What mods need a remap?

[boggissimo]

Hi all,

I'm gathering bits to add a bit more power to my 2.0 WRX. It's a factory PPP so already a bit better than standard, but as ever, I want more.

Just wondered what mods can be done (by me) as the bits arrive, and wouldn't require a remap? I won't ask about the panel filter, but what about these:

1. fuel pump
2. pink injectors (thanks @Rdlangy1!)
3. headers
4. up pipe
5. down pipe
6. TMIC

It might come down to ease of access in the end, and getting a load of stuff done at the same time as it gets mapped with a VF35 would be more sensible, but would be interested to know...

[Red Baron]

I'd have thought the fuel pump and TMIC are the only things you could safely fit without a remap. I may be wrong though.

[Rdlangy1]

+1 with Shane on this one..

anything that plays with gases in and out, or amount of fuel going in (fuel pump not included) will require mapping IMO

[boggissimo]

Cool, they're probably the only things I could fit myself anyway!

[Scott.T]

What year WRX ?

[Steve_PPP]

As above, what year WRX?

If its an earlier newage, it might still have a cat in the uppipe, so check for this. If it does, change for a decat uppipe - this can be done without a remap.

The PPP will have removed the centre (3rd) cat, so you'll just have the standard Subaru downpipe cat. If you go decat downpipe and fuel pump (can do TMIC as well) plus a remap and you'll be circa 280bhp (without changing injectors/turbo).

If you're going VF35, then add the pinks and remap. Headers still not necessary at this stage but ported oem headers will help a bit

[asperformance]

with the up-pipe "pre-cat" then all new-age 2.0 WRX cars have these as std..........

no other Impreza model had them

Harvey Smith 'trick' up-pipe will help maximize the response but we do always suggest a map to get the best out of them

[boggissimo]

Thanks all. My WRX is a blob (05 reg), with the PPP. I've bought a Toyosports decat up pipe from someone on ebay.

It should be at around 270-280 bhp already with the PPP, shouldn't it?

I don't want hassle at MOT time so will keep whatever cats I need for that, but a decat downpipe has been suggested. Aiming for a safe 320ish, so I don't kill my gearbox or internals!

[asperformance]

in general most of the ebay type stuff is oversize in terms of diameter and the only thing going for it is price..........

PPP car is around 260-265 std

[Steve_PPP]

I think you'll be closer to 250bhp for a newage wrx with the PPP. They very rarely made near the 265bhp Prodrive claimed when rolling roaded.

If you need it to be MOT friendly, then you will need to keep a cat in the downpipe. Try and pick up a decent sports cat downpipe and then with VF35/pinks etc and a remap you should see 320ish.

Not seen the toyosports uppipe but if its got a larger internal diameter than standard then i'd put it back on ebay and get a genuine STI one or a harvey uppipe from Alyn. Bigger is not better with uppipes

[boggissimo]

Yeah, wouldn't be surprised if it was closer to 250, or less after 12 years and 110K miles!

The toyosports one fits the standard newage setup (2.5" I think?), so should fit OK. If not, I got it at a bargain price so can probably get my money back quite easily by selling it on.

http://www.ebay.co.uk/itm/Subaru-Tur...e/263120340283

[Steve_PPP]

I'd personally shift that on and get something better. The internal diameter of the uppipe (turbo side) will be much less than 2.5" (that's the standard exhaust size, post-downpipe). I'm not 100% sure but i think the internal diameter of the standard uppipe is around 1.7" ?

Alyn should be able to tell us what size the ID is on the harvey uppipes, you won't go wrong with one of those.

[boggissimo]

OK, well the up pipe has arrived, will measure the diameter at the ends and inside and see what it is.

Also been scouring ebay and there's a used VF43 going for £400 - is it worth £50 more over a VF35 in case I want bigger power in the future? Or am I just wasting money for a 2.0 WRX lump and 5 speed...(think i might have answered my own question)