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Set about gutting the pre-cats today, found on first few attempts that long drills and sharp chissels etc was quite an effort, after digging around and realising that woodwork wasnt happening, I tried my 10 mm sds auger bit
It made it like ice cream.... first one actually over heated warped itself out and snapped like toffee, used chisels to finish that cat off,
Second cat took about 30 mins to clear out.....
I used an 18mm auger bits, keeping it cool between blasting through the guts of it.... some piccys attached .. quite pleased with result ....

thanks for posting i'm doing mine and a most other work in april

Hey Rolskii, did you keep the downpipe upside down whilst you removed the pre-cat material?

Cheers, Nige.

Is there any sensors on the pre-cats? can you remove them? or if you put it back no problems with the ECU? and need a special remap?


Cheers,


( I know by doing this you have the same results as with a sport cat!! and it is far cheaper!!)

@ Nige...... no .... now tell me I was supposed too .....

.... did think about putting some compressed air backwards to clear more sh1t out... like i said .... did think ....

quattrosteph - Lambda sensors but removed to get the cats off anyway,

Yea, I would be inclined to do it upside down to stop any crap clogging up the main cat.... BUT... I fancy making some de-cat pipes for the main cat too, so If I did those first that would be nice and easy......

Good job on the pics by the way!!

Rolskii, hi.

Now that you've carried this mod out, what are the effects ? Does the car feel different at say low, mid or high rev range ?

If this mod proves useful, I can see a few tuners offering the work alongside their other products, (MRC Remapping etc).

Let us know what you feel about the results.

Regards,
rsdreamer.

Hi rsdreamer,

Not sure that I will be able to do that as a initial increase, they are not fitted yet, i was planning on doing it when i pull the lump out, heads,k04's,sound manifolds,ic's etc..
but i did think about as its got an MTM chip and milltek, seems alot of hassle as i have no ramp and doing above work soon anyway ..... let the sun shine i say....

As soon as i fit them (first its brakes & suspension ) i will let you know the results

cheers
David

why not use hss bits that are use for drilling steel .they wont heat as bad . you can get them with a stepped shank to fit 1/2"chucks

The mod allows much more quicker spool etc I think. I'm haivn gmine done by MRC next Monday. It is a relatively well known mod.

Just to add.... these are rs4 down pipes, which are 400 cell pre-cats, after talking to Minhea, he told me they are a right pig to do, due to it being 400 cell cats, not s4=200 cell cats in downpipes.

I would definately recommend using some auger bits, they just bore into the guts, clearing the destroyed debri as quickly as it can cut.... which wasnt slow .....
keep your auger bit from overheating, you may even get 1x18mm a/bit to do both pipes, but have some long chisels or v.sharp instrument to break down the remanence left between holes, make sure your drill is up to it .. or you may burn the armature/clutch on it.
Go see your local HSS hire ..... its not yours if it goes pop then(I used my own.. )

Is it put back on the car now? If yes how is it ? Loud......and f.....ing fast!!?

Not Yet... gonna get a new y-pipe from milltek b4 it goes together ...
I am waiting for TartanRob's post on his work... have you posted Rob...??

miltek to y pipes?

What they like mate?

When youve put it backon the car let us know what its like mate especially sound wise. Does it make a lot of difference to standard miltek?

Cheers

Okay dude,
I should do it this week, need to get a couple of lambda sensor blanks, as rs4 d/pipes have provision for 2 on each,
anyone know where i can source some, or shall I just get a couple of dissed ones and use them.... rather blank's in there..?
The issue as it stands is all i got to add to the s4 milltek system is an extension to compensate for the rs4 n/s d/pipe not being as long as the s4 n/s d/pipe,
dont know the exact length yet, the o/s is same length and diameter(60mm external) -
also Milltek has got welded reducers on ends of system that mate to downpipes, so its a simple insert of pipe, it needs some new clamps on anyway, plus I am gonna use the rs4 clamp to go over the extra piece i am inserting on d/pipe end, normal clamps on the milltek reduced pipes arent to clever ...... so should'nt be too bad....
I will post it when I do it, from that I will decide what I am doing, whether to get a correct y-pipe made up from milltek /+ 3"test pipe ...
But I tapped my mate up with workshop, so its possible... sod doing it any other way ....