InTurbo

iTrader: (3)

Hi.
What's the most amount of power anyone's got out of a standard turbo on a 2.5 sti? And what mods needed to achieve it.

BILLETBEANZ

iTrader: (1)

If its a stock engine its the pistons u need to be worried about..

BBB3

iTrader: (7)

I think 350 is the limit before it ****s it self

Marietto

iTrader: (13)

Mine was running 350/370 and rock solid. Opinions vary on the maximum safe power but are all in the same ballpark, but everyone agrees the pistons are the weak point on the Hawkeye STI. There are plenty running 360 or 370 safely - any more then you are in the territory of when it goes rather than if it goes. One of the NESF members has been running his at 390 and has about 90,000 on the clock and has never had an issue, but he is very lucky to get away with that up to now really.

The standard VF43 turbo will max out about 390 ish and all you will need is a remap and a decent panel filter (if you are brave enough to max it out on standard pistons)

InTurbo

iTrader: (3)

Got mahle power pak pistons fitted and arp head bolts and cosworth gaskets!
So what do you think the stock turbo can do?

Marietto

iTrader: (13)

On paper the VF43 is a 400 BHP turbo but you will max it at about 390

InTurbo

iTrader: (3)

Will try and max out the standard turbo as soon as the engine is run in.
Must be a way of improving the vf43 with porting or fitting a better compressor wheel?

BBB3

iTrader: (7)

On my impreza I have a VF43 made a nice 352 bhp and the spool was nice

Marietto

iTrader: (13)

Better off getting a different turbo bud - the VF43's still sell for decent money £350 to £390 ish. They are a lovely turbo. Get yourself an MD321T or SC46 - I am sure you will see a few for sale on here if you keep any eye on the for sale section. They do sell qiuckly though as they are a sought after turbo. Once you go over the 400 mark though you are then in the territory of needing other upgrades such as fuel pump, front mount intercooler, injectors and recommended other upgrades such as upgraded sump & oil pick up pipe, a good set of GT spec tubular headers & up pipe (none of the ebay crap), 3 inch exhaust system - it ends up costing a fortune! Best max out what you've got and see how it goes.

InTurbo

iTrader: (3)

So what bolt on upgrade would produce over 400bhp on a 2.5?
So many turbos out there I do know what's what lol

InTurbo

iTrader: (3)

Thanks you answered my question befor I asked it!Lol

Marietto

iTrader: (13)

I have just gone through the same stuff you are considering so I am speaking from experience (about the costs anyway! ) I took my engine builder's advice on everything. I'm 300 miles into my engine run in and all my bolt ons are getting fiited on 15th-17th Feb and a remap by Bob Rawle on 21st Feb

If you need any more info bud just PM me and I can give you the full costs of all of the parts I have bought & used. I am not one for using the cheapest alternatives, especially when it is for something as critical as an engine so you could do it cheaper than I did but I wanted it to last and get the maximum power out of the parts I bolted on.

fasteddie84

iTrader: (1)

I’m in the same boat as you mate.

Here would be my final spec for around 390/400 on the standard turbo:

Full 3” Decat exhaust
Panel Filter (not sponge/foam as these can collapse)
Uprated clutch
Fuel pump
Forged pistons
Steel rods
New crank bearings
11mm head stud set
Modified oil pump
Cosworth sump baffle
Secondary air-pump delete
TGV butterfly delete
Ported headers
Harvey up-pipe
NGK Iridium spark plugs ILFR7H
Samco silicone intake hose
Remap

If I was to go over that, I would go for:

Tubular headers (GT spec gen 2 or Carl Davey)
Front mounted intercooler (Hybrid)
Cold Air Induction Kit
Turbo (20g or MD321H or SC42 or SC46)
3 port boost solenoid (although unsure if this is actually needed)
Fuel pressure regulator
Parallel fuel rail conversion
Tufnol inlet spacers
Uprated injectors
340lph fuel pump
Oil cooler kit

Most of the bits are more for safety rather than power.

At the max of the turbo, you will be running the injectors at 94% duty cycle so close to max.

Be careful about the turbo cracking between the wastegate port and the exhaust port. It’s a common problem.

The biggest things stopping you going over 400 are:
Headers
Turbo
TMIC
Injectors

InTurbo

iTrader: (3)

Thanks.
Ive already got fuel pump, full 2.5 decat, du luck panel filter, and a map by bob rawle. He road dynoed it at 357 /425 at 1.35 bar before it was rebuilt.


