I just got the 60k mile tune up thing done to my '04 Blazer. Driving on the highway going about 70mph the RPM is about 1800. Driving around town at about 40-45 the RPM is at about 1400. I'm just curious if this is going to hurt the engine or anything. Before the tune up the RPM was at about 2600 on the highway and 1800 in town.. thanks for your help!

-T

 

2 wheel or 4 wheel, auto or standard, and what's the axle ratio?

 

RWD, Auto.. axle ratio??? No clue..

 

2600 sounds crazy high. I'm right at 2000 doing 70-75 depending on load.

In town much lower.

Sounds like your tune up did what it was supposed to

 

Yeah, I wouldn't mind being at 1800 at 70mph. I'm at 2000 at that speed.

 

Yeah, we need some better information than what is provided like exact speeds and RPM readings for various speeds...

To determine your axle ratio, check the RPO codes in your glove box. At 1800RPM doing 70MPH, I would venture a guess at 3.08:1 rear end gears with a possibility of 3.42:1 because I do believe that the extremes came with smaller tires.

 

I think at 70MPH I'm at like 2200RPM... in 5th gear, lol.

3.42s and 30" tires...

came stock with 235/75/R15s...

If the engine doesn't have to work as hard, the RPM's will be lower in whatever gear you're cruising in...

 

now that my torque converter is locking my rpms are at about 1800/1900 @ 65

used to be like 2250 went i would just be in overdrive w/o locking TC

 

yea tc lock makes a huge difference.

At 70mph my tach is at 2050 rpms. 30" tires, 3.42 gears, and auto tranny with upgrades.

 

Thanks ya'll.. maybe I can stop fixating on my tach. and start watching the road!