BabyBenz6spd

On Local roads I'm usually in 4th gear doing 40MPH with the RPM somewhere between 2400~2600RPM. Sometimes I'll use fifth gear at around 2000RPM......however I found the engine has no Power at this range and gets annoyed that I have to downshift to make a pass.

I've gotten use to keeping the RPM range atleast 2500RPM when driving....does this sound high or average?

On Highways, I easily go over 3000RPM even in 6th gear crusing at 70MPH. I'm getting the sense this is a pretty "Revv-Happy" engine. However, I found the Redline on my car starts at 6000RPM. Comparing with a lot of cars with ATLEAST A 6500RPM Redline (Example, friends Sentra SE-R, Subaru Forester (SOHC engine!), Maxima) All have Higher Redline than my car~

I can understand why a lot of V8's and some larger V6's have such a low Redline (6000RPM), but we have a I4 engine.......wouldn't it make sense to have a higher Redline??

mick1

seems high to me I would keep the engine at around 2000 rpm .

BabyBenz6spd

Perhabs that larger 3.2L V6 is providing you with much more Torque on the low end

mick1

of course, that is only for cruising . if i want to out run anybody, I would have to go to all the way up to the redline . can't beat anybody by changing gears at 2500 pm

dna_errors

I have a C240 instead of a C230, I'm not sure about the difference between 240 and 230 gear ratio.
On 6th gear with my car, 3000 rpm = 75 mph.
I cruise at 3000 rpm and I usually don't upshift until I hit 3000 preferably 3500. Powerband on my car starts between 3500 and 3600. Anything below has very little power to speak of. I agree with you (although you were referring to the 230 engine) that this is definitely a rev happy engine.
I guess I upshift later than most people ... I come from motorcycle riding where 6000 rpm is considered the shifting point even for street riding (although the redline is at 14500 ).
In case you wonder, I had a C320 automatic loaner for 700 miles ... It has shorter gear ratio. I believe 3000 rpm 5th gear auto is around 82-84 mph.

breastroker

Even with my 5 speed automatic, I will run in 4th in heavy traffic, and third gear around town. I do not like to keep the engine at 2000 RPM, I prefer at least 3000. Remember the supercharger is not engaged normally if you are cruising with high vacuum.

Only on trips do I keep it in 5th to get max gas mileage.

This engine could easily rev with the Hondas, but the supercharger is self limiting. Heat and power consumed increases beyond what the supercharger can add at 6500 RPM, that is why the rev limiter is so low. On the M271 engine 1.8 Liters, the supercharger would be turning close to 17,000 RPM if th engine was turning 7000. That is over the limit the supercharger can handle.

nukblazi

That doesn't sound right. I have an '02 so, there are some major differences, but I cruise at 85 in 6th @ 3,2k-3,3k RPM.

vadim

2500 RPM is not high by any means. This is where the poor 4-banger just creeps to the optimal torque plateau. 2000 RPM is on the underrev side.

These cars are created for high speed autobahn cruising at 200+ km/h. At these speeds the engine would be spinning at well over 4500 RPM in 6th gear. Judge yourself.

czachari

Cz

accbenz

I usually shift around 3200 RPM's, 2500 is probably a little low to be shifting. When I'm cruising I'm in gear at around 2500 though.

taylor192

I don't even use 6th unless I'm the highway cruising for a long time.

5th is great, 140 kmph to work without hitting 4K rpms.

I find I keep the rpms between 3500-4500. Maybe that eats a little more gas, yet the power is always there, and I prefer to drive, not cruise.

tonewheel

This was dicussed previously a few weeks back. I started that original thread, so let me throw in my .02

I asked the same question - - where do you shift? Personally, I had been shifting my 04.5 C230SS at 2500 for each shift, and highway cruising between 70/80 in 6th, where the I4 sits at around 3,000.

Now, Vadim suggested that was too low a shift point, as the engine drops from the 2500 shift down to around 2000 for the next gear. He suggested my engine, and me, would be happier and healthier shifting around 3500. He was right. (Except 1st gear, which is much shorter.) By shifting around 3500, the drop for the next gear matches better, and never less than around 2400. Smoother...much smoother, and I've found power that doesn't live in those lower RPMs.

Remember, there's a redline indicator for a reason, and I never approach it. But you can do more damage by under-reving your engine than by over-reving. That engine of yours is meant to wind up, as torque is hiding under 2500.

Don't be afraid to (reasonably) push your engine. And kick up your shifts (2 - 6) to around 3500.

mick1

don't know about mercedes but on my old bmw 328i, if you went above the redline, the engine would automatically cut off to avoid damage to the engine. that feature saved my engine a few times

ayilar

There is little power below 2600 rpms. Once the engine is warm, I'd say that shifting below 3500 rpms is a waste of the engine.

