ej25/ej20tt hybrid

[bigwilliestyles1]

Your not going to get even near 200kw without some mega mad scientist shit going on and big dollars.

My GTB was heavily modified

Saw this thread and had to post. I havent posted in a while and forgot my login details

I have owned my GTB for 3 years and have never had a problem. Secondly, with 20-24 psi, and for those mods, you should have had around 200awkws easily. Have a brief look on any of the forums (including this one) and you will realise that with an exhaust, slight increase of boost and a basic tune these cars generally achieve around 190kw atw. With the forged internals you should have been able to increase boost for heaps more fun. Chadza for instance has 185kw with just exhaust and tune. I have seen stock examples get 150kws atw. Billsy on ozlib got up to 220kw atw. He also later stroked the engine to a 2.2 and found the output was the same and that the power was limited by the turbos flow.

But I have to agree, going single is probably a good choice for modding and for that nice linear power. Im actually toying with going down that track now

With an aftermarket Intercooler, 3" dump pipes into 3-3.5" Single exhaust, after market wastegate/bov and boost controller, we are certain the 225kw atw mark will be achieved. However the AFM was faulty, and a new one was needed, and fuel pump failed. Also found the fuel pressure regulator was not working.

Sounds like a great achievement. What car did the engine come from? Thought I would also mention, you should also post the build up on some other lib forums, subyclub.com and ozliberty.com

[Jim]

I still disagree with you.

Im talking Gen2 GT-B here, NOT Gen3. And using the sequential setup.

Billsy had so much mad scientist self fabrication stuff going on, it would nearly be impossible for anyone esle to replicate his results. Also i believe he got that power figure running the turbos in parrallel and NOT sequential. And i think it was running E85 if i recall.

My 165atw was with THE most powerful readily available Subaru TT-config turbos without modifications to the turbos and i was at the very edge of my limit of more power. Everything else was done. Running more than about 18-20psi on any standard Subaru TT turbo combination is just chasing your tail and useless, as you go beyond their optimal efficiency and wont make any further gains. Its not a simple case of more boost = more power, theres a wall at some point. Mine made the 165atw on a peak of 18psi and wouldnt make any more power with more boost, it actually made slightly less. An engine with forged pistons isnt the be all of engines either, reduction in engine friction, resiliance to detonation and a bit more tolerence is all. Just having forged pistons doesnt instantly give you 50kw.

For me to have got any closer to 200kw in a sequential setup, i would have had to have used aftermarket turbos, aftermarket ECU and a bigger fuel system. But the time and money needed to go that far with a flawed system, i considered a waste.

Later Gen3 B4's and GT-B's have the advantage of a slight capacity increase with the EJ205, different comp ratio, bigger 550cc injectors and a tunable ECU. But show me a B4 thats not pinged to death on the crappy AUDM tune. I think TT's have the best results and reliability left untouched, every single person i know who has had a TT has had nothing but dramas. Sure theyre fun when they are working but overly complicated and over engineered.

Dont get me wrong, im not TT bashing and i really enjoyed the challenge of milking as much as i could out of it, but it hit a wall and wasnt worth the time and effort to continue. So i bought an MY07 GT-B which shits all over it with just a 3" TBE and CAI

Also if you opened your eyes on "other" forums, you will find a vast majority of TT owners are abandoning them for Subarus easier to mod.

Let me know when you get 200kw atw with your TT. And not with a disney dyno readout, with consistant 1/4 mile times and trap speeds.

[bigwilliestyles1]

I agree with you and already acknowledged that going single is the best mod you can do with the TT but wanted to make the point that there are plenty of 3rd gen TTs with around 180kw atw with just an exhaust and tune.

Im not aiming for 200kw on my system. If I decide to mod further than what I already have, it will be with an sti long block and a single turbo

[ej25tt]

"Secondly, with 20-24 psi, and for those mods, you should have had around 200awkws easily."
Boost was set @ 14.5PSI, and the only mods that had beendone to the engine were the pistons and rods. Exhaust is being made, im getting a hyperflow intercooler, turbosmart plumback and boost controller.

"Sounds like a great achievement. What car did the engine come from?"
Thanks mate! I thought so given the tenacity of some of the other repliers. Will keep you up to date. And thanks for the idea, I will try and get the info up on those other sites when I get the chance...

"Also if you opened your eyes on "other" forums, you will find a vast majority of TT owners are abandoning them for Subarus easier to mod...Let me know when you get 200kw atw with your TT. And not with a disney dyno readout, with consistant 1/4 mile times and trap speeds."
Jim, the fact that other owners would rather give up then finish what they started, is the reason why those of us who keep trying end up with "Individual" cars...And as for letting you know when the car gets 200kw atw, I take instruction from noone, let alone someone as cynical as yourself. However, I will let you know, just so you can savour the defeat. And hopefully you will be man enough to apologise. And as for your comments regarding "Disney Dyno Readouts", I don't think Dyno Dynamics, the worlds leading Dyno Manufacturer, would have the reputation they have, and the consistency of their dyno's performance, if they were "Disney Dyno's" as you refer to them (Not that I comprehend what a Disney Dyno acutally is). But rest assured, I will make sure I get a few runs done to be able to post them up here, just for your perusal.

