Taz_devil

Hi there, first post here

Recently bought my first WRX after driving a 99 RX for 8 years. I know its old, but everything seems ok with the car. The car is a 2001 Australian model. I have never owned a turbo charged car before, and I don't understand their mechanics very well yet

I have installed the GFB non-underdrive pulley I recycled from my old car, as I had not long purchased it. I also recycled the catch can. The car is otherwise stock

I installed a boost gauge yesterday, for a bit of fun yesterday and for testing purposes. It shows ~ 17 hg vacuum at idle when first started, this becomes ~20 hg when the engine is warm. Not sure if this means I have a leak?
Boost reads about 10psi in 2nd, seems to max out at ~12psi in 3rd, 4th and 5th. I haven't tried taking it up to ridiculous speeds and I'm not sure if that makes any difference or not. I have read that max boost for this model is 14.5 psi or 13.5 psi depending on who you ask. I don't seem to be quite reaching this. I understand that atmospheric conditions play a part, it is quite warm here at the moment....

I'm just a bit paranoid that something is not quite right or perhaps could be improved to get everything I can out of it. My question is, do these numbers sound ok, or should i get to diagnosing a problem?

Taz_devil

I have given the BCS a clean by hooking up to the battery and clicking it over while spraying in some break cleaner... Still stuck at 12 PSI max. Anyone?

madscoob

iTrader: (3)

12.52psi = 0.87bar thats about right given the fuel grade being 99ron or 100ron as in japan, i suspect they are probably mapped for lower grade fuels ie usa aus taz etc but i could be wrong someone on here will know the boost eates for different countries

Taz_devil

Maybe fuel has something to do with it, i use 98 octane BP ultimate, but that is by Australian octane ratings. If it was getting to 12.5 I would understand, but its hitting 12 max, somewhere between 11-12 probably. Perhaps the gauge is slightly out? I have checked the lines and everything is plugged in ok, can see and cracks and the restrictor pill is in the correct spot. If it was only making wastegate pressure, i would only get like 9 psi max right? So the solenoid is doing its job somewhat... Maybe its all normal and within expected parameters?

After the car was serviced 2 days after I bought it, it was noticeably smoother, but boost didn't seem to kick as hard as it did when I drove it home. I also forgot to mention, I installed a GFB non underdrive crank pulley recycled from my other car as I had only just purchased it. I put it on when it came back from the service. It seems much less bogged down at low revs, and the boost comes on smoother, but this is what made me start to question whether something was wrong, as the g-force 'kick' is not as profound. So I'm not sure whether this is just the consequence of it revving quicker from down low, or a boost issue.

JDM_Stig

iTrader: (3)

have you checked the NPS ?
As mentioned boost looks right for a standard car.

Taz_devil

I haven't checked that, what sort of effect would that have? I've noticed the car makes no boost in neutral when you rev it (I think?) so if that is what it does, it's probably working fine?

JDM_Stig

iTrader: (3)

Vehicle feeling lethargic

Taz_devil

I may give this a try shortly, but I may have found the issue. I bought a cheap boost gauge ($30) and the needle is not a 0 when the car is off, It is around 5 vacuum. Either this is intentional, or the gauge is a bit shoddy?

Also, the way I have installed it, I cut a hole in a rubber grommet where some wires enter the cabin near the pedals, above the plastic trim that goes under the front wheel arches. The hole was not very big, and it is pinching the line somewhat, whether this would affect readings i'm not sure?

also my vacuum readings seem pretty spot-on to what they should be, so if the gauge is reading low, perhaps my boost is infact fine but I have a slight vacuum leak?

Taz_devil

I bought a slightly more expensive (but still cheap) gauge, this one zeros correctly. It shows around 20 vac and about 13psi in 3rd, couldn't really test 4th at the moment as there are no long bits of road where I live :P So I think I have the issue sorted.

bludgod

iTrader: (3)

target boost for the AUDM bug wrx is 13.61 psi assuming your at 14psi or more atmospheric pressure. If you drop below 14 atmospheric then the ECU will reduce the boost target a little so as not to over work the turbo.

Also the peak boost is only requested from 2400 to 4800rpm so try for 3rd gear low revs starting with someone watching/recording the gauge whilst you drive to try and get a good idea of what's happening.

For a cheap gauge, I'd also allow for a 1 or 2 psi swing either way (tho i've seen some shockers!) so I wouldn't be put off by that. Is there anyone nearby with a laptop who could plug in as that will be the most accurate way to see if the car is hitting it's targets.

Taz_devil

My regular mechanic has a cable and can diagnose things, I could get him to take a look.... He scanned it the other day when I popped the infamous p0340 cam position sensor code when it redlined... Might just get one myself though, eventually, as I want to get it tuned. It seems very intimidating though, I'm not a computer wizz or engine expert, so I'll probably pay to have that done

bludgod

iTrader: (3)

if there's no local tuners to you and you want to invest in a wideband o2/tactrix cable I can hook you up with an e-tune. If you just want to log data to investigate then all you need is a cheapy vag com KKL lead with the FTDI chipset - they are 5 to 7 quid on amazon these days.

Get your spanner man to log the target boost, manifold relative pressure, feedback and fine learning knock corrections along with the IAM/RPM etc. and see what shows up. if he's using romraider and can create a log then post it up but if not even a screengrab of target boost vs manifold pressure will show you if the car is hitting it's target or not which will help point your investigation in the right direction.