RexNuts Subaru Forums

Looking at upgrading to one of said turbos. Anyone already got one and love it/ hate it? What supporting mods are you running and how does the car drive? Mine is a daily and needs to stay that way and not become a laggy piece of piss

If you know of anyone that runs a setup like this then please let me know!

Cheers for any feedback

Is your car laggy now? mine with AVO550 gets full boost in 4th flat road about 4800rpm, apparently that's shit and you should be able to get full boost by 3000rpm Paul said he could get a 3450 to come on full boost with my set up (almost same as yours) at around 4200rpm
Mate big turbo's will be laggy, external gated turbo's seem to bang on a little harder, how much power you after

You wont get anymore power with a GT30, go the 35

Alot of variants of the 30 wrecks... I agree with davesti go the 35.
If possible try to get your hands on the HTA35R

What's so special about that gt35 you mentioned?

HTA Wheel helps with spool

link to a Ford forum but this guy explains it well.

http://www.modularfords.com/forums/show ... ter-Turbos

The FP "HTA" turbos are upgraded with billet alloy compressor wheels. The wheel is lighter which will aid in spool.

http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=CTGY&Store_Code=FP&Category_Code=WRX-Turbo

It's up to you mate, if you want a cool dyno sheet to place on the dashboard at car shows & don't mind having a street car that is only enjoyable within 5000-8000rpm, go the basic GT35 setup.

If you want something you will enjoy in many driving conditions, but will only have 280-300kw atw, go the GT30

If you want a GT35 that spools good, you need to invest in fancy plumbing & better fuel. Gear ratios will help too

GT3071R with 44mm Tial External Wastegate. You should see full boost by 4200RPM. There is currently a Kit on Ebay that gives you a good look @ what you get. [link]http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370281277632&viewitem=&sspagename=STRK%3AMEWAX%3AIT[/link]

On anything but a STi 6 speed with a forged engine, it would be pointless. You'd smash up ur box and throw a piston through the heads into your tyre, crash, burn and explode in a blaze of overboosted glory.


Also for that sized Turbo, I'd recommend either 272 or 280 duration cams. You should see around 300kw at all four with that one.

A GT35 with a 6speed manual with be ghey, gears are too short. If you are really want a GT35 then get a 5 speed with PPG gearset. Longer gears = more boosting time!!

Can we see a list of mods you currently have? Including internals. Thanks.

Car goes something like this:

Engine: EJ25T rebuilt by TRP Tony Rigoli

Engine Mods:
o Dowelled block
o 2.5L STi rods
o Wiseco forged pistons and rings
o ACL bearings
o ARP head studs
o Plumb-back oil catch can
o Engine detailed in two-pak
o Perspex engine cover

Induction:
o APS 65mm cold air intake
o Innovative T3/T4 turbocharger
o Turbosmart Ultra-Gate38 38mm external wastegate
o APS Stealth Black intercooler (4in core) with red piping
o APS plumb-back blow-off valve

Injection:
o Walbro in-tank fuel pump
o High-flowed STI 750cc injectors
o MRT billet fuel rail
o Aeronautics fuel regulator
o Braided fuel lines
o GReddy Profec B-Spec II boost controller

Exhaust:
o Rocket Industries exhaust manifold
o 3in HPT-coated dump pipe
o 3in stainless steel mandrel-bent exhaust pipes
o 3in catalytic converter
o XFORCE 3in muffler with 4.5in Canon

DRIVELINE

Gearbox:
o STi six-speed manual with quick shifter

Clutch combo:
o Exedy brass button clutch & heavy duty pressure plate

Differential:
o STi R180 rear diff

Brakes:
o Standard Brembo/STi calipers & discs
o Bendix Ultimate pads
o Race Brakes braided line

SUSPENSION

o Whiteline Group 4 adjustable coil-overs
o Noltec adjustable strut tops
o Whiteline strut braces front & rear
o Whiteline 22mm swaybars with adjustable front and rear links
o Whiteline polyurethane steering bushes
o Whiteline lower ball joints and tie-rod ends
o Whiteline adjustable rear arms
o Polyurethane bushes
o Rear diff cradle lock-in bolts

WHEELS/TYRES

o O.Z Racing Prodrive 18x7.5in wheels
o Maxis 225/40/18 tyres

INTERIOR

o STI seats (rear with STI logo)
o Door trims with ‘Atomic WRX’ symbol embroidered in micro-suede
o Momo gear knob with micro-suede gear boot
o Pioneer AVIC F20BT Double Din 7" Touch Screen HU

EXTERIOR

o Electric blue paint
o STi body kit
o Sedan front guards with customised VE Commodore indicators
o 22B bonnet vents
o STi front lip
o BMW M3 side mirrors
o STi rear flares
o Modified rear bar
o Custom STi top wing
o Subaru lower rear wing & lower rear diffuser
o MY06 STi Wagon rear clear taillights

PERFORMANCE

Power output: 340hp atw = 253kw atw

The weak point in your build is the rods.. Check out what power those can hold. Everything else should support it.. Maybe a low temp thermostat and PWR Radiator.

