Stupid question.

Just purchased a used 2007 Tiburon gs with a four speed automatic tranny. At 65 mph on the highway it pulls 3000 rpms; at 60 it pulls 2700 rpms. This seems high for a vehicle that is supposed to get 30 mpg on the highway. Does a 2007 have an overdrive button someplace? I did not get a manual with this used vehicle. Also id 30 mpg a pipedream?

Also where is the best place to get replacement clips that holds down the cover that goes over the cargo area in back?

Thanks

 

Welcome to the forum. No, those aren't stupid questions.

First, Overdrive isn't a button you push, it's just any gear ratio in the transmission that has less then a 1:1 ratio. For example, the automatic transmission in your 2007 Tiburon GS 4-cyl automatic has the following ratios:
1st gear = 2.842
2nd gear = 1.529
3rd gear = 1.000
4th gear = 0.712 (this is an overdriven gear)

As you can see, gears 1 thru 3 are not overdrive but 4th gear is.

Now, using the overdriven 4th gear ratio of 0.712, the final drive ratio of 4.407 and the 205/55-16 tire diameter of 24.9" you can determine the correct RPM for any speed. For example:
70-mph should be at approx 3000-rpm
65-mph should be at approx 2500-rpm
60-mph should be at approx 2100-rpm

That's fairly close to what you are getting but not exact. So I would suspect the converter in the trans is not locking like it's supposed to do on the highway. That will allow for some slippage and raising the rpm for any speed by about 400-500 rpm. I'd have that looked into.

The other thing is your fuel economy. I don't know where you heard the 4-cylinder automatic Tiburon could get 30-mpg but the EPA ratings for your car are 20-mpg city and 27-mpg highway (source). Now, 30-mpg isn't out of the question but you would have to drive like a 90 year old granny with the A/C off and the windows up to get it. In "normal driving" I wouldn't expect more than 25-26 mpg. Remember, this is a 3000-lbs car with a 138-hp 4-cylinder engine and a 4-speed automatic trans.

Hope that helps.

 

Great explanation Nova. I appreciate the time and effort

 

Nova your the best lol