Piggies - Loud or not?

[pilla]

Evening all. Looking to gut the pre-cats on the stock downpipes and use the non-fouler inserts but cant seem to find any videos on the web of a stock system with the pre-cats gutted. Unsure if its going to sound boomy or crap. Im only interested in that specific noise that the top end aftermarket exhaust systems produce and not the boomy, crappy, loud sound that the cheap versions produce. Can anybody advise?

Also i cant seem to find non-foulers in the UK. Would a o2 riser/boss work instead or does it have to be non-foulers specifically? My welder is knackered and i would like to do it this way until i get a new one.

Thanks guys.

 

[aragorn]

Forget the defoulers. If your car has rear lambdas, get them mapped out.

If its a 1998 car as per your sig you wont have any rear lambdas and can do whatever you like to the cats without issue.

The primary lambdas (which is all a '98 car has) must remain in place as per the factory location, they are used for fuelling corrections.

The usual piggy pipe mod keeps the secondary cats in place, and the noise increase will be minimal.

Even with a full decat it'll remain pretty quiet on the stock exhaust.

 

[pilla]

Yeh its registered august 99 but logbook says declared manufactured october 1998. It started life on an irish plate AKZ 8799 according to the service book. The dvla also cocked the vin up aswell on the v5. It states WAO2228DZXA037367 on the v5 but the service book and vehicle states WAUZZZ8DZXA037367 - Its been like that for last 16 years so didnt wanna mess about with DVLA in case they pulled it in for a check or something.

Anyway thanks again aragorn. I'll update this when the new exhaust sleeves arrive and i get stuck in.

 

[aragorn]

yeh they only fitted the second pair of lambdas in 2000> cars so you've no worries.

 

[pilla]

Not a good day. Neighbours coil spring snaps so i promised to fix that when the part arrives. In-laws starter motor loom has fell to bits on his crappy mazda somi promised to do that aswell. Thinking to myself "my car is running good. Im happy, gonna go home and gut the downpipes seeing as the new exhaust sleeves have arrived."

So i get all my gear out. Tools, jack, axle stands, pop the bonnet to start the task and low and behold, my header tank seems murky. So i unscrew the cap and yes, you guessed it, its chocolate milkshake time.

Now it seems to run ok albeit its felt a bit shy on power last few weeks but i put that down to a n75 fault on vag self test.

Sump oil and oil filler cap show no signs of mixing. Oil is nice and brown... ish!

Any ideas? Few threads say oil cooler but this has put me off bigtime, just when i was about to begin modding. I checked the fluids last week all was fine. Have been pottering about in it since, no abuse at all.

 

[aragorn]

coolant issues in the S4 are rare. The oil cooler is about the only part that i've heard failing, and even then its mostly on 1.8's rather than the 2.7.

Are you sure its oil? the red coolant sometimes looks a weird brown color, especially when looking thru an old reservoir thats gone all yellowed. suck some out and see.

 

[pilla]

Ive just took it on a good boot round the industrial estate and its running great. No smoke. No abnormal noises. Checked oil and filler cap on return. All clean. Header tank is literally black. Its a new tank aswell. I will put laptop on now and put a pic up. Its a thick film of oil on top of the coolant. Coolants all still there. Once it cools down in half an hour i will open the cap back up and see how much more has gone in there.

 

[aragorn]

yeh, probably the oil cooler then. You can probably bypass it and change the coolant and see if thats cured it? If so you know to replace the cooler.

 

[pilla]

Yes, I will bypass the cooler and flush the coolant see what happens, do you know where theres a decent guide for it kev, i had a search and alls i could find was sketchy stuff from over the pond.

 

[pilla]

Think i got the drift, (not bypassed one before) I just join the 2 coolant hoses together and monitor the outlets for oil leakage? Also i think theres an oil cooler on a 2.8 A6 quattro in the local breakers, Im assuming that would be a straight swap? Thanks Kev!

 

[aragorn]

yeh just join the pipes and see what happens.