For an upgrade to the GT30? What sort of rods should I be looking at upgrading to?

I'd suggest Argo or Puater. Even Manley I beam Turbo Tuffs. I just wouldnt trust standard STi's for a 300kw job. Better safe than sorry right?

Argo and Puaters can be $$ around the 1100 dollar mark, Manley's are around 850 ish. Then u have labour for assembly.

Wouls upgrading the rods be enough to increase boost or are upgraded cams an essential to run more than 21psi? Definitely better safe than sorry

Rods dont much care about the boost, its the power that the engine is producing (intensity of the explosion) Each rod will be rated @ a certain HP..

Cams essentially keep the valves open longer, to put more air/fuel into the combustion chamber. It is measured in degree's. 272o of the duration being open, out of 360o. There is also the matter of 'Lift' the cam produces, Meaning how much it lifts the valves from the valve seats (closed) allowing even more air/fuel to be applied. The 'lift' increase also uses the valve springs to force the valves back into position, putting extra tension on them. Without upgrading valvesprings with your cam, you also risk 'Coil bind' witch means the spring cannot force the valve closed properly during the combustion process, resulting in compression loss, and ultimately engine failure.

Ok no worries. I'll look into some Rods with a GT30 turbo upgrade I'm thinking and maybe look to aim for about 280kws. Thanks for explaining everything - not everyone can explain things so simply!

Running more boost, is just increasing the the compression of the Air. Resulting in more Air to be mixed in the combustion chamber. Increasing the boost puts pressure on Head gaskets and eventually the cyclinder walls and the heads of the engine. 14mm Head Studs are advised when using over 25psi of boost also a good headgasket, say a COMETIC, to ensure the seal of the headgasket under high Pressure conditions.


NP at all man, Just get your workshop to run you through what I said to make sure. As much as I love to say im 100% correct, I am ultimatly human, the more input u get the better!

Awesome - thanks mate

So with my current set up if I get 14mm Head Studs (any brands in particular?), new rods (say rated up to 320kws?) I could run a GT30 at more than 21psi? Maybe look at around 280kws?

I couldnt tell, It all depends on how much power the car makes @ 21psi. But the max boost pressure of a GT30 (depending on what thrust bearing it uses) is around 2.5bar.. That is somthing like 36.25psi lol. You couldnt run that even if u wanted too (You'd probably crack a cyclinder wall or push your heads off the block.

I've known some skyline boys to produce 420hp off of a GT30, not sure what .AR tho.

Get the rods rated to @ least 500-600hp. Build it tuff. Rods are very important.

As for brands, Its up to you man, just google around, possible ask some engine builders what the suggest.

Ok no worries. At 21 psi my car is making 253 kws. Certainly don't need to be pushing 36psi! No worries, have spoken with Tony Rigoli Performance and I think they use Billet Rods. I'm going for a power run on their dyno next week and will have a chat to them about new rods, head studs and the turbo! Thanks again for all your help!

What are those GT30's rated at anyhow? I don't think you'll see 300kw with one of those turbos, I have been incorrect before though!

I wouldn't pull your engine apart now, if you were to go the bigger beefier rods, you could also try Rigoli's, they use PAR to good effect, I have light weight Par rods, 570 grams each and also use Rigoli 14mm head studs.
Everyone sais don't go bigger turbo, I say do it, you'll only look back in a years time and go I wish I had done that, then you got to go through all this bull shit again, if you don't like the 35 I'll buy it off you down the track mate.

If your car is making 253 on a Rigoli dyno that would be about 265 on Autotech dyno and 280 on Pulse dyno
With a 3540 don't expect a hell of a lot of difference in over all power, its the torque that'll get you frothing

all od that is correct except the coil binding part. when it coil binds this means the cam has to much lift for the spring so when the cam is at full lift the spring has been completly sqashed and the spring basicly botoms out. so the spring twist to try and compress more! (that is what coil binding is)

what your refering to is more spring presure or , if the springs dont have enough seat cracking presure the valve wont return quick enough before its on compresion stroke! they also call it valve bounce or valve float.

But your on the right track good work!

Not sure what my car is making at Rogoli's dyno-it's getting done tomorrow week. The 253 came from Jem's dyno at Ingleburn. That's what the previous owner told me.

Either way with the turbo upgrade won't I need the new rods and head studs? Or they would just be to run more boost? What sort of RPM would a 35 come on?

As my car is my daily driveability is massive..I'm just thinking the 35 will be too laggy for what I'm looking for? I think I'd rather settle for better driveability but not as much power.

Ahh decisions decisions!

What RPM are you seeing full boost now in 4th straight road/

I don't think you'll need rods and head studs if you stay under 270 - 280kw, you engine should handle 22psi boost as is anyhow