Jay A3 's 1.8T On-Going Build Thread

Jay A3

#because Racecar
Thanks for the pics buggy. Not exactly what i wanted to see...
I will go on the hunt for a better housing

Jay A3

#because Racecar
Time to add something to the progress thread i think... Been 2 weeks before i have written anything!

I have had the fmic setup in my house for the last few weeks. Still packed in boxes. Decided to take it all out last night and put it together to see i have everything covered. (Help from prawn and Reesy) All i needed to account for was the welding of 2 additional pipes for the N75 and DV.

Im not one to just jump in head first without doing the research so i have created the following diagrams to show you how i plan the install...

Going to fit this in the next few weeks so just wanting to make sure all is covered...
If you see anything i need to amend or change - any advice is greatly appreciated!
(please remember this is for the 1.8t FWD and similar to the A3 quattro - main difference is the quattro requires the map sensor pipe)

Full setup

Hotside setup

45 degree pipe that requires welding

Thanks Again!
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Jay A3

#because Racecar
I think the time between posts in my thread seem to be getting longer and longer!

Another update...
Finally got the FMIC fitted, took a little longer than expected as i was ordering pipe after pipe after pipe to get the intercooler fitted as tightly as i could. Constantly pm'ing and texting Prawn and Reesy with questions... Thanks guys!
the OEM hose was starting to split. Trying to force a 63mm alloy pipe into a 57mm hose wasnt secure enough! I learnt that the hard way (popped off while driving on the motor way)


Eventually all pipes fitted and i managed to keep the fog lights, only need to now dremmel away at the fog light covers...

Also in the post came the air vent pod and Turbo smart boost gauge
Decided to fit this in and wired it into the dimmer switch as someone warned me that the gauge can be a little bright at night.


Next step is trying to find a place that will supply and fit a 2.5" cat back system
Any suggestions for an A3? Anything but Miltek as they are a little pricey for me...

Jay A3

#because Racecar
Just got back from giving the old girl a road test... The piper cross panel filter defo works better than the cold or intake pipe I had. That and the fmic the car is pulling more with better response.

I was getting between 13-14psi running an rtech stage 1 map... Does that sound right?! I think I need to invest in a Ross tech cable soon!

Jay A3

#because Racecar
Slight electrical issue... When the dimmer switch is not on maximum brightness the lights all flicker
I did post this up earlier in the week but not much feedback... Did get a suggestion to check the resistor, not exactly sure how to check this, but also wanted to know if there is anything i can check?

Here is the video of it flickering



Registered User
Where did you get your dimmer from? Some dimmers work by toggling on/off very quickly! If you have the wrong voltage dimmer or there is an LED it will show as a flicker.

Jay A3

#because Racecar
The dimmer is the standard Audi one. The little rolling switch next to the headlights... Wired it up to that... It looks it's getting inconsistent voltage. When the headlights are off the dash dials still light up but don't flicker. As soon as the headlights are on then it flickers...

Jay A3

#because Racecar
I had taken friday off work as my car was booked in for friday at AMD for a long life 2.5" cat back system. Received the call on Tuesday to say we cant do Friday now - at that moment my heart sank, i wanted to cry. Then the next few words were my glimmer of hope! We can fit you in Wednesday or Thursday? All i had to do was persuade the manager to let me switch my day off.

Result! I dropped the car off to AMD Essex at 8.30am and was told the work will be done by end of play.
So i patiently waited with the phone literally attached to my ear! Got a call at 3pm today and i thought this is it, my car is done

But sadly no, they had called to say my 3" dp is fitted, but they are having problems fitting the long life system. I thought oh no! My heart cant handle another bit of bad of news.... The silver lining reared its head again (I have been one lucky ****** so far) we will fit the milltek system instead if thats ok? I was in 2 minds as the price for milltek was not in my budget. They said we will do it for the same cost - Oh my god i wanted to jump with joy - i bit my lip and thought no, now is not the time to look like a nutcase in the middle of ikea! I casually accepted the choice :whistle2:

Got another call at 5.30pm and was told the car was ready, however we have noticed the car mis-fires when its warmed up.
Turns out it is the ignition amplifier / module that sits on the air filter box. We can change it but stock is not available until Friday. Audi require £150 or so for this. Contacted my local garage and he may have a used one from an audi he stripped a year ago. (You must be thinking "This is one lucky B*******)

Anyway enough talking:
See the results for yourselves!

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Jay A3

#because Racecar
Another successful weekend sorting out little problems.
Firstly the Dimmer switch issue.. Turns out it was the resistor itself. Now i managed to source one (Thanks to Reesy) The lad seems to hoard spares for my car.


