club.liberty.asn.au

Long time between updates

Sold the gtx3076 and v banded headers.

I have now installed the gtx3071 0.63 rear on my previous psr equal length headers and twist mount adapter.

Gotta say this turbo is much better suited for a street driven 2.0 litre auto. I instantly felt the difference in response (most at moderate throttle).

The 0.63 is more restrictive up top, and the 71mm compressor runs out of puff about 7500rpm as opposed to the 76mm which went to 8000, but I much prefer the car with this turbo for the 2.0 litre.

I have a set of jdm spec c twin scroll headers that I bought and was going to go through a twin scroll twist mount, but funds are tight at the moment (trying to finish the gem ASAP) so this will be on hold.

I have the twin scroll turbo that ill be running but that will be unde wraps for now.

Mick

I did read somewhere that the stock spec c ts headers pose a restriction for bigger turbos, might be worth researching

On a 2.5 with stock location or internal wastegate turbo, yes I can believe that.

But on my 2.0 litre, I dont believe I will have a problem. Hear me out on this.

Alot is involved in header design: pressure waves, sound waves, harmonics, flow vs velocity, etc. The factory headers are by far the best in terms of being tuned harmonically. Reliability is another thing, as the headers are cast stainless which are excellent for longevity as well as heat retention, which helps spool.

However I agree that compared to aftermarket headers the spec c oem headers have smaller primaries (from head flanges to the up pipe). This helps with velocity and pressure down low (increased efficiency at lower to mid revs and boost), although may cause backpressure buildup in high rpm / high boost situations.

With twin external 45mm gates on a custom twin scroll twist mount adapter, I believe I can solve for the pressure problem at high boost/ high rpm. The twin gates effectively act as additional pre-turbo relief valves, so once desired boost is reached (or approahing this boost limit), the gates open to provide presure and flow release for excess exhaust gases, essentially reducing exhaust backpressure where it would ordinarily be high. I see this as a backpressure modulation system really.

Mick

So this was supposed to be for the lib - given the gtx3071 is on there for now (which I'm actually loving), and because I sold the precision 6466, this might go on the gemi.

When does the 3071 come on song? And what boost are you targetting?

Making turbo choice right now

I also wonder how a .73 rear housing would affect things in terms of breathing to 8k..

aijii wrote:When does the 3071 come on song? And what boost are you targetting?

Making turbo choice right now

Full boost of 28psi in 3rd by 3900 and about 3700 in 4th (Auto don't forget)

That's with optimized dual avcs settings but running on the richer side of best power rich. Could lean it a little and probably add 1-1.5 degrees of timing on spool up but without a dyno / enough legal road to tune it properly I won't risk it

Would highly recommend the 3071 for a street car up to 330awkw - great turbo
Mick

Ahh I edited as u posted I think...

I also wonder how a .73 rear housing would affect things in terms of breathing to 8k..

I want the broadest power band as possible, the rebuilt w20 bottom end will spin to 8.5k easy..

How bad is the drivability on the 3076 ? Was that with .63 or .82?

0.73 what housing is that? Kinugawa?

That will be fine to get you to 8000rpm in your power band

The 3076 had an awesome hit but in my opinion too laggy for a street ej20 - what you lose in top end punch is well made up for in transient response and lower end torque / fun.

I would stick to a twin scroll setup if I were you - there is absolutely no doubt that it works and when setup well will be the most fun for the street and circuit hands down.

Twin scroll gtx3071 (blouch 2.5xtr twin scroll) or custom twist mount up pipe for a Garrett twin scroll 0.63 ni-resist stainless cast rear housing. Yes 0.63 as the Garrett ni-resist twin scroll housings are sized exactly the same as single scroll equivalents. This will give you insane spool and still support up to 330awkw on e85.

Mick

.73 - kinugawa/mamba.

I was originally considering a TS blouch (I have a single 2.5XTR with PSR EL headers now on the 2.5).

Problem is $$ - with headers (and tomei headers, the runners on the psr ones are small), turbo, new dump, its well beyond what a twist mount setup would cost if I go one of those mamba ceramic BB turbos.

What size primaries do your spec c ts headers have ? looking to sell now that you love the 3071 ?

The primaries on the twin scroll are smaller than the single scroll no doubt, but these are not a bottle neck until you chase over 500whp

I might actually be interested in selling the twin scroll headers, yes.

Let me know if you're keen

Mick

check pm

In other news, I picked up my Audi s3 sedan this week

Love the response of this thing. No where near as "fun" as the liberty in mid to top end, but the n/a like spool and dsg make it extremely nice to drive daily

Mick

aijii wrote:.73 - kinugawa/mamba.

I was originally considering a TS blouch (I have a single 2.5XTR with PSR EL headers now on the 2.5).

Problem is $$ - with headers (and tomei headers, the runners on the psr ones are small), turbo, new dump, its well beyond what a twist mount setup would cost if I go one of those mamba ceramic BB turbos.

What size primaries do your spec c ts headers have ? looking to sell now that you love the 3071 ?

I have this exact setup - Tomei twin scroll headers and a mamba GTX3071R on an EJ207 shortblock with 20X heads and MY11 STi cams. Sadly it was factory defective, and it's just returned from warranty. It'll be a month or two before I get it running right I would think.

dr20t wrote:In other news, I picked up my Audi s3 sedan this week

Love the response of this thing. No where near as "fun" as the liberty in mid to top end, but the n/a like spool and dsg make it extremely nice to drive daily

Mick

Very nice. Some would say it's an overpriced Golf R , but they are damn nice inside.

Thanks Bob - yes it is absolutely an overpriced R - subtle difference being boy racer vs more mature look in my opinion.

Most likely looking at a dump pipe and tune - apparently should get it up to 290kw and sub 4 seconds 0-100.

Mick

Guys taking serious offers on the Lib now.

Refer for sale thread which I've revived in the cars for sale forum

Mick