what the best way to upgrade

[62f100]

im going from a ford tbi to a bigger gm tbi. im not changing any sensor except for tpi. so should i start a new file or just change the constants to reflect the new injector? thanks for any opinions.

[jsmcortina]

Unless your opening time was set right and will be set right you will likely need to do a little retuning, but in general keep your tune and make the ReqFuel adjustment in the constants page.

James

[62f100]

thank for the info. nothing was realy right about the tune,but im using ford sensors & have those reading right.i needed the bigger tbi & had the gm sitting around so it was cheap.