Easy enough to change: 3 torx screws from the panel under the steering column. A couple more screws on the internal fuse area then it all pops off.

I also managed to find the spare ignition amplifier/module in the garage.


Again really easy to change over, 2 plugs to pop off by pressing the metal pins inwards and pulling away. Then its just 2 x 7mm screws. Seems to be running ok at the moment, put the snap on diagnostics machine on it and no faults. Ideally i need to vag com it just to be sure...

Question: This module seems to act as a heatsink, would it be advisable to apply some heat dispensing paste on the metal contact?

Had time so i slapped the car on the lift to get a better look at the AMD workmanship on the Miltek. Very happy with it, strong and solid.

Here some pics:



Back box


Tail pipes


moderately amusing
that exhaust is mint jay!
as an engineer, i love a good weld, especially combined with stainless steel!
al thats left to say is you jammy ******! well done mate! :sm4:

Jay A3

#because Racecar
hahaha... that was my first bit of luck for ages!
Im really chuffed with the work and how helpful AMD were. Cant fault a good bit of engineering and fitting. :icon_thumright:

Changed your mind about inters yet!?

Jay A3

#because Racecar
Just come back from picking up the misses and the dimmer switch resistor was an Epic fail... The flickering is still there, i will have to trace it back and come up with another solution... Any ideas?

Jay A3

#because Racecar
Another saturday at the garage to try and sort out a problem that recently came to light. When casually driving the boost seems to drop for a second and picks back up again causing the car to stutter. Problem is very intermittent, it may happen once or twice a week.

Couple of symptoms was the intermittent boost lost, wasn't able to boost past 5-6psi or 4k revs.

VCDs didn't pick up anything, i got in touch with someone who has the program they use at the main dealers (I cant for the life of me remember the name).

This picked up an intermittent fault pointing at the Altitude sensor. (Never crossed my mind these parts will go wrong also)
I believe these sensors are only on the AGU and other engines would have map sensors instead. I was told that the Altitude sensor controls the amount of air pressure to be mixed in the fuel (Please correct me if wrong)

Anyways i managed to find a second hand one and have put that in place - fingers crossed it has been solved.

Here is the part for reference:

Part number: 853 919 562 Bosch
TPS was charging around £95-£100


Problem was still there for another two runs to the shops, but has been fine after that!
If the issues are still there we will check the wires from that sensor to the ECU; failing that i may need to get hold of another ECU and get it re-programmed.

While there we thought better check the coil packs and plugs. We have spotted there was oil which could also contribute to the problem above. Gave it a quick clean as a temporary measure.

Since oil is getting into the plugs, we thought rocker is coming off anyway for a new gasket why not check the cam belt too!? Belt has only done 32k miles but over 5 years, we could see that its was slowly sliding off. So fitting a new cam belt kit is due within the next week or so along with the rocker cover gasket.

So as you tell, trying to get this running standard is becoming more like a money pit.


Well-Known Member
VCDS Map User
What you want to do mate is just smash in a K04 conversion.


Well-Known Member
VCDS Map User
Did some logging on Jay's car last night and it read close to 158 g/s. I will email him the files later and I'm sure he'll post them up.


Did some logging on Jay's car last night and it read close to 158 g/s. I will email him the files later and I'm sure he'll post them up.
at a mild 14psi too!

Jay A3

#because Racecar
small update...

After seeing westy and his frog green engine bay, it got me thinking...
I managed to get hold of another rocker cover and thought why not do something to dress up the engine bay a bit.
Went to my local powder coaters and got it all done in (RAL 1018)

Changed the gaskets at the same time as i had little oil going into my plugs

The cover stands out a bit nicer now, all i need now is to get the inlet mani powder coated too!

at a mild 14psi too!

14psi is good considering my car decided to have another hissy fit yesterday! Drove it home, no problems boosting as it should. Reached about a mile away from home and it started to stutter. All of a sudden i couldn't push more than 4-5 psi, which is standard actuator pressure!? nursed it home, popped the hood to check for any leaks, couldnt see anything.
Turned the engine off, then back on again and the problem was gone.... phantom boosting.....


Registered User
Looking good jay. When you get the mani done it'll really light up the engine bay :)

It sounds like your car went into soft limp mode for some reason! Have you scanned for any errors?

Jay A3

#because Racecar
Looking good jay. When you get the mani done it'll really light up the engine bay :)

It sounds like your car went into soft limp mode for some reason! Have you scanned for any errors?

I meant kermit green, not frog green!
No not got access to scan the car until saturday...
Noobie question - I could be completely wrong, but does the AGU even have a limp mode?

Jay A3

#because Racecar
Managed to get a better look at the car this weekend. Been experiencing hunting revs.
A few guys have told check for leaks; one pipe welly said was the "INLET PCV BREATHER PIPE" which was a very common fault.
i thought i would just order one and change it to be safe.

