Audi R15 , What could it be ?

[zac510]

I don't think there's any way Audi will be going down the production engine part. It might be good marketing but I think it's too risky in terms of if it is not fast enough then it would be a major embarassment. This is compared to the option of a custom engine at a cost that Audi can afford. They're up against Peugeot and their huge budget here, not fighting for 'best privateer' or 'best petrol'. They can't afford to make a poor decision, they need the best engine they can possibly have for a race and that means bespoke.

[gwyllion]

Originally Posted by bodgit

there is a deisel v12 version coming out

As I said earlier, the road R8 V12 TDI is in the freezer.

[gwyllion]

Originally Posted by HORNDAWG

Read the P-2 diesel rules!!!

I did.

Engine using head cylinders, valves, pistons, connecting rods of a production engine. This engine must be used in a production car built in a quantity of at least 10 000 units per year. These pieces must not be modified. Two stage charging devices and air/air and/or air/water heat exchangers are permitted.

A lot of production parts can not be changed. Only crankshaft and camshaft can really be changed. And of course the turbocharging and fuel injection system are free.

Your suggested changes is not allowed.

Originally Posted by HORNDAWG

So a Q7 should be getting it's 4.2L streched to 4.4L with new heads, valves, piston and rod assy's that will be very conducive to even more performance.

[HORNDAWG]

Originally Posted by HORNDAWG
Read the P-2 diesel rules!!!

I did.

Hmm, really?

Quote:
Engine using head cylinders, valves, pistons, connecting rods of a production engine. This engine must be used in a production car built in a quantity of at least 10 000 units per year. These pieces must not be modified. Two stage charging devices and air/air and/or air/water heat exchangers are permitted.

A lot of production parts can not be changed. Only crankshaft and camshaft can really be changed. And of course the turbocharging and fuel injection system are free.

Everything can be changed in a manner, other than the heads, valves, piston and rod assy's exactly as it states in the rules!



Your suggested changes is not allowed.

Huh? My suggestions are to a Q7 engine, in a production unit, and I would guess, not knowing the exact laws in Germany, can be done at any time!

These changes would facilitate the needed changes to improve the engines parts (that are mandatory for the race engine) and performance for applying it to racing!

Quote:
Originally Posted by HORNDAWG
So a Q7 should be getting it's 4.2L streched to 4.4L with new heads, valves, piston and rod assy's that will be very conducive to even more performance.

R.I.F.



L.P.

[Hugewally]

Originally Posted by HORNDAWG

R.I.F.

copycat...

[gwyllion]

I highly doubt Audi will build a special Q7 as homologation special. The design criteria for a race TDI are fundamentally different that those of SUV. The engine should for instance be able to start in winter and drive more than 10000 km

BTW it should not be stretched to 4.4. That can be done by a different crankshaft.

[TWK]

Are you suggesting that since a manufacturer can't modify a production engine directly for the track they'd actually redesign a 10,000 unit engine with parts intended for racing, then sell 10,000 of them for the road before they go racing? That strikes me as fantasy land.

[JAG]

What manufacturer's do have a suitable diesel road car engine?

If it's only a handful, wouldn't the ACO put together new 2011 P1 diesel regs to help interested manufacturer's?

Afterall, Production/GT2 engine regs are still up in the air, so diesel regs could also change.

[chewymonster]

The V10 engine would have to be a 4.6 liter. Audi went for the V12 to have small cylinders. I think they will likely continue with the current V12. Everyone basically runs the biggest engine that the ACO allows for the category.

[gwyllion]

Originally Posted by chewymonster

Everyone basically runs the biggest engine that the ACO allows for the category.

That makes sense for petrol engines: biggest displacement means lowest revs, highest fuel economy and highest reliability. However, that could be a problem for diesel: you don't want less revs, because the power band is already very narrow! And you have to lower turbo boost, which means all your engine parts are actually overdesigned (for more boost) and could be lighter.

[deggis]

Originally Posted by JAG

What manufacturer's do have a suitable diesel road car engine?

If it's only a handful, wouldn't the ACO put together new 2011 P1 diesel regs to help interested manufacturer's?

I agree. The PDF just says "present generation LM P2 engines". I perceive it means a general outline. I really doubt everything stays untouched, especially what comes to diesel.

[gwyllion]

Some rumors Marshall Pruett picked up: http://auto-racing.speedadmin.mindco...-le-mans-blog/

Rumors have Audi’s new R15 engine on the dyno and running strong. Rumors also have the engine smaller and lighter than the first generation TDI powerplant, which makes sense, as a V10 would tend to be smaller and lighter than a V12…

They are also rumored to be moving from a 5spd to a 6spd. When the R10 was on the CAD screens in ’05 they had no reference to draw from for gear ratio choice, and went with a 5-speed as the billion lb-ft of torque could easily pull each gear. With Peugeot opting for a 6-speed and using the shorter gear splits to exploit optimized RPM drops, Audi’s been caught out with a design that needs updating.

So, be on the lookout for an open-top R15 with a diesel V10 driving through a 6-speed…can you hear the faint sounds of Peugeot engineers whimpering? They just fired the 908’s designer, Paolo Cantone…maybe they should ring him up and see if he’ll come back.