As an aside, the C's engine does shut off right above 6000 rpms -- rather abruptly if I may say so. I wish the redline were higher, say 6500 rpms.

tyro

What are you guys talking about??
My redline is 60 rpm and I typically shift around 30 rpm.
6000 rpm! Ha!

gaiex

At highway cruising between 80/92mph in 6th, rpm's are at 2200-2600.

In city I can easily run in 6th at 30mph with only 1500
rpm and step on the gas and there it go...

Thats one thing about the wonders of a diesel engine, a MB one

You guys are forgetting one thing, the torque, thats why there is allways a shifting point, when the torque is allready available. In my case at 1600rpm I have 340Nm constants to 3800rpm (redline at 4500rpm and max. power at 4200)

Other thing, its a diesel but it do 0-60 in 8,5s and 140mph (all stock, and its the small diesel engine 2.2)

tonewheel

We're not forgetting torque. And you're driving a car that's not the point of this discussion.

BabyBenz6spd

Its good I'm not the only one feeling low on Power under 2500RPM with this little 1.8L I4.

Another reason to shift above 3500RPM is you actually hear the Supercharger working when the needle passes 3000RPM........and I just love to hear my Supercharger working!

And a personal opinion, Since you are using Premium Fuel (Which is required for C230 Kompressors) Don't be afraid to Ravv your engine (Say above 3500RPM~ 5800RPM range), as long as you are not not bring the needle to the REDLINE area consistantly.......your engine will be fine.

mctwin2kman

I shift at or just a few ticks below redline. I love the sound of this engine when rev'ed to her limit. Mine cuts out at 6500RPM if I get a little slow in my shifting. The actuall redline according to MB is 6200 RPM for the 1.8L engine. I sometimes shift at about 4000-4500 if I am in a slow drive mood. When cruising at 75 MPH if I recall correctly I am spinning like 3200 RPM+-! That is even perfect for getting up hills without a downshift and still able to accelerate.

mikefl52

The fun of driving a manual is that you get to play with the gearbox, choosing the right shift points for your car, mood and driving conditions. The downside is that you also have to make those shift changes when you need to and don't feel like it, such as when overtaking when the engine is rotatating at 2000 - 3000 rpm. If you were in an automatic the car would still shift gear, it's just you wouldn't have to take any action.

The C230K 4 cyclinder like pretty much all other 4 cylinders requires quite a high rpm to achieve it's torque. Just try driving others 4 cylinder models such as the Acura TSX and RSX or the Honda 2000 which all have lots of HP, but have very little low end torque.

The classic american V8s on the other hand have an overabundance of torque and can pull at very low rpm.

This was all just a difference in philosophy between European and US cars for a long time. If you buy a car with a small engine (1.8 or 2.3) you will need to work the gearbox if you have a manual or if you have an automatic it will downshift often when required. Enjoy it.

Outland

Beat the **** out of it. The 1.8 is weak on torque, youre not going to be able to dip into the 1400-2500 and have any pull. The M111 does this, but the smaller 1.8 can't. Just be glad its not a C240.

Lugging an engine will do damage over time, overreving it can damage it in an instant. However, unless you engage 1st gear at highway speeds, youre not likely to ever over rev the engine. The ECU will begin to retard the ignition after you cross the redline, and will shut off the fuel if you push further. Beyond that, the valves will float due, as the springs are designed to do so at such high rpms, preventing you from climbing higher. So, beat the **** out it.

Capt Nemo o2

Did a little experimenting tonight...

At 75mph got 27.4mpg in 6th, at 55 got 29.5 mpg in 6th!
At 50mph got about 27mpg in both 5th and 4th
At 40mph got about 25mpg in both 5th and 4th...

Moral of the story... You get about the same gas mileage in 4th as you do in 5th for 40 to about 50mph, so you might as well stay in 4th, its not underreving, it puts you into a more suitable rpm range if you need to accelerate.

Thats all, whether this is useful to anybody or not, I dont know!!!

mick1

i noticed that automatic transmission cars would run at lower rpm . for instance, my dad's c320. it would be at 1,500 rpm most of the time in city driving. so, I didn't think 2,000 rpm for cruising was that low for a manual since my car engine was the same as his.

I wonder what rpm the c230 with auto would be at in normal city driving.

vadim

The original poster has a 4-cyl engine, for which 2000 RPM is low.

BabyBenz6spd

At 2000RPM on our 1.8L I4, Supercharger isn't really doing much.......Its pretty much producing the same power as a Corolla 1.8L at this RPM. 1.8L moving a 3200+Ib car isn't easy.......thats why its a night and day differents when RPM starts to arrive at 3500RPM, and Supercharger starts Boosting a lot~ (This is the range when people use our Supercharged I4 to compare with some V6 engine in terms of power)

This is why some people choose to cruse around town in the 2500RPM range, and others lower to save gas.....but you all get to drive in your own style.

I choose to cruse around town @2500RPM because I hate to stop when the light just turned yellow, and I have to stop because I have no power to make it over in time. If you can make it over, you save couple minute of your life~ lol