Dinan has modified and maintained my BMW's for nearly 25 years. In my experience he builds engines that will last (2 for me) and his claimed dyno numbers seem to relate to on-the-road performance. I've got stage III suspension and 3.45 gears which made an enormous difference to my M5
He's also got the only independent service organization I've seen that has grown to significant size without quality going to hell. Steve (and his wife) are also in business to make money -- you can't grow and fund development if you aren't profitable.
I'm not going to dwell on Steve's discussion of why all of the quickie dyno numbers are bullshit, drag of cold fluids and stabilization of underhood temperatures are a discussion in itself. He can document the 30hp rear wheel differences people are seeing.
The good news -- 100 octane gas is worth 15-20 hp. This is a really cost-effective modification.
The bad news -- our California re-formulated gas will cost 5-10hp.
Big power, big bucks: the exhaust manifold is being tooled now and will probably be available in 3 months. It will be expensive (?) and take 16! hours to install (and if you have to pull the engine later for any reason presumably another 16 hours). Per Dinan's very expensive Ricardo software, the exhaust manifold is the major limitation on naturally aspirated power and combined with exhaust, larger throttle bodies, intake trumpets, and a raised intake plenum there's 448hp at 6500 RPM (and no loss at the low end). With the addition of new intake cams, and accessory underdrive he's still on target for 460+hp naturally aspirated.
No 24hp for airbox insulation?! When I talked to Steve late last year, he thought heat soak of the airbox was a significant factor. After testing, he concludes that the major contribution is reversion thru the intake and insulating the air box is a waste of time.
Why not 500 or 515hp? According to the Ricardo program, 500hp requires bigger valves and ports (don't forget, the heads and headers are the same as the 540). Dinan's labor and fabrication costs (Northern California is VERY expensive even today) are very high and he doesn't think enough people will pay $20K+ for 500hp to justify his investment. He can get 500hp cheaper with a supercharger.
The supercharger is still under development, but it looks like 100+hp on it's own (at $15k+) which can be added on top of all the naturally aspirated mods to get 560+hp.
So maybe some of the German 500hp claims are possible - if they're really doing the head work and providing exhaust manifolds - the quoted prices at today's exchange rate should allow that.
I've got to say that after Sears Point, it's clear that I've got to be a lot better driver before I can do anything with more power.
Good info here.
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