need tuning advice

[asite57]

I want to run 225/5016 tires which will throw off my wheel speed sensors I have the torque app can I use that to correct the speedo? If not how can I correct the speedo?

[blueguy]

You can't without an actual tuner.

Why do you want a smaller sidewall?

It's just going to give you more wheel gap.

[asite57]

i think it looks better 60 sidewall is just to much i might lower it in the future i know getting 17'' wheels is the best option but i cant afford it

[matt5112]

the PCM and BCM would need to be adjusted.

Unless you didn't care about ABS and leave it disabled all the time.

Then you'd only need to adjust the PCM.

PCM is $100 in credits via HPT or whatever the guy charges in DHP, if DHP can do it. Never looked into it, own HPT myself.

the BCM can only be changed by a tech 2.

So dealer or some shop who happens to have one would be your options. Don't think a dealer would do that for you though.

[asite57]

wait so lets say i get a 225/50R16 tire and dont wanna tune anything, my speedo will be off i can live with that. will that affect my traction control and abs?

[matt5112]

you can't legally "live with it".

It must be accurate or a certain percent higher as it effects your odometer as well.

Yes, both won't work properly.

[blueguy]

225/50/16 is 6.7% too fast compared to the factory 225/60/16...

Meaning when you are going about 60 mph, the speedo will read 55-56 mph.

[matt5112]

Opposite

[Fivefingerdeathpunch]

lol i read that and did a "huh" moment.

[darkhorizon]

wait so lets say i get a 225/50R16 tire and dont wanna tune anything, my speedo will be off i can live with that. will that affect my traction control and abs?

It wont hurt much... Trucks do it all the time...

You will get more "miles" on your car.. but it probably doesnt matter that much.

[asite57]

miles and speedo dont really matter that much idk im considering just biting the bullet and getting 17'' wheels you guys conviced me not to get the 50 with tire

[blueguy]

lol, I did say fast.

whoops

[Z34Phoenix]

one thing not considered.... a smaller diameter tire will give the effect of a different final drive. i run 245/45-17's these increase my final drive. i havent done the math now that i have the 3.29's but when i had the 3.73 gears for my DOHC, it made it equivalent to running a 4.10 ratio on stock tires. so im guessing my 3.29's with the same tire is more like a 3.69

another thing to consider is that the load on the engine will be different as well. since 60mph isnt really 60.

my advice is if you have access to a tuner to tune it. this way the speedo is right, and with a proper tune the shift points will be right for the load at the new mph and that you don't have KR due to a change in the final drive ratio.