Forscan and the 2020 GT500

[MidnightStars]

I have a 2021 GT500 and will be changing my rear tires from the stock 315/30R20 to M/T ET Drag Race 305/45/R18. I realize that I need Forscan to make the change. in the ECU and I have a few questions.

1) I plan on using a PC to make the changes but also like the fact I can use my Iphone. On Forscan's website under supported adapters it shows OBDlink EX USB for Forscan. It shows the OBDLink MX+BT for Forscan Lite. It looks like the MX+BT is more $$ , has more software, supports more OS but not sure if its the best adapter for Forscan in my situation. I'd also like to use the OBDlink on my wife's Durango and not just for my GT500. Can anyone advise me?

2) Can someone tell me how and what to input to make the change to my car for the change to the 305/45/R18 tires ?

3) I am planing on possibly putting 1" taller tire in the front over the factory 305/30R20 as well. I am hearing that chaning the tire size in the front will usually cause an error code. It seems the adjustment in Forscan talked about here is only to address the rear tire. Any advise on how to get a taller tire in the front in conjunction with the rear?

Thanks!

Forscan Lite is way more limited. It is primarily set to serve as a way to view codes w/o the need for your laptop.
FORScan FAQ

Why "Lite" version for mobile platforms and not "full"?

"Lite" means this version of application is simplified to be used on mobile devices as safe as possible. Service and Programming functions are not safe, and using them on mobile devices is quite not desirable because of the platforms nature: using wireless devices (that are less reliable than USB ones), possibility to get application killed or freezed by OS during a critical operation (e.g. because of incoming call or other reason) and so on. Nevertheless, we think on adding relatively safe service functions to FORScan Lite.

Get the OBDLink EX USB to OBD-II, and Forscan w/ the Extended License (free for two months) for a laptop or tablet. I have a small 13" laptop (an oldie) that I'll be dedicating for my car, but you it's not necessary for a dedicated device. If you want to go for any other cable, get one that supports HS/MS Can bus lines (either with a toggle switch, or electronically)--MS CAN bus is a Ford specific OBD-II protocol.

Finally, how to change tire size: How to use FORScan to adjust tire size - FORScan forum

As for your wife's Durango, you would need to see if it has any OEM specific protocols (depends on year model).

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[bent98]

Forscan Lite is way more limited. It is primarily set to serve as a way to view codes w/o the need for your laptop.
FORScan FAQ

Get the OBDLink EX USB to OBD-II, and Forscan w/ the Extended License (free for two months) for a laptop or tablet. I have a small 13" laptop (an oldie) that I'll be dedicating for my car, but you it's not necessary for a dedicated device. If you want to go for any other cable, get one that supports HS/MS Can bus lines (either with a toggle switch, or electronically)--MS CAN bus is a Ford specific OBD-II protocol.

Finally, how to change tire size: How to use FORScan to adjust tire size - FORScan forum

As for your wife's Durango, you would need to see if it has any OEM specific protocols (depends on year model).

Thanks for that. I ordered the EX as per your recommendation.

Regarding the link you provided, Its generic to all Ford vehicles, can you validate is this is the exact process for 2020+ GT500 vehicles? Are there any missing or extra steps in this instruction guide?

What about changing the front tire height?

 

[MidnightStars]

Thanks for that. I ordered the EX as per your recommendation.

Regarding the link you provided, Its generic to all Ford vehicles, can you validate is this is the exact process for 2020+ GT500 vehicles? Are there any missing or extra steps in this instruction guide?

What about changing the front tire height?

I highly doubt it would be any different. If they are, you can always ask for help on the FORScan forums.

And there is no need to change any setting for the front tires (don't think there is any option anyway). The speedometer is based off the rear drive wheels. And the tire settings are for all tires--doesn't make sense to have different sized tires in terms of overall diameter.

 

[bent98]

I highly doubt it would be any different. If they are, you can always ask for help on the FORScan forums.

And there is no need to change any setting for the front tires (don't think there is any option anyway). The speedometer is based off the rear drive wheels. And the tire settings are for all tires--doesn't make sense to have different sized tires in terms of overall diameter.

Well the issue is that since I am putting a 1.5" taller tire on the rear (which Ive been told doesnt throw a code but will throw off the speedometer) I will want to put taller tires on front. Ive been told that once you chang the front tires you can get codes thats why I am asking. I need to put a taller tire on the front so the car doesnt rake and get it higher off the ground because I will be installing kooks long tubes and a whipple which requires you to drop the engine by 1/2-3/4 of an inch so it clears the strut tire brace.

 

[Jmeo]

You will not get codes changing the front height, and you will not affect the speedo by changing the front height. You only need to do the changes in Forscan for the rear tires.