Straight forward 5 minute job
Removing the metal plate thats connected to the dip stick pipe and inlet mani
Stuck my hand round to see if i could feel anything unusual and i could feel a split.
Whipped out the pipe

Replaced it with this

Drives ok, boosting fine and hunting seems to have gone..

The car also developed another problem this week, where the turbo spooling noise was louder! Sounded like an old diesel
I thought the worst and blamed it was the turbo on its way out. Although performance was not affected (which eliminates the turbo for now) the split pipe didn't help either. Put the car on the ramp and turns out 2 DP bolts had completely come off! Found another 2 bolts to use

Anyone know of better bolts to use or is OEM ones the way forward?


oem ones jay.
are yours studs with nuts? or bolts into the turbo?
i bought k03 studs and nuts for my downpipe you see, and the nuts are pretty much designed to go on rally tight once, cant think of the name of them, but they dont spin on the thread if you know what i mean, they go on tight and stay there.
i personally wouldnt use just any old nut, it'l drive you mad if they keep coming undone


Registered User
Jay I tried bolts and they were falling out every 5 minutes. Changed to OEM studs with proper exhaust nuts and it's been fine ever since. I went a little over the top and used loctite and nordlock washers on everything.

Jay A3

#because Racecar
Thanks chaps I will look into picking up some studs and nuts this week. No dramas so far but don't fancy the bolts falling off every other day!

Jay A3

#because Racecar
Today has been a successful day!
Quick shout out to beachbuggy (Dan) for the refurb, Ben (Parson Performance) for fitting and reesy for the enjoyable company.

Dan refurbed my turbo with new seals and gave it the once over. He had also supplied me with the gaskets and studs i needed.
Earlier in the week i also picked up some new nuts for the Turbo to Downpipe, 13 manifold nuts and the manifold gasket.

Met up reesy and Ben this morning for some McDonald’s before we went to the garage. (Very nice chaps!)

Coolant was first drained and Ben nearly suffered from 1st degree burns lol luckily for him he was a very quick mover and dodged out the way...
Wasn’t long before downpipe, turbo and manifold was out

Here is the old K03: There wasn't much play in the shaft but the housing had cracks all over it

Close up

Here is the new k03s turbo (Purchased from Reesy 80k – it had done about)
Dan really did a brilliant job cleaning it up for me!



All fitted in along with the new tip and 70mm Jetex cone filter. The heat shield isn’t in yet as the cone kept slipping off the MAF.
In the earlier posts i mentioned that i have been suffering boost issues; intermittently it only boosted up to 5psi and no more.
Checked the pipes and replaced the breather pipes with the following:


I noticed that when the boost problem happens, it also cuts the engine out, turn ignition back on it works fine.. which got me thinking it could be electrical. Ben had a spare N75 valve to hand, so that went straight on. Not had an issue so far today!

Took it for a warm up lap before booting it to see how if there were any issues. Reesy kindly scanned the car and no error codes showed up.

Also pointed out is that i need to pick up two front tyres soon. Loads of tread left, but bold on the inside. I will need tracking sometime next week.

The k03s is a lot smoother than my k03 on this stage 1 map. It definitely pulls more and still has more to give. You can hear it just keep sucking in air.

Stage 2 Remap is definitely on the cards and very soon!


Registered User
Nice one mate

You portray reesy very differently to how I remember him lol ;)

Jay A3

#because Racecar
He's a good lad that Reesy and Ben too. Reesy also supplied the tunez although some of the tracks coming out do have me a little concerned about him lol


Well-Known Member
VCDS Map User
Cheers Stacey you cheeky fker!

Glad the car was better mate, definitely seemed to go a lot better then it did on the way to the garage.. Hopefully that N75 solves all your problems. Just be careful you don't get the bug and get a k04..


Certified Audi nutter
Gold Supporter
Oh balls this looks bad, think I really will end up being the slowest S3 out of our bunch :sob:

Jay A3

#because Racecar
All of a sudden the car doesn't want to play ball again. Similar boost problem has come back. One minute it's running fine, the next it's idling at 500 revs, feels like the turbo is thinking about kicking in, then it catches it back up and I have full boost! It cut out on me again when this happens. Been advised to unplug the n75 and run it like that to see if the issue comes back, if not tem its the n75. Pipes all looked ok. Any suggestions as right now I'm back to standard map...


Registered User
Bring it down at some point mate and I'll sort it for you. An n75 issue will not make it idle low, it just won't boost correctly. Unplug your maf and see if the low idle issue disappears, agu engines rely so heavily on the maf being a1.