- DPi - Daytona Prototype international - yes, with a little i...
- Daytona Prototypes have never been the most popular or successful class in sportscar racing - but they are uniquely American. And that is what DPi is setting out to be. Take the global "standard" for tier 2 of prototype racing, LMP2, and give it an American flavour.
Not American in the sense that they are American cars but in the sense that they reflect the sportscar Americans know (and buy).
And it will be coming to a racetrack near you next year...
The given in this situation is that the cars will have a range of powerplants - manufacturer branded - this has always been the way in DP - Chevrolet, of course, but through the years Honda, BMW, Ford, Toyota, Nissan, even Porsche.
(Interestingly, those manufacturers have often branded as their " high end" marques; Cadillac, Acura, Lexus & Infiniti. There's a clue as to the way things may go...)
But this is the time when the worldwide LMP2 class is removing any link to manufacturers and standardising on an "anonymous" Gibson powerplant installed in one of 4 chosen constructors' chassis. and these constructors are really "racecar" companies - ORECA. Onroak, Dallara, Riley. So where does the manufacturer fit in?
The compromise solution is:-
- Take any one of the Racecar company LMP2s
- Install manufacturer's powerplant
- Change the bodywork to suit the powerplant
- While about it you may as well add other distinguishing styling to the bodywork
- But not in any way affect the aerodynamics.
This new item - the DPi - becomes a new homologated car - a mixture of standard racecar constructors bits, an engine, gearbox, electronics etc and some custom body parts.
All of these are integrated by, and homologated by, the racecar constructor - these are not "aftermarket" customisations. Each DPi will be an official product with the "headline" name of its powerplant manufacturer.
So to the famous diagram below, from Racer July 2015, the dark blue bits and the powerplant come from the "big name" be it Cadillac, Honda or whoever and the other bits from a given one of the "chosen four" ORECA. Onroak, Dallara, Riley
So that's it simply - now all we have to do is set rules for the changes to the bodywork and for the powerplant...
The Racer article has much on the dimensions of the body panel - best check there for details but the arrangement is summarised in this slide:
Basically there are 2 full length "boxes" as well as the engine cover and the areas between the front fenders where the manufacturer can stamp their style and accommodate their bits but in no way alter the aerodynamics (did I already say that!?)
Before we leave styling for now let's make it clear. Manufacturer styling does not need to mean creating a racing lookalike of a road car - In DPs Corvette was the exception here - in LMP2 Honda and Mazda have never had a line of street car styling - this class is not heading towards DTM or GT500. Look at the Le Mans Cadillac, Bentley and BMW LMPs to see where we are going.
The powerplant is of course very vague hoping to cover just about any option and certainly those from early adopters GM, Mazda, VAG and Honda.
Dimensions are "length from 535mm (4-cylinder) to 685mm (V8), width from 370mm (4-cylinder) to 890mm (V10), height from 500mm (4-cylinder) to 752mm (V8)," and "crankshaft height from 77.5mm (V8) to 120mm (V8)"
Weights are partially defined; V8s (150-180kg) and V10s (260kg). V12s and diesels are not listed as options. turbocharging is only mentioned as options for 4- and 6-cylinder engines.
Capacities are indicated as a 2.5L limit for 4-cylinder turbos, 4.5L limit for 6-cylinder turbos, 6.2L limit for NA V8s, and 5.2L limit for NA V10s
So at the moment it seems the limits are defined around what IMSA has been asked to accommodate... Chevy LS3 V8 crate motor and Audi's R8 V10 being fairly obvious in there! Bit more analysis needed...
There is a bit in the rules which allows a DPi to run at Le Mans 24 hrs - but it has to be fitted with the normal LMP2 body for it's base constructor. So how's that going to fit over the manufacturers powerplant? I think forget this - as a way of competing for the 3rd fastest class it's not going to get many takers.
It's since become clear that this route was also doomed by the expectation that prospective Le Mans entrants, whatever their powerplant, would use the same Electronic Control Unit (Cosworth) specified for the spec Gibson engine in LMP2 - unlikely...
But could DPi have another road to Le Mans - with LMP1 compatible chassis and petrol powered engines they could go the LMP1 "Privateer" route - they will all be non-works teams if ACO wants to keep it "Private" or perhaps the category will just become nonhybrid LMP1.
Download latest LMP2 Technical Regs - here
BOP etc? more answers from Mark Raffauf (Aug 2016)