it could me down to how much load the car is being put under as all other gears are reading around the 10 mark.


I see that some of you are saying that 10 seems too low while others are saying its ok. Could it be the the people that are saying its too low are comparing it to s3’s and quattro’s ?



This is what the gauge is showing at idle now:

And this is how I've got it plumbed in:

Im confused .....lol

 

[HTC]

Find a nice steep hill and set off in 1st at low speed up the hill. Then boot it ... you'll soon see full boost. Good idea with the elastic.

I can't remember, but isn't the vac input to the DV controlled by the N275? Might get more accurate readings straight of of the inlet manifold? Mines the simple AGU engine, so it's a bit different.

 

[A3tell]

i have an older agu engine, and i have mine connected to the vac that runs off the fuel reg. it seems pretty consistant.

 

[Westy]

I've plumbed mine into the hose under the inlet mani that goes to the fuel pressure regulator. But then again Ive ripped out the N249 valve anyway

 

[A3 T]

Find a nice steep hill and set off in 1st at low speed up the hill. Then boot it ...

It gave this a go today (cars behind me weren't too happy....lol), and it did exactly what you said it would.

I also tried it while not on a hill and the boost still shot up. It seems like if you are cruising fast (without being on boost) and then try to floor it , the reading on the gauge isn't so high.

oh yeah... the reason the idle is either just below or just over the 20 seems to be dependant on whether the air-con is on or off.

So does this all seem normal then?

Thank again for all the replies

 

[Prawn]

plumbing a gauge into that place on a standard AUM will get odd results, because when the N249 operates to try and control wheelspin, it'll open the DV, and you'll see no boost on the gauge.

Plumb it in before the N249, or on the FPR line for a more accurate result.

Also, to all those saying 10psi seems low, it's not. it's high.

a standard AUM shouldn't be seeing more than about 7psi tops.

the 150bhp figure is made from 6-7psi, and I'm yet to see a standard car that makes much more than that.

 

[A3 T]

Plumb it in before the N249, or on the FPR line for a more accurate result.

I don't suppose there's any posts showing these points is there ?

I just read a couple of threads like this one: http://www.audi-sport.net/vb/a3-s3-forum-8l-chassis/106555-tapping-boost-gauge.html where it seems its not a good idea to T into the FPR.

I'm confused again......LOL

 

[A3 T]

??

 

[EDY S3]

yes my car is a 225 s3 on 13 psi