Speedometer re-calibration? 3.73 gears,tires

[FivepointOHYEAH]

Howdy, I am trying to go from a 27.3 diameter tire to a 28+ diameter tire and go from a rear axle of 3.31 to 3.73.

I know mechanically it will be not so bad but I dont know how to re-calibrate my ECU or speedometer. I could buy a tuner but not sure if that would void my warranty by just adjusting the ratios in the computer even though it wont touch how the engine runs at all.

I appreciate your input.

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[Livernois Motorsports]

Howdy, I am trying to go from a 27.3 diameter tire to a 28+ diameter tire and go from a rear axle of 3.31 to 3.73.

I know mechanically it will be not so bad but I dont know how to re-calibrate my ECU or speedometer. I could buy a tuner but not sure if that would void my warranty by just adjusting the ratios in the computer even though it wont touch how the engine runs at all.

I appreciate your input.

A tuner can fix that calibration for you no problem! We have our MyCal tuner that we can hook you up with, and custom tuning to cure your ailments!

 

[FivepointOHYEAH]

A tuner can fix that calibration for you no problem! We have our MyCal tuner that we can hook you up with, and custom tuning to cure your ailments!

Will simply using the tuner to recalibrate the system cause Ford to see that I have tuned my car? Because I dont want to tune it yet, or appear that I have tuned my car, yes i do understand an actual tune effects the engine while this will not.

 

[68fbjjz109]

I am curious about this as well. As I may try and find a complete 3.31 or 3.55 carrier from an automatic car to swap into my Manual GTPP.

 

[Livernois Motorsports]

Any modification that like that you make like that needs to be explained to the ECU. So "tuning" is the correct way to do so. We have tuned hundreds of S550's without failure. If you have to make an oil change trip to the dealer or something just flash it back to stock, easy peasy! Your MyCal holds you stock file at all times as well as upto 4 custom tune files.

What is the aversion to tuning?

 

[oilfieldtrash]

Howdy, I am trying to go from a 27.3 diameter tire to a 28+ diameter tire and go from a rear axle of 3.31 to 3.73.

I know mechanically it will be not so bad but I dont know how to re-calibrate my ECU or speedometer. I could buy a tuner but not sure if that would void my warranty by just adjusting the ratios in the computer even though it wont touch how the engine runs at all.

I appreciate your input.

Just my opinion but pretty sure ford could tell it was accessed by an outside tuner. Whether or not you touched the engine parameters or not I'm betting they'd love to void your warranty by claiming you tuned it if it could get them out of an costly engine repair. Good luck on claiming you never touched the engine in that scenario.

 

[oilfieldtrash]

Any modification that like that you make like that needs to be explained to the ECU. So "tuning" is the correct way to do so. We have tuned hundreds of S550's without failure. If you have to make an oil change trip to the dealer or something just flash it back to stock, easy peasy! Your MyCal holds you stock file at all times as well as upto 4 custom tune files.

What is the aversion to tuning?

Right now I'm sitting on a stock engine I can drive at full throttle up to 60k miles and not worry one bit over a powertrain repair. I can literally smoke the tires coming out my driveway everyday and not have a single worry about something breaking. That is piece of mind and why people buy new cars. If I wanted to be on the hook for my car I'd bought a used car and saved myself some money.
I respect what you guys do and appreciate that you exist for those that decide to tune their cars. Do understand it's not for everyone.

 

[kcphoto21]

Hey guys, first of all sorry if this question is in a wrong thread.

I have a 2016 Mustang that came with stock 20" wheels. Problem is the tires are summer only. I live in midwest where it snows.

So, I bought stock 18" wheels and tires from eBay thinking I will run all seasons in winter and summer only wheels in summer.

Wanted to ask if I need to re-calibrate the speedometer.

Here are the dimensions.

Stock summer only: 265/35R20 = (265 * 0.35)*2 + (20"*25.4) = 27.30 inches
All Season tires: 235/50R18 = (235 * 0.5)*2 + (18"*25.4) = 27.25 inches

There is a very small change in diameter, do I still need to re-calibrate the speedometer.

Many thanks!

 

[dgc333]

No need to recalibrate the speedo. Those are stock sizes from the factory. You can see more difference than your calculated difference brand to brand or even model to model within the same brand.

There is no standards for how tires are to be measured so there will be differences in actual tire dimensions from the advertised size.

 

[Gibbo205]

Any modification that like that you make like that needs to be explained to the ECU. So "tuning" is the correct way to do so. We have tuned hundreds of S550's without failure. If you have to make an oil change trip to the dealer or something just flash it back to stock, easy peasy! Your MyCal holds you stock file at all times as well as upto 4 custom tune files.

What is the aversion to tuning?

Ford can still detect the car has been tuned/flash even if you restore the stock file before visiting the dealership.

The moment you flash/tune the car your warranty is void on the powertrain if Ford wish to do so as they can detect it.

 

[68fbjjz109]

Ford can still detect the car has been tuned/flash even if you restore the stock file before visiting the dealership.

The moment you flash/tune the car your warranty is void on the powertrain if Ford wish to do so as they can detect it.

I would have to double check, however I believe stateside they still have to prove your tune caused the failure. Right now Ford offers gears, and differentials. But no means to appropriately change the ECU settings if a customer decides to use a Ford Performance gear set on their Mustang. Seems very shortsighted.

 

[Livernois Motorsports]

Ford can still detect the car has been tuned/flash even if you restore the stock file before visiting the dealership.

The moment you flash/tune the car your warranty is void on the powertrain if Ford wish to do so as they can detect it.

What is detectable is that someone accessed that port. That is the same thing that would be seen if you plugged in a code scanner. This counter would also keep the exact same record every time that your dealership plugs into your OBDii port. The fact that you accessed the port for WHATEVER reason does NOT void any warranty. We have hundreds of vehicles that are sent to us from dealerships for us to mod!

In order for them to void anything they have to prove that the tune caused the failure. We have been doing this for years across the 3 domestic makes without any fires.

 

[Gibbo205]

What is detectable is that someone accessed that port. That is the same thing that would be seen if you plugged in a code scanner. This counter would also keep the exact same record every time that your dealership plugs into your OBDii port. The fact that you accessed the port for WHATEVER reason does NOT void any warranty. We have hundreds of vehicles that are sent to us from dealerships for us to mod!

In order for them to void anything they have to prove that the tune caused the failure. We have been doing this for years across the 3 domestic makes without any fires.

Of course but most Ecu have a hex of flag entry that changes checksum when the car is tuned / remapped that is different than what is registered when just plugging in a code scanner.

Most modern ECU's have first of all a flash counter and also a checksum in the Ecu which changes when the car is tuned and does not revert back.

 

[Livernois Motorsports]

Nobody is saying that tuning is undetectable, but the dealership does not have the desire to waste money and go through lines of coding to find a tune. As long as we have been tuning we have not failed a client's vehicle VIA tuning, nor to my knowledge have we had any denials either.

 

[Gibbo205]

Nobody is saying that tuning is undetectable, but the dealership does not have the desire to waste money and go through lines of coding to find a tune. As long as we have been tuning we have not failed a client's vehicle VIA tuning, nor to my knowledge have we had any denials either.

That was all I was getting at buddy.

I think no one is questioning your abilities, if I was to get my car tuned I'd probably go with you guys as you seem the most clued up and have dug that bit deeper than other tuners with the S550 platform.

My point was should your engine explode, Ford can detect if the car is or was tuned in the past at which point they can deny a warranty claim, even if the tune was not the cause for failure. Your then at the stage of courts and having Ford to prove the cause of the failure or not deny warranty and fix the vehicle.

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