Twin scroll a 2.5 good idea?
 

Hey folks thinking of upgrading my 2.5 Sti soon. I love the torque of the 2.5 and I was just wondering if fitting a twin scroll would be worth it

Plan would be to run 450 max with a forged engine

I'm just wondering if it's feasible? As I could just bolt of an sc46

Or would a standard position twin scroll garett provide quicker spool on a 2.5?

Cheers

Steve

just build it right and bolt a sc46+ on (mine out spooled twin scroll setups anyway hahaha), twin scroll needs alot more parts than just the turbo.

Cheers tidgy I'm aware I'd need more than just the turbo but was wondering what people's thoughts were on the subject

Steve

The clever bit would be to bolt on a bigger twin scroll to get max benefit!

You could have the same spool up as the sc46 etc but on something bigger.

I love to hear of people doing something different, definitely go for it

Did The Litchfield type 25 have a hybrid twin scroll?

I know St do a twin scroll 500 wonder what it would be like on a 2.5

I know I'd need twin scroll headers and DP

But I'd need these even if I went for a normal turbo upgrade anyway so best just to buy them and see what happens lol

Steve

I think you'd struggle to match the sc46+ version spool wise, mine was hitting full chat around 3300rpm hahaha

Type 25 http://www.type-25.co.uk/engine_turbo.asp

My Litchfield Billet LM420 hits 1.7 Bar at 3500 rpm gives me 450bhp, 420 lb/ft and pulls like a steam train! -twin scroll is the way forward!

You will need the rest of the bits as well (DP, Headers, Uppipe) but well worth it.

Russell

There was a thread the other day where it was mentioned that twinscolls when launched in high revs that then remain at high revs through the gears doesn't hold boost very well.

Not convinced twinscoll is better just different.

Cheers for the info guys was just to see what people's thoughts were on it the idea it's a long way from being done but it's something to think about

I don't know about top end holding well as the last turbo I had on my 03 blob was a 321T

That did tail off towards the higher rpm but was mapped to do that I believe

I'm sure if the twinscroll was mapped to not tail off I'm sure it could achieve the same?

Thanks

Steve

If your launching and then up the box so your 5-8k rpm then the boost will be lower assuming your on a standard twin scroll turbo as the boost doesn't hold to high rpm. Check check the peak boost you would need to floor it from a lower rpm say 2500rpm in 4th, you won't be doing that on the strip.*Was it a glued track? 5000rpm at full throttle should have enough power not to bog, hour day though so maybe lots of grip available__________________Jolly Green Monster LimitedFull time mapper and Ecu Expert*Mobile Road and Dyno mappingwww.JollyGreenMonster.co.ukFollow Jolly Green Monster Ltd on*facebook***

sc46 will be more than enough on single scroll mines spools well and pulls hard to red line I prefer the low down grunt I get with the big bang

Pretty sure Tim from JTi runs a 2.5 twinscroll with good results and over 500bhp

http://bbs.22b.com/forums/showthread...tchfield-LM480

I'm running a forged 2.5 with twin-scroll sc46. I don't go much above 5500rpm...I don't need to, so you wont need to worry about it "tailing off" at the higher end.

I have gone even further steve in the interests of something that hasn't been done yet my SC42/46 twin scroll has been clocked and rotated on my spec-c engine 2ltr classic not 2.5 tho haven't run it yet hopefully in the next month once my syvecs is fitted and the cars mapped will be interesting to see what the results are.

Attachment 69962

I had on my last spec-c the type 25 hybrid twin scroll they have come on a long way from those days I would say go for it as the old saying goes you will never know until you try it

Wow, look at that.:thumb:

Your cars a work of art Gus, quite honestly in my opinion one of the best looking classics out there. The attention to detail and finish is superb.


Joe

comparing 2.0 with 2.5 is pretty pointless, they have very different capabilities and reactions on different turbo's.

Here the graphs from mine, forged 2.5, sti inlet manifold, perrin intake pipe and wing mounted ind kit with the new sc46+ turbo. Still on standard management and limited boost due to heat issues of top mount. Was still runing standard wrx headers as well so even more to come lol

anyone got better spool than that? lol

Attachment 69963

Attachment 69964

Not very good at reading printouts but am I right to think that the top pic is the boost going up straight away then holding all the way. If so it deserves this:eek2:and maybe this :notworthy

haha yeah thats the boost profile. On road spool is even better, but that's the same for all cars and just a trait of the dynos.

sold it before ever managed to find out what it would do pushed further, plan would have been front mount, headers, syvecs and see what she did.

[QUOTE=Tidgy;11470170]comparing 2.0 with 2.5 is pretty pointless, they have very different capabilities and reactions on different turbo's.

I agree with you on that Tidgy horses for courses tho it depends what you are wanting to use the car for.
As for my old Hawkeye spec-c RA on 650 injectors running the hybrid twin scroll gave me 415/398 peak 1.6 bar flatlining at 1.5 bar right through

Thanks Joe its been a long build seeing as I originally gave myself 365 days to do it :) it gave me too much time to check on other peoples builds then changing mine again and again will be finished in the next couple of months :) promise

[quote=gussy;11470378]biggest thing with those figures are a 2.5 would be 430-450ftlb at that sort of bhp. for road and occasional track then can't beat the low down grunt of the 2.5, but the 2.5 be pushed as hard as a 2.0 :(

So as you say very much dependant on what your planned use is :thumb: