Have decided to bite the bullet and go for a 2.5 ltr engine and i would like to know everything i will need to do this properly.
And lets just say for arguments sake im starting from scratch no mods!!!

Any help would be appreciated.

oh and please dont just direct me to other threds i am finding some of the hard to follow. i need to know from the basics.

 

sorry forgot to say what i want to use the car for.

i want a really torquee daily drive with plenty of power.

 

Basics...
Mappable ecu
injectors
Clutch

That is pretty much the bare minimum, further on from that:
Turbo
Intercooler
Gearbox

Rob

 

What base car?

 

1997 turbo 2000 impreza

 

Suggestions:

ECU: Power FC - cheap, capable
Fuel system: Fuel pump, >=550cc injectors, some 740s are better on idle than Denso 550s.
Intercooler: from new age STi, with big scoop and undertray
Turbo: 20G turbo is big enough for the standard 2.5
Others: Headgaskets, oil, coolant, use standard heads
Breathing: Induction kit, headers, uppipe, turbo back exhaust (downpipe, mid, backbox)
Brakes: AP 4 pots
Suspension: P1 suspension, stiffer rear antiroll bar, "antilift" kit, geometry
Gearbox: UK six speed (which gives you long 5th and 6th gears and a front Suretrac diff) with gear linkage and propshaft, and a suitable clutch, IMHO stick with the stock flywheel, far better manners

Should do about 400 BHP and 400 lbft on Optimax with reasonable reliability, 1.4 bar mid, 1.2 bar at the top.

Check your insurance and add up the costs first. Consider the labour and downtime on the car.

 

Very good advice IMHO

Rob

 

And a total 'DIY' cost might be............5.5K from scratch?
911

 

Agree with John

£750 - ECU: Power FC - cheap, capable
£400 - Fuel system: Fuel pump, >=550cc injectors, some 740s are better on idle than Denso 550s.
£450 - Intercooler: from new age STi, with big scoop and undertray
£850 - Turbo: 20G turbo is big enough for the standard 2.5
£200 - Others: Headgaskets, oil, coolant, use standard heads
£1000 - Breathing: Induction kit, headers, uppipe, turbo back exhaust (downpipe, mid, backbox)
£1200 - Brakes: AP 4 pots
£450 - Suspension: P1 suspension, stiffer rear antiroll bar, "antilift" kit, geometry
£2000 - Gearbox: UK six speed (which gives you long 5th and 6th gears and a front Suretrac diff) with gear linkage and propshaft, and a suitable clutch, IMHO stick with the stock flywheel, far better manners
£1200 - 2.5 block

Rough cost £8500, at a quick guess

 

soon adds up doesn't it!!

ouch!

 

thanks for the advise anybody want to add anything?

is there anybody in the salisbury/bournmouth area that has done this?

 

I would go with 550 or 740 JECS injectors in preference to the 550 densos. PowerFC will need a new MAF sensor for thos levels ideally, a Z32 sensor can be had second hand for about £120.

Revolution downpipe and syste with some cheap headers such as Gruppe-s will probably come in a little less than £1000.

It's not cheap to do it properly. But you could use an upper limit of 350hp with controlled torque around 300ft-lb (which will be available very easily on a 2.5 with no lag), get a used TD05 turbo etc. Get some used 440 injectors and the pump and reg.

Going the 350hp route would leave a reliable engine and the option to upgrade the turbo, fuelling and gearbox at a later date. A 2.5 with a td05 turbo will be almost lagless, with plenty of torque, but may leave you frustrated as the torque drops away rapidly to keep the power within the limits of the injectors and turbo. The next step would be larger turbo and injectors, but keep the torque to a low but sustained (through the RPM range) level of

Paul

 

Sorry to highjack the tread but if I was to do this on aMY04 Sti I wouldn't need some of the above equiment, gearbox, intercooler, brakes etc. The 2.5L is the increase in the bore or the stoke?
Reading other threads would the heads fit directly on to the 2.5L block?

What if you for the time being replace the 2.0L for the 2.5L block and bolt everything back on.
Remap the ecu. And add features later like a bigger turbo, FMIC, and such like.
Where's the best place to get the block?

 

The 2.5 will be a straight swap on a newer car, just bolt everything back on with slightly thicker head gaskets, even the remap will not be required for normal running, just plumb the turbo actuator direct so you are running minimum boost and you are ready to drive. Obviously getting a remap is a good idea, but the engine will be running conservatively as the same airflow will come at lower boost (so it will run slightly richer and less advanced) on the unfettled ECU.

The 2.5 has increased bore AND stroke, and is a relatively comfortable engine geometry.

