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ok stupid question (since this is my first 911)... i like the sound, and i hope (think) its normal, but the engine gets really raspy near redline... is this typical?
When I did the MK I muffler mod, my car sounded very raspy right before it hit redline.
Yes, but to me (being a drag racer), S54's feels like they stop pulling before that. I always shift a car the split-second I feel the engine plane out, puts the engine in a better torque range to carry the car quicker IMO.
Don't rule out your engine's oil viscosity when running an engine with hydaulic lifters. Too thin an oil can reduce lift at high rpm's.
That is an old school theory, don't you think? The weight of the valvetrain in the M96 is very light (no pushrods, lighter spring rates) compared to an old V-8. I mean, we are still talking 40 weight oil that I assume most are running.
a MAF in its early stages of decline can cause this issue (so can a dirty one!). turn off the car, unplug the MAF, and go for a drive. if the car pulls hard to redline, change your MAF.
That is an old school theory, don't you think? The weight of the valvetrain in the M96 is very light (no pushrods, lighter spring rates) compared to an old V-8. I mean, we are still talking 40 weight oil that I assume most are running.
A hydraulic lifter is still a hydraulic lifter. As the speed of the piston increases, improper oil often prevents the lifter from a full pump which in turn decreases valve lift. This was, in fact, a problem in the old days and continues to be a problem today.
Remember, there is a HUGE range in allowable viscosity in 40 weight oils. Not all 40 weight oils are alike.
A hydraulic lifter is still a hydraulic lifter. As the speed of the piston increases, improper oil often prevents the lifter from a full pump which in turn decreases valve lift. This was, in fact, a problem in the old days and continues to be a problem today.
Remember, there is a HUGE range in allowable viscosity in 40 weight oils. Not all 40 weight oils are alike.
You think high-revving, modern engines have float, especially Porsche engines? I would think not but I wasn't there when the valvetrain was designed.