Nice wheels on your hawk! What are they?

Marietto

iTrader: (13)

Rota G Force 18 x 9 in Gunmetal & Yokohama Parada Spec 2 stretched tyres

InTurbo

iTrader: (3)

That's an expensive list!
Think ill put headers and swap out that foam filter and make another appointment with bob and see how it gets on.

Lets us know what figures you get when you get it mapped by bob.
Think I should be seeing him around the end of feb would be good to see a dyno comparison.

Marietto

iTrader: (13)

Will let you know what figures I get but my bolt ons that are getting fitted after my forged engine build is run in:

Turbo Dynamics billet MDX555-450 turbo (same as MDX321T)
HDI Hybrid GT2 Pro Front Mount Intercooler
RCM GT Spec 2 Tubular Headers DEI heat wrapped by Harvey Smith (RIP)
Harvey Smith (RIP) 3 bolt "Trick" up pipe DEI heat wrapped
Bosch Motorsport 850cc Injectors
HRC340 Race Grade Fuel Pump
Cold Air Induction kit - not chosen yet

All brand new parts so a good saving could be made buying 2nd hand

InTurbo

iTrader: (3)

You should be well over the 450 mark I guess with that lot. Think ill keep an eye on your progress for my future mods.

What the TGV butterfly delete in your list?

Marietto

iTrader: (13)

I haven't done the TGV delete on mine it was FastEddie - not really needed for me. All it is meant to do is reduce cold idle emissions. Nothing more, nothing less. Once your vehicle is warm, the butterfly valves open fully and remain that way. There is a claimed HP gain of about 10-12 HP but I haven't bothered with that on the advice of my engine builder.

fasteddie84

iTrader: (1)

I would be interested to know which CAIK you go for.

Who is your engine builder and mapper?

The TGV are the bits that fit between the inlet manifold and the heads that house the injectors. They have valves in them to restrict air into the engine for startup and emissions. The car can operate without them and they restrict the air a little bit so good to remove them. They can also get stuck so good to do it when the engine is out. You can DIY or buy some already done like the cosworth ones.

The Spec C doesn't have them fitted at all so goes to show that they are a waste of time.

Marietto

iTrader: (13)

I am not sure on the CAI at the moment. My engine builder is going to recommend one for me. My engine builder is based in Chester Le Street, Co. Durham. He's called Andy Kindon, AK Automotive, Subaru Specialist. You can get his details on the NESF (North East Subaru Forum - http://www.nesf.co.uk/) My mapper will be Bob Rawle

InTurbo

iTrader: (3)

Bobs got very good rep. And I can only praise the map he did for me.
The car had so much more torque after he worked his magic.
He takes his time makeing sure the cars healthy before you go out. and checks it over when hes finished with it.
and very safe doing the road mapping too.

Marietto

iTrader: (13)

I know all about Bob bud - he runs regular mapping days up at my engine builder's place. I can't wait till he maps the sh*t out of my hawk on 21st Feb

Marietto

iTrader: (13)

Well it all came together today in my Bob Rawle mapping session and the car achieved between 440-450 bhp and between 480-500ft/lb torque. Well happy with that

InTurbo

iTrader: (3)

That's a good result! Had to put of my session with bob.
iv ran into a problem with vibrations in 5th and 6th that I've still not Found the cause!

Marietto

iTrader: (13)

That's bad news bud. I hope you get it sorted out soon. Have you asked any of the experts what it might be?....oops just read your other thread and see you've asked quite a few!

53

iTrader: (41)

I'd be more concerned about boost pressure and the VF43 tbh they're not that robust.

chopperman

The only problem i've heard with the VF43 is some developed a very small crack in the corner of the waste gate exhaust housing. I believe it doesn't really effect the turbo performance at all and most owners are unaware of it. Other than that the VF43 is robust. Boost is not normally raised about 1.65 bar due to its size. Any more pressure just makes hot air.

Blocks85

The vf series turbos are good but standard design the wastegate port is too small which leads to the housing cracking.
Ian 'pez' perry a friend of mine had his vf43 ported by big d woth his inlet setup to lose comp surge/ boost creep and thats making 400/423 on a 2.5 hawk with no problems what so over.
He ported my vf35 and that was mapped at ENGINTUNER last weekend and now produce 352/360.
Cheers Chris

Scooby_Norm

I'm running 362bhp and 419 torques on standard turbo and cosworth pistons etc for a good while now, doesn't miss a beat!