why can't i rev my 95 more then 4000 rpm's in park.?
07-10-2007, 10:57 PM
#21
PopaDopaDo
True Car Nut
Originally Posted by jr's3800
There are differences in the model years... I think its more related to the PCM..
My 91 has no rev limiter... Just a fuel cutoff.... Don't ask me how I know this
And I wasn't free revving it
My 91 has no rev limiter... Just a fuel cutoff.... Don't ask me how I know this
And I wasn't free revving it
07-12-2007, 06:04 PM
#22
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Hey, something I know a little about!
Most modern ECUs will cut fuel in PARK to keep the engine from reving for too long.
Some of you have perhaps rev'd past 4K in NEUTRAL or DRIVE however. Very few manufacturers have a low end rev limit in place, only at the high end 6K+.
On my RS6 they implement a rev limited in DRIVE to keep owners from power launching. This is when you are in DRIVE, holding down the brake with your left foot and holding up the parking brake. On a launch (1/4 mile track, etc.) you first rev the engine to get the RPMs up, drop the parking brake while releasing your left foot from the brake.
On the RS6 the torque is so huge (twin turbo V8 @450HP, 480FT Lbs torque stock) that the problem is not the engine smoking but the transmission. It simply can't handle it. The rev limiter kicks in at 3,000 RPM while in DRIVE.
New cars with SMG, DSG, etc. have "Launch Modes" that essentially perform a power launch that is controlled by the computer. BMW'* M3, M5 and M6 all have this feature. Audi'* R8 and Lambo models have it as well. F1 shifters don't have an "automatic" mode so you are always using the paddles to shift.
I have performed a few power launches in my RS6 at the 1/4 mile track. It'* fun and give you good times (12.8 is my best) but is not good for the car long term.
So, keep in mind that the ECU is also trying to protect the automatic transmission as well as the engine. You can rev an engine all you want to the upper end limiter without any short term damage. Its when you then "dump" the transmission into gear when bad things happen.
Here'* a link to my 12.8 Sec run as my friends thought it would be funny to set me up against a full-on dragster Camaro that handed me my rear-end! I had been winning all day against the club cars (Southeast Lexus Owners Group and GT3000 Club). There were a few real dragsters there practicing on the track. You can hear them laughing in the background...
http://s49.photobucket.com/albums/f2...TrackDay90.flv
Most modern ECUs will cut fuel in PARK to keep the engine from reving for too long.
Some of you have perhaps rev'd past 4K in NEUTRAL or DRIVE however. Very few manufacturers have a low end rev limit in place, only at the high end 6K+.
On my RS6 they implement a rev limited in DRIVE to keep owners from power launching. This is when you are in DRIVE, holding down the brake with your left foot and holding up the parking brake. On a launch (1/4 mile track, etc.) you first rev the engine to get the RPMs up, drop the parking brake while releasing your left foot from the brake.
On the RS6 the torque is so huge (twin turbo V8 @450HP, 480FT Lbs torque stock) that the problem is not the engine smoking but the transmission. It simply can't handle it. The rev limiter kicks in at 3,000 RPM while in DRIVE.
New cars with SMG, DSG, etc. have "Launch Modes" that essentially perform a power launch that is controlled by the computer. BMW'* M3, M5 and M6 all have this feature. Audi'* R8 and Lambo models have it as well. F1 shifters don't have an "automatic" mode so you are always using the paddles to shift.
I have performed a few power launches in my RS6 at the 1/4 mile track. It'* fun and give you good times (12.8 is my best) but is not good for the car long term.
So, keep in mind that the ECU is also trying to protect the automatic transmission as well as the engine. You can rev an engine all you want to the upper end limiter without any short term damage. Its when you then "dump" the transmission into gear when bad things happen.
Here'* a link to my 12.8 Sec run as my friends thought it would be funny to set me up against a full-on dragster Camaro that handed me my rear-end! I had been winning all day against the club cars (Southeast Lexus Owners Group and GT3000 Club). There were a few real dragsters there practicing on the track. You can hear them laughing in the background...
http://s49.photobucket.com/albums/f2...TrackDay90.flv
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