A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Fuel and Exhausts

D3 - Fuel and Exhausts Everything to do with getting fuel into the engine, and fumes back out again

Reply
 
Thread Tools Display Modes
  #1  
Old 5th February 2020, 07:16 PM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Senior Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 147
Default Feedback 4.2tdi backboxes removal findings! All good

Ok guys thought I'd give some feedback to anyone interested on what I found with tuning the D3 4.2tdi and removing its back boxes.

I got her last May after having a nasty crash in April in my 2006 A8 D3 3.0tdi after aquaplaining and the car had to be written off, tbh I felt gutted as it was my pride and joy but no one was hurt which was the main thing. Since getting my new A8 in May I had it tuned a decent tuner in Sunderland after a previous tuner diagnosed it as "already tuned" with turned out to be bs and were trying to get out of tuning it. Initially it was down on power on the dyno at 299hp/630nm and they managed to get it to 340hp/866nm ( apparently they tried to get it higher but it may have been due to carbonisation the low hp figure).

Even after getting this remap done I felt it could have more potential as I always felt it lacked that initial kick in the back sometimes. I had my exhaust backboxes removed last weekend and replaced with stainless steel straight through (still have dpfs) just as I had on my previous 3.0tdi, however the 4.2tdi now feels like a completely different car after circa 500 miles since getting it done, the difference is day and night, it's more responsive and definitely feels fast at accelerating, the exhaust tone is nice as well, no resonance at 60mph, can hear it just slightly increase in exhaust tone cruising on the motorway, under hard acceleration you can hear it and sound great. There's a few videos online on people who have had it down with the dpfs out as well and it's pretty similar.

Anyone who's got a D3 4.2tdi I'd recommend doing it as It has made the car more enjoyable to drive who would have thought those metal cans at the back made so much difference.
__________________
Jonny P
New: Audi A8 D3 2006 4.2TDI Quattro Sport
Old: Audi A8 D3 2006 3.0TDI Quattro Sport RIP
Reply With Quote
  #2  
Old 5th February 2020, 08:20 PM
snapdragon snapdragon is offline
Senior Member
 
Join Date: Nov 2011
Posts: 1,669
Default

Nice one spiderman Are you getting a popcorn limiter?
Reply With Quote
  #3  
Old 5th February 2020, 08:27 PM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Senior Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 147
Talking

As tempting as a popcorn limiter is snapdragon it might just land me with an ASBO I've heard it on a D4 tdi sound pretty brutal, the things we tinker with!
__________________
Jonny P
New: Audi A8 D3 2006 4.2TDI Quattro Sport
Old: Audi A8 D3 2006 3.0TDI Quattro Sport RIP
Reply With Quote
  #4  
Old 9th February 2020, 07:02 PM
lordchris lordchris is offline
Member
 
Join Date: Oct 2017
Posts: 64
Default

Thanks for the update.

If I can sell my w12 I will be looking at getting this done on my d3 4.2tdi.

So these are you back boxes just at the rear? Any drone ?

Did you consider an xpipe ?

Thanks
Chris
__________________
2005 A8 W12

Previous
2006 A8 4.2TDI
Reply With Quote
  #5  
Old 10th February 2020, 08:37 PM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Senior Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 147
Default

Hi Chris, just at the rear, cats and dpfs still in place(I'd love to get shot of them as well tbh), weighted the backboxes as well 14.5kg in total!

I've previously owned the D3 3.0tdi and had this done by the same company however there was an audible drone if I was honest (although tolerable) at 60mph this was over 2000rpm and overall was louder on idle.

The 4.2tdi though at 60mph no resonant drone at all, just a very faint increase in exhaust sound. If you plant the foot though you get a more aggressive tone and you can definitely tell it's a V8. It's almost Like Audi wanted to disguise that it was a V8 diesel, I think it sounds great. I would have thought getting a 4.2tdi that would be a down grade for you coming from a 6.0 w12 some beast that car! The cats and dpfs do a lot of muffling so I hear. Would an X pipe be of benefit do you reckon?
__________________
Jonny P
New: Audi A8 D3 2006 4.2TDI Quattro Sport
Old: Audi A8 D3 2006 3.0TDI Quattro Sport RIP
Reply With Quote
  #6  
Old 11th February 2020, 02:57 AM
lordchris lordchris is offline
Member
 
Join Date: Oct 2017
Posts: 64
Default

Hiya, iv had the 4.2tdi for a few years now. It has a remap and dpf gut. So itís pretty quick. In fact I would go as far as saying itís as quick as the w12. Only twice the fuel economy.

So initially I planned on keeping the w12, I only got it, but this has highlighted just how good the 4.2tdi is.

If I can sell on the w12 with no loss Iíll keep the tdi.

Alternatively if I canít sell the w12 itl be going in for new flexis and an xpipe and Iíll be in exhaust noise heaven, albeit at the expense of fuelling the beast.
__________________
2005 A8 W12

Previous
2006 A8 4.2TDI
Reply With Quote
  #7  
Old 11th February 2020, 08:22 PM
jonnypym123's Avatar
jonnypym123 jonnypym123 is offline
Senior Member
 
Join Date: Oct 2017
Location: Northumberland
Posts: 147
Default

Sounds like you've got a dilemma there Chris, or just keep both
the w12 has a load more hp however I'm guessing here the weight and less torque put it on par roughly performance wise with the 4.2tdi, it's funny how these figures work.
I watched a video of someone recently getting the backboxes off their w12, very nice indeed and sounds unique, not many w12's flying about. again another Audi that was 'muted' to some degree set it free!
__________________
Jonny P
New: Audi A8 D3 2006 4.2TDI Quattro Sport
Old: Audi A8 D3 2006 3.0TDI Quattro Sport RIP
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 05:16 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.