448-th boost leak question :)

[vprelovac]

Hello Boys,

I have recently performed an upgrade of my 3B S2. Now is has 202 kW chip, de-cat pipes, new 2.5 bar sensor and stiffer wastegate spring.

The car finally runs really nice but after a run with a g-tech where it showed 14.6 s time for quarter mile I was wondering if everything else was OK. So after installing a boost gauge I could measure these pressures:

Idle -0.6 bar
2nd gear: 0.9 bar @ 3000 falls to 0.7 @ 6000
3rd,4th,5th: 1.1 bar @ 3000 falls to 0.7 @ 6000

So after doing a search and reading some 100 out of 447 threads that showed up on search, I am wisely guessing a BOOST LEAK

Now I am wondering what is the easiest way to test it in DIY mode. I do not have a special pressure test kit only some regular tools found around a regular workshop.

What else to check if by chance everything seems to hold?

On the bright side after I fix that I am thinking I will have another performance bump so

Thanks and cheers all

[Jonas_R]

Why do you believe that you have a boost leak? If you get 1.1 bar boost in 3rd gear, i would say that you def. dont have a boost leak. If you dont experience suddenly cut off's where your face ends up in the windscreen then you def. dont have a boost leak.
The numbers seems fine if you ask me, dont think a normal 3b boost to 1.1 bar.

/Jonas R.

[dm80]

A stock 3B runs at ~0.8 bar. Chipped/re-mapped would be 1.1/1.2 - according to the guys at MRC. So as Jonas says - doubt you have a boost leak..

[vprelovac]

We had another go last night... The wastegate spring was slightly adjusted so the max boost went to 1.2 bar around 3000 RPM. But it gradually falls down over the rev range to about 0.8 bar at 6000 RPM. Shouldn't it hold boost better then that?

[Jonas_R]

Dont think it should hold max boost all the way, but I guess some of the chip guroes can answer that.

/Jonas R.

[lune]

Amended below

[lune]

My understanding is that the chip is programmed the boost to drop off as you get into the higher revs. So what your describing sounds about right I would'nt go fiddling with the wastegate spring, as you could end up doing more harm than good

[dan_b]

The stock S2 turbo physically can't maintain full boost all the way to the red line, the tail off is normal. 1.1Bar is good for a chipped stock turbo, sounds like you're in good shape to me.

[HPmuirt]

Whilst everyone seems to have come to the conclusion that the car is boosting normally, I am wondering why the 1/4 mile times are down?

I run a stock ABY which recently did repeated 14.3s 1/4 miles, whilst the chipped cars seemed to be turning in 13.5s or lower.

Cheers n

Si

[vprelovac]

The car made 13.95 sec 1/4 mile and 5.75 sec 0-100 km/h last night on the third run (previous were all worse). That is not bad but I was expecting something in the range of 13.5 sec too that is why I suspected this 0.4 bar pressure drop first (from 1.2 - 0.8).

Any users of chipped 3B's can confirm this kind of pressure drop as normal?

[s2dude]

The car made 13.95 sec 1/4 mile and 5.75 sec 0-100 km/h last night on the third run (previous were all worse). That is not bad but I was expecting something in the range of 13.5 sec too that is why I suspected this 0.4 bar pressure drop first (from 1.2 - 0.8).

Any users of chipped 3B's can confirm this kind of pressure drop as normal?

Errmm....
A Gtech is not reliable enough to determine a "proper" 1/4 mile time.

You need to get to the strip and put some times down for definitive results.......

Sounds fine to me.

[vprelovac]

I also got 25 seconds for 0-200 km/h. How does that stand in comaprison with other cars?