Porsche back in Le Mans!

[xpensive]

It will be a twin-turbo V8, all according to my crystal ball.

June 15, 2013

I think so.

[WhiteBlue]

I doubt someone has the feeling the 1.6l v6 engine was the ideal choice for a lemans winning package but we ´ll see.

F1 and LMP1 will follow the same philosophy of maximizing efficiency. The most efficient engine will in the end win. In the case of the F1 engines we know positively that for a 1.6L format and 27.8 g/s fuel flow a four cylinder would have been superior to a six cylinder. The expert group wanted to adopt that format, but Ferrari managed to stall the plan.

LMP1 will have basically the same conditions with limited fuel flow so that again the most efficient engine will win in the end. Contrary to F1 no format is specified. You can go for what you think is the most efficient design in terms of cubic space, cylinder number and layout. While there are certainly some packaging and structural advantages in V engines I feel that in terms of optimum cubic space and cylinder number the reduction in fuel flow - (-22%) is mentioned - will lead to much smaller numbers. V8 should be totally uncompetitive in my view.

[xpensive]

The engine must also fill other criteria, both chassis-wise, where an I4 is hopeless, and marketing-wise, where an I4 is hopeless.

[WhiteBlue]

The engine must also fill other criteria, both chassis-wise, where an I4 is hopeless, and marketing-wise, where an I4 is hopeless.

We will see. The marketing requirements are not must haves. If an engine wins it will create its own marketing success. Chassis wise I4 is much less of a problem than many people think, but rigidity and packing concerns can pull a lot of designers into trying V4s or VR4s IMO. I believe that all factory LMP1 engines from 2014 will be turbo charged. At least the regulations allow 4 bar of boost pressure to all engines, petrol and diesel alike. The regulations also require all of them to be hybrid. I don't think anybody can afford to build an NA engine simply because it will not provide the efficiency advantages a downsized turbo with up to 4 bar will automatically offer. From that it also follows that 8, 10 or 12 cylinders will not exist any more. The regs are written to make the engines more similar to the average road car and those simply don't have more than six cylinders nowadays.

I would be very surprised if we see any cylinder number above six at all. The six will probably only be selected by marques that have F1 aspirations such as Honda. There is a rumor that Honda is preparing an LMP1 with Wirth.
http://auto-racing.speedtv.com/article/ ... gulations/
Wirth is also an experienced F1 constructor. So the LMP1 car could be a test mule for the F1 Honda engine that will only run in 2015 in the McLaren. In that case it must be a 1.6L V6 with turbo electric compounding system. Honda might not look at winning LMP1 but at racking up many miles of testing for the F1 units.

[matt21]

I've heard much less optimistic rumours about the Porsche LMP1 drivetrain. In-line turbo 4 (the future Audi DTM engine!) + FWD hybrid system, probably the same as in the R18.

There are speculations that the DTM will switch to 2L-V4-engines (half of an actual engine).
So this would make sense for for the Volkswagen Group then, because Audi will get mileage on the engine two years before the introduction in the DTM.

[xpensive]

Admittedly, I was not aware of the 2014 fuel-flow restrictions, which gives another perspective of course.

This will be quite a challenge for a V8.

[WhiteBlue]

There are speculations that the DTM will switch to 2L-V4-engines (half of an actual engine).
So this would make sense for for the Volkswagen Group then, because Audi will get mileage on the engine two years before the introduction in the DTM.

matt21, can we have a source for that speculation? I find it very interesting. I did find :
http://www.autosport.com/news/report.php/id/107154
It says that all DTM manufacturers have agreed to race turbocharged, 2L 4-cylinder engine from 2015 or 2016 and that would include DTM America and the Japanese Super GT500. So in addition to Merc, Audi and BMW you would have Honda, Toyota and Nissan all pulling in the same direction. How about a VR4? Would that make sense? IMO the answer is yes. It would be more compact and more rigid than an I4 and less expensive than a V4.

