Performance/ mileage off since level

[Mikeybl]

Hey Gang

I've got a quick question.

I put a 2.25"f/ 1.5"r Readylift leveling kit and 305/50r20 Cooper AT's on back in November. I knew I'd take a hit on mileage, but it seems to keep getting worse each week. I've lost 3-4 mpg and it's increasing. Performance is also off, passing on the highway is painful at best. Is this ALL a cause do to the lift and tires, or would it be needing a tune up? I have also noticed my oil temp gauge is moving more when I throttle, and for the first time between oil changes, I actually have to top up my oil.


Any help would be awesome, Thanks!

 

[Rd05lly]

Did you correct speedo for tire size.

 

[Mikeybl]

No. According to GPS I'm only out 1 km/h. I know I probably should have it addressed, but I have gone from 1 tank a week to almost 2.

 

[Rd05lly]

The added rolling weight is not helping from tire and wheel upgrade. Check mileage difference on GPS and trip on next tank. Maybe tune up time are you letting it idle to warm could kill your mileage too.

 

[Mikeybl]

Thanks, I'll probably get a tune up done, just didn't want to if its just the tires/ lift. I guess it can't hurt any.

 

[Rd05lly]

Getting a tune will fix the speedo and the get up and go as well. But data log and make sure everything is right first.

 

[TacHoe]

what size gears you got?

 

[Mikeybl]

what size gears you got?

No idea lol. Whatever stock is. its an 07 slt

 

[TacHoe]

No idea lol. Whatever stock is. its an 07 slt

Go here CLICKY first and put your VIN in. This will decode it all in an easy to follow format, and will outline EVERYTHING about your vehicle, even some things you didn't know (for me it was that I had power folding side mirrors, and 3.73 gears).

Start here and look for gearing size. Depending on your gears you may have put on tires that were too big to compensate for the gearing. This may be the reason you are experiencing what you mentioned. I would start here in your search to discover "why". Then worry about the fix, because the fix may be going with a smaller diameter tire, as opposed to say getting a tune to adjust the speedo.

There are also threads, and links here that I have seen that explicitly go over how to determine what your "actual" gear ratio is once you have put larger tires on. Search around a bit both here and on the web, the actual calculator to determine such was very difficult to follow for me personally but the explanations provided by other members helped clarify; how it works, what my tire size limit is for my gear ratio, etc

 

[Rd05lly]

http://www.4lo.com/calc/geartire.php