I finally got a chance to make this topend comparison that I promised a few weeks ago. The test mule was my Dad's early 1st month production 046. It's always been a fantastic runner. The saw is all original and stock, with the exception of a MM mod. The DP muffler cover is even original. First of all, the numbers.
OEM Mahle
Exhaust - 103°
Transfers - 117°
Intake - 73°
Squish - .032"
Compression - 172 PSI
Meteor
Exhaust - 103°
Transfers - 122°
Intake - 72°
Squish - .016"-.022" (Reverse Tapered)
Compression - 178 PSI
Both saws start, idle and rev perfectly. Matter of fact, there's almost no difference of any kind in the useablilty or power of either topend! To say I am shock, would be an understatement! This Meteor topend runs fantastic. It only has one serious problem. That is the reverse taper and resulting tight squish. At the outer edge of the piston, where it should be the tightest, it's a nice .022", right where you'd want it. On the very edge of the combustion chamber, it's only .016". It should be greater than the .022". Had this been even .001"-002" tigheter, I would not have been comfortable running it. The rest appears to be purely cosmetic. Yes, I want a nice clean port, but it's obviously not hurting performance.
Both saws were tuned in the wood where they ran best. Surprisingly, both ended up in the 14,300-14,500 range. I don't know what it is about this saw, but it's always been a runner. Perhaps the ignition timing is more advanced than what we're used to. Who knows. If I tuned either topend to 13,500, it would be crazy rich and almost impossible to clean up in the cut. Grant it, I wouldn't run them this lean for long extended work, but my effort was to tune both saws to max performance. For a work tune, they both would still be about 14,000.
OEM Mahle
Exhaust - 103°
Transfers - 117°
Intake - 73°
Squish - .032"
Compression - 172 PSI
Meteor
Exhaust - 103°
Transfers - 122°
Intake - 72°
Squish - .016"-.022" (Reverse Tapered)
Compression - 178 PSI
Both saws start, idle and rev perfectly. Matter of fact, there's almost no difference of any kind in the useablilty or power of either topend! To say I am shock, would be an understatement! This Meteor topend runs fantastic. It only has one serious problem. That is the reverse taper and resulting tight squish. At the outer edge of the piston, where it should be the tightest, it's a nice .022", right where you'd want it. On the very edge of the combustion chamber, it's only .016". It should be greater than the .022". Had this been even .001"-002" tigheter, I would not have been comfortable running it. The rest appears to be purely cosmetic. Yes, I want a nice clean port, but it's obviously not hurting performance.
Both saws were tuned in the wood where they ran best. Surprisingly, both ended up in the 14,300-14,500 range. I don't know what it is about this saw, but it's always been a runner. Perhaps the ignition timing is more advanced than what we're used to. Who knows. If I tuned either topend to 13,500, it would be crazy rich and almost impossible to clean up in the cut. Grant it, I wouldn't run them this lean for long extended work, but my effort was to tune both saws to max performance. For a work tune, they both would still be about 14,000.
No, I told you so, or anything like that, lol?