The cooler is differnet on early V6's between the S4 and NA engines.

from chassis "Y" onwards, the S4 switched to using the same cooler as the NA engines, but i believe the coolant hoses changed at the same time, as did the threaded fitting into the oil pump housing.

 

[pilla]

Righto, Ive took the undertray and fron bumper off and had a look, seems a bit tight for space but i think i can manage it, emptied the header tank and gave it a quick rinse out with some soap powder so i can see the water level again, had to throw it half back together for the school run, should be fun with no bumper or headlight fitted. Will update later on. Fingers crossed.

 

[pilla]

Fitted the headlight for the school run, good job i did because police were outside the school. Anyway, by-passed the oil cooler, what a pain in the **** that is, no space at all. Low and behold the oil cooler is ******* oil out. What do you reckon Kev, cap off the outlets and let it fill with oil?

 

[aragorn]

I wouldnt advise that, given engine oil pressure can exceed 5 bar, when it does fill up its a lot of pressure to be contained somewhere that it shouldnt be.

Needs replaced!

 

[pilla]

Just made some nice bungs aswell from a mazda 3 wishbone balljoint end! I wont use it then till i get a new cooler. Cheers mate

Any idea where i can get a half decent cooler for not too much money ! The febi ones on ebay state "from 8DY 000 001 only"

 

[aragorn]

is your chassis number pre-Y?

 

[pilla]

WAUZZZ8DZXA037367

Thats mine, im not thinking straight, mine is post Y, so obviously its gonna fit, ? think i need a pint after today.

Im confused, I dont know if mine is post or pre Y now.

 

[aragorn]

yours is X, not Y.

 

[aragorn]

028117021D is the original cooler.

 

[aragorn]

if you want to use the newer type, you need a few of the water hoses, including the metal hardpipe that runs across the front of the engine AFAIK.

 

[pilla]

right, theres two of those on ebay, genuine old audi stock, I noticed that on these older ones, one of the 2 holes is plugged, whereas on later ones, both holes are open. They are listed for a golf diesel, would you take a quick look kev, just want to be absoloutely sure before i order it. Thanks.

http://www.ebay.co.uk/itm/NEW-GENUI...sh=item5d646b08ce:g:G3AAAOSw2x1XLFBV#shpCntId

http://www.ebay.co.uk/itm/Audi-Oil-...292308?hash=item3f64cffe54:g:t~sAAOSwNphWYFNF

I'll pull it all apart tomorrow from the top and have a look at the part number just to be sure, might aswell do the downpipes tomorrow aswell

 

[aragorn]

thats the right part

 

[pilla]

Oil cooler will be here tomorrow, until then, I re-fitted it all as it should, so i can use the car to do the school run. Oil level is good, as is coolant, just slight mixing, luckily only one way. Seems the water is holding the oil in, because it was p*ssing out with the coolant jacket bypassed. Managed to get the downpipes off and gut them aswell, whoever had been here before me forgot to tighten the bolts on the n/s transmission mount up, managed to wiggle the o/s dowpipe out without removing the mount, good job, because it looked like a right mare to get at. 2 new exhaust sleeves and a shed load of fire putty later and we have good seal, although i think one of my flexi joints is on its way, still holding though! Took about 12 hours to do and those heatshields are an absoloute pain in the ****, they got left off, much easier without them.

End result: Definitely more kick when the turbos hit, and also more punch after changing gear.

Few pics for reference.

 

[aragorn]

the sheilds are there so you dont set fire to the wiring and hoses at the back of the engine Turbos get HOT.

 

[pilla]

Ive zip tied all the wires right out the way but what i'll do is chop the bottom half of the shields off. I should be able to fit them from the top then.

 

[aragorn]

aye, just refit the top half that covers the turbine housing.

 

[pilla]

Chopped em, managed to squeeze them in from the top, also fitted the new oil cooler and flushed system a few times, much better now, old one was the original, so it lasted the best part of 18 years, thanks for the info Kev, very helpful.