Been reading some things and lots of people say the 2.5 has a lot more torque than the 2.0. I'm getting a jdm 2.0 2006 sti which I'm assuming is a twinscroll? If so what difference will the twinscroll make? More torque?

 

Hi,

All Jdm newage cars are Twinscroll, Revs to 8k, equal manifold gives a better noise.
the engine is stronger than any uk engine, they do make good torque and quicker spool.

Jdm impreza are far better in everyway

 

The JDM 2ltr twin scroll is a different beast to the 2.5 single scroll, the twin scroll produces more torque and lower down so its a better all round drivers car, where you can put your foot down at 1500 rpm in top gear and go, the 2.5 wont, they are laggy that way and need to be around 3k before you feel the urge.

 

Won't the single scroll pin you back more though because all the boost comes at once, gives a better thrill I assume.

 

It doesnt actially, by the time a single scroll gets rolling the twin scroll has gone, thats what makes the twin scroll such a nice drivers car, power is more linear and comes in lower down the rev range. Work both through the gears and there wont be much in it, except the lag

 

Exactly what Tony say; single scroll feels faster but only because you are sat there waiting for it to spin up, whereas other modern performance cars have already got up and gone LOL.

The pin in the seat sensation is a indication of a peaky torque curve (nothing. nothin. Wait for it . Wayhey off we go). Which is exactly the opposite of what you want in a drivers car. If you need to pin people in the seat with a twinsroll just gently accelerate to above 2000rpm then mash the throttle pedal...the sensation is now controlled by your right foot rather than when the turbo eventually wakes up.

 

Not all JDM newage car are twinscroll..... V7 single scroll...

 

Being equal length and twinscroll, really fattens up the torque curve and response

 

Wouldn't you say that would feel more like a NA car, if you suddenly plant your foot and get a grunt of power.

 

you got that the wrong way round? even a twin scroll wont have the low down grunt or torque of a 2.5. I'm yet to see a twin scroll have as good bhp vs torque as a 2.5

Are we talking standard engines here to tuned by the way?

 

Even on a 2.5 a twin scroll will be long gone....

Although a 2.5 twin scroll would probably be the ultimate....

 

The 2.5 doesnt have as much low down grunt as the 2ltr twin scroll, try it in a slightly modded one v a standard 2ltr twin scroll and the 2 ltr will still happily go from 1500 rpm whilst the 2.5 wont want to go anywhere. Turbo technology for you

 

2.5 Twin scroll with unequal headers.

Win.

Seriously though, I am 100% agreed on the twin scroll setup spooling quicker and having a smoother delivery (smoother but less 'fun' IMO), but I cannot understand why people think it sounds good? I owned a blob JDM with a full miltek. Sounded like any other car with an exhaust. It didn't sound bad as such, but it didn't sound good either.

 

^
I have this set up and find it very responsive, car has a higher torque figure than bhp.

 

Un equals sound worse.... restrict performance, sound terrible and generally poor quality

 

I'm talking about the unequal length just for the sound.

The sound is purely down to personal opinion. As said, for me, the JDM sound just isn't my cuppa tea. Why?.....because it sounds like any other car with an exhaust. I personally love the Impreza burble, as do a lot of folk, and equally, a lot of folk love the JDM sound.

 

Exactly alot of people would probly see a jdm screaming past with a Honda civic sound track and wonder what's wrong. They may have the superior engineering but the burble is something that is synonymous with the Impreza.
From what I've heard in real life the 2005 and lower cars have the best "Subaru" sound the 2.5's sound similar.

 

They do sound more "race car" like the twin scrolls but there's nothing like a ul Impreza purring past at low revs. Guaranteed to get most people on the pavement ahead off you looking back

 

I have a hawk JDM with resonated full Milltek. It sounds meh and I am looking at exhaust options.

I also have a JDM blob with a deresonated H&S system that sounds simply extraordinary...better than any single-scroll I've personally heard and easily the best-sounding four-pot I've come across.

 

So would you say although the JDM is better spec, the UK version is actually more fun to drive.

 

Any graphs of a car with that?

For comparison, my old hawk was a 2.5, single avcs wrx heads, single scroll s46+ billet, standard wrx headers.

 

Yes - which is a good thing IMO. Instant throttle response, huge torque in any gear at any revs. A twinscroll EJ207 feels like a really brawny NA six.

Depends on what you mean by "fun to drive". You don't get the shove in the back due to turbo lag, but in terms of flexibility, wide power band, responsiveness and sheer usability the twin-scroll is streets ahead.

 

JDM is better spec and more fun to drive

 

Better spec yes fun no

 

Sorry, I lolled

When you are there and you are going, oh foot down, nothing, change gear, now have power, come to corner, oh change gear, now have power, drive, slow down, foot down, no power, change gear, power, yes thats fun....

Twin scroll is foot down, power, gone, fun all the time

Basically you have never driven a twin scroll JDM.

 

You are comparing a modified remapped car to a standard car, but lets put this into perspective, below 2.5k your car is dead, lifeless, the jdm twin scroll out of the factory will pull from as low as 1500 rpm which makes it more flexible for every day driving, simples

 

if I was going to buy a jdm it would be a evo 9gt lol, I can sacrifice a bit of lag for the boxer burble

 

If I was to buy jdm it be a R34 gtr

 

 

What a load off b******* its easy to keep in the boost. You drop a gear or two as your breaking for the corner so when you lift off the clutch and brake and get on the gas your at the right rpm. Lag is only there when your in the wrong gear at the wrong time. Launch the car and will have no lag up untill top speed