What WRX motor for BC5?

[Munkvy]

Im getting sick of the issues I keep having with my old BC5 factory motor, so considering swapping in a WRX motor.

From what I can gather searching here and RSLC my best bet is V1/2 WRX correct? And thats a straight swap, except for needing to swap some of the BC5 sensors onto the WRX engine?

And if I was to go for a V3/4 engine, I would need to swap manifolds - correct? Ie the looms are sufficiently different to no longer make it a bolt in job?

Next, how much advantage is there between the generations of engines? Ie whats the major differences between V1/2 WRX over BC5 and whats the advantage of V3/4 over these? I assume its heads and cams are improved in each generation from what I have read. I am aware of the closed deck vs open situation. Can anyone expand on the other differences for me?

And, finally - has anyone got an engine to suit? Preferably somewhat local - as shipping will hurt a bit I imagine. Im not 100% on following this path yet, but am quite keen to make sure I research this properly.

[Joker]

are ya after a parts motor or a working donar?

[Munkvy]

 JoKer said:

are ya after a parts motor or a working donar?

complete motor, well except for manifolds - dont need them.

[SubLeggy]

ive got a v4 sti long block sitting in my shed. i ran it in my rs when i had it. it ran on a rs manifold and rs injectors. its done 98,xxxkms. on the down side its got a leak comeing from the rocker cover gasket seals. there was no knocks etc comeing from the engine when i had it running. am located in the wgtn area if you might be interested.

[Munkvy]

 SubLeggy said:

ive got a v4 sti long block sitting in my shed. i ran it in my rs when i had it. it ran on a rs manifold and rs injectors. its done 98,xxxkms. on the down side its got a leak comeing from the rocker cover gasket seals. there was no knocks etc comeing from the engine when i had it running. am located in the wgtn area if you might be interested.

You have PM

[Shale]

V4 definitely a gruntier choice by far, rather than the v1/v2 which IIRC are a hoik'n'toss straight in. We re-used the BF5 loom from under the manifold in my car, rather than what came with my V2 WRX engine. No issues aside from coils being antisocial...definitely a more robust EJ20G...and with added balls for sure.

V4 needs some rewiring IIRC as it thinks it's a 3-plug driven monster.

[wildturkey]

 Munkvy said:

Im getting sick of the issues I keep having with my old BC5 factory motor, so considering swapping in a WRX motor.

From what I can gather searching here and RSLC my best bet is V1/2 WRX correct? And thats a straight swap, except for needing to swap some of the BC5 sensors onto the WRX engine?

And if I was to go for a V3/4 engine, I would need to swap manifolds - correct? Ie the looms are sufficiently different to no longer make it a bolt in job?

Next, how much advantage is there between the generations of engines? Ie whats the major differences between V1/2 WRX over BC5 and whats the advantage of V3/4 over these? I assume its heads and cams are improved in each generation from what I have read. I am aware of the closed deck vs open situation. Can anyone expand on the other differences for me?

And, finally - has anyone got an engine to suit? Preferably somewhat local - as shipping will hurt a bit I imagine. Im not 100% on following this path yet, but am quite keen to make sure I research this properly.

what issues u got with ur factory mota?

[Munkvy]

Currently its not starting and havent worked out why - but it could be any of a number of things. But Ive had several leak problems, and the factory heads arent great for flow/reliability/power so a good time to replace them anyway.

[Shale]

You're not in AKL eh - I know where to get well-priced 20Gs that come with a start-up warranty, and are tested for the usual dopey stuff like refusing to start, epic leaks and BEB.

+1 just biff the damn thing and start fresh with a slightly more ballsy motor that's not so keen on misbehaviour.

[BC5RA]

Advantages over the RS engine are widely known, with the heads being much heavier (due to valve train componentry) and needing shorter maintenance intervals (blockage of tiny oil gallerys = noisy lifters)

The pick of the earlier generation EJ20G's would be the STI RA engine; they were the first to get under bucket solid lifters.

The differences between V4 WRX and V4 STI shortblocks are the obvious uprated internals, however the heads share the same Valve port and size, but different cam profiles and the WRX heads being shim over and the STI heads shim under, this also applies to V3 STI and WRX with the difference to V4 being shim over bucket on both heads.

Basically use the bottom only up until MY98 bolt on your ancillaries and turn key.

[Munkvy]

 BC5RA said:

Advantages over the RS engine are widely known, with the heads being much heavier (due to valve train componentry) and needing shorter maintenance intervals (blockage of tiny oil gallerys = noisy lifters)

The pick of the earlier generation EJ20G's would be the STI RA engine; they were the first to get under bucket solid lifters.

The differences between V4 WRX and V4 STI shortblocks are the obvious uprated internals, however the heads share the same Valve port and size, but different cam profiles and the WRX heads being shim over and the STI heads shim under, this also applies to V3 STI and WRX with the difference to V4 being shim over bucket on both heads.