Admittedly, I was not aware of the 2014 fuel-flow restrictions, which gives another perspective of course.
This will be quite a challenge for a V8.

http://www.lemans.org/wpphpFichiers/1/1 ... n_2014.pdf
This is a good place to read about the rules and the intentions of the rule makers behind them.
I'm glad you don't have to eat another old racing suit on this one. Your crystal balls have earned you some strange diners in the past if I remember right.

[Sombrero]

Here the last 4 cyl. in-line engaged in le Mans by Porsche.

[WhiteBlue]

That must have been the 1981 prototype 944 turbo. I bet the new turbos will look quite a bit more sophisticated. But a nice bit of history.

[Pierce89]

There are speculations that the DTM will switch to 2L-V4-engines (half of an actual engine).
So this would make sense for for the Volkswagen Group then, because Audi will get mileage on the engine two years before the introduction in the DTM.

matt21, can we have a source for that speculation? I find it very interesting. I did find :
http://www.autosport.com/news/report.php/id/107154
It says that all DTM manufacturers have agreed to race turbocharged, 2L 4-cylinder engine from 2015 or 2016 and that would include DTM America and the Japanese Super GT500. So in addition to Merc, Audi and BMW you would have Honda, Toyota and Nissan all pulling in the same direction. How about a VR4? Would that make sense? IMO the answer is yes. It would be more compact and more rigid than an I4 and less expensive than a V4.

Admittedly, I was not aware of the 2014 fuel-flow restrictions, which gives another perspective of course.
This will be quite a challenge for a V8.

http://www.lemans.org/wpphpFichiers/1/1 ... n_2014.pdf
This is a good place to read about the rules and the intentions of the rule makers behind them.
I'm glad you don't have to eat another old racing suit on this one. Your crystal balls have earned you some strange diners in the past if I remember right.

When you say "vr4" are you referring a super narrow v angle with only 1 head like the VW vr6?

[WhiteBlue]

When you say "vr4" are you referring a super narrow v angle with only 1 head like the VW vr6?

Yep, VR engines are a VW specialty and they fit the bill of a compact, rigid and affordable engine. The famous Scirocco VR6 comes to mind.

[xpensive]

Thank you WB, as I recall you and I had colorful argument over the concept of flow-restriction a few years back, didn't we?

Anyway, there we are and quite obviously, an I4 would theoretically be more sneaky than the V8, but I still believe that
Porsche will take the latter route, if nothing else to prove a point.

[WhiteBlue]

Yes we disagreed over a number of things, fuel flow and cylinder numbers in F1 and COTA being some examples. I researched the DTM story today and I got the impression that Porsche's LMP2 V8 will have a relatively short life. DTM was contemplating the move from V8 to turbo 2L for 2014 and they only delayed it because BMW had just introduced their V8 and needed some years to write that investment off. That is the reason why the 2L turbo engines will only come in 2015 or 2016 to DTM. The Porsche V8 could be exactly the same story. Too late for LMP1. The fuel restrictions will be too severe IMO.

[marcush.]

the VR concept is a cost saving child as it is cheap to produce.Performance and efficiency wise it´s a nightmare methinks .No ways this would be the card to play for a oem to go racing even though I have seen one driving in LeMans ... at least on testing days...
last time we saw a vr engine in lemans was 2004 (Ian Dawsons Radical team with Mountune sourced Diesel power...it smoked heavily...)

so we may see a V8 for year one to get the train going and come back in 2015 with either v4 or i4 propulsion.? both powertrains could be derived quite easily from the things already developped...

[xpensive]

USF1 and MrM comes to mind.

Now, is it that obvious that an I4 per definition would be more efficient than a V8? I'm not so certain when you take everything into account, imbalance and all, besides, a V8 will give you a natural stiffness as fully-stressed member.

Moreover, how much will it matter at Le Mans, when you pit you pit, they have to give some leeway to the privateers?