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D2 - Engine Bay Everything under the bonnet

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  #11  
Old 23rd February 2020, 07:09 PM
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Goran Goran is offline
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This JHM video seems to indicate you could be better off upgrading headers etc to get the best all N/A power out of it, vs adding weight with supercharger.
Both routes are quite expensive I imagine. I looked into well made long tube headers and the cost seems to be in the region of £2.5k minimum.
Personally I think its not worth it, unless you know someone or are a really good mechanic / welder and can make/install/test things yourself.
If you want a faster car best to buy something with bigger engine and lighter.

https://www.youtube.com/watch?v=3n7xVwjWWD0
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  #12  
Old 23rd February 2020, 10:08 PM
Audifan Audifan is offline
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Originally Posted by MikkiJayne View Post
Yeah the M90 is an odd choice for the 4.2. I just found that out the other day and was surprised they didn't use the M112. I assumed that since they were just going for very light pressure boost (5psi I think) that the M90 was enough. Personally, I'd just spin the M112 slower.

I picked up an S4 TVS supercharger the other day to have a play with that on the V8 but unfortunately it is far too short. I was working on the same theory as PES used I think - the TVS can make 500hp on a 3.0, so it should make 500hp on a 4.2 right? Problem is, its so short it would need to sit on such a big spacer it would poke out of the bonnet / hood. Not a good look for a D2 Plus, being designed for an FSI engine, the TVS is far too wide for the port-injected engines anyway so it'll probably just be office art!

The Jaguar / Range Rover M112 is probably the best one to use, sitting in the V with a chargecooler on the top. Loads of custom fab work though, and the big Eatons are expensive over here. Too expensive to buy on a whim just to see anyway. A screw charger from an AMG would be even better, but they are silly money. Maybe when all my other projects are done
Yeah it's for sure a odd choice.

One thing I noticed between the G4 kit for the C5 S6/D2 S8 versus the B6/B7 S4 is that the supercharger unit has a long nose on the C5 S6/D2 S8 versus the short nose on the B6/B7 supercharger. So there is some room to put a larger supercharger unit and just need to use a shorter nose to make up the difference in the length.
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  #13  
Old 23rd February 2020, 10:11 PM
Audifan Audifan is offline
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Quote:
Originally Posted by Goran View Post
......If you want a faster car best to buy something with bigger engine and lighter.
Yeah it's usually what people say and yes I could've done that but what's the fun in that
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  #14  
Old 24th February 2020, 11:19 AM
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Goran Goran is offline
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Its the standard argument people have used on me, I guess I started to believe it too

It is fun to tinker, and the D2 is a very unique large car, it is cool to have a ultra fast large car. I wish you luck and hope you achieve your dream.

In my opinion the first thing I would do is convert it to manual. That is the biggest single gain. By book values it will accelerate over 1sec faster, 5.2s to 62mph vs 6.4s auto. Also it loses 100kg.
You could even convert it to the newer S4 manual gearbox (I think its code is 0A3?), Dave on here has done that, you save another 10kg over the stock manual, and get smoother shifts and better gearing.

Then you could do a ton of other weight savings some of which are not too expensive others can cost a lot.

Lithium battery saves 20kg
Audi TT MK 1 front seats save 40kg
OZ Ultralegarra wheels save around 22kg over stock 18" wheels (for 5 wheels)
JHM lightweight brake discs save around 14kg if you change fronts and rears
Removing a few other bits like electric sun blind, SAI motor, heated windscreen controller, etc, saves around another 10kg
Custom exhaust with sport cats can save 10kg or more. If you have crazy money you could get a full titanium or inconel exhaust and save even more weight and get some performance gain.

Then on that foundation add the engine mods to your taste, and it should be very fast.

All that together is over 100kg and should get the car weight down to around 1650kg which is impressive for such a large car, and keeps it looking almost factory standard with minimum loss of comfort.

Last edited by Goran; 24th February 2020 at 11:32 AM.
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  #15  
Old 28th February 2020, 12:40 AM
Audifan Audifan is offline
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Yeah it's always easier to say just buy a different car if you want to make tons of power.

Well my car has already have been put on a diet before I purchased it with a manual transmission swapped in. I've read some where that the 01E 6 speed is 150 pounds lighter then the automatic transmission. Also the exhaust has been changed prior to my ownership so there is a little weight savings there.

One upgrade that I have waiting to do to my car is installing new set of wheels that I bought. I did take out the full size spare as the tire was junk and the wheel was out of round.
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  #16  
Old 9th March 2020, 07:44 PM
Audifan Audifan is offline
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I did some more searching about doing a twin turbo setup and came across this post where the heat from the turbos was causing all kinds of problems so my question is there a way to get air flow to the turbos to help reduce overheating problems? Also while searching, I found that there was a twin turbo diesel V8 available. Are these turbos located in the same location like the C5 RS6? If so, what did Audi do to combat the heat problems from the turbos?
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  #17  
Old 9th March 2020, 08:09 PM
MikkiJayne MikkiJayne is offline
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Thats some nasty hack manual swap to still have all the auto solenoids and the TCU

The heat damage is not surprising - its the same sort of issue Martin had with his RS8, due to the engine bay being smaller because of the bulkier superstructure. Less airflow means the heat stays put. It would probably need everything in the exhaust flow to be ceramic coated and then well shielded back there to stop cooking everything.

Annoying that the only pic of the turbos is too blurred to see anything - it would have been interesting to see those since it's still using the original manifolds rather than the RS6 ones.

The 3.3 TDI had its turbos back there too, but diesels burn cooler than petrols (stock ones anyway) plus they had a lot of heat shielding.
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  #18  
Old 9th March 2020, 08:32 PM
Audifan Audifan is offline
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Interesting, since my car had a manual transmission swapped in, I wonder if the auto solenoids and TCU were removed? Where are the solenoids and TCU located? So I can see if they were removed from my car.

Will coating the turbo with a coating like this and installing a turbo heat shield blank like this be enough to prevent cooking everything?

Interesting, I didn't know that diesels burn cooler then petrols
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  #19  
Old 9th March 2020, 09:15 PM
MikkiJayne MikkiJayne is offline
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The TCU lives in the electronics box with the ECU. The solenoids are part of the transmission valve body.

Yes, that sort of coating on manifolds, turbine housing, possibly downpipes. A turbo blanket might also help, plus I was thinking of metallic shields bolted to everything with air gaps in between.

Diesel burns slower and cooler than petrol / gasoline, although add turbos to either engine and they can get very toasty. Stock for stock though, a diesel engine tends to be cooler and has less thermal management hardware. My A6 TDI will cool down to about 60 degrees if it just sits there idling, and takes forever to warm up in the winter.
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  #20  
Old 9th March 2020, 11:03 PM
Audifan Audifan is offline
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When I get a chance too, I'll take a look in the electronics box to see if the TCU has been removed. If for some odd reason the solenoids were left on my car, what side of the car would they be so I can take a look?

Would it be possible to add some ducting to help direct airflow to the area where the turbos are located to help with cooling?

Interesting.
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