Basically use the bottom only up until MY98 bolt on your ancillaries and turn key.

Thanks, that was the sorta info I needed to know Any more info?

[BC5RA]

What specifically?

[Munkvy]

How do the RS heads differ from V1/2 WRX and STi heads?

[Guest boostcut]

v1/2 wrx heads are a rs head im sure, they both look identical side by side.

v1/2 sti has solid buckets too. if i was you. id be doing a v3/4 rebuild and just re-wire to suit. a bit of a hassle but sweet when its not your daily?

[Munkvy]

 boostcut said:

v1/2 wrx heads are a rs head im sure, they both look identical side by side.

v1/2 sti has solid buckets too. if i was you. id be doing a v3/4 rebuild and just re-wire to suit. a bit of a hassle but sweet when its not your daily?

Trouble is the cars already been off the road since Targa Rotorua! So yeah, need to get out there and competing to give the sponsors exposure etc. That and I need to stop entering the GTB in events - as Im slowly killing it.

Good to know regarding heads thanks. I will look at the budget with the co-driver and see what we can do. We think we have found whats wrong with the engine - so assuming thats sorted easily and cheaply we will chuck it on the dyno and see what happens. If its still not delivering the goods I will look to sourcing a V3/4 engine and putting RS manifolds on it most likely.

[Guest keltik]

save up 2k and slam that ez30r off trademe in it

Will solve your engine reliablity issues for a long time

[Munkvy]

 keltik said:

save up 2k and slam that ez30r off trademe in it

Will solve your engine reliablity issues for a long time

And also chuck me out of any class for rally cars But yeah, not a stupid idea as a way to improve reliability I agree!

[Guest keltik]

really no class for under 3000cc non turbo? dont know anything about rally....or motorsport in general to be honest

[Munkvy]

National level class is only 4WD turbo - maximum of 2L. There is also an Open class at National level and thats still 2L maximum from memory? Infact as its a national series Im pretty sure the cars have to run as per FIA homologation for the car - so 2L Turbo. But the open class you can run a bigger restrictor and less weight etc.

All the regulations I have seen for smaller scale events (ie local rallies - rather than national status ones) have just listed a Pre 96 4WD class and open 4WD. The assumption always seems to be that cars entered will be based on 4WD 2L turbo. I dont know if they would let you run in something with a 3L! However, for other events - ie hillclimbs, track days, sprints etc there wouldnt be an issue.

I did see a Leone on Trademe with an EJ25 (N/A) in it. Not sure that it would be that competitive, but a bit different at least and perhaps more reliable.

However, Im now going to look at the regs for the open class in the national series as you have me curious!

[Munkvy]

So sad - Friday night and Im home on the internet.

Anyway, just had a look and yeah requires the car to run the same engine as it was homologated with. So would have to run EJ20 still. Not really that relevant as I would never enter it into that level of competition (Im short about $100-150k to be able to do that!). But a clear example of the intent of the rules.

However it would make for a fun car with a 6 in it.

[BC5RA]

 boostcut']

v1/2 wrx heads are a rs head im sure, they both look identical side by side.

v1/2 sti has solid buckets too. if i was you. id be doing a v3/4 rebuild and just re-wire to suit. a bit of a hassle but sweet when its not your daily?

[quote name='Munkvy said:

How do the RS heads differ from V1/2 WRX and STi heads?

Not true. WRX heads had 1 bolt coil pack RS heads have 2 bolt coil pack.

These were offered in the Australian domestic market as a Factory conversion as a cure for noisy lifters that the RS heads are known for.

RS vs V1/V2 WRX heads the differences are as follows, RS use a rocker from the cam to the valve, WRX heads cams operate directly onto the valve. Both heads are Hydraulic lifter type.

The oil galleries have been modified to suit.

I believe the V2 STI heads are not much different from standard WRX heads with perhaps different cam profiles, as already stated STI RA heads are the pick.

[Guest loren]

From reading over at seabright, it seem the regs are designed to prevent anyone

beating the WRC teams and the like. It wouldn't be hard to build a race car that

consistently beats a WRC car, but they don't want that.

 Munkvy said:

National level class is only 4WD turbo - maximum of 2L. There is also an Open class at National level and thats still 2L maximum from memory? Infact as its a national series Im pretty sure the cars have to run as per FIA homologation for the car - so 2L Turbo. But the open class you can run a bigger restrictor and less weight etc.

All the regulations I have seen for smaller scale events (ie local rallies - rather than national status ones) have just listed a Pre 96 4WD class and open 4WD. The assumption always seems to be that cars entered will be based on 4WD 2L turbo. I dont know if they would let you run in something with a 3L! However, for other events - ie hillclimbs, track days, sprints etc there wouldnt be an issue.

I did see a Leone on Trademe with an EJ25 (N/A) in it. Not sure that it would be that competitive, but a bit different at least and perhaps more reliable.

However, Im now going to look at the regs for the open class in the national series as you have me curious!