Paul

 

weirdness

 

What kind of Power and torque would you expect using the vf35 turbo and a remap?

I have the PPP on already so keeping this exhaust, (I'm not a big fan of the full de cat noise) and maybe a bigger turbo but keeping the TMIC what would be the max power I could safley achive?

Whats the max power achived from the STi TMIC?

 

A cost effective option for the early MAF is to fit the original sensor to a larger tube prior to the remap, this allows a simpler, better flowing intake to be made. This mod is not required on the 99 onwards cars.

Don't forget to add labour to the above costs unless you are really handy !

I've just remapped a 2.5 conversion which was on a Sti6 typeR and it retained the std intercooler, std headers, std gearbox, VF hybrid turbo (similar to TD05 flow) and std injectors. Only mods were panel filter and decat.
It wouldn't be any record breaker regards peak power output but what an excellent car to drive Instant response and a v e r y wide power band, floor it in 5th from 2500rpm at it just takes off !!
If possible, get a run in a 2.5 running say 330/350bhp before you decide that you need more power.
With the same power level in a 2.5 v 2.0 the 2.5 will simply leave a 2.0 standing on acceleration, particularly in the 'in gear' increments.

Andy

 

From a person that has one (2.5l sti6 type r v.ltd), the 2.5l conversion produces bags of torque low down and through the mid. Restriction on the conversion is the upper rev limit due to the increase in stroke. (set at 7100rpm at the moment). Mods inc: 2.5l bottom end, hybrid VF23, Apexi Power Fc, Decat H&S up/down pipe, Apexi N1 backbox, uprated clutch & fueling, all running at 1.2/1.3 boost. Only problem experienced is the power tails off sharpish after 5500rpm due to the turbo. Would be fine on a 2L but the 2.5l really needs a td05 to produce the goods further up the power band. New age TMIC is fine up to 400bhp apparently. New I\C, injectors and turbo on route easter time! Not too good on mpg but grin factor more than compensates.

 

Lol. You must be faster at typing!

 

lol, really enjoyed driving that car Doug Edited my post to say sti6 not 5 !

You could achieve similar power from the 2.0 on the VF35, (350 ish) the big difference would be the torque and instant response from the 2.5.
The later Sti intercooler is well capable of coping at this level. I have ran around 450bhp on this intercooler on a 2.3

Andy

 

Speak to the SoobyClinic. They did the conversion on mine and will be able to answer any other queries.

 

doh beaten to it, lmao, was gonna say have a word with adam or kev at the clinic they'll sort you out.

 

Doug,
Where did you source your parts from? and who did the work. The sti6 will be lighter than the my04 sti of mine but I think the 2.5L is the way to go.
You can do the initial work with the block and then add to it as funds permit (as far as I can see anyway)
Ok scoobyclinic

 

All work was done by the Clinic before i bought the car. (with the exception of Andy.F fitting and mapping the Apexi.FC.) I would strongly advise having it done professionally because mine decided it didn't want to play anymore when a stone went throught the oil cooler. The engine was still young on its conversion and the ScoobyClinic agreed to pay for half the rebuild. (all happened to the previous owner!) Wire mesh now covers the front as a precautionary measure against it happening again!
Just go's to show, sometimes it's a good idea to have things like that done by the experts incase anything does go wrong so you're covered by a warranty and doesn't cost an arm and a leg to fix.
Saw a 2.5l bottom end for sale on here somewhere the other night.

 

Correction, cant of been under warranty still, last owner paid for the whole cost of the rebuild. Over 3k.

 

There's an Apex Power 2.5L stage 3 "engine" going but I don't know if it's the short motor or the full engine. It's more expensive but it should have the forged pistons and rods!!!

I have a machanic that can do the work he's worked with Subaru engine rebuilds before, but is there any special things to be aware of before starting?

 

It's the torque tailing off after 5500 rather than the power. I expect you will find the power reaches a plateau, possibly falling gently. Seeing as power is the product of torque and speed (RPM) it must fall with increaseing RPM if the power is static.

Paul

 

You might be right Paul. No point in going over 6500 though as she runs out of puff! TD05, mmmm! Still, from 2500 up to then, omfg!

 

I'm not sure what particular VF23 hybrid is fitted to your car doug, but on the std headers a TD05-20g would actually spool quicker !!

I have a deltadyno graph of your cars power and torque when I initially set up via EcuTek and you are correct, no point in exceeding 6500rpm.

Andy

 

What was she producing? Would there be any benefit in changing the headers when changing the turbo etc? Keeping my eye out for bargins till easter time.