shift points for stock cam???
- Thread starter Foxfan88
- Start date
TrunkFunk
Banned
A lot of it is feeling derived from just driving the car. If you are numb to the world around you it may be a bit more involved. Knowing the mannerisms of your car is more helpful than internet racers throwing figures out.
If you want a figure, how about 5200-5500 depending on which gear. The drop between each gear is not the same either.
Get to know your car.
Where were you shifting when you beat that Cobra?
If you want a figure, how about 5200-5500 depending on which gear. The drop between each gear is not the same either.
Get to know your car.
Where were you shifting when you beat that Cobra?
onefstsnake
New Member
Well if you can find a stock 5.0 Dyno sheet then shift when the power drops off.
The shop I take my car to says that a stock 5.0's power drops off before 5K.
I usually shift at 4800. After 5K the valves start to float...
The shop I take my car to says that a stock 5.0's power drops off before 5K.
I usually shift at 4800. After 5K the valves start to float...
timewarped1972
Member
Michael Yount
Mustang Master
Try these as a starting point -- let your et's guide your adjustments.
1-2 shift - 5000 rpm
2-3 shift - 4800 rpm
3-4 shift - 4600 rpm
Those should let the car drop back to right around the torque peak with each successive shift. Your quickest acceleration times should come if you can keep the car in the meat of the torque/HP curves.
1-2 shift - 5000 rpm
2-3 shift - 4800 rpm
3-4 shift - 4600 rpm
Those should let the car drop back to right around the torque peak with each successive shift. Your quickest acceleration times should come if you can keep the car in the meat of the torque/HP curves.
onefstsnake
New Member
IntenseBlue said:
It happens alot on older engines. The springs are old and cant close the valves quick enough at higher RPM.
25thmustang
Mustang Master
My stock motor I would shift at 5200 on an aftermarket tach (stock tachs are usually off some) and it got me decent times...
But like stated before, you have to know your car and where it likes to be shifted! Some cars its higher some lower (also with all the tachs being off different amounts, who knows where your actually pulling the gear)!
But like stated before, you have to know your car and where it likes to be shifted! Some cars its higher some lower (also with all the tachs being off different amounts, who knows where your actually pulling the gear)!
Michael Yount
Mustang Master
Foxfan - a set of dyno curves are really helpful -- you'll clearly see at what rpm the torque/HP to the wheels peak at. Armed with that, and your tranny gear ratios you can calculate what rpm you'll fall back to with each shift. You don't want to hold to far PAST the power peak in a gear, and you don't want to fall to far below the torque peak with each upshift. I suspect your torque peak occurs a bit higher than 3000. However, if it does actually occur at 3000, then your power peak is probably in the low 4000 range somewhere, and shifting even lower than I suggested may result in quicker times.
The old C4 Corvettes (mid 80's LT1) were shifted around 4400 rpm to achieve quickest lap times in road racing. Other than making noise, there was simply no reason to rev them any higher even though you could spin them up past 5000 in the lower gears -- it just resulted in going slower because you were well past the engine's power peak.
If you're serious about optimizing shift points, spend $50-70 for a dyno day and see what your actual torque/power peaks occur at rpm-wise. As mentioned above, a tach that matches up with the dyno tach helps too....
The old C4 Corvettes (mid 80's LT1) were shifted around 4400 rpm to achieve quickest lap times in road racing. Other than making noise, there was simply no reason to rev them any higher even though you could spin them up past 5000 in the lower gears -- it just resulted in going slower because you were well past the engine's power peak.
If you're serious about optimizing shift points, spend $50-70 for a dyno day and see what your actual torque/power peaks occur at rpm-wise. As mentioned above, a tach that matches up with the dyno tach helps too....
Michael Yount
Mustang Master
Keep in mind too the shape of the curves has an impact on all this. If the curves are real 'peaky' then shifting too high or too low has a bigger impact on acceleration rate compared to what happens with relatively flat curves.
25thmustang
Mustang Master
Your best bet. Go to the track with a notebook...
Change only the shift RPM, and see what was affected (where in the pass did it improve or was it hurt). This is the only real way to see what your car likes.
Change only the shift RPM, and see what was affected (where in the pass did it improve or was it hurt). This is the only real way to see what your car likes.
ninety1gt
New Member
onefstsnake
New Member
25thmustang
Mustang Master
TheChevyEater said:
Care to share the ETs you speak of???
My dads car with a stock cam (4 degrees retarded) went from 12.4s to 12.1s merely by going from 5500 shift points, to 6000 RPM! Granted his isnt like the cars mentioned here, but the right shift point for a car can be a huge improvement!
