Curious 318ti driver

[tomslik3]

I have a couple questions for you knowledged people out their. I have a 95' 318ti w/oem wheels and tires. Chipped, with cold-air. Live in Calif. My question is. What should I be tach-ing at(rpm), doing 70mph. It scares me to drive any long distance at 3500 to 4000rpm. Or is that normal. Also, I have GPS navigation in my car. And it displays my mph. Which is 4-5 mph faster than what the car speedo says. Whats up with that.
Thanks for any info..................

[CirrusSR22]

The speedo should be reading a few mph faster than the actual speed. So, if the speedo says 70mph, the GPS should be showing 67 mph or somewhere near that. That's how all BMWs are, even the newest ones.

As for cruise RPM, that seems a bit high for 70 mph indicated. The automatic transmission cars (in 4th/top gear) I believe should be very near 3,000 RPM at 70 mph indicated. The manual transmission cars (in 5th/top gear) slightly higher, somewhere near 3,250 at 70 mph indicated.

If you are above 3,500 RPM at 70 mph, the previous owner probably installed a non-stock differential in an effort the get better acceleration. You can check this by looking at the differential tag. In the back cover of the differential there should be a small metal strip held in place by one of the diff. cover bolts. It'll probably be corroded by now (if it's still there), but it should either have "3.45" or "4.44" etched into it depending on whether your car is a manual or automatic respectively. Those are the gear ratios that came standard.

[familytruckster]

all of them are ~5 mph fast. You should see what some other cars read. It's a built in "safety" feature.

[tiFreak]

Originally Posted by familytruckster

It's a built in "safety" feature.

that's to keep BMW safe from lawsuits, not to keep you safe

[vsonix]

I rev @ about 4.5k in 5th at an indicated 90-95mph.
Funnily enough fuel economy doesn't seem to suffer too much at those speeds whereas my old car which was a 16v 2.0 would gulp down the petrol when at that rev level.
M44 loves to rev! Engine noise can get a bit wearing on long motorway runs but you get used to it eventually.

[FMD]

my car hits 5k at around 80mph w/ a 4:10 final drive, I wouldn't worry about it. my gas mileage is pretty terrible though I must say.

[dave45056]

Originally Posted by CirrusSR22

The manual transmission cars (in 5th/top gear) slightly higher, somewhere near 3,250 at 70 mph indicated.

I concurr... my stock 5 speed, stock diff ti revs exactly that.

[jca]

My ti automatic and my Z3 five speed both turn at 3,000 rpm at 70 miles an hour. I once owned a Mazda RX 2 rotary four speed that turned 4,000 rpm at 70 miles per hour.

[Mad-Machine]

It won't hurt your car if that is what you are worried about.

I have a fiat 124 spider that tachs at 4grand for 70mph.. car has 120,000+ miles on it.. mostly highway