club.liberty.asn.au

Hey all,

I have a 2004 Subaru Liberty GT 2.0L Auto and have the following mods on it:

GFB TMS Blow Off Valve
Invidia Cat Back Exhaust with quad mufflers (all stainless steel)

When I brake very quickly and come to a complete stop the car idles very low and has actually stalled a couple of times on me, could this have something to do with a tune needed or vacuum leak from the BOV?

Also I will be soon fitting the following mods, so if I don't need a tune for the above mods would I need it once I have installed the following:

Down Pipe with High Flow Cat (either the PHAT, Invidia or X-Force)
CAI (either AVO or Hyperflow)
And possibly an AVO Top Mount Intercooler

Also how much would a tune roughly cost and any reputable but reasonably priced tuners in Sydney?

Any advice will be highly appreciated

search button buddy, all of your questions have been answered many times before.

Yeah but my main issue is this question I have asked:

When I brake very quickly and come to a complete stop the car idles very low and has actually stalled a couple of times on me, could this have something to do with a tune needed or vacuum leak from the BOV?

could be vacuum leak or some hose lose. Have you tried putting the stock BOV back on? Just running an exhaust system in itself shouldnt be causing that. A tune will make full use of the exhaust, but it is possible to run the car without a tune.

Set your bov to 100% plumb back then report back.

I see little point in the listed mods and a tune without a better turbo.

yes the exhaust makes it sound and breathe a little easier
but all that making it breath easier is making the stock turbo fall over at lower RPM.

sounds like an air-leak issue with the low idle

Cheers for the reply guys and I will check all hoses etc over the weekend.

Robbks wrote:I see little point in the listed mods and a tune without a better turbo.

yes the exhaust makes it sound and breathe a little easier
but all that making it breath easier is making the stock turbo fall over at lower RPM.

sounds like an air-leak issue with the low idle

At the moment you would be fine without a tune, it would run a little rich I would imagine. After your next round of mods you would need a tune for sure.
Robbks, the turbo would fall over up top, as it moves outside it efficiency range. All those mods would improve flow, so the turbo would spool up faster, and have to do less work to make a give inlet pressure, hence cooler air, hence more power. Also the the bigger top mount would have greater cooling ability, further adding to the this. Changing turbos is a fairly big operation. In short, those mods have a point, the car will go hard, but boost will taper off in the high rpm range.

I would imagine you stalling is caused by your blow off valve venting to the atmosphere. Sell that pointless shit on ebay and put the stocker plumb back on. External venting blow off valves are sheer wank, they make you look like a teenager in the early 2000s. People will think you drive a green Civic and rob trucks hauling electrical goods.

Thanks heaps for the detailed response.

I will get the tune done once the Dump Pipe, CAI and TMIC are fitted.

I have been informed by MRT that a CAI is pointless on these cars and they do not make any difference however forum members here are saying otherwise, which is true?

And also my BOV does have the option of recirc or atmospheric so I can play around with that.

The CAI isn't useless. As a means of lowering inlet temp it isn't too effective, but as a means of getting more air to the compressor of the turbo it is a winner. Basically treat it as a way of removing restrictions in the intake path. Take a look at the hard (as soft) plastic tube work that makes up the stock intake, it has a lot of bends and chambers that serve to lower the noise of induction.
That said, at the level of modification you outlined in you initial post I would suggest a good panel filter for the stock airbox and a silicon inlet pipe from phat would be enough. Also carry out the resonator delete as detailed in many places on this forum. You WILL need a tune after changing the inlet pipe, you are really changing the dynamic of the airflow into the engine there.

I was speaking to a very well reputed tuner on the weekend who has done a back to back dyno run with CAI/high flow panel filter and the difference was 0.0kw. That was on his own 2.5L with over 300kw atw. Perhaps the style of CAI and/or other mods might make a small difference? If you search there is much debate over this, but perhaps someone out there has dyno results to show an improvement with CAI?

Needless to say, Ian's theory makes perfect sense, don't get me wrong.