E39 M5 or 996 C4 quicker?

[JayP1]

Recently bought the M5 and love it, but 3rd gear and onwards acceleration doesn't blow me away. It's really quick to 50, but after that it doesn't feel that fast. Having owned a 996 C4, I can say that felt pokier at higher speeds but having seen lots of videos on Youtube and stats on various websites, the M5 should be quicker in most scenarios.

I'm starting to wonder whether some specific problem causing my M5 to feel sluggish at higher speeds. Any views?

[OdramaSwimLaden]

The M5 should be quicker, but also smoother too. Maybe this is why it doesn't feel it.

[SteveS Cup]

If you've just bought it can you 100% say in your mind that it's recently had a proper service?

I've noticed big differences in the responsiveness of a lot of cars with much lower performance than an M5 just by giving them a really good service and putting in good spark plugs etc.

[anonymous-user]

Never been in a 996 but my m5 only feels fast over 80ish when you notice it keep pulling.. maybe different driving position and I imagine the 996 may be a bit more vocal on standard exhausts thus adding to the feel of speed.

[wackojacko]

M5 IMO I've been in a Carrera 2 and that didn't feel that quick.

....whereas the M5 felt slightly quicker, you can still feel it pulling nearly as hard over 80 than it does at 30.

[Lust4Life]

When the MAF's went on mine it felt WAAYYYYY down on power - as soon as they were changed it was a rocket ship again.

Cheers,

Phil

[Zwoelf]

Mass airflow meters as referred to above - or possbily a VANOS fault, resulting in power loss.

http://www.m5board.com/vbulletin/e39-m5-e52-z8-dis...

Follow the links there to just about anything and everything you could ever need to know about E39 M5s - and probably a lot you didn't

[JayP1]

wackojacko said:

M5 IMO I've been in a Carrera 2 and that didn't feel that quick.

....whereas the M5 felt slightly quicker, you can still feel it pulling nearly as hard over 80 than it does at 30.

OK, so from the sounds of it something is definitely not right. Going to give the MAFs a clean out with carb cleaner and see if that helps. Vanos was replaced about a year ago I believe.

[Terzo123]

There's a way of testing your MAFS via the on board computer, which will let you know if they require replacing.

Someone with more knowledge than myself should be able to talk you through it.

edited to add, just saw the link above, it has the instructions for doing the test.

[Baz Tench]

I've never driven a 996 C4 but 50 and above was the part that impressed me the most with my M5.

[derestrictor]

Sounds v odd; Fünfenstein feels manically quick as you approach and then gallop through the ton.

Indeed, once leptonning with all due dilligence, it feels ballistic and nothing short of rampant.

[JayP1]

derestrictor said:

Sounds v odd; Fünfenstein feels manically quick as you approach and then gallop through the ton.

Indeed, once leptonning with all due dilligence, it feels ballistic and nothing short of rampant.

Yes, that's what I would have thought from a 5 litre V8 - something not right. Will try the MAF tests and see if it throws anything up

[wackojacko]

It is a REAL M5 isn't it ? not a replica 540i ?


Not saying it isn't...... just a thought....

[DanGPR]

For the sake of a hundred quid or so, would it be worth throwing it on the dyno to see if it's down on power at all?

[Vixpy1]

DanGPR said:

For the sake of a hundred quid or so, would it be worth throwing it on the dyno to see if it's down on power at all?

And if he booked it in on a Sat it would only cost him £40

[wackojacko]

Vixpy1 said:

DanGPR said:

For the sake of a hundred quid or so, would it be worth throwing it on the dyno to see if it's down on power at all?

And if he booked it in on a Sat it would only cost him £40

[Laird]

JayP1 said:

Recently bought the M5 and love it, but 3rd gear and onwards acceleration doesn't blow me away. It's really quick to 50, but after that it doesn't feel that fast. Having owned a 996 C4, I can say that felt pokier at higher speeds but having seen lots of videos on Youtube and stats on various websites, the M5 should be quicker in most scenarios.

I'm starting to wonder whether some specific problem causing my M5 to feel sluggish at higher speeds. Any views?

Google 'M5 secret menu' and learn how to read the MAF readings. A healthy car will record anywhere between 130-140 litres of air per minute(?) at full throttle (ideally in third or fourth gear). Anything less than that and there's a fair chance your MAFs are shot. As M5's of this flavour are hugely sensitive to MAFs, I suspect a dodgy MAF will cause a noticeable deterioration in performance.

But in short, yes an M5 should feel noticeably quicker than the C4, especially above 50mph where they tend to shrug off the weight and hit light speed with astounding ease.

[Laird]

DanGPR said:

For the sake of a hundred quid or so, would it be worth throwing it on the dyno to see if it's down on power at all?

See my post above. The OP can do this test for free.

[derestrictor]

Fwiw and although there exists (in practice) a massive difference, the old Fünf feels quick enough to have me question just how much quicker things with 500+ bhp are...

(The answer is they'd kick its sorry, late 90s ass but the delivery is truly that impressive.)

Ito high level strafing, I'd even go as far as claiming it's in a very special league, despite recent conclusions that its cross wind stability is on a par with the gently puffing sail of an Arabian dhow.

[JayP1]

Did the MAF test and it seemed to be fine. Acceleration in 2nd gear is blistering and the torquey feel in 3rd is also impressive, it's just when you are at speed and you drop down a gear to pass something at motorway speed that it doesn't feel that great.

Might change airfilters and plugs this weekend to see if that helps. Am starting to wonder if maybe it's just me getting used to the acceleration or just not feeling the shove because of the linear delivery and the comfortable ride.