Max RPM of the M271?
 

So I was going around 90mph tonight (closed conditions of course) and I decide to floor it. I was past the redline and quickly approaching 6200RPM, so I let go of the throttle...

My question is, why didn't it shift? What is the maximum RPM the M271 can go up to safely? Also, could it be since I put in a K&N Filter yesterday, the ECU hasn't really "adjusted" yet? (I say "adjusted" b/c I know the filter doesn't do much.)

Thanks! :y

Redline is actually either 6200 or 6250 on the M271 engine. My rev limiter kicks in at 6250 RPM. On my Coupe they have redline marked at 6000RPM but in the engine specs it is 6200RPM.

I noticed the samething once before but I tried it again and did not let go of the throttle and than it corrected itself.

Yea, you're fine.. dont worry about it.

I redline the RPM and hit 6200RPM in 5th gear going 120MPH couple days ago, I was going WOT and I felt the fuel cut off around 6300RPM before I shift quickly into 6th gear. (I wasn't racing, just driving fast to pass couple cars)


So I would say the Maximum RPM is probably 6200RPM if you are pushing it. BTW, I love to downshift while entering into a ramp from 6th gear -> 5th-> 4th->3rd watching the RPM jump to 6000RPM then it engine brakes to 4000RPM and jumps back up to 6000RPM again :zoom: this engine sounds great in the high RPM zone~ :naughty:

120mph to pass up some cars. Did you share the freeway with and Enzo and Porsche CGT? hahah

are you sure you were in 5th at 120mph, that seems too slow for that speed because I think you hit 110 in 3rd?

wrong. rev limit is 6500 RPM but you have to be in dyno mode to do it.

I know the following speeds are true for the auto: 1st: 30 2nd: 50? 3rd: 80

Redline (6200) with stock tires and a 6 MT

1st --> 30mph
2nd --> 50mph
3rd --> 77mph
4th --> 105mph
5th --> 132 mph
6th --> 157mph

There no way in hell I can hit 110MPH in 3rd gear, maybe a Dodge Viper....but not my C230 :v

No I was trying to pass a 95-99 Nissan Maxima and a Scion TC that was doing probably 90MPH (Road was clear so 90MPH felt slow to me)

If I see a Enzo or a Porsche CGT I wouldn't even attempt to pass them, I keep up with them from behind and enjoy the view :y 120MPH is like crusing speed for either of those cars and my C230 is Revving its ass off getting to 130MPH then the governer kicks in to ruin everything~ :zoom:

:rolf: :rolf: :rolf: so true! haha

agree with the engine sounding great at high rpm :naughty:

you can hit 110 mph in 4th at 6500 rpm in dyno mode!

and if you don't believe me...

I put my car in dyno mode and it behaved really strangly I cant even explain it was slow to start and the revs were really strange and the touch shift or watever you guys want to call it didnt work either anyone ever have this?

What is "dyno mode" ?

dyno mode completely disables the ABS and the ESP.
first read this
and if you don't find it after you read that, read this

i try to shift a little before or at 6k to try to get the most out of the powerband. anything over over obviously results in fuel cut off at redline, but remember the power band only goes up so high and then power starts to go down again.

189HP@5800RPM <-- This would be a good shifting point :)

That actually works out pretty good with the 6 speed up through 3rd gear because that puts you right around peak torque RPM range in the next gear.
https://mbworld.org/forums/attachmen...id=65763&stc=1

Can you please explain what the chart mean? I know its gear ratio, but can you please explain what numbers to look for? in order to find the best shifting point :p I've never seen this kind of chart before. thanks~

Well its a chart of the speeds in Z mph at X RPM in gear Y.

According to MB, the M271 hits peak TQ between 3500 and 4000 RPM. So your car to be in/near (right before is best as that would give you more time with peak TQ) that range when you shift into the next gear. Taking that into account, you look at a the speeds you would be doing in the next gear. You want to be doing that speed when you engage that gear.

IE: 1st to 2nd shift --> If you shift at 5800 RPM from 1st to 2nd you would be doing about 27.4 MPH when the shift is started. Give some room for momentum figrure you will end up at 28 MPH in 2nd which puts you at ~3400 RPM, right before peak TQ.

This would be more efficient if you use your own dyno sheets to see what RPMs your peak in TQ and HP. (This chart is for a M271 6speed w/ stock diameter rear tires)

I was testing out these numbers the other day and my max at 4th was pretty close since I am on 18's 40 series tires. After shifting to 5th it felt real good! Felt like I could keep pouring it on. The engine sounded crazy screaming down the freeway. Hopefully I can try and max out 5th.