750+ rwhp gear change

Bartly · Apr 10, 2017

Doctor Fishtail said:
You can do whatever you want. Buying ring n pinion is cheap. Finding a shop that can set them up correctly is a gamble. I chose to buy a complete pumpkin from Ford. $930 You do not have to adjust speedometer.

Tommy V said:
Are u saying when u go from 373 to 331 u dont need the flare tool to adjust the speedo?

dubster99 said:
He's saying if you buy the entire pumpkin from ford instead of just swapping the gear in your current pumpkin, you don't need the flare tool.

So hate to probably ask the obvious, but read this today and wanted to reply back and ask the same question as Tommy. So now I gotta know how the pumpkin is telling the speedo the correct info when it's swapped vs. having someone just replace the R&P. Is their some module on/in the pumpkin that updates the cars cornputer to the right speed?

Tommy V · Apr 10, 2017

dubster99 said:
He's saying if you buy the entire pumpkin from ford instead of just swapping the gear in your current pumpkin, you don't need the flare tool.

I dont think thats the truth,the speed sensor info either comes from the wheels speed sensors or the oss which is in the trans.So imo either way the correction needs to be done.Im changing my ring and pinion because i want to keep my torsion diff.

Doctor Fishtail · Apr 10, 2017

Tommy V said:
Are u saying when u go from 373 to 331 u dont need the flare tool to adjust the speedo?

No you do not need it. I ordered the Flare tool and never opened it. Got a refund. Our ECUs compensate for the small change going from 3:73s to 3:31s.

Tommy V · Apr 11, 2017

Doctor Fishtail said:
No you do not need it. I ordered the Flare tool and never opened it. Got a refund. Our ECUs compensate for the small change going from 3:73s to 3:31s.

Ok cool thanks for the heads up man,im doing a ring and pinion this weekend and that will make life alot easier. :headbang:

pwny · Apr 11, 2017

Doctor Fishtail said:
No you do not need it. I ordered the Flare tool and never opened it. Got a refund. Our ECUs compensate for the small change going from 3:73s to 3:31s.

I feel like I'm asking a question that's been answered but just wanted to ask one more time for clarity. Is this regardless of whether you go with a full pumpkin or just the ring & pinion setup?

Bartly · Apr 11, 2017

Doctor Fishtail said:
No you do not need it. I ordered the Flare tool and never opened it. Got a refund. Our ECUs compensate for the small change going from 3:73s to 3:31s.

So it compensates by correcting to the actual mph the car travels or does it compensate by still displaying the speed but will be off from alctual mph? Just seems strange that changing the rear gears wouldn't make the mph be off?

dubster99 · Apr 11, 2017

Doctor Fishtail said:
No you do not need it. I ordered the Flare tool and never opened it. Got a refund. Our ECUs compensate for the small change going from 3:73s to 3:31s.

I've never heard that before, because the small change of going from 305/35 to 305/30, the speedometer didn't adjust itself. Have you verified via gps?

Tommy V · Apr 11, 2017

dubster99 said:
I've never heard that before, because the small change of going from 305/35 to 305/30, the speedometer didn't adjust itself. Have you verified via gps?

Yea im not sure about this either,my speedo is off a little from tire size change.I will let u know after i do my gear change this weekend.

dubster99 · Apr 11, 2017

Mine was off 4-5mph from my GPS with the bigger tire.

Tommy V · Apr 11, 2017

dubster99 said:
Mine was off 4-5mph from my GPS with the bigger tire.

Yup im about the same,i will tell how much and if mine is off more this weekend.If so im sure its an easy fix.

dubster99 · Apr 11, 2017

Whipple flare tool or modifying the as-built data is the only way to change it. Ngauge and X4 will not.

Tommy V · Apr 11, 2017

dubster99 said:
Whipple flare tool or modifying the as-built data is the only way to change it. Ngauge and X4 will not.

Hey bud good news,i personally just went out to my car and hooked up my sct4.Once u get to wheir u are loading the tune it ask u for any changes.If u select yes the ×4 will display different gear ranges,select the one u want and it will redownload the tune u have in the computer now with the gear change being the only change.It works!!!.

Tommy V · Apr 12, 2017

Sct x4 does correct speedo now,u have to make sure it is updated.From my reading the update happened back in 2016.

5.0yote · Apr 12, 2017

Tommy V said:
Are u saying when u go from 373 to 331 u dont need the flare tool to adjust the speedo?

And no you do not need the whipple tool for your speedo going from 3.73 to 3.31s, there is a min max range that the ABS module looks at for the speedo, tire ratio etc. IF you do not go so far out of spec it will still read accurately.

For instance going from 3.31 to 3.55 in my GT and in my EBM netted no difference, however had I gone to something like a 4.56 from 3.31 it could possibly be out of range.

That is the nice difference between the S197 going off the trans and the S550 going off the ABS module.

Tommy V · Apr 12, 2017

5.0yote said:
And no you do not need the whipple tool for your speedo going from 3.73 to 3.31s, there is a min max range that the ABS module looks at for the speedo, tire ratio etc. IF you do not go so far out of spec it will still read accurately.

For instance going from 3.31 to 3.55 in my GT and in my EBM netted no difference, however had I gone to something like a 4.56 from 3.31 it could possibly be out of range.

That is the nice difference between the S197 going off the trans and the S550 going off the ABS module.

Gotcha,yea i knew the speedo got its info from the bcm and it could make small adjustments for tire changes.Didnt think it would correct for gears but if it does thats great,but theirs alot of guys saying their speedo is off still.I do know now that the sct does correct for this,weather i need it or not i will see this weekend.373 to 331 is a pretty big change.My buddy has a whipple with flare and he said he had to correct for his drag radials.

750+ rwhp gear change

Bartly

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Tommy V

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Doctor Fishtail

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Tommy V

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pwny

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Bartly

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dubster99

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Tommy V

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dubster99

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Tommy V

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dubster99

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Tommy V

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Tommy V

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5.0yote

AKA Bananana & 3.7Cyclone

Tommy V

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