[chernaudi]

Well, Audi wanted to run a V10 back in '03'04, but, like Peugeot, opted for the conservative route with the V12. The same kind of applies with the 5 speed Xtrac transmission.

So, if Marshall's rumormill source is right, the new Audi could be a highly evolved R10 with a truly optimized engine, gearbox, aero and chassis package-all should help with weight disribution and make the R15 somewhat more compact-both were things that Audi had to be looking at since the R10 was rolled out in '05.

[Ultimo]

I asked this elsewhere but go no answer, what is the technical motivation for having a V10 instead of a V12 in this case? I mean I don't know engine mechanics well but it seems logical to me that there are some optimal cylinder dimensions/volumes for certain displacements and that say a V8 and V12 would not necessarily have equal performance at a given displacement (not considering structural or weight or balance issues - sheerly enigne performance).

Mr. Pruett said that some at Audi wanted a V10 for the R10 but were overruled from the top which also begs the question: why would this be done? I mean Peugeot opted for a V12 as well so there is some merit in it I figure. Do you guys think that this V10 will be smaller displacement and that Audi will hope to gain an advantage on the smaller (or is it larger?) air restrictors for smaller engines?

[TheNewBob]

Originally Posted by Ultimo

Mr. Pruett said that some at Audi wanted a V10 for the R10 but were overruled from the top which also begs the question: why would this be done? I mean Peugeot opted for a V12 as well so there is some merit in it I figure. Do you guys think that this V10 will be smaller displacement and that Audi will hope to gain an advantage on the smaller (or is it larger?) air restrictors for smaller engines?

I'd say the marketing maybe had a little bit to do with it - Audi don't have any V10's in their road cars, do they? Or at least they didn't in '03/'04. Which makes me wonder why they would be developing a V10 now for an R15...

[ger80]

Because the smaller restrictor size will change the optimum configuration even more to the V10.
Rename the car to Volkswagen, they have a V10 TDI

[zac510]

Audi have the V10 in the RS6 models but not diesel to my knowledge. Maybe in one of the big Q-models?

Ultimo, if the V10 is a smaller capacity and it surely will be because the restrictor is smaller, the engine will be shorter, lighter and thus the car will be closer to the minimum weight. There will probably be other smaller benefits too.

I am not 100% sure, but considering that knighty has spoken about the strength of the pistons in these two V12 diesel racing engines, the V12 configuration was probably to keep the bore size and pistons smaller, making them stronger.

The diesel fuel burn characteristics might have made a typical petrol high bore/low stroke combination impractical too, adding additional justification for the V12 dimensions.

I can't wait to see it.

Maybe Peugeot ought to build a new engine but mate it to the 908 for one more year before the '909'.

[chewymonster]

Originally Posted by zac510

I am not 100% sure, but considering that knighty has spoken about the strength of the pistons in these two V12 diesel racing engines, the V12 configuration was probably to keep the bore size and pistons smaller, making them stronger.

Exactly. Audi said something similar when the R10 came out. So a V10 would only be good for a 4.6 liter engine. So it's all up to the new rules, can a 4.6 liter engine do as well as a 5.5 liter engine. Previous ACO rules basically say no. But some have said that maybe this is the way to go for the diesels.

[gwyllion]

The new rules give 10% less, so the displacement of the engine might have to decrease with 10%, which give 5.0 liter.

[knighty]

yes, it will be interesting to see which direction pug an audi go with the diesel regulations........heres my 2 pence worth.......talk of a V10 sounds logical, but as some of you have suggested above, it screws the bore size if you want to stick to 5 litres (which is a 10% capacity reduction)........currently Audi are running an 83mm bore with alloy pistons.........Pug are running an 82mm bore with steel pistons.........if you knock off 2 cylinders from the current 5.5 V12 that would be a 4.58 Litre motor, so you would have to find another 0.4 litres in the 10 remaining cylinders........which come to think about it, is not out of the realms of possibility, so it may happen........but generally speaking for diesels, the bore is preferred to be smaller than the stroke, principally to keep the static compression ratio high, typically 16-18:1, as the re-entrant bowl takes up a lot of volume.........but on the flip side, I'm sure going the V10 route would have several chassis benefits too, as on the real tight ALMS circuits, the Audis have been seen to struggle, so I dare say it would make them more nimble.........I do seem to remember hearing that way back when Audi started the diesel project, they did try the V10 route but they couldnt make it durable, hence they went for a V12......so I dare say it would be easy for Audi to ressurect that project.

Forget using the VW V10 - its an antiquated old engine design and does not even use common-rail technology - no way would Audi use that turd.

[Duff_44]

Also keep one thing in mind:

With a diesel engine, you can only rev it so high before the injection timing gets thrown off. It's not like a petrol engine where you can run a smaller engine but rev it higher with advanced ignition timing and get the same power.

Since the diesels have an upper limit on what they can be revved to regardless of the displacement, a smaller engine will actually try to suck less air through the restrictors. Going with the smaller engine could end up being an advantage in both performance and weight (and fuel economy perhaps?)