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Old 20 May 2013, 10:20 PM
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Eddy555sti
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Default Turbo help?

Right guys I have jus replaced my ej20 block with a ej25 sti usdm closed deck block in my v3 sti I also have all the supporting mods but my vf34 has given up just wondering what would be a better turbo for this setup or will I be better of purchasing another vf34 any advice would be appreciated and if any one has a turbo let me know thanks
Old 21 May 2013, 02:41 PM
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Old 21 May 2013, 04:39 PM
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joz8968
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I'd plump for the SC42 Billet.

Watch that gearbox...!

Last edited by joz8968; 21 May 2013 at 04:40 PM.
Old 21 May 2013, 05:00 PM
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Thanks mate I've also uped to the 6 speed
Old 21 May 2013, 05:21 PM
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A 450hp turbo is best suited for a 2.5, a MD321T or SC46, have heard good reports on the SC42.
I have a non billet MD321H for sale which made 441hp on my 2.5 running 20%meth but this is a 400hp rated turbo.
Trev

Last edited by trevsjwood; 21 May 2013 at 05:22 PM.
Old 22 May 2013, 12:44 PM
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SC42 billet + 2.5 = great combo. Well into the 400s, but excellent spool-up/driveabiltiy. API recommend this combo.

SC46 billet will get you to and beyond mid-400s, at the expense of a little lost spool-up when compared to the 42.

Remember though; c.450-470 is pretty much the limit for a built 2.5 - with 'proper' forged pistons of your choosing (in place of the OEM hypereutectic tripe). Moreover, you don't want to push more than 1.3bar.

Last edited by joz8968; 22 May 2013 at 01:15 PM.
Old 22 May 2013, 01:54 PM
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trevsjwood
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Originally Posted by joz8968
SC42 billet + 2.5 = great combo. Well into the 400s, but excellent spool-up/driveabiltiy. API recommend this combo.

SC46 billet will get you to and beyond mid-400s, at the expense of a little lost spool-up when compared to the 42.

Remember though; c.450-470 is pretty much the limit for a built 2.5 - with 'proper' forged pistons of your choosing (in place of the OEM hypereutectic tripe). Moreover, you don't want to push more than 1.3bar.
But not 1.3 bar for a built motor surely?
Trev
Old 22 May 2013, 02:01 PM
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API, for example, either keeps to 1.3bar... Or it might be pushed to 1.5bar(?) - because stronger head studs/HGs are used.

I can't quite recollect the boost target, to be honest.

Last edited by joz8968; 22 May 2013 at 02:05 PM.
Old 22 May 2013, 02:24 PM
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I know from experience care needs to be taken at high boost, cylinders fret and cause fatigue to the HG but with a good spec, head studs and gasket, should be ok to run up 1.6.
OP mentions closed deck but not sure what that means in US terms.
Trev
Old 22 May 2013, 02:41 PM
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With appropriate head studs, we will run a freshly built 2.5 at 1.6 - 1.7 bar 1.8 seems to shorten the the life of the block by quite some distance. As once it starts flexing, it seems to lose all integrity and flexes more easily and then a failure is never far away.

1.3 bar is the APi safe limit for a standard engine on all standard kit.

We use the SC42 for regular road 2.5's that want spool and fast easy driving. The 46 version gets better, higher, headline numbers but is not for everyone.

David
Old 22 May 2013, 08:17 PM
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Thanks guy really appreciate all the advice who will be the best person to map I'm located in Leeds don't mind going out but not far out thanks
Old 22 May 2013, 08:25 PM
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Thanks to DOB for clearing things up.
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