any way to get the rpms down when in 5th?

[guitarliketom]

i know its the way the car is geared but when im doing above 75ish in 5th in my 318is im running at about 4k rpm.
I'm pretty sure the answer is no, but is there anything I can do to keep it from running so high?:dunno:

[Ramine]

not really mate, i suyppose changing diff? will giuve lower rpm, but i dont see the problem, the is revs to 6.2 anyhow, so is fine.

[AW328i]

I use to think revving past 4 grand was bad but these engines can handle it!

[Waveho]

I've seen kits with larger diameter spindles to expand travel time for the belt (e.g., adding space for the belt to travel to the alternator, a/c, etc.), thereby requiring less rpms for the same power. You'll need a new belt. I don't know anyone who has done this, but it is possible.

[slim17265]

I have a 280SL which when I drove it on the interstates I also was taching 4000RPM @65MPH. I had big 18 wheelers driving right into my trunk the whole time. I solved it by going to a larger rear tires. I put on a set of Yokohamas which were about 1-1/2" taller (it will increase the rake on the car by 3/4" in rear, looks hot) this will give you a reduction of about 6-1/2% and makes all the difference in the world..check it out

[Rickman]

Sometimes the auto version of a car has a higher diff ratio (lower number). Tyres will make a difference too, but usually not too much. The diff is the way to go I reckon. Perhaps check the Bentley manual for ratios and see what your local wrecker has in stock. You have to realise though that if you go for top end, then the car will suffer at the bottom end. It will be slower to pick up speed, so do your homework before you change anything.

[cwsqbm]

i know its the way the car is geared but when im doing above 75ish in 5th in my 318is im running at about 4k rpm.
I'm pretty sure the answer is no, but is there anything I can do to keep it from running so high?:dunno:

Usually the 4cyl has a different final drive ratio to help acceleration. Change it to one from a 6cyl manual car and you'll run much less rpms on the highway but your off the line acceleration will suffer.

[ozbod1]

chuck your useless 4cyl engine and fit a 6cyl!! sound best option to me??

[Crcrzy12]

Yeah...sell the car and get a 325 or 328...if you can't get something else, try the tire trick...you don't really wanna mess with your diff because you have a 4 banger.

[Rickman]

FWIW, I just bought a new set of Bridgestone Grid 2's for my ride and noticed on the brochure that it gives the outside diameter and revolutions for the various sizes. A 185/60R 14" spins @ 576 revolutions per Kilometer, while a 225/50R 17" does only 509. Outside diameter is 578 & 658mm respectively. There are varying degrees in between.

You would need a slide rule and a Math degree to work out the revs on your engine, but it could be done and you could work out how much lower your revs would be. This assumes that the larger wheel size would fit on your car though.

[slim17265]

#l NO brochure will give you exact size, it is what they call manufacturers "TOLERANCE", meaning although they advertise a tire to be 25.0 in dia. it can be and most times only 24.5 or less. Since I buy a lot of tires and gear ratio is critical for some of my race cars it is practically impossible to deal with companies that give you nothing but estimates. I deal with Tire Rack with the purchase but I have to shop around to find who locally has the tire I need and go there an measure it then evaluate how much more it will be when it "plumps" up with air...anyhow if you know the size of your worn tire, say 25.0 and the new tire actually measures 25.25 this would then be 1% larger and you would then find that your speedo would be showing that you are going 1% slower than you actually are, although in retrospect we then have to deal with the wear factor, so if your new tire measures the same as manufacturer installed then there would be no change in speedo reading.

[Andycapps]

I know...put a 6-speed in it! They shoulda came with a 6speed