Phil555

iTrader: (1)

Hi all, can anyone tell me what scoobies are fitted with a twin scroll? Looking at getting rid of my beloved classic for something abit newer and was after a scoob with a twin scroll.

Thanks,

Phil.

turboDean

iTrader: (4)

If you want Twin Scroll it's got to be a JDM STI, not sure from which year they started, Blobeye on i think.

Phil555

iTrader: (1)

Cheers. Imports only then?

timchump

when the jdm sti twin scroll models started, were all the jdm sti's from then onwards twinscroll or could you still get single scroll?

TonyBurns

iTrader: (3)

All MY03 JDM STi's onwards are twin scroll, JDM wrx's are still single scroll.

Tony

Elmer Fudpucker

Can someone please explain to me what exactly is so good about a twin scroll turbo?

TonyBurns

iTrader: (3)

Better power delivery, virtually no lag between gear changes if your quick enough
That about sums it up

Tony

Elmer Fudpucker

Are you sure about that?Presumeably its to give a constant gas flow.?

In Marine Turbo Applications,ie diesel vee's.A pulsed gas flow gives better
performance but poorish longlivety where as constant gas flow turbo's give poor performance but last longer.

Therefore I'm not entirely convinced that twin scrolls are anything special to shout about

I stand to be corrected,they say a little knowledge is a dangerous thing don't they

stevebt

iTrader: (8)

as said all JDM STI from 2003 onwards unless you have the cash to waste on another type of impreza

stevebt

iTrader: (8)

i agree !!! im pulilng my hybrid twin scroll off in favour of a single scroll turbo, as i think the twin scroll is a little slow when compared with a quick classic car

TonyBurns

iTrader: (3)

Simple fact is that you wont get a single scroll turbo of the same size to spool up as quickly as a twin scroll turbo, just look at the UK car v the JDM twin scroll, 1500rpm (if not slightly lower on a remapped car) to start to pull, much higher on a single scroll (2-2.5k rpm)
They are so good that I wont be getting another single scroll turbo impreza, for I have seen the light (for the last 3 years )
Drive both, then come back

Tony

Elmer Fudpucker

I work for the worlds largest Turbo manufacturer,they tell me twin scroll or twin entry is for reliability and not performance,sorry

stevebt

iTrader: (8)

tony


your car has a standard twin scroll and your happy with it ??? i paid out for a HYBRID twin scroll and i wasnt too happy !! so i have went single scrolll !!!! i researched a hybrid rotated twin srcol turbo but was told by nearly everyone that it was a big waste of cash

TonyBurns

iTrader: (3)

The proof is in the driving
Fastest production Imprezas run twin scroll turbo's, that includes the older cars (lighter, similar bhp) v heaver cars.
Though you can add that a 6 speed box helps (plus the lack of lag between changes means...... )
Honestly, you need to drive 2 similar cars, 1 with single scroll and 1 with twin scroll, that will prove the point

Tony

TonyBurns

iTrader: (3)

Best person for hybrids is Shaun as he has one on his car but supporting mods probably help on that front and yes, more than happy with the twin scroll

Tony

stevebt

iTrader: (8)

my mods go well above shauns !!!! as he will go the same direction i have

Elmer Fudpucker

Sorry not buying it mate,Jap cars may be superior,but trust me it ain't the twin scroll

stevebt

iTrader: (8)

i cant see what the big deal is ??i run 1.9bar but i think my old classic with 20g was far quicker !!!!

T5NYW

iTrader: (4)

I have to agree partically with both sides here

I have owned 2 UK cars 1 classic and 1 bugeye and 2 JDM's 1 Type R and type 20. the Twin Scroll turbo does seem to drive better up the road than single scolll(being mindfull of ermaps etc) , although there is not hte initial "Kick" in the badk like the single scroll the twn certainly lasts a lot longer before peaking IMHO.

Although seemily lots of forums/turbo sites disgree with thiis mostpeeps that have UK's and been in my car agree. maybe perception is better than reality


Tony

911

Last year I drove my Sti v3 20g with a few mods at a hillclimb weekend at a track close to Powerstation.
During the saturday dinner break I went to visit the boys at PS for a chat. Ian allowed me to drive his tuned twin-scroll black Type C in anger.

The turbo response was fantastic compared to my 20g, lots of torque very very low down, very flexible and it is immediatly there after a gear change.(those 6 speeders are fab too)

He would not allow me to take it back to the hillclimb...

Graham.

GazTheHat

I posted a question about this on another thread, but didn't get an answer.

So the twin scroll spools quicker (apparently). What are we talking about?

1 bar by when?
Full boost by when?

ex-webby

Just for the record and based on what I have done on my car....

Standard VF36 twin scroll gave me 1 bar @ circa 2700rpm, 1.6 bar @ circa 3200rpm. Hybrid twin scroll gave me 1 bar @ circa 2600rpm, 1.7bar @ circa 3100rpm. The hybrid twin scroll also supported 380bhp / 360lbft. I am not aware of any single scroll on a 2ltr that would give me those headline power figures and also the same response and power band.

The Stage 2 article (which includes all the turbo work and more) will be published over the next 14 days, so you can read more about it then.

Stage 3 is underway and should be finished within a month..... this is going a totally different route and should be quite quick .... more details on this very soon!

A number of people comment that they have powerful cars that are quick, and a number of those people take a lot from what their cars acheive on the rollers..... that is fair enough, but I also have real world performance figures from my current 2ltr twin scroll setup (stage 2) that has seen the car acheive the following:

0-60 3.85secs
0-100 9.5secs
1/4 mile in 12.5secs
0-60ft in 1.6secs

I would be very interested to know what other peoples real world figures are, for similar levels of tuning in a similar newage vehicle. The fact that the conditions have never been the best during any of the above real world figures, I am very confident that those figures could be bettered even at it's current level of tune.

I appreciate that my car is lighter than a standard STi, but nether the less, this car is quick for it's level of tune.

GazTheHat

Thanks. Now i've got a clearer picture.

The twin scroll is quicker to spool, but only marginal then really.

MrRA

Impressive figures Shaun

Davey P

iTrader: (1)

I thought there was quite a difference between the single scroll and twin. Took out a 05 STI Type UK and there was loads of lag and nothing really happened under 4k rpm. Took out a Spec C with the Twin Scroll turbo and you could really tell the difference, hardly any lag off the line and between gear changes, the car just picked up and went!

GazTheHat

Aye, a standard UK car is really slow to get going, but a few changes and that is much lower and better/easier to drive. (or even the PPP will sort it out).

Davey P

iTrader: (1)

Fair point, expect you could say the same about a twin scroll car.
Can't comment on a PPP'd car as I've never driven one.

GazTheHat

I don't know if just a remap would do it? As i had exhaust/filter fitted at the same time, but it's below 3k then, instead of around 4k mark. I presume the PPP would be about the same region too.

Plus the figures above by the WebM are for a "played with one".