Engine conversions for the D2

[Goran]

Its a shame it went up in flames. Yes good point about the LS block length, I was measuring up the D2 engine bay it would be tight.
If I had the money I would like to try it, I love the simplicity of those big capacity engines, all that torque and HP with no turbos or any other complicated parts.

Also I like the light weight. My D2 weighs around 1710kg now and I could lose another 10 by removing the aux heater and some other parts. Thats compared to 1865kg of a stock auto D2 4.2.
With a LS3 plus Tremec T6 RWD gearbox I would save another 8kg for the engine, another 20kg gearbox, and mabe another 10kg for front drive shafts.
That could take the weight down to around 1660kg which is not bad for such a big car.

Although D2 rear wheels might be too narrow to lay down all that torque?

[MikkiJayne]

Swap the seats for TT ones and save another 40Kg

You can get plenty of rear tyre under the D2. The rear diff is the limiting factor though, since its not designed to take the full load of whatever monster engine is up front. The RWD B5 guys often break them - first the support bracket breaks in half so they upgraded to billet. Next, they shredded the ring and pinion so cryo-treated those. After that either the casing splits in half, or the rear shafts snap.

Tbh I don't really understand RWD conversions in Audis. Just buy an E36 or E39 which are better cars than a hacked up Audi could ever be.

[Goran]

Lol I still have those TT seats in the shed. Do you want them?
I decided I can't part with the electric recaros.
You are right, if I want to try something with more hp or rwd I'll jut buy another car and leave the poor D2 alone

[MikkiJayne]

What colour are they? Project D2 Ultra needs some black ones

[Goran]

Originally Posted by MikkiJayne

What colour are they? Project D2 Ultra needs some black ones

They are black of course
I'm happy to donate them to the project.
I took one of them apart trying to figure out if there was more weight to be saved but I should have all the parts.
The leather may need a bit of care its been sat in a shed for 2.5 years

[RICKY D]

Some interesting reading guys.

Goran I echo your comments regarding the big LS lumps. There’s something really appealing about a big powerful NA American lump. I was following a thread on another forum a few years back and the guy managed to spin a bearing on his e90 m3 and went with an LS unit. It sounded immense. I never saw it complete though as the thread dried up

That got me thinking today, how easy, or hard, would it be to increase the power on the standard s8 engine without going forced induction? Is it even possible? I would love to get the power up to 400bhp, possibly manual conversion, increased Rev limit to 8k+. If I was take it to a motorsport shop could they make custom headers, different cam profiles, forged pistons etc? Imagine a higher revving, screaming S8 with a manual trans

So....can it be done? Actually as I’m typing I realise the engine already exists....well sort of the v8 in the B7 RS4. They do apparently suffer from coking up quite badly from what I hear and never make stock power figures. Hmmmm

[Goran]

I'll jump in cheekily in although MJ is the one to ask about this.

I looked into it briefly but it seems new headers would have to be one of the components upgraded to come near to 400.
JHM do headers for the B6 S4 which could be used for the D2 I guess. Looking at what they did to their S4 to get it close to 400 you would need a whole new exhaust system, sport cats or no cats, port polish, some kind of port spacer which they claim increases hp, and a really good remap. All of this would cost thousands, for a small hp gain its not really worth it especially since those crazy S4 B5 V6s can put out so much power and torque with good turbos.

Well designed headers are really expensive, and you will spend at least another £2000 on a well designed exhaust and sport cats.

Fun video , I like the music

https://www.youtube.com/watch?v=3n7xVwjWWD0

You could go here and spend probably over ten thousand on inconel headers an exhaust
Great place

https://www.primarydesigns.co.uk/exhaust-design

[MikkiJayne]

Originally Posted by RICKY D

Actually as I’m typing I realise the engine already exists....well sort of the v8 in the B7 RS4.

They work pretty well with the intake de-coked and de-flapped. I know of one being transplanted which made 420hp on the dyno after that work so exactly on spec.

The electronics though Taken out of their native home, the two ECUs are properly grumpy about missing all the modules! Its much the same challenge as using a 4.0T or 3.0T tbh, for only another 60hp. Not sure if it would be worth it? We'll probably see in a couple of weeks if this transplant behaves itself.

Re tuning the 4.2, I'm sure there is some scope for porting the heads, making better headers, high flow cats, etc. Not sure how much more you could get from cams since the S8 already has a more aggressive profile. Might be worth sending some to a cam specialist like Newman to see what they think.

Throttle bodies on it would be quite spectacular too, albeit at the expense of torque. There's the option of a supercharger too, which would probably put it in the same range as the RS4 but with less hassle. There was one advertised on Audiworld a few weeks ago.

[Adrian E]

I'm sure I've read of people using the supercharger for the original big Mini Cooper S to provide some light boost in multiple applications. Cheap as chips to buy, but as above the challenge is in getting it working without spending more money than a more powerful option (or one with greater tuning potential) in the first place....

[MikkiJayne]

The M45 on the Mini is too small for a 4.2, but it works well on 1.6 or smaller engines. It would strangle a 4.2 though.

The M62 from the early Merc 230 Kompressor is about right for a 1.8 to 2.0. I had two of them mocked up on a 3.6 Audi V8 many years ago (one feeding each side) but the belt arrangement was crazy

The M112 from Jags is the right size for the 4.2. If that could be mounted in the V with a charge cooler on top of it, similar to the Jag setup then that would be quite effective. It would be quite a lot of fabrication obviously but entirely feasible.

PES actually did a kit for the 4.2 many years ago using a standard Eaton M112, and it included a CNC'd manifold and charge cooler system, which is what was up on Audiworld a while back. I didn't have 5K spare though

If you know someone with a CNC and / or tig welder then its probably on a par cost-wise with transplanting a B7 RS4 lump. 3D printing prototype manifolds and brackets is entirely possible too, so you can mock everything up before cutting in to a few hundred £s worth of billet aluminium.

I did look at using the 3.0T blower for some light boost as it has chargecoolers built in, but being an FSI engine, the chargecoolers are right where our port injectors go so that's not going to work.

A screw charger from one of the big AMG Mercs would be pretty cool too, but those are very expensive. The M112 can be easily found on ebay for £400.