Another Re-gear question
12-28-2018, 09:37 AM
#21
Haha, they thought of that. Once the Flashpaq is paired to a VIN, it only works on that VIN. I was thinking the same thing... I thought "why can't my off-road shop just program this!?" It's fine though, it wasn't that expensive and it's worked great for me.
12-28-2018, 10:42 AM
#22
Senior Member
3.73's will give your truck an effective gear ratio slightly lower than what you have now, and that's good. You need to go a little beyond "status quo" in order to compensate for the extra mass and increased rolling resistance of the larger/heavier tires. I would consider 3.73 to be the minimum gear if you're going to go through with it. I wouldn't hesitate to go with 4.10's if you plan on staying with 34" tires. I've done 3 re-gears over the years, and two were on the same truck/same tires (14x36). First one got 4.56, second time around I went with 4.10. I liked the 4.56 WAY better. My point is, don't fear the gears. You'll have plenty of people trying to rationalize how the ECO doesn't need deeper gearing, due to the fact that it's boosted. Hogwash. As stated in the previous post, torque to the wheels equals engine torque x axle ratio. If you're on the fence between two ratios, go low (numerically high).
-- Another way to look at it. If your truck was still bone stock and you re-geared it to 3.55, that's about how it's going to perform with the big tires and 4.10's. You won't be sorry.
-- Another way to look at it. If your truck was still bone stock and you re-geared it to 3.55, that's about how it's going to perform with the big tires and 4.10's. You won't be sorry.
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PerryB (12-28-2018)
12-28-2018, 10:56 AM
#23
Senior Member
Engine RPM is based off a crank sensor - period. It's crank revolutions, absolutely nothing else.
The 'Revs' that handhelds use for speedo calculation is tire revolutions, not the same thing.
I'd go 4.10s for 34/35" tires. It won't be 'too aggressive'. Factory Raptors come with 34.5" tires and come with 4.10s both 6 and 10spd. Transmission / engine - power / torque is irrelevant.
The 'Revs' that handhelds use for speedo calculation is tire revolutions, not the same thing.
I'd go 4.10s for 34/35" tires. It won't be 'too aggressive'. Factory Raptors come with 34.5" tires and come with 4.10s both 6 and 10spd. Transmission / engine - power / torque is irrelevant.
Last edited by WarSurfer; 12-28-2018 at 10:59 AM.
12-28-2018, 12:10 PM
#24
Engine RPM is based off a crank sensor - period. It's crank revolutions, absolutely nothing else.
The 'Revs' that handhelds use for speedo calculation is tire revolutions, not the same thing.
I'd go 4.10s for 34/35" tires. It won't be 'too aggressive'. Factory Raptors come with 34.5" tires and come with 4.10s both 6 and 10spd. Transmission / engine - power / torque is irrelevant.
The 'Revs' that handhelds use for speedo calculation is tire revolutions, not the same thing.
I'd go 4.10s for 34/35" tires. It won't be 'too aggressive'. Factory Raptors come with 34.5" tires and come with 4.10s both 6 and 10spd. Transmission / engine - power / torque is irrelevant.
12-28-2018, 12:33 PM
#25
Agreed as well. That's why I didn't mention the tach in any of my posts and we went to just discussing actual effects on the truck vs the terminology.
That said, all of the adverse effects of changing tire size that we discussed (speedo, odometer, mpg readout, etc) still hold true, so a programmer would still be something to look into. even with an actual gear swap. If not for any other reason than avoiding a speeding ticket!
That said, all of the adverse effects of changing tire size that we discussed (speedo, odometer, mpg readout, etc) still hold true, so a programmer would still be something to look into. even with an actual gear swap. If not for any other reason than avoiding a speeding ticket!
12-28-2018, 02:16 PM
#26
Agreed as well. That's why I didn't mention the tach in any of my posts and we went to just discussing actual effects on the truck vs the terminology.
That said, all of the adverse effects of changing tire size that we discussed (speedo, odometer, mpg readout, etc) still hold true, so a programmer would still be something to look into. even with an actual gear swap. If not for any other reason than avoiding a speeding ticket!
That said, all of the adverse effects of changing tire size that we discussed (speedo, odometer, mpg readout, etc) still hold true, so a programmer would still be something to look into. even with an actual gear swap. If not for any other reason than avoiding a speeding ticket!
And no, you never mentioned anything about the Tach. You did say in your first post that the programmer would raise the RPM's because tire size is part of that formula, and that is what I was hung up on because it isn't possible. I think it was just a misunderstanding of what you were trying to say and how I interpreted it. But its all good man! Thanks for the input, didn't mean to be a thorn in your side haha
12-28-2018, 02:44 PM
#27
Haha, all good! I've enjoyed chatting with you!
12-28-2018, 06:39 PM
#28
Junior Member
The speedometer is driven by the transmission output speed sensor + programmed gear ratio + tire size. The rpm is never used for this calculation. To prove this: while coasting, put your truck in neutral and rev the engine. You will see the RPM's change with no effect on the speedometer. Speed, RPM and throttle position are calculations used in the shift points.
12-28-2018, 10:18 PM
#29
12-29-2018, 06:49 AM
#30
Thats actually false. On a 34” tire, to get the same feel of stocks with 3.55 then you go to 3.73. You can use this ratio calculator to see.