hey folks i need some clarification again.. I have a 3007 silverado with the 4.8 and 465 4 sp with 245/70-17. Have a chance to put a set of 305/40-22 for an unbeatable price.. My neighbor is letting me use them now.. My concerns and questions are what can i realisticaly expect to see as far mileage and performance loss. I know about the more breaking required but I went to a comparison calculator and the difference is 3.8 %. ok is that alot,
heck i don not know...? As of now i have only done the k&n setup and a single/dual out magnaflow.. And since I didn't put the monitor sensors in, yes the lite is on. So can someone shed some lite on what to expect to get as the deal is too sweet to pass up. And at 900/1200 bucks a rear end gear swap aint gonna happen.
thanks

 

Well I can't help you with a 3007 Silverado. You'll have to wait another millennium for info on that.
Jk dude, what is your rear gearing? Those big wheels may help you on the highway some, but be prepared to pay for it in the city. Thats like going from a 3.73 to 3.42. Thats one serious loss in acceleration. As for the gear swap, it doesn't cost $900. I know of a few reputable shops in my area that would do it for 250.

 

You can get a ring and pinion from Rons Machining Services for about $200. most shops will put them in for 150-250. A dealership might charge 900 but they are out of their ******* minds.

 

Sorry about my mistakes guy, lol, I don't know my gearing..will it tell out rite on that little rear end tag or is there some formula i need. Also will a programmer do anything? I guess what I am asking is this, if I buy a programmer that compesates for different tire size, does that readjust my speedo or will that actually help me in the mpg dept? or do i have have to go back to basics and change the gear ratio to get a better mpg/performance backk??

 

DON'T GET A PROGRAMMER!!!!!!!!!!!!!!!! No, bad driver!
No seriously dude, check out Nelson, Wheatley, or Black Bear (our sponsers here) for a tune. Great stuff, 100x better than off the shelf programmers. As for the gears, they're listed in the glove box as codes. You will need to get lower gears to compensate for the taller wheel and tire combo. And yes, a tune will calibrate your speedometer. Not only that, but it can help with the MPG's by making your engine more efficient.

 

for gearing these are the RPO codes you will look for in your glove box.
GU4 3: 08 ratio

GU5 3:23 ratio

GU6 3:42 ratio

GT4 3:73 ratio

GT5 4:10 ratio

 

Oh man, pray you don't have 3.08's. Otherwise you're going to end up waving Prius' by until you're up to speed.

 

lol. I doubt. I think the 3.08's are only a 6speed option.

 

Oh I know, chances are he has 3.42's. Seems to be the most common factory set-up.

 

Got the gu5 3.23. Is this good or bad?