club.liberty.asn.au

Don;t run a 2L TT subie in parallel
it's an ultra-laggy pig to drive and has no benefit at all.
you get no boost until ~3500rpm

i feel the term "VoD" may be a little mis-under-stood in some cases here
VoD = Valley of Death.
referring to the drop in power and torque that is seen on a dyno graph when the system switches from single-turbo to parallel twin-turbo operation.
It's horrible, but easily driven around.

VoD needs to be minimised by good boost control strategies and porting of everything in the Secondary turbo's exhaust path

XXB4XX wrote:If I had my way, I would've preferred my GT now to have been Twin-Turbo WITH vod.

I agree, in the sense that the auto GT is pretty much always on boost and it just feels so flat

The B4 setup, when tuned right, isn't so much of a 'valley', but just a flat spot where you don't get additional power that's linear to engine rpm.

Yeah the valley comes from the older Gen2 Leggy GT's (like mine) that had over-sized exhaust housings, especially on the secondary which made the problem worse.

I agree (from driving mine) the instant torque available from at TT Auto is great fun to drive with,
squeeze the throttle hard and it flares the torque converter, then it just sits on 3200rpm and 16PSI....
bloody good grunt for towing...
but flatten the throttle and it kick backs a gear and fknwhoosh... the secondary is in play and you're over legal speeds damn quickly

I think we have gone against every forum and every thread and agreed that VOD - Win.

Tangcla - you are spot on, you take boost for granted on the GT, as it is always boosting, and you don't get that second rush..

because I had my b4 for so long, with so much mods, every car I drive that's turbo, I always automatically wait for the 2nd turbo, but get left immensly dissappointed.

XXB4XX wrote:Tangcla - you are spot on, you take boost for granted on the GT, as it is always boosting, and you don't get that second rush..

My tune has been set so that even at partial throttle I'm almost always in excess of 0.6 bar

LOL my tune is set to "factory stock"

coming from a 20+ psi B4.

XXB4XX wrote:I think we have gone against every forum and every thread and agreed that VOD - Win.

Losing acceleration cannot be WIN.
the kick in the back of the secondary coming on song = WIN

I still like my TT though, but they're not a optimal design by a long stretch
they waste a lot of energy in the terrible exhaust setup that has exhaust gas changing flow direction during the changeover (VoD) process.

This is why you need more boost.

XXB4XX wrote:I'll be the odd one here,

Keep the VOD, it was probably the best part of owning my B4.

Once you tune the ECU / Exhaust / CAI / and Boost, the thrill of the Vod is awesome.

I remember seeing people squirm and freak when I punched the throttle in 2nd gear with just the primary, and then the look of absolute terror once I hit that little gap followed by the MASSIVE rush of the 2nd turbo kicking in.

If I had my way, I would've preferred my GT now to have been Twin-Turbo WITH vod.

Dammit you have me excited about geting a B4 :S (I hope my application is approved)
And I agree, its a feature of the car more than a curse. With a tune and exhaust it can be minimized and enjoyed

Hi there mate,

I was in a similar situation a few years back. Went from a 1999 WRX(mildly modified) to 2002 Liberty B4. At first i was a little dissapointed with the B4 performance , VOD and the crappy factory tune. An ECU tune on these things are a MUST!. Forget the VOD you need it to stop the pinging. I ignored this at the start and 9 months in to my ownership the engine went bang! Yup you guessed it right big end bearing failed. I have got the engine rebuild with all forged internals by a reputable shop in Sydney. After the engine rebuilt , I installed a cold air intake kit, turboz back exhaust system , larger top mount and i have got the car retuned at Tunehouse (brilliant job). the car was producing around 172 kw atw and mid to low 13s down the quarter. That was until the primary turbo shat itself! ( about 6 months after engine rebuilt) I guess it couldn't handle the increase in boost (17psi). During this time it was a pleasure to drive and very minimal VOD , but over time you learn to live with VOD (just be careful with your gear changes, if you change gear into VOD rev range you are screwed! the car wont move for literaly 3- 4 seconds!). As i said after the tune it was brilliant to drive.When the primary turbo failed I converted the car to single turbo with custom exhaust system , manifold etc and was running Vf34 with P20 housing with some other supporting mods i.e fuel pump, resized injectors, the car transformed into a weapon with excess of 210 kw atw and mid to low 12s down the qtr i was very happy with it. Then as the car got older things started to fail on it. Things like timing belt tensioners, power steering pump, alternator etc. After a while i got sick of fixing things on it and i managed to return the car back to standard (that was a mission took almost 5 months!) and sold it. As Liberty B4s are getting old now , its a challenge to find a decent one out there.

I guess it all depends on what you want to do with the car... I now have a Liberty GT, eventhough it doesnt have as much power,its a pleasure to drive but as brendon suggested you always wait for that second turbo to kick in !!!

