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A free revving 5.8? That would resemble a GT's power curve, only way more fun! Will it be able to spin to seven grand occationally and remain reliable?
I can easily wait a few years for this evolution... Develop away!
It already exists, in Jim Corenman's car. And there is another one on my engine stand in the assembly room, which will run on my test stand, early next week.
I don't see Jim's dyno results with and without prototype intake, in my files.
I'm not sure how this became a sociological discussion. The point I was trying to make and on which Greg provided some examples is that there's no single cost figure that gets a 928 from state A to state B. Outside of the detailed context of a specific 928's present condition (state A) and what that 928's owner wants to achieve (state B), any number tossed-out into the air is going to be setting the wrong expectations. Wrong expectations result in either lost clients or unhappy clients.
Furthermore, it's an unhappy fact that "state A" can't be precisely determined until the 928 is in pieces.
I do so enjoy your lectures. There's probative value in googling 'sarcasm', and in the context of the internet/coding the "/" means to stop, or discontinue, or end of the condition previous.
Now, for my defense of asking. the 911 was brought up in passing, and we have an engine builder who would be considered the erzats GB over there. Suppose one were to lunch their intermediate shaft bearing on said 911 engine, and want it sorted. Even the baseline job, with modest upgrades starts over $20k. The chassis is only worth $7-9k sans engine. Like all engines, 928, 911, 904, it's obvious a teardown, and inspection is required.
I do so enjoy your lectures. There's probative value in googling 'sarcasm', and in the context of the internet/coding the "/" means to stop, or discontinue, or end of the condition previous.
Now, for my defense of asking.
I'm not sure why you feel the need to defend anything. I didn't 'attack' you. I assumed your sarcasm might have been due to poor communication on my part. But, that's apparently not the case. /done with this.
I'm not sure why you feel the need to defend anything. I didn't 'attack' you. I assumed your sarcasm might have been due to poor communication on my part. But, that's apparently not the case. /done with this.
'Defense of "asking" ', not "attack". If you setup a strawman, it's easy to knock it down. BTW, if you would go back to the start, I didn't request anything from you. You felt the need to lecture us on why pricing is not included. I get it, but you just won't leave it alone. Really, find out what "/sarcasm" means.
I get the distinct impression that this motor, presumably something similar to what Jim C commissioned you to build, is probably the motor Porsche should have built had they not given up on the 928 when they did. To do it in a motor that looks stock and is so elegant is very commendable.
That extra layer of power and torque would compliment the auto box [2.54] very nicely and would bring the car right up to date performance wise and mated to a 6 speed box even more so.
Here's a dyno chart from Jim Corenman's 5.8 liter build - 968 pistons, Carrillo rods, Greg's crank, Devek headers, cats, Colin's cams (IIRC), and a massaged S4 intake. It made more peak hp than my 6.5 stroker did before I added Greg's exhaust.
Here's a dyno chart from Jim Corenman's 5.8 liter build - 968 pistons, Carrillo rods, Greg's crank, Devek headers, cats, Colin's cams (IIRC), and a massaged S4 intake. It made more peak hp than my 6.5 stroker did before I added Greg's exhaust.
With a 12.5% transmission factor, that's 450 horsepower, at the flywheel.
And over 350 ft.lbs of rear wheel torque from 2800 to 5800.
You're making me want to tear down my 5.0 hybrid again and stick one of your GTS stroke cranks in it.
So tempting with the 16 valve top end I spec'ed. I wonder if one of them will eventually come to a 928 event so we can see it in person.
Because from the way you describe it makes it sounds like a 928 engine cranked to 11 vs a 6.5 stroker which is a strong 16 lol.
Pure displacement is one thing. but there's something else going on here, which wasn't obvious until we started building these engines and driving them.
Known for a very long time ("old school" Chevy small blocks) there's a bit of "magic" to be found in the stroke to connecting rod length ratio. A 1969 Z-28 engine, with the shorter stroke (and same length rod) has a completely different personality than a 350 Chevy with the same heads, compression ratio, and camshaft. The 302 is a very "free reving" engine, which just loves to keep on pulling in the higher rpm range. The 350 is more of a "lump"....kinda lazy.
The "long" rod rod in these 5.8 engines completely changes the personality of these engines.
Here's a dyno chart from Jim Corenman's 5.8 liter build - 968 pistons, Carrillo rods, Greg's crank, Devek headers, cats, Colin's cams (IIRC), and a massaged S4 intake. It made more peak hp than my 6.5 stroker did before I added Greg's exhaust.
ROB:
Didn't we also dyno Jim's engine with the prototype intake manifold?
I know the "crudeness" of the prototype was very flow restrictive on the "top end" of the 6.5, and we were not "thrilled" with the results, but didn't it show the potential of this change on the "little engine"?
The dyno curve of Jim's 5.8 liter motor above was done in January 2016. We never ran the prototype intake on his 5.8 motor. But we did run it on his 5.0 motor in October 2013 (which had what, 240,000 miles on it?). I confess I can't remember its configuration (ie- whether it had the GT++ cams and L2 headers on by then- I assume so since it put down 320 rwhp, and Jim had XX,000 miles of sharktuning tweaks in that 5.0). Here's the dyno of that 5 liter motor with and without the prototype intake, it picked up 38 hp and 24 tq . I particularly like the slope on the hp curve between 5900 and 6300 rpm- the runner length was close for that displacement.
Would be bitchin' to see the 5.8 with that intake. You'd be close to 500 crank N/A hp.
Known for a very long time ("old school" Chevy small blocks) there's a bit of "magic" to be found in the stroke to connecting rod length ratio. A 1969 Z-28 engine, with the shorter stroke (and same length rod) has a completely different personality than a 350 Chevy with the same heads, compression ratio, and camshaft. The 302 is a very "free reving" engine, which just loves to keep on pulling in the higher rpm range. The 350 is more of a "lump"....kinda lazy.
The "long" rod rod in these 5.8 engines completely changes the personality of these engines.
Rod length to stroke ratio has been a factor in perf engines for a long time. Getting it tuned for a specific car, and mission is pretty important. One would not want or need a flat 12 F1 engine that idles at 4000 and redlines at 16,000 for street application(weird ratio I'm sure). Geometry of the engine is interesting study.
I know the "crudeness" of the prototype was very flow restrictive on the "top end" of the 6.5, and we were not "thrilled" with the results, but didn't it show the potential of this change on the "little engine"?
I remember at the time thinking that the new intake was better suited/optimized for the 5.0 - exciting results for sure since I'm a 5.0 kind of guy.
05-02-2019, 11:15 PM