AND JIM, FOR YOUR INFORMATION, MY CAR IS, AND WILL BE RUNNING THE FACTORY MANIFOLD AND TURBOS, WITH THE FACTORY SEQUENTIAL TURBO CHARGING, modifications limited to turbo back exhaust, intercooler, wastegate, boost controller, tune, and 2.5L forged bottom end!

[Dropz]

I just read this thread to watch people argue now

Lols....

[Jim]

Fuck me you people just cant take advice without thinking its a personal attack. You're all so quick to put your shields up.

A dyno gives you a pretty number, thats great. Its a essentially a tuning tool and not much more than that. If you want a REAL power figure, throw it down the strip, crunch the numbers with your trap speed and times and you will have more accurate results.

Its all good to have a fancy peice of paper, but its all about how it should feel on the road. A dyno printout really is more useful to make sure AFR's are in check and the power is coming on how it should be, or how you want the tune tailored. You cant just show up and slap your peice of paper down with a number on it.

I have yet to see a TT B4 or GT-B get close to, or past 200kw atw and put the power down on the road reliably.

If you can prove me wrong, in which i encourage you, i will eat humble pie.



Im not having a go at anyone for trying, im just inputting my own personal experience and that of others regarding the TT system.

Its a fantastic system (when it works) but at the same time overly complex and difficult to modify beyond the usual bolt ons. If you want to have a stab at the TT system with a 2.5, go for it. Just take sound advice on board.

Also just to add some input to your proposed build, i would be going an aftermarket primary turbo of sorts. With a TBE and 2.5, a standard Subaru primary will eventually over spool itself to death. Its easy enough to do it on a 2.0.

[ej25tt]

Thanks Jim, and upgrading the turbos will be the next step, after i beat the 200kw. I will actually be getting them rebuilt & high-flowed, to increase their ability to handle 450-500hp, giving me a good amount of margin.

I do ask how you can use 1/4 mile times to calculate HP/KW. Trap speeds whatever. I quite enjoy mathematics, and am curious as to the equation you use. Honestly, I am genuinely interested.

As for your very poor reasoning for as to why dyno's cant be relied on, the commonly used unit of HORSEPOWER (HP), in particularly BRAKE HORSE POWER (BHP) was determined by the application of a De Prony Brake. Which was eventually adapted to become a Dynamometer. HP is calculated as follows;

1 HP ≡ 33,000 ft·lbf/min by definition
= 550 ft·lbf/s since 1 min = 60 s
= 550×0.3048×0.45359237 m·kgf/s since 1 ft = 0.3048 m and
= 76.0402249068 kgf·m/s 1 lb = 0.45359237 kg
= 76.0402249068×9.80665 kg·m2/s3 g = 9.80665 m/s2
= 745.69987158227022 W since 1 W ≡ 1 J/s = 1 N·m/s = 1 (kg·m/s2)·(m/s)


Or given that 1 hp = 550 ft·lbf/s, 1 ft = 0.3048 m, 1 lbf ≈ 4.448 N, 1 J = 1 N·m, 1 W = 1 J/s: 1 hp = 746 W, or, .735-745kw, KW can quite accurately be determined by use of a Dynamometer. As a Dynamometer is simply a modern, more efficient way of calculating modifications improvements on engines, so as not to need to remove them for Engine Dynamometer Testing. Difference being the results are given by the output at the wheels, not the engine. But none the less the results are 'generally' reliable. The reason for varied results can be affected by differences in the following;

1. Regularity of Calibration of Dynamometer.
2. Conditions of Environment at times of Testing (air temp, ambient temp, etc etc.)
3. Mechanical Variations (timing component wear, Oil contamination causing increase of friction, carbon build - up on plugs between Dyno -Runs), shit which people don't generally consider when looking at results. (yes i know they may only have minor affect, but none the less, together can contribute to losses in HP/KW output.)

All shit which also affects outcomes of any test of output on any engine, at any time. On the track you need to also consider wheelspin (i know you get some on a dyno but minimal), changes in air temp whilst car is actually physically moving...etc etc.

My moneys on a dyno. Though not perfect, what is? Unless you want to engine dyno everytime you do a modification...

[AndySTi]

[Jim]

But therein lies the problem with Dynos. There are so many variables that it would be impossible to get the same number each time. I could garuntee you could jump onto 3 different dynos, with the exact same mods and lets say for arguments sake exact same weather conditions, and you would have 3 different readouts nowhere close to eachother. Dyno operators can stick any number they like on your peice of paper to make you a "satisfied" customer, they are a buisness after all. And i have heard of cases of that very thing being done.

They are purely a tuning a tool. Graphs are important, not numbers.

Consistant 1/4 mile drag runs are a better way of getting power figures, its real world driving, on the tarmac. Your only variables there are your skill and the weather.

Formula is: Horsepower = Weight x (velocity/234)3

So lets say your car weighed in at 1450kg, to be close to 200kwatw, you would have to run a trap speed of about 102mph. Which would be roughly a low 13 second pass. Based on the weight of the car.