 

[MidnightStars]

Well the issue is that since I am putting a 1.5" taller tire on the rear (which Ive been told doesnt throw a code but will throw off the speedometer) I will want to put taller tires on front. Ive been told that once you chang the front tires you can get codes thats why I am asking. I need to put a taller tire on the front so the car doesnt rake and get it higher off the ground because I will be installing kooks long tubes and a whipple which requires you to drop the engine by 1/2-3/4 of an inch so it clears the strut tire brace.

Putting in taller tires in general without recalibrating the speedometer can throw codes, granted that they're tall enough. That's a large enough jump to where the transmission will try to shift early, then notice the load change isn't anywhere near on par on what it thinks it should be. That can usually kick out codes, or stunt your car into limp mode.

Either way, the codes aren't a big deal, and won't damage your car simply because you changed the effective gear ratio. If the FORScan changes don't work out, you can re-write the AS-BUILT data back in (speaking of which, the very first thing you should do is back up all your AS-BUILT data to your device).

 

[Epiphany]

I would space up the rear of the hood a good 3/8" to 1/2" as you barely notice it except right at the rear of the hood itself and probably only if you knew it was done. You could then space the strut tower brace up a good 1/2". I'd consider that before playing with engine height, which can affect driveline angles, or dealing with tire issues, etc.

 

[bent98]

I would space up the rear of the hood a good 3/8" to 1/2" as you barely notice it except right at the rear of the hood itself and probably only if you knew it was done. You could then space the strut tower brace up a good 1/2". I'd consider that before playing with engine height, which can affect driveline angles, or dealing with tire issues, etc.

I didnt know that was possible.Do you know anyone who did that?

relating to the tires, I would also like to get this car higher off the ground especially with the taller tire in the rear but not having to lower engine and maintain strut tower is a plus

 

[bent98]

Putting in taller tires in general without recalibrating the speedometer can throw codes, granted that they're tall enough. That's a large enough jump to where the transmission will try to shift early, then notice the load change isn't anywhere near on par on what it thinks it should be. That can usually kick out codes, or stunt your car into limp mode.

Either way, the codes aren't a big deal, and won't damage your car simply because you changed the effective gear ratio. If the FORScan changes don't work out, you can re-write the AS-BUILT data back in (speaking of which, the very first thing you should do is back up all your AS-BUILT data to your device).

Wouldnt the tune take that into consideration? Definalty wouldnt want limp mode. Plus many people run this rear tire combo, just not front.

 

[bent98]

You will not get codes changing the front height, and you will not affect the speedo by changing the front height. You only need to do the changes in Forscan for the rear tires.

There is an issue with the ABS sensor that can throw a code depending on front and rear tire combos from what I’ve been told

 

[Epiphany]

I didnt know that was possible.Do you know anyone who did that?

I've done it on other cars. Don't see why this one would be any different. Years ago we did it for better airflow at the cowl as well as clearance. Aero is indeed managed much better now than it used to be though.

 

[Jmeo]

There is an issue with the ABS sensor that can throw a code depending on front and rear tire combos from what I’ve been told

I suppose anything is possible. I was running 1" taller tires (front & rear) on my GT500 for a few months without getting codes, but I was running taller tires front & back at the same time. I believe the real issue (besides incorrect speedo) is when you run smaller diameter tires on the rear. In my experience the front tire has height has not thrown any codes.

 

[bent98]

I suppose anything is possible. I was running 1" taller tires (front & rear) on my GT500 for a few months without getting codes, but I was running taller tires front & back at the same time. I believe the real issue (besides incorrect speedo) is when you run smaller diameter tires on the rear. In my experience the front tire has height has not thrown any codes.

Thank you for confirming . That’s what I deduced as well. Tell me , the Instructions that midnight provided https://forscan.org/forum/viewtopic.php?t=15994

Is that exactly what you did? I’m wondering if there any extra steps required or not.

 

[bent98]

I suppose anything is possible. I was running 1" taller tires (front & rear) on my GT500 for a few months without getting codes, but I was running taller tires front & back at the same time. I believe the real issue (besides incorrect speedo) is when you run smaller diameter tires on the rear. In my experience the front tire has height has not thrown any codes.

I also forgot to ask what size rim/tire and rim offset did you run in front ?

 

[Jmeo]

Thank you for confirming . That’s what I deduced as well. Tell me , the Instructions that midnight provided https://forscan.org/forum/viewtopic.php?t=15994

Is that exactly what you did? I’m wondering if there any extra steps required or not.

Yes, this is the same as what I did.

I also forgot to ask what size rim/tire and rim offset did you run in front ?

I was running 315/30/21 fronts and 325/30/21 rears before I got the wide body SE and went back to stock front and 345/30/20 rears.

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