Difference between 3.0si & 3.2M

[mason storm]

I know there has obviously been much talked about this before but just want to get my head around a few things.

The 3.0 is rated as 0-60 of 5.7 secs, the M at 5.0 seconds (although in the real world 0-60 means nothing and it's the acceleration figures while moving that really count) . The M has a higher reving engine 8K vs 6K for the 3.0, the M has more torque but arrives at higher revs while the 3.0 actually has slightly more lower down.

Now I understand the concept that the 3.0 has more torque low down meaning in gear times will be quicker for overtaking at low revs. Correct me if I am wrong. Also alot of people say it's torque that increases acceleration times and not power (BHP) so it it the extra torque that gives the M more acceleration or does horsepower come into it also? if not why do the M divinsion bother giving you all that extra horsepower if it's useless? I know this is actually quite a complicated issue and there is more invlved including gearing, tyres weight etc but just wondered why (what are the factors) the M is faster accelerating?

Also will the M be any faster below 6,000 revs?

Let the debate begin..........................................

 

[Taz]

i drive an automatic, i think on the road you won't notice that much difference, maybe on a track it would show up

 

[Zed_Steve]

Just to clarify, the 3.0si engine revs to 7000rpm.

 

[Andy]

yep lots of debate on this from day 1... the 3.0si is a cracking engine so it does get pretty close with fuel consumption being much better but...

the M at 5.0 seconds

it was agreed at launch 5.0 was conservative, 4.8s was achievable in the right conditions, sometimes a 2nd gear start. a difference of almost a second at that end of the clock is very noticeable.

why do the M divinsion bother giving you all that extra horsepower

you sir, need to drive one.

 

[mason storm]

Just to clarify, the 3.0si engine revs to 7000rpm.

Yes sorry, I think max power is at 6,700 ish while the M is 7,900

 

[pilchardthecat]

I drove both back to back as it's a common dilemma - is the additional cost of the M worth the additional expense.

Yes it is, was my conclusion

The 3.0 is a great engine, but it's lazier, and has good mid range but doesn't have the rasping urgency of the M and doesn't have the kick-in-the back at the top end. The 3.0 is queter and softer and an altogether different experience.

The M has a lot more drama. It's not just about power but the way it's delivered.

But it's faster than (or as fast as) some very exotic cars.

Top gear for example....

 

[mason storm]

yep lots of debate on this from day 1... the 3.0si is a cracking engine so it does get pretty close with fuel consumption being much better but...

the M at 5.0 seconds

it was agreed at launch 5.0 was conservative, 4.8s was achievable in the right conditions, sometimes a 2nd gear start. a difference of almost a second at that end of the clock is very noticeable.

why do the M divinsion bother giving you all that extra horsepower

you sir, need to drive one.

Sorry what I really meant was what performance related reason would the M division bother giving you all that extra horsepower rather than giving you more torque. I realise that it's a thing of beauty the M engine my mate use to have one and I loved the way the engine sounded at 8,000 and the feeling of winding the revs up.

 

[mason storm]

I drove both back to back as it's a common dilemma - is the additional cost of the M worth the additional expense.

Yes it is, was my conclusion

The 3.0 is a great engine, but it's lazier, and has good mid range but doesn't have the rasping urgency of the M and doesn't have the kick-in-the back at the top end. The 3.0 is queter and softer and an altogether different experience.

The M has a lot more drama. It's not just about power but the way it's delivered.

But it's faster than (or as fast as) some very exotic cars.

Top gear for example....

Wow great track time obviously the way it works on track is impressive which will also the the changes to the suspension, brakes etc

 

[Andy]

awesome you've got that screengrab.. that was an Imola Roadster built just after mine

 

[pilchardthecat]

awesome you've got that screengrab.. that was an Imola Roadster built just after mine

I think people underestimate these cars rather a lot!

 

[Taz]

it would be intersting to see an head to head, an M, a 3.0 manual and a 3.0 automatic

 

[Andy]

01:37.3 BMW Z4 3.0i Very Wet Negatively effects lap times by ~6 seconds

so apparently 01:31.3 against 1:24.0 & 5 seconds difference... not that their track is any good, but remember runflat tyres, electric steering, /m diff etc..

the si is still a very quick car.. just not as urgent and a lil more comfortable

head to head, an M, a 3.0 manual and a 3.0 automatic
----------------------- ^1st, ^2nd ................ ^ last

8)

you should know.. weren't you behind me for quite a while yesterday?

 

[Taz]

i was being polite and sticking to the rules

 

[mason storm]

getting back to my question can any techno geeks explain the importance of power vs torque and how it affects acceleration? Some say power is irrelivant in acceleration but I'm not sure this is right as I get the feeling high reving engines with high power outputs does affect acceleration you just have to use all the revs e.g. s2000, no torque but decent power

 

[pilchardthecat]

Read this

http://www.largiader.com/articles/torque.html/

Acceleration is a function of power, weight and gearing.

Power is derived from torque (the force exerted) multiplied by the engine revs (the speed of the object the force is being exerted upon).

 

[EdButler]

If were just taking Engines into consideration here, they're both completely different animals and both should be driven to be appreciated. If you're a petrolhead, the only instance you'd pick an si over an M though is if you had your very sensible hat on (IMO)!

Dynamically they're not far out though. Having driven an M and a 3.0i, handling characteristics are similar as you'd expect. The M certainly feels heavier over the nose, but the Diff is fantastic for controlling the power/oversteer. I certainly haven't had much problem following/leading on the Z4 runs (in my 3.0i) due to small amount of flat out straight roads, but a track would undoubtedly be different!

In summary, it does take more effort to get 100% out of the M, but that's part of the fun. Otherwise we'd all be driving boring 2.0T/TDi's everywhere! Yawnn

 

[mason storm]

Sure but I'm not talking about fun, take it for granted the M is much more fun I'm just thinking what are the engine differences make in outright speed?

I'll take a look at the link to see if it helps, just hope it isn't too technical.

 

[Hark]

I drove both back to back and the difference to me was night and day. 3.0l didn't excite me at all.

Would make a nice cruiser but didn't feel like a sportscar.

 

[Smokin]

The M is more than just the engine. Mine is a daily driver so the 3.0Si was for me.

Torque gets you going, and the 3.0Si would have a jump on the M, but the greater horsepower and higher red line would mean they would catch you and pull away. The M also has a limited slip differential, which on the track would be an advantage. Not to mention it also has hydraulic steering rather than the electronic in the non-M.

On the street, in daily driving, they're equally good. On the track, the M has the advantage due to the sum of its parts.

 

[mason storm]

Having read the link to the explenation of HP and how it's related to torque at a certain RPM starts to make more sense, and confirms that all those people that say torque is what gives you your acceleration are only half right (when looking purely at torque figures quoted for a car) and that a high power engine with high revs just delivers power in a different way (a fun way).

Still really need to test drive an M vs a 3.0 soon to feel what they compare like when taking everything into account. I remember my mates M being really flat when corning, virtually no roll at all.