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Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 8:45 am
by Robbks
nickknack wrote:My B4 makes 145atw with stock tune, a cai and an exhaust...



every stock B4 make 140-145 ATW
206KW at the flywheel, then you burn up about 50KW in drivetrain losses

for the combined airflow capacity of the two turbo's they should easily make 190ATW on about 17psi.
but teh entire system is so restrictive that you're lucky to get 165 out of them.

With a tiny TD04, 2.5" exhaust and tuned for 16psi (only on 95RON fuel) made 150ATW in my GT forester.

Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 9:25 am
by ej25tt
Robbks wrote: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



Do you know anyone that has done a parallel set-up yet. Other than removing the ECV/ICV on the factory system?

Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 9:48 am
by Robbks
Billsy did.
NFI what sort of setup it's running now. probably 2x GT35's :angry2: :bad:
Simultaneous TF035's would probably work reasonably well on a 2.0
or TD04's on a 2.2 or 2.5

The problem is the subie firing order is not suited to running fully separated twins
they fire the cylinders on one bank, then on the next, so you have two exhaust pulses close together and an eternity before they appear again.

You'd really need to pair the rear cylinders into one exhaust runner and the front into another.

I see no real benefit in equally sized simultaneous turbo's.

Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 10:53 am
by nickknack
Robbks wrote:
nickknack wrote:My B4 makes 145atw with stock tune, a cai and an exhaust...



every stock B4 make 140-145 ATW
206KW at the flywheel, then you burn up about 50KW in drivetrain losses

for the combined airflow capacity of the two turbo's they should easily make 190ATW on about 17psi.
but teh entire system is so restrictive that you're lucky to get 165 out of them.

With a tiny TD04, 2.5" exhaust and tuned for 16psi (only on 95RON fuel) made 150ATW in my GT forester.


Ah gotcha! It would be nice if the B4 had come out with a decent sequential arrangement like the gtrs, supras, fds etc but I will convert to single one day!

Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 2:23 pm
by ej25tt
Robbks wrote:Billsy did.
NFI what sort of setup it's running now. probably 2x GT35's :angry2: :bad:
Simultaneous TF035's would probably work reasonably well on a 2.0
or TD04's on a 2.2 or 2.5

The problem is the subie firing order is not suited to running fully separated twins
they fire the cylinders on one bank, then on the next, so you have two exhaust pulses close together and an eternity before they appear again.

You'd really need to pair the rear cylinders into one exhaust runner and the front into another.

I see no real benefit in equally sized simultaneous turbo's.



what sort of performance did he get from it. did he ever reveal any figures?

Re: similtanious turbos

PostPosted: Tue Jul 02, 2013 4:48 pm
by telemekas
The Prova Legacy 2.5L with parallel TD04s what configuration? (assume they are WRXs TD04L-13T-6cm) recorded 245Kw ATW @18psi. The headers were just right and left banked, with the turbos repositioned down low.
Liberty B4 2.0L with straight bolt up sequential hybrid TD04s --> 225kw ATW @17.5psi.This one also had the sequential system modified, similar to the Supra TT

Re: similtanious turbos

PostPosted: Tue Aug 13, 2013 9:43 am
by N AF73R
Im not sure if I got really lucky with my B4 and it is one of the rare engines that just seems to make more power or if you guys all got shitty tunes from inexperienced tuners.

With CAI, TMIC, TBE, SYMS dump pipes and a tune i have 195kw atw @ 16psi across the board. And I believe it would be even more on MRT's dyno as I have been in a MRT 210kw B4 and mine was considerably faster so assuming the MRT dyno reads a bit high.

I have no VOD whatsoever, my power just keeps on climbing through the rev range and I absolutely love my car. After hearing of a local B4 owner take his car to Pulse racing and strap on bigger twins and haltech for around 250kw I am very interested in upgrading the TT setup which will be the next step happening soon.

Re: similtanious turbos

PostPosted: Tue Aug 13, 2013 8:30 pm
by SmokinScoobs
how and where did you get it tuned?

Re: similtanious turbos

PostPosted: Thu Aug 15, 2013 1:14 am
by N AF73R
First tune was done by previous owner (a few years back now) and pulled 191kw at Chip Torque in QLD
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I got it retuned at Port Hacking Automotive by Ben who managed to get 195kw out of it. Got me to more power in less revs and bcauz I was a mate of a mate I got looked after (and also bcauz i dumped alot of money at that shop haha). It was only a sort of touch up dyno tune just improving on the already good tune.
Image

Im having so much fun in my B4 again since getting my license back but I just cant find all the boost leaks or exactly where the problem is coming from and its really starting to annoying me. Such an overcomplicated sequential TT system, would be so much easier sometimes with a big single but the twins are so much fun. Im slowly replacing things till I pinpoint the problem but I think its time for me to play a qualified mechanic to do the job haha.

If theres any B4 guys around i'd be pretty keen for a cruise or catch up. And im always keen for national park if anyone goes down that way

Re: similtanious turbos

PostPosted: Sat Apr 04, 2015 2:52 pm
by scooby491
hey guys

Apologies for bumping an old thread

i recently got me a gen2 (97) ej20tt with manual box behind it...
conversion went perfect in me gen2 sedan....

but has anyone ever thought about just getting custom headers done up? to eliminate the gasses from each bank fighting each other?
im getting a full engine back, with those headers, fabbed up and installed for $2k.....

no other mods as yet (so factory), you guys are/were getting 10+psi boost yes? i'm only generating 6psi tops..... thoughts?

again apologies for bumping old thread