6.5L rebuild adventure finally begins
12-17-2008, 11:57 PM
#77
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FYI, my stock motor (90 S4 auto) with 6 psi boost (Murf Kit) put out 406 rwhp (~507 chp), I'm now at 531 rwhp (~665 chp?) at 14.7 psi with a hybrid 5.0 L S4 engine.
3 valve heads rock. ford makes a pretty cool head on a 5.4L that can put out 500ft lbs ctq and 445 chp w/only a 6psi twinscrew on top of a stockish bottom end. iirc, the best we've seen on a 928 6psi motor was about 380 rwhp/350 rwtq. oops. this is a pcar site. sorry. didn't mean to start any trouble. hahaa
12-18-2008, 06:35 AM
#79
By SVP928
No meaning really to pick anybody out as such but more the theoretical arguement between 2v and 4v engines. Basically they can be very close in terms of efficiency. Peak brake mean effective pressure BMEP is a measure that can be used quite effectively to compare engines. BMEP in an F1 engine is only fractionally more than in a Nascar Cup engine.
In fact when compared, the cup engine has a faster piston speed both in terms of mean speed and peak speed. The cup engine is highly restricted in design and use of materials, no doubt if the restrictions were lifted the cup engine could equal the F1 engine in terms of BMEP. The highest figure in BMEP terms I have seen was a MOTO GP engine which had 16.1 BMEP which is enormous, from memory the cup and the F1 engine were in the high 14s.
Greg
The 2v-vs-4v argument really comes down to simple math. There is simply more valve area available for a given combustion chamber size with 4 valves than with only 2. You have only to look at the highest-output NA engines to see that they all are 4 or even 5 valves per cyl.. At max valve size, a 4V engine will flow more than 2V., its as simple as that....you could even look at the "import" drag engines for comparison- the NA Hondas are making more HP/cu.in than any 2V available...no disrespect intended, just a fact.
In fact when compared, the cup engine has a faster piston speed both in terms of mean speed and peak speed. The cup engine is highly restricted in design and use of materials, no doubt if the restrictions were lifted the cup engine could equal the F1 engine in terms of BMEP. The highest figure in BMEP terms I have seen was a MOTO GP engine which had 16.1 BMEP which is enormous, from memory the cup and the F1 engine were in the high 14s.
Greg
12-19-2008, 02:21 AM
#83
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Not home yet. Simply re-attached to the vehicle.
Exhaust detailing and then dyno tuning ~monday give or take shop schedule. Suspension and brakes already done. Hopes for delivery one or two days ahead of Santa.
Exhaust detailing and then dyno tuning ~monday give or take shop schedule. Suspension and brakes already done. Hopes for delivery one or two days ahead of Santa.
12-19-2008, 02:23 AM
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PS - I'm particularly proud that I'm _still_ running original 20 year old factory paint on my cam covers that are hiding all that 6.5 liters of displacement...
12-19-2008, 02:30 AM
#86
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[homer simpson] Mmmmmm, CARB "compliant", Mmmmmmmm [/homer simpson]
12-19-2008, 02:36 AM
#87
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My wrench Peter just moved over to Schneider Autohous, BTW. I think they are planning on being there too.
12-19-2008, 02:42 AM
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> i would have taken the time to do the refinish whether its 2 pac or powder coat...coz it is going to go.
Perhaps. But for now, it looks extra stock, and is holding up quite nicely
Perhaps. But for now, it looks extra stock, and is holding up quite nicely
12-19-2008, 06:38 AM
#89
Nordschleife Master
