Shift Points and RPMs
#1
01-26-2003, 02:48 PM
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Shift Points and RPMs
I did a search and could not come up with the answer I was looking for. I know this was discussed over a year ago and is being discussed on the NLOC board.
What is the safe shift point for maintaining max. HP and torque? Consider the variables, if one has a a pulley of 4 lbs or greater creating additional heated air to be ingested and an enahnced trans. valve body (Fatory Tech).
Do we really need to spin 5400 to 5600 rpm to make good quatrer mile times and "stay in the power band"? After 4900 rpm my peak HP starts flling fast and torque curve went south after 4000 RPM... I assume this varies from truck to truck.
Ron
What is the safe shift point for maintaining max. HP and torque? Consider the variables, if one has a a pulley of 4 lbs or greater creating additional heated air to be ingested and an enahnced trans. valve body (Fatory Tech).
Do we really need to spin 5400 to 5600 rpm to make good quatrer mile times and "stay in the power band"? After 4900 rpm my peak HP starts flling fast and torque curve went south after 4000 RPM... I assume this varies from truck to truck.
Ron
Last edited by Masterloggie; 01-27-2003 at 12:16 AM.
#2
01-26-2003, 05:15 PM
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#3
01-26-2003, 05:40 PM
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I'm thinking the same exact thing, except my research is not done with.
See url: My view on hp gains
See url: My view on hp gains
#4
01-26-2003, 08:41 PM
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Tundra,
Thanks for your input. If you have theory at this point I would like to know what it is. I have sent my chip back to Sal for reprogramming the AF mixture (my truck is inherently rich). I am thinking about dropping the shift points on the reburn. What RPM would you are anyone else intrested in this subject suggest?
Just doesn't make sense to be in the part of the power band at a high RPM with the HP falling and the torque falling drastically.
Ron
Thanks for your input. If you have theory at this point I would like to know what it is. I have sent my chip back to Sal for reprogramming the AF mixture (my truck is inherently rich). I am thinking about dropping the shift points on the reburn. What RPM would you are anyone else intrested in this subject suggest?
Just doesn't make sense to be in the part of the power band at a high RPM with the HP falling and the torque falling drastically.
Ron
#5
01-26-2003, 10:53 PM
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It was explained to me in depth but I'm burnt so I forgot exactly how it went.
The tuners are aware that our HP and Torque drop off quite quickly once we get into the 4000 plus RPM range. They also know we can loose as much as 20 to 40 HP in the next 1500 RPM.
But trial and error still shows it out ways shifting sooner which would now start the next gear at a lower RPM and also at much less HP and Torque. It also means loosing the momentum of the motor and Power Band, you know the old inertia rule, once in motion tends to stay in motion. I still disagreed and moved my shift points back down to stock AND HATED IT. I immediately moved them back up to 5500 RPM and all 6 programs I've been through since, have all shifted there. I wouldn't have it any other way (I even tried 5700 RPM, but found that a tiny bit much)
One night I had a computer problem and had NO shift points and NO rev limiter. I pinned the tach time after time waiting for a shift and the SOB was pulling like a MO FO way past 6k. So even know we may start loosing power in the mid 4's, we still got plenty in the mid 5's.
The tuners are aware that our HP and Torque drop off quite quickly once we get into the 4000 plus RPM range. They also know we can loose as much as 20 to 40 HP in the next 1500 RPM.
But trial and error still shows it out ways shifting sooner which would now start the next gear at a lower RPM and also at much less HP and Torque. It also means loosing the momentum of the motor and Power Band, you know the old inertia rule, once in motion tends to stay in motion. I still disagreed and moved my shift points back down to stock AND HATED IT. I immediately moved them back up to 5500 RPM and all 6 programs I've been through since, have all shifted there. I wouldn't have it any other way (I even tried 5700 RPM, but found that a tiny bit much)
One night I had a computer problem and had NO shift points and NO rev limiter. I pinned the tach time after time waiting for a shift and the SOB was pulling like a MO FO way past 6k. So even know we may start loosing power in the mid 4's, we still got plenty in the mid 5's.
#6
01-26-2003, 11:20 PM
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i started a similar discussion on nloc and over in the harley forum... check here...
https://www.f150online.com/forums/sh...hreadid=104495
http://www.datsuns.com/Tech/whentoshift.htm for a technical article that may explain better what I am trying to do...
Ken
https://www.f150online.com/forums/sh...hreadid=104495
http://www.datsuns.com/Tech/whentoshift.htm for a technical article that may explain better what I am trying to do...
Ken