Coverting a 2.5 N/a to 2L turbo

[PLO-80Y]

Hi Guys, Names Danny just joined this forum.
I've been a member of rexnet for about 6 years although never really sus'ed the liberty forums.
Anyways if you know rexnet, U'd probably know that i have a V6 Sti with was written off. I started wrecking it then thought of a good project. So yesterday i purchased a Gen 4 Liberty as i like the look of them and am planning on converting it into a V6 Sti in a way. Anyway i have a few questions which you may be able to answer for me....

Firstly has anyone done this conversion before?
Should i use the factory Liberty harness and modify or use the V6 harness?
What is the rear diff ratio of the standard 2.5L Gen4?
Can i register an EJ25 Liberty with an EJ20 block?
What other problems do you think im going to encounter doing this conversion?

Regards
Danny

[Woodduck]

Im really confused When you say V6, you mean flat 6..yeah?

And are you planning on converting your 2.5 to a 3L flat 6 like your thread says....or a 2L turbo like your heading says?

Major confusion!!!

[Hotwire]

Was reading this thinking V6, why are you asking about EJ20 when you want a V6? then realised you mean Version 6

SO - I'd imagine you would need an engineers cert for the conversion, including brake and handling upgrade tests.

For the harness, I'd imagine they would be rather different as I dont think the 2.5i have AVCS on intake and exhaust like the GT (does the STi have dual AVCS or intake only?) anyway, I'd imagine a whole STi harness transplant would make it "easier" but can't confirm or deny

Welcome too btw.

[Woodduck]

I get it now! Was very confused!

[teK--]

V6 = version 6. Shoehorning a V6 into our cars would be a mega conversion

If you want straight bolt-on rather than ultimate power, you could buy the AVO turbo kit for NA engines.

I'm not sure how well the 2.5i gearbox would handle having a V6 STi powering through it.

[swingn]

Post an intro champ

& show us from pics of this V6 STI

[Hotwire]

Oh, and for the diff ratio (presuming MY04-MY06)
For MT
F) 3.700
R) 3.700

For AT
F) 4.111
R) 4.111

For reference, auto GT is 3.272 - man that sucks! No info on 2.0T MT ratio's, but I'll guarantee they'd be better than the auto - goes some way to explaining the MT better 0-100kph times.

[Adrian2627]

It's going to be a big job especially when it comes to the ECU and pollution systems. The V6 is 99/00 and the Gen 4 will be at least 03/04 so you might have some issues rego wise with emissions. Your best bet is to consult an auto engineer as to the legality and what's required.

Once you get that sorted then I'd be looking at keeping the 2.5 block and adding the V6 top end/turbo to that. Yeah, its going to mean a piston change, possibly rods too if you want to do it properly, but you'd end up with a far more streetable combo in the heavier Liberty. The extra capacity is going to mean faster spool times/less lag and better low mid than the 2.0. You could then sell off your STi bottom end to help cover costs.

[nytrojen]

It's going to be a big job especially when it comes to the ECU and pollution systems. The V6 is 99/00 and the Gen 4 will be at least 03/04 so you might have some issues rego wise with emissions. Your best bet is to consult an auto engineer as to the legality and what's required.

Once you get that sorted then I'd be looking at keeping the 2.5 block and adding the V6 top end/turbo to that. Yeah, its going to mean a piston change, possibly rods too if you want to do it properly, but you'd end up with a far more streetable combo in the heavier Liberty. The extra capacity is going to mean faster spool times/less lag and better low mid than the 2.0. You could then sell off your STi bottom end to help cover costs.

Isn't it illegal to put an engine into a chassis if the engine is older than the chassis? I thought you could only go the other way around - ie: put a newer build engine into an old chassis

[scary]

mate from a purely mechanical side it is an EJ2xx series engine so no issue. I assume you are going to run the V6 gearbox?? If so run the rear dif as well as the 2.5i will be an open diff on lsd. Will need a custom tailshaft (no Big Deal) run an aftermarket computer and anyone you has half a clue about subarus will be able to wire in the sensors as not much has changed.
Legality cahnging from a N/A to turbo is the only issue and emmisions as it is a later model car.

But essentially they are all the same lomp of aluminium and it will bolt straight in

[Adrian2627]

It's going to be a big job especially when it comes to the ECU and pollution systems. The V6 is 99/00 and the Gen 4 will be at least 03/04 so you might have some issues rego wise with emissions. Your best bet is to consult an auto engineer as to the legality and what's required.

Isn't it illegal to put an engine into a chassis if the engine is older than the chassis? I thought you could only go the other way around - ie: put a newer build engine into an old chassis

Exactly why I wrote to consult an auto engineer. There's a lot of mis-information and speculation floating around on forums and engineers deal with what's what everyday and know exactly what you can and can't do. With a project like this you should always make sure you can do it before throwing a spanner. It's the old measure twice cut once approach.

[Subie Boy]

I recently turbocharged my 2.0R at Pulse Racing, it was engineered and took it to RTA and they approved the car (got myself a blue slip). No dramas!

[Drew]

if you're in Melbourne, go and have a chat with the guys at STi... I know they have done a few transplants not dissimilar to this...

[specbtommy]

I recently turbocharged my 2.0R at Pulse Racing, it was engineered and took it to RTA and they approved the car (got myself a blue slip). No dramas!

if you don't mind me asking what did it cost?

[Subie Boy]

Once I detail my car and take photos, etc. I will do a write up on it (Member Profile)!

Here is one pic from a camera phone.