[sooobi]

Twin Turbos = AIDS

Hope this helps!

[Robbks]

I'll completely agree with ol jimbo up here in most ways...
he's been there and done just about anyting to get that thing to make power, although i feel his car did make less power than other TT's with the same mods.

I know that my TD04 equipped GT Forester made 150KW ATW running 17PSI on a realistic reading dyno
And my Legacy was definitely more powerful and faster than the fozz. how much? don;t know, never got a chance to put it on a dyno or down the strip once i'd got it running correctly.
It's first trip at teh drags (running VF18/19 @16psi, 440's and a shithouse tune) netted me slow passes and 94MPH trap speeds.
And it doesn;t really even matter how good or bad your launch is. as long as you get it moving and you're accelerating flat out, trap speeds will be very close to teh same, just your ET will change

The issue (as ol boy pointed out) with dynos is the variables, particularly the gear used and the ramp rates.
A couple of Big Sydney workshops use Ramp Rates that don;t effectively represent the load that can be produced when on the road, and as such will give nice high numbers for rexnet e-cred. (Disney Dyno's)

I do believe that 200 ATW is achievable with a 2.5 and b4 turbo's
a TD04 on a 2.5 Xt forester will make 170ATW
but you're going to be running ~20psi and choking it in the top end. you need some bigger exhaust housings to flow the power you're trying to make.

the headers/ up-pipes/ ECV and intake are simply too far restricted to go much further, and you're suffering huge pumping losses with the factory stuff in place.

[Jim]

See Rob thats exactly my point, 165kw atw is what i got on a dyno. Could have been anything, and even the guys said the dyno was low reading, but i didnt care about the number, i wanted to see how it ran on paper with a graph.

If my TT had been reliable enough it would have gone down the strip for sure, ( Got thrown off twice at staging for dropping water lol ) but i know i was no where near 200kwatw. Using the 1/4mile time would have given me a more accurate power figure. 200kw atw was my goal at the start, but i threw in the towel becuase it couldnt be done with what i had, and worsnt worth the outlay in cashand unreliability when it was my only car.

[ej25tt]

The bloke that helped build my car is about to have his HillClimb car finished, and once tuned, we'll both be doing trap speed and e/t runs. this with repeated 225+ readouts, should surely be enough for anyone to agree at that point, that i will be the first to do so! again, it seems everyone is failing to take into account, this is not 2.0L, and is now 2.5L, meaning 25% larger displacement, which in turn will have an affect on output. and given that 2.0tt's have been tuned to 185-200, an extra 20kw is not much extra to seek to achieve, especially with 25% better capacity. I comprehend it doesn't necessarily work that way, but merely a 10% gain out of 25% larger capacity would see that target met. again, my aim here is to prove that a sequential turbo set-up on a boxer, can net 200+kw atw, and hopefully even 300hp. But i guess we will see. and if for some reason, my calculations turn into 2+2=1.8695439 and not 4, then i will humbly and gracefully apologise to all concerned, especially Jim, however, i am confident that my combination is capable of that and a bit more.

we shall all soon see.

[Jim]

Yeah but your not getting the big picture here, like its been said many times over.

The stock Subaru sequential system will be your biggest dissapointment and down fall of the system. All the factory TT gear is designed for a 2.0 capacity engine. Its not just a matter of extra capacity must = winning.

- The primary turbo will overspool itself to death.
- The turbine housing sizes will choke the engine in mid and upper RPM range.
- The ECV port is restrictive, even on the 2.0 setup.
- Pushing the turbos beyond their optimal operating range wont net any gains.

I honestly do not believe the factory TT gear will compliment the increase in capacity.

[telemekas]

The bloke that helped build my car is about to have his HillClimb car finished, and once tuned, we'll both be doing trap speed and e/t runs. this with repeated 225+ readouts, should surely be enough for anyone to agree at that point, that i will be the first to do so! again, it seems everyone is failing to take into account, this is not 2.0L, and is now 2.5L, meaning 25% larger displacement, which in turn will have an affect on output. and given that 2.0tt's have been tuned to 185-200, an extra 20kw is not much extra to seek to achieve, especially with 25% better capacity. I comprehend it doesn't necessarily work that way, but merely a 10% gain out of 25% larger capacity would see that target met. again, my aim here is to prove that a sequential turbo set-up on a boxer, can net 200+kw atw, and hopefully even 300hp. But i guess we will see. and if for some reason, my calculations turn into 2+2=1.8695439 and not 4, then i will humbly and gracefully apologise to all concerned, especially Jim, however, i am confident that my combination is capable of that and a bit more.

we shall all soon see.

What turbos will you be using?
Billsy gernerated 229Kw (107/229) ATW sequentially (3rd gear Boost 19psi) using VF26/VF27 combination with 2.2L (the ECV and the turbine housings were ported)
These turbos were essentially maxed out at the time.
Swapping the primary VF26 exhaust housing from P14 to P16 would probably yield a significant increase.
However as you have a 2.5L you could use some high flowed RHF5 comp wheel ->VF14 BB CHRA onto P16/P18 housing.