i bought my car with the ppp already fitted and was wondering what my options were to modify the exhaust to improve the flow, but i also need it to pass mot.

i was thinking of a prodrive cat but unsure which to have fitted

 

Hi,

Sports-Cat down pipe (Prodrive one as fitted to STi PPP) and de-cat up pipe (e.g. H&S or STi) with a remap will see approx 270-280bhp with vastly improved spool, torque and fueling on that car. It will also pass an MOT or roadside spot check with ease.
Can de-cat for marginally more power but you will have emissions 'issues'.
Also as the car is PPP then you don't have the 3rd cat in your exhaust system anymore (came fitted with a straight through cat delete pipe) so you'd need to source one and then fit for MOT time.

Cheers,

Stewart.

 

Would I need a remap immediatly after fitting the Sports-Cat down pipe and de-cat up pipe?

 

Yes.
As well waiting until you've got a mapping session booked then get the bits fitted just ahead of the remap.

 

I have just done this to my WRX. STI 8 TMIC, STI decat up-pipe, Prodrive sports cat down pipe, Prodrive 3rd cat removal pipe. PFR7B plugs and green panel filter. Andy F remap car now making 281BHP/295 Ft/Lbs Torque. The driveability of the car has improved no end and the extra power and torque is excellent.

 

Where did you get the parts from?

Whos Andy F?

 

I did the same upgrade as Arch - without the STi Intercooler. Makes a big difference to the performance of the newage WRX.

I bought my PPP High Flow Cat downpipe from Ebay. Look out for the newer model with the heat shielding built into the metal of the cat area, the older ones were slimmer around the centre and had an external fluffy heat jacket.

Andy F is a highly respected (on here) ECU mapper - but of course there are other mappers.

If you replace the up-pipe with a decat one (Highly recommended) then you will have a CEL issue if removing the EGT sensor. The EGT sensor in the standard cat uppipe cannot cope with the higher temps when you remove the cat. If replaced in a decat up-pipe it will read temps too high and could possibly disintigrate.

There are several fixes for this such as mounting the EGT into the new downpipe (where temps are lower) or using a simple 2.2k Ohm resistor in place of the EGT sensor and wiring which basically fools the ECU by returning a constant reading which is within its acceptable range.

Make sure you replace the fuel pump for a Walbro 255 if you have a standard WRX fuel pump. If the WRX already has PPP then check if the pump has already been replaced. For £70ish it's a well worth safety measure to ensure that the fuelling remains constant with the increased demand after mapping.

 

Pretty much sums it up
I sourced parts on here SIDC and ebay. Just be patient and they will come up.

 

As above - and Andy is based in Port Seton. Where are you mate ?

 

I'm in south wales.

Does anyone know (or know how to find out) the Subaru part number for the 'Prodrive Sports-Cat down pipe'?

My Subaru dealer said they can't find a part without a chassis or registration number.

 

just to be sure

I need:
a straight through pipe to replace the pre cat converter.
an sti ppp front cat converter.
and a rear cat converter to fit just to pass mot.
and the a remap.

 

I'm thinking I could use the registration plate of any sti bugeye but that seems too easy.

 

PPP parts are not meant to be sold seperately by the dealers, not sure if you gave the number from a car listed as having a full kit on it if they could source one or not.

Simon

 

Surely they could get the parts induvidually, what happend if you had a cat failure through poisoning etc. You would only need the cat not the whole kit. But they might want proof that you already have the kit on your car. Like a certificate or a bill.

Jase

 

If you fit the PPP sports cat downpipe you will not need to add another cat for MOT as this single cat alone will keep you within spec for emissions.

I would say you need (using the names on the diagram for reference)

Straight through pipe to replace the Midpipe (rear catalytic converter)
Stainless exhausts manifolds headers

Straight through pipe to replace the Uppipe (Pre catalytic converter)
Stainless exhausts manifolds headers

Sports cat downpipe to replace the downpipe (front catalytic converter)
eBay.co.uk: Subaru Impreza Sports Cat (item 260130151921 end time 25-Jun-07 21:09:31 BST)
(This example is an older model with the external heat jacket - I'd recommend a newer model as in my previous post)

ScoobyBits | Online Shop - Exhausts
(scroll down to Scoobybits Downpipe with Sports Cat)

http://www.scoobyworld.co.uk/catalog...products_id=76
(See Ninja downpipe)


This will keep you legal and you will not have to mess around at MOT time.