Redline RPM
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Redline RPM
I recently acquired a 1985 F250 diesel with the 6.9 Navistar. It is a T19 no OD equipped model. Unfortunately it has not tach. I calculated out a rpm at speed graph for every gear, but, I have no idea what the redline rpm's are. I know peak torque is at 1400 rpm, peak hp at 3300.
Does anyone know the redline rpm's?
Thanks
Does anyone know the redline rpm's?
Thanks
Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
My tach has a yellow line and then a redline.
Yellow line starts at 3,300 rpm, redline starts at around 3,800 rpm.
My IP on the 93' turbo physically cuts out around 3,500 rpm when lightly loaded. (sudden loss of power) It probably would keep going further up to 3,800 under load.
Have never redlined my 91' N/A so I am not sure what it would do. Usually the the E4OD shifts up when you try to exceed 3,300 rpm.
Seb......
Yellow line starts at 3,300 rpm, redline starts at around 3,800 rpm.
My IP on the 93' turbo physically cuts out around 3,500 rpm when lightly loaded. (sudden loss of power) It probably would keep going further up to 3,800 under load.
Have never redlined my 91' N/A so I am not sure what it would do. Usually the the E4OD shifts up when you try to exceed 3,300 rpm.
Seb......
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Most IP's are generally set up for 3500 to 3600 RPM at WOT and no load.
Some will not go that fast, others go faster.
Some will not go that fast, others go faster.
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Elder User
Joined: Sep 2006
Posts: 561
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From: Edmonton, Alberta Canada
Whats the maximum amount of time that you can stay in the yellow/red line before it starts to damage your engine, and does it matter if you're pulling something or not? Will the damage be more severe if you're pulling something?
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Fleet Mechanic
Joined: Sep 2005
Posts: 1,509
Likes: 3
From: Ladner, British Columbia
You will know you have overdone it when:
Seb.....
- Your windshield starts to turn green with Antifreeze.
- Push Rods and Headbolt start to put dimples in your hood as they pop up against the hood.
- The guy driving behind you starts turning on his headlights because his day suddenly went to night.
- You are experiencing a sudden loss of power.
- You suddenly realize that redline means don't run beyond that or bad things might happen to your truck.
Seb.....
Elder User
Joined: Sep 2006
Posts: 561
Likes: 0
From: Edmonton, Alberta Canada
Ok...I know that part, I just want to know like...how many seconds can you stay in there before damage starts to occure. Like when you hard steer left or right, you're only supposed to do it no longer than 5 seconds or it will damage the pump or something like that.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
The engine is governed out at an RPM the engine can stand to run at for days at a time. driving around at 3300 RPM will be much harder on your wallet when you get to the fuel pumps than it will be on the engine.
The only way to overspeed the engine is dropping down a hill and letting the engine overspeed or downshifting at a speed to high for the next gear down.
I can run 48 MPH in third gear with my 4 speed at 3300 RPM.
If I tried to downshift from 4th to 3rd at 65 MPH the RPM would shoot up to 4400 RPM.
That would not be good for the engine or the wallet.
The only way to overspeed the engine is dropping down a hill and letting the engine overspeed or downshifting at a speed to high for the next gear down.
I can run 48 MPH in third gear with my 4 speed at 3300 RPM.
If I tried to downshift from 4th to 3rd at 65 MPH the RPM would shoot up to 4400 RPM.
That would not be good for the engine or the wallet.
New User
Joined: Jun 2006
Posts: 17
Likes: 0
[QUOTE=Hamberger]You will know you have overdone it when:
that was dam funny reading this reminded me of u might be a red neck if.........
- Your windshield starts to turn green with Antifreeze.
- Push Rods and Headbolt start to put dimples in your hood as they pop up against the hood.
- The guy driving behind you starts turning on his headlights because his day suddenly went to night.
- You are experiencing a sudden loss of power.
- You suddenly realize that redline means don't run beyond that or bad things might happen to your truck.
that was dam funny reading this reminded me of u might be a red neck if.........
Elder User
Joined: Sep 2006
Posts: 561
Likes: 0
From: Edmonton, Alberta Canada
Originally Posted by Dave Sponaugle
The engine is governed out at an RPM the engine can stand to run at for days at a time. driving around at 3300 RPM will be much harder on your wallet when you get to the fuel pumps than it will be on the engine.
The only way to overspeed the engine is dropping down a hill and letting the engine overspeed or downshifting at a speed to high for the next gear down.
I can run 48 MPH in third gear with my 4 speed at 3300 RPM.
If I tried to downshift from 4th to 3rd at 65 MPH the RPM would shoot up to 4400 RPM.
That would not be good for the engine or the wallet.
The only way to overspeed the engine is dropping down a hill and letting the engine overspeed or downshifting at a speed to high for the next gear down.
I can run 48 MPH in third gear with my 4 speed at 3300 RPM.
If I tried to downshift from 4th to 3rd at 65 MPH the RPM would shoot up to 4400 RPM.
That would not be good for the engine or the wallet.
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