Question about IMSA tech bullieten 07-15.

[chernaudi]

This bullieten says that Acura and Porsche must run the ACO mandated restictors starting at Lime Rock. However, the AER and Mazda/AER engines can still run to 2006 specs. And it also didn't say anything about the Zytec Engineering and Judd 3.4 V8s.

Does Acura and Porsche have a design advantage over the other LMP2 engines, or is it just that their factories?

And in general, do the 3.4 V8s have an advantage over 2.0 inline 4 turbos, and if so, what is it. I mean, the 3.4 V8s rev like old F1 engines(like the Cosworth/Ford DFV) and(like the DFV) use a flatplane crank. And the 2.0 four banger turbos are boosted to the roof. So it's little wonder that LMP2s(in addition to their frail chassis construction) are unreliable.

But then again, the Zytec ZG348 is the same engine used in A1GP cars, and, by rules, should last a race season. Maybe that's why it's such a good LMP2 engine now.

But do the 3.4 V8s have a definent advantage over the 2.0T L4s? And do the Factory(Porsche/Acura) engines have an advantage over other 3.4 V8s?

[The359]

There are no Zyteks or Judds running in ALMS. If someone shows up with one, IMSA will make a decision then.

This move is basically to equalize the field to allow Mazda to catch up, and likely to stop the ACO from denying LMP2 teams invitations to Le Mans in 2008 because they are running outside of spec.

But then again, aren't the LMP2s running below the minimum weight?

[chernaudi]

They will next year if IMSA keeps the '07 spec rule in force. Next year, the LMP2 cars will have to add 50 kgs to their weight, irregardless of make/car.

[paul-collins]

http://www.imsaracing.net/2007/alms/...in%2007-15.pdf

Please read the bulletin. It does not specify Porsche or Acura. It says

1 - all cars to use 2007 ACO restrictors now except that
2 - turbo cars get one restrictor break and run at 2.7b instead of 2.5b and
3 - mazda gets the electronic throttle cable allowed.

Sounds to me like there's a suspicion within the IMSA offices that the NA/turbo equivalence isn't quite right now...