Transplants

[welwynnick]

The Audi V10 has really caught my attention recently, for lots of good reasons. It's not too big or heavy, but has lots of cylinders, lots of capacity, lots of valves, a deep-breathing top end and a strong bottom end that withstands lots of revs and lots of torque. It's a great engine with great potential. I've been reading as much as I can about it, and that meant stumbling across information about other engines as well.

One of the ones that caught my eye was the W12 used in big Bentleys, A8's and Phaetons. It sounds like a daft configuration, but it does pack 12 cylinders and 6 litres into a small volume. Although 25kg heavier than the V10, the W12 is actually 152mm shorter and 116mm narrower. And it uses the same transmission......

What price a W12 transplant into an RS6?

Somebody's already put one into an A6:

http://engineswapdepot.com/wp-content/u ... 20x349.jpg

https://images.caricos.com/a/audi/2018_ ... 0x1440.jpg

Of course, the problem is if I want to drive something with a W12 under the bonnet, I can buy a Flying Spur for the same price as an RS6.

Nick

[corgi]

My question is why...

The W12 is, heavier than the V10, produces less power and without major work has less potential for tuning

[welwynnick]

I wasn't being serious, it was a flight an fancy.

Truth is I can hardly wait to be driving a V10 around, but I was just thinking about some of the fundamental limitations. The V10 seems to get as far as 850bhp without using ethanol, methanol or octane booster, which is very good in itself, but I wondered where you go from there.

The W12 has more capacity, more cylinders,more valves, and the surprising bit is there's more room around it. I've been thinking about options for air filters and especially water charge coolers, and they all need space. The W12 might allow a bit more of that.

Nick

[IanH755]

V10 seems to get as far as 850bhp without using ethanol, methanol or octane booster, which is very good in itself, but I wondered where you go from there.

Its the chassis thats the problem, not the engine as the chassis has very poor heat management & air flow and cooling parts are too small due to the big engine in a medium sized bay that restrict the power so much. If you take it out and drop it it into something bigger than a A6 chassis, or something hacked to pieces, you can get 1250+hp just fine and I wouldn't be surprised if a rebuilt engine could make 2k hp like the TT Lambos do in the US etc -

Much bigger turbos will fit - A6 suspension towers get in the way.
FMIC with more volume and cooling ability - A6 limited to SMIC unless you chop the front up, ditch A/C etc.
Bigger airflow pipes/filters with smother run - A6 is just garbage.
Less underbody heat retention - A6 is again very poor and retains far too much heat.

I think its the GOGI Golf (a hacked up mk4) wirh the V10 which makes 1250hp as the front of the car is completely chopped apart for maximum airflow and cooling.

[welwynnick]

There are lots of US companies that turbo the Gallardo, Huracan & R8 V10 - Underground, Hennesy, Heffner, Sheepey, ETS, and they all seem to get 900bhp on stock engines and 1250bhp on modified engines. They don't have the packaging constraints of a "family" car, so the intake and exhaust plumbing is short, fat and straight, and they have huge water intercoolers. Interestingly, ETS appear to say their stock set-up runs at 10 psi boost, which I think is the stock RS6 boost?

Lamborghini engines will be more highly tuned - more cam lift and duration etc though I'm not sure how much difference that makes with forced induction, but a powerful NA engine is a good starting point for a turbo engine, and the V10 does seem to be a very good starting point - better than the Aventador's V12, because the bottom end isn't as strong.

So the V10 is a great tuning platform, but if you want big power you have to get a lot of air in and you have to get a lot of heat out. And that takes space. Hence the advantage of the W12.

My initial thoughts were about fitting large water intercoolers down the sides, but an FMIC makes a lot of sense. If the radiator was moved backwards 100mm that would allow space for a custom FMIC in front measuring 67 x 43 x 10 cm, which totals 29 litres. That's double the best current solutions and should be enough for big power installations.

Just a flight of fantasy of course. I don't even know if the W12 can rev beyond 6000.

Nick