The real reason why GT3 doesn't use DFI?
 

I was reading through my latest Evo and they rated the GT3 engine the second best engine for the year. Incidentally that makes three runners-up for the GT3 COTY, Track COTY, and Engine of the year. They said it is using the old case because DFI can't keep up with the high revs in the GT3. I haven't seen this posted here before but does make some sense. Has anyone heard this? Seems like something they will fix as they improve the technology and I'll bet we see DFI in the next gen GT3.

I thought it was because DFI was not allowed in GT3 racing.

Not sure how much it is worth, but I've read two points: 1.) Performance was not worth the extra weight gain, 2.) Motorsport teams would find their current motors obsolete due to homolagation requirements.

I don't think that is true as the Audi DFI motors spin to about the same level as the GT3

+1.


RS4/R8 V8 engines from audi spin to 8200-8400

Ok, this bugged me a bit since I too recall reading about it. Found the old Excellence article on the first drive (Aug 2009, p.45). At p.49 Andreas Preuninger is quoted thusly as to why no DFI:

"We already run a very high compression ratio on this motorsport-derived engine compared to a mainstream Porsche motor. So adding DFI would have meant a lot of extra work for very little gain. As it stands, we improved fuel economy and emissions over the old 3.6 motor."

F458 has DFI and spins to 9K or more

Since the TT motor has arleady come out with the 9A1 motor it will be shortly
in the GT3 next revision if we get one in the US.

Not unless the Cup and RSR use the 9A1 too, right?

Grant,
yea of course but for production purposes it doesnt make sense financially to keep that one motor for one car that sells such a limited production number.
Somebody else correct me? I thought once the TT went with its sales numbers compared to the GT cars,
the 964 cased GT1 Motor was gone.

All current porsche racecars of the 997 platform use a variation of the GT1 based motor, with the RSR being 4.0L with DFI.

^ news to me.

that's great. DFI with the old block....
i wonder if that's what the next RS will be.....

There is no DFI for 2 reasons:
1. There is no DFI head that can mount on a GT1 block. Porsche would have to design and cast a new cylinder head.
2. The new 997.2 engines have not yet been proven for durability.

It is certainly not a rev limitation for DFI. The V10 in the Audi R8 Lambo Gallardo has an 8500-8700 rev limit with DFI.

The 2010 GT3 RSR does NOT have direct injection. The reason why they increased displacement was because of the smaller restrictor plates mandated this year. The new 4.0L is rated at only 450 hp versus the previous 3.8l at 465hp. The smaller restrictor plates do not allow the engine to breath at higher rpms as the previous engines, so they increased the displacement and changed gearing to improve power/acceleration across the lower rev range.

The word I got was that only the RoW gt3rs would still keep the gt1 block for racing hommogulation, all others get the 9a1/dfi/pdk, including the gt3 and gt2. Supposedly in model year 2011.

^ so you are saying that as far as USA is concerned, by 2011, EVERYTHING will be 9A1?