2V4V

Marc,

Yes, I'm well aware of the world of semi-solid (and solid billet) blocks. I try to leave my cave as often as possible. Hmmm, now you got me thinking of a full CNC 928 block again...

FWIW, "All-motor" is (seemingly) the new way of saying NA - it made it outside the drag world a while ago, but if everyone is more comfortable with NA, that's fine too. I think the warm-fuzzy drag kiddies were trying to make the NA crowd not feel bad about finishing so far behind the force-inducted crowd...

100 HP/L is very impressive at merely 6000 RPMs. However, most newer high output cars are not limited to 6000 RPMs. And lots of them from Japan Inc, are getting really close to 100 HP/L. While meeting current emissions regs.

Of course, all the really huge specific HP outputs we kick around are generated at really high RPMs. Which none of us will ever see on streetable cars. Or, at least I don't forsee the 1HP/CC dealer-showroom floor Accord coming anytime soon.

I was trying to be very conservative in HP/L comments, so as to keep it in the realm of the obviously "streetable". Sure, you can do 300HP/L for the street, but it's gonna be a bit tough to live with at times.

You must be joking about BSFC, right?

Of course drag racing Supras/whatevers are gonna have very rich mixtures. All force-inducted drag cars do, what's the point? The world is different on the long track - one does not run WFO for very long at Laguna/LeMans/Nurburgring last time I checked. Mixtures are only enriched during boosted conditions, the rest of the time, same basic A/F ratios as NA.

Regarding SAE 880142, that's quite old work(16+ years. A lot has changed in the last 16 years.) Doesn't invalidate it, but still old work using some really old tools. In re-reading several other papers that reference that work (and 910042 and others), I still come to the same conclusion that the research lead me to before - that dissimilar metal expansion was the *greatest* cause of cylinder deformation in all of the cases. I'm not the only one who reaches that conclusion.

If you look at the analysis of the cylinder under load (after finish machine work and clamp-down) I just can't see how one would conclude leaving an open deck does anything but foster more deformation. Throw in the fact that (open deck) you leave the cylinder walls to completely manage the peak compression load deformation of the combustion event - it's right there up top - and another strike for open-deck.

Then, factor in the lower sealing area for the head gasket that is available for clamp down, and open-deck comes up short again.

If one were to make the cylinder walls incredibly thick (like 1"or 2"), then I guess you could make a case for open-deck, but that does not seem to me the realm of the practical.

I'll do a thorough re-read of the documents, perhaps there's something I'm missing.

Greg

mark kibort

Lets see Mr Faulk, Ive been racing the 928 for over 7 years now, specifically, over the last 3 seasons, my engine has seen 50+ race days. (ie thats 50hours of flat out racing, or like two back to back 24hours of daytona) and produced times/performances for the car to be in the top 10 in pro-racing series 13 years later than its production date! (ie 1:40.2 vs the top 10 SpeedVision Time at laguna 1:40.2 where there were 40+ pro drivers/teams entered). the 928 engine has not even shown any signs of wear. (except my fluke cam sprocket teeth issue, but its still running strong) Because the 928 engine and chassis WERE designed as race engines (with their limits noted), they are excellent race cars and have very durable race engines. I have not heard of many engines being as dependable as the 928 engine in club or pro racing. Look at Andersons success with only a stroker modification in the initial days of his experience.
BMWs have been constitantly evolving over the last 10 years, fixing many of their overheating, block,crankshaft, cam and valve issues.. the 928engine out of the box, as it came from the factory, can run within its design, produced a proven 400hp all day long, and would be a top contender in the new Grand Am Cup series in GS class (stock production cars, with suspension, exhaust, and tire size mods, at specific racing weights on DOT race tires) eg. M3, Z06, saleen, cobra, audi, porsche 996 non cup car, etc

The big issue with racing the 928 in the "old" days, and as was noted, they ran the 928 in stock form, very heavy, and unmodified. yes, in this form, the 928 is not a good platform. But, when you look at the series available today, and match the mods done to other cars in Grand Am GS class, or even Grand Am SGS or GT, the 928 with equal mods would do quite well. IN fact, wouldnt it be great if we were allowed to run a stockish, gutted 928S4 in 24hours of Daytona again. at the lighter weights, its engine dependability, and with big wheels and tires, the car would actually place quite well with the right pit crew over a 24hour race!
Imagine double stinting tires, economy on gas, and dependability of its "non race engine"?

Sure, if Faulk was talking about taking the 5 liter engine and make it a true race engine making a lot more hp (meaning 500hp plus, and 7500rpms), then yes, the design may have its issues. But from the responses so far, none of which are insurmountable.

again, look at andersons 6.5 liter and its track record so far, and of course and my stock 5 liter S4, still running strong after never being apart since it was made in 1986. And also not having any of the precieved weaknesses addressed. (ie oiling, trans cooling, etc) all stock stock stock!!

I challenge you to find any car 10-15 years newer that has run faster at Laguna with a stock engine and that was not a factory race car.

928. still the best car every put on the road, and the most potential as a production based race car, 20 years later.

mk

heinrich

and applause Mark -- every word correct and true.