1.8T AGU custom 3" exhaust from turbo back? Decent gains?

[Stanley]

I have an A3 with generic remap and CAI and hopefully soon a FMIC.

Im looking to have a custom exhaust made up to release a few more donkeys too.

I have a friend who can do the whole system in 3" for sub £200.....

As with turbo'd cars needing as little back pressure as possible, im looking to get a 3" system from the turbo back with as little restriction as i can get away with.

If i ran no silencers at all, would it be deafeningly loud?

Im not keen on a chavvy sounding exhaust, but if its faster then thats fine!

Any opinions/suggestions would be grand.

As usual handjobs/fingering for sensible answers.

 

[Broken Byzan]

will make very little difference to actual power at standard tunes.

 

[Welly]

will make very little difference to actual power at standard tunes.

He said it's mapped dude I think.

Anyway, a downpipe always a good mod on a mapped car, solely because the downpipes are ridiculously restrictive in OEM form.

Not sure on the volume, but running with no silencers at all I suspect it would be just that.

 

[Broken Byzan]

Still the original DP is hardly gonna make that much resrtiction on the std blower.

I have a bee in my bonnet on the thing where exhausts add 10-15 bhp, air filter 5 bhp, special plastic coated spark plugs 3 bhp, etc etc IRL it's not true and lots of end users are not best impressed.

I spose i was a bit short, but the long and short of it is, for £200 it's a good price, don't expect huge gains is all

 

[Stanley]

Im not expecting the car to be a supercar due to having a large exhaust fitted in any way shape or form.

Basically it cant do any harm.

As said the standard downpipe is very restrictive so its a good place to start for freeing up a few ponies.

Thanks for the replies.

 

[Welly]

I have a bee in my bonnet on the thing where exhausts add 10-15 bhp, air filter 5 bhp, special plastic coated spark plugs 3 bhp, etc etc IRL it's not true and lots of end users are not best impressed.

Oh, with you completely, 15 BHP from an exhaust.... not gonna happen in reality.

The OEM kit is gash though, and the 3" variant will greatly help spool, and aids the already small turbo with producing boost for that little bit longer.

 

[Broken Byzan]

I hear ya mate. spool will be better, but i would expect max power to be moved up the rev range where the poor turbo has ran out of puff. WIll prob sound the ****** tho...

By the mod addition table i recon i must have abot 400BHP,lol

 

[Welly]

By the mod addition table i recon i must have abot 400BHP,lol

No, no, no. 4000 BHP.

 

[s3dave]

Faster out Faster in......

 

[Welly]

Faster out Faster in......

....says my missus.... *cough*

Sorry to lower the tone there, I simply couldn't help it. :thumbsup:

 

[Stanley]

Ive noticed that my AGU really tails off higher up the rev range, so anything to help this will be welcome.

Going to go for a hidden tailpipe too so's not to attract Saxos.

 

[Welly]

Ive noticed that my AGU really tails off higher up the rev range, so anything to help this will be welcome

This happens on AGUs more than the other engines. The reason is that the AGUs have a large port head. They consume more air flow than the later versions' small port heads due to inlet port size.

A downpipe won't aid this greatly, and the K03 turbo simply cannot more enough air to keep the pressure up. This is why you see a drop to 10 PSI or less probably at the top end of the revs.

Going to go for a hidden tailpipe too so's not to attract Saxos.

Hmmmm, but Saxo bashing is just sooooooo much fun....

 

[DaveA3]

im getting my cat back on the 4th with just the 1 silencer so may be able to give you a rough idea although im going for 2.75 or 2.5 inch not decided yet. will have a decat in the new year. might be too late by then but ill put a post up either way with my results.

 

[Stanley]

Mehh..

Even if the gains are small, its more shiny bits under my belt.

And if it sounds horrific, ill buy ear plugs.

 

[A3Tom]

I had 2 boxes put in mine...it was too boomy under low rev load for my liking. 1 massive box at the back and one in the middle...happy days.

No silencers will sound crappola

 

[rob_sri]

want the biggest boxes at the back furthest from the engine for the better note and tbh you should feel a gain especially with a decat system

 

[Stanley]

So a 3" system all the back to a large muffler/silencer on the tail end of the system would work best you reckon?

Going to do this and ive also just got a FMIC for it too. Will set about removing parts tomorrow....

 

[rob_sri]

yeah depends on the volume you're after.. if not squeeze another box at the end of the system

 

[DaveA3]

i heard 3" would sound too boomy regardless and that 2.75 or 2.5 is better? dunno the truth behind that though

 

[JBS Sales]

Unless you are looking to run above 400bhp a full 3" system is not really required. I would personally use a 3" downpipe leading to a 2.5" cat back system.

We currently have some bargain offers on the Milltek cat back exhausts which offer great flow and would be definately more suited to running a K03 than a 3" system.
Milltek Non-Resonated Cat-Back with Twin 76mm Tail Pipes - JBS

If you have any further questions or queries please do not hesitate to give me a shout on 01246 455 005.

Seb Hampson
Parts/Sales Advisor

 

[S3 Paul]

So... We all say we need 3 inch down pipes and a good free flow exhaust...
Have all read threads about the REAL gains of a good free flowing air filter...
However, Mark (Byzan A4) has just said its all rubbish,
Anybody want to buy my Miltek? Green cotton? 3 inch down pipe? Front mount?
Dont need any of them now ive seen the light !

 

[s3dave]

So... We all say we need 3 inch down pipes and a good free flow exhaust...
Have all read threads about the REAL gains of a good free flowing air filter...
However, Mark (Byzan A4) has just said its all rubbish,
Anybody want to buy my Miltek? Green cotton? 3 inch down pipe? Front mount?
Dont need any of them now ive seen the light !

????
The faster you can get it out the faster you can suck it in on turbo cars........End of....

 

[S3 Paul]

I know dave,
Was just a joke,
Yes each mod can not realy have a bolt on gain number on the box,
We all know which bits hold our cars back, Sorting each of these problems moves the power possible up until you hit the next bottle neck and so on ...
We used to call it tuning syndrom years ago...constant upgrades as one mod highlights the problem of another...
The more that can get in faster and colder CAN make more power aslong as the resulting waste gas's and heat can get out of the way,
Rather than a bolt on direct gain figure its more of say what power can be realised without said bottle neck.
Stage one ... remap with new DV and a panel filter
Stage two... Free flowing exhaust ( Down pipe and cat/decat if funds allow) new TIP
Stage three... 3 inch down pipe with sports cat ot decat a FMIC and if you want to stay bolt on... hybrid turbo with uprated fueling,

The mods at each stage to me didnt have a gain figure each, More of things idealy needed to acheive the best results at each stage without compromise.

Sorry for droaning on. We are sat here at work waiting to be allowed to shut down for christmas