compression braking... lockup ?
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
compression braking... lockup ?
Interesting thing I noticed this morning....
took the vette out for a morning run to clear the cobwebs......
Anyway, once the oil was warm and flowing easily I knew it was OK to pull a few more revs.
I found a suitable test track and applied my cobweb removal procedure....
Several hard pulls through 2nd gear to redline....
I love this car. pulls so strong all the way through to next gear change.... no drop off that I can sense in the butt-o-meter all the way to 5500~5800. Got to get it back on the dyno. I think this Holley carb has made a significant difference.
The interesting thing I noted though, was a compression lockup I detected when backing off throttle sharply.
I was accellerating flat chat in 2nd and got to just over 5500, (about 70mph) and as I released the throttle, the rear locked up momentarily before engine rpm drop began to pull car up under engine compression.
I've experienced rear lock up due to engine compression when braking heavily into a corner at Mallala (local race track), but never experienced lock up under engine compression alone... well , not on a straight dry surface that is.
I'll definitely have to be aware of backing off sharply on a wet road/track.
For those guys that autocross/road race..... is this typical?
engine has 10.3:1 static compression.
took the vette out for a morning run to clear the cobwebs......
Anyway, once the oil was warm and flowing easily I knew it was OK to pull a few more revs.
I found a suitable test track and applied my cobweb removal procedure....
Several hard pulls through 2nd gear to redline....I love this car. pulls so strong all the way through to next gear change.... no drop off that I can sense in the butt-o-meter all the way to 5500~5800. Got to get it back on the dyno. I think this Holley carb has made a significant difference.
The interesting thing I noted though, was a compression lockup I detected when backing off throttle sharply.
I was accellerating flat chat in 2nd and got to just over 5500, (about 70mph) and as I released the throttle, the rear locked up momentarily before engine rpm drop began to pull car up under engine compression.
I've experienced rear lock up due to engine compression when braking heavily into a corner at Mallala (local race track), but never experienced lock up under engine compression alone... well , not on a straight dry surface that is.
I'll definitely have to be aware of backing off sharply on a wet road/track.
For those guys that autocross/road race..... is this typical?
engine has 10.3:1 static compression.
Last edited by OzzyTom; May 24, 2008 at 10:06 PM.