P.S Forget about the parallel turbo setup as B4 does not have enough cc to handle 2 turbos. I considered this option when the primary turbo gave up on me.

If you have any questions drop me a pm!

Cheers

Ras

XXB4XX wrote:I think we have gone against every forum and every thread and agreed that VOD - Win.

Tangcla - you are spot on, you take boost for granted on the GT, as it is always boosting, and you don't get that second rush..

because I had my b4 for so long, with so much mods, every car I drive that's turbo, I always automatically wait for the 2nd turbo, but get left immensly dissappointed.

Having a GT for a month i do find the single much better and more predictable. And am not dissapointed at all.
But i also expect every turbo to have the secondary kick.

However i have a few times forgotten to change gear and hit the limiter cos i was waiting for the secondary to kick, oooppppsssssss.

I've had my B4 for a couple of weeks now, only had a chance to take it out for a couple of decent runs the last few nights.
My opinion on the TT setup and VOD is still undecided.
Initially I felt that the main power delivery is too high in the rev range, it's unuseable in most driving situations in the city, you're doing 80km/hr already in 2nd by the time the second turbo kicks in, which seems to be at 5000rpm for me.
However, the first turbo does deliver good driveability for what it is, reasonable low end torque, but nothing you'd call "exciting".

Got me to thinking you've really got 2 different cars when you buy a TT B4, the car from idle up to 3500rpm, and the monster that emerges from 5000rpm to redline.
It's a 2001/02 vehicle, at that time did they have turbos that spooled up as early as they seem to do in current cars? Linear power delivery in stock unmodified cars was barely an option in a turbocharged 4cyl from my recollection of those days (i had mates with 99 and 00 WRX's). What we've got is Subaru's take on what you get in the current high performance turbos, power from down low delivered in a linear fasion (with a little more up high), unfortunately the trade off is a dead spot in the rev range.

I started off a little unimpressed, but the more i think about it, the more happy i am to be driving a TT B4, it seems like they were really doing everything they could with the turbo technology at the time to create the best driveability. Pretty iconic vehicle.

I could be wrong, happy to be corrected, i'm no mechanic so a lot of what i say above could be bullshit.

anyway, my opinion of the b4 is still developing, it's been a bit up and down, but i'm trending up.

the top end is great, and theoretically the car should make 200KW ATW easily with the flow capabilities of the stock turbo's (equivalent to a 2L with a VF34-P20)
but the sad fact is the intake and exhaust systems are a joke that rob the car of so much power and efficiency.
my GT forester with TD04 on it (tuned and good exhaust) made 150KW ATW with bugger all effort, and it was faster than my heavuily modded TT which should have made lots more power given the fuel it was sucking in....

Robbks wrote:the top end is great, and theoretically the car should make 200KW ATW easily with the flow capabilities of the stock turbo's (equivalent to a 2L with a VF34-P20)
but the sad fact is the intake and exhaust systems are a joke that rob the car of so much power and efficiency.
my GT forester with TD04 on it (tuned and good exhaust) made 150KW ATW with bugger all effort, and it was faster than my heavuily modded TT which should have made lots more power given the fuel it was sucking in....

Robbks is right. I spent alot of time and money trying to get what i could out of the B4 sequential set-up. I wanted to get 200+kw and achieved it. but what a fuck around. And truth is, there is soooooooooooooo much that can upset the B4 set-up. Air temp changes in summer, oil viscosity, intake temperatures, vacuum/pressure lines, solenoids etc. unless you really need to do it, or must have it that way, don't do it. either leave it reasonably stock, or change the set-up all together. Dont get me wrong, i enjoyed every minute of driving mine (was 2.5 though) but it just isnt worth it for most. my old set-up is going back onto a 2.oL and in something else. But i'm currently converting to parallel.

with the money it cost me to get the figures, i would now prefer to go EZ30r and supercharger/TT for less moeny, and shit loads better performance and economy. Theres just not enough people out there that know how to go about getting alot of power out of these things. and for good reason. the smart ones stop while they are ahead. (yes Jim, I said it. haha)

If you are interested, when i'm finished my conversion next week, i will post a build thread on it, so you can make ya own mind up whether its what you want to do...

Robbks wrote:the top end is great, and theoretically the car should make 200KW ATW easily with the flow capabilities of the stock turbo's (equivalent to a 2L with a VF34-P20)
but the sad fact is the intake and exhaust systems are a joke that rob the car of so much power and efficiency.
my GT forester with TD04 on it (tuned and good exhaust) made 150KW ATW with bugger all effort, and it was faster than my heavuily modded TT which should have made lots more power given the fuel it was sucking in....

My B4 makes 145atw with stock tune, a cai and an exhaust...