S65 vs S85
S65 vs S85
Author
Discussion

TheAngryDog

Original Poster:

12,954 posts

234 months

Tuesday 12th February 2019
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As we know that these are similar engines (the s65 is an s85 with 2 less cylinders in essence), how come the V8 makes its power at 8300 rpm yet the v10 is 7750 rpm? Anyone know?

Theone8181

482 posts

157 months

Wednesday 13th February 2019
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I guess physics must come into it. Running a v10 at high rev must be far more difficult than a v8. Also there's alot more mass to move.

Prinny

1,669 posts

124 months

Wednesday 13th February 2019
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I have no factual knowledge, but suspect when designing the engines, there were targets of >100hp/litre, in the same way that traditionally BMW always tried to have a 500cc/cylinder size.

As soon as the desired output was reached with sufficent longevity criteria met (somewhat tongue in cheek as you know wink), then that was the brief met.

The fact that they both exceed the margin by a little bit - but not to the same extent is possibly down to pumpling losses - i.e. there’s more inherent pumping losses on the v10 vs. the v8. That makes sense to me - but I’m a long way removed from my engineering classes.


cerb4.5lee

42,469 posts

205 months

Thursday 14th February 2019
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Be thankful for the lower rpm and the extra torque in the M5! biggrin 8300rpm is miles too high in the M3 for me(on the road at least), and you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.

KPB1973

938 posts

124 months

Thursday 14th February 2019
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cerb4.5lee said:
....you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.
Apart from peak torque being generated over 2k rpm lower down the rev band.

Wills2

28,570 posts

200 months

Thursday 14th February 2019
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KPB1973 said:
cerb4.5lee said:
....you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.
Apart from peak torque being generated over 2k rpm lower down the rev band.
Yeah keep it below 6000rpm and you've got about 330hp to play with I sometimes wonder how I got into work...



cerb4.5lee

42,469 posts

205 months

Thursday 14th February 2019
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Wills2 said:
KPB1973 said:
cerb4.5lee said:
....you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.
Apart from peak torque being generated over 2k rpm lower down the rev band.
Yeah keep it below 6000rpm and you've got about 330hp to play with I sometimes wonder how I got into work...

I knew I'd get some stick for this Lads!! hehethumbup

All joking aside I think that the kerbweight plays a really big part of it not feeling very torquey to me personally(My 330d had more and I was used to that for 6 years). The M3 was epic very high up the revs though and I've never disputed that. driving

Theone8181

482 posts

157 months

Thursday 14th February 2019
quotequote all
cerb4.5lee said:
Be thankful for the lower rpm and the extra torque in the M5! biggrin 8300rpm is miles too high in the M3 for me(on the road at least), and you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.
I've found that too in the m3. Seems to take ages before there's any power (I was spoiled with a turbo car asy last car).

cerb4.5lee

42,469 posts

205 months

Thursday 14th February 2019
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Theone8181 said:
cerb4.5lee said:
Be thankful for the lower rpm and the extra torque in the M5! biggrin 8300rpm is miles too high in the M3 for me(on the road at least), and you have a window of 6000rpm to 8400rpm when the engine is absolutely brilliant...but for the rest of the time not a lot really happens.
I've found that too in the m3. Seems to take ages before there's any power (I was spoiled with a turbo car asy last car).
Yes and it is one of the few cars that I've had where there wasn't any point in putting your foot down at low revs...because it took an age to pick up. Cog swapping was needed to get the revs really high and then floor it.

Turbo engines do really spoil you for sure with their on tap performance. N/A engines need a much different approach...you have to thrash them to death and you'll be motoring then! driving

Prinny

1,669 posts

124 months

Thursday 14th February 2019
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True, but... 5th gear from 30mph going all the way to the limiter in the M6 doesn’t get old, and the changes in tone, as the cams come in, the heady rush to the red line, it’s intoxicating - though admittedly it’s not something you can do in the UK (legally).

It’s actually more ‘fun’ than 2nd/3rd, etc - you get to experience something special. The only thing I’ve driven that did similar was the DB7 vantage. The car’s likely coming over to NL with me soon, so when I do, I’ll have to take a side trip to DE and get a dashcam video of it.

Tony B2

752 posts

200 months

Friday 15th February 2019
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Going from 2500rpm to 8400rpm in a single gear is one of the joys of the S65 engine. Likewise the S85

The ever changing intake and exhaust music and the ever increasing thrust is still a thrill after more than 10 years (jeez....) of ownership.

I think the S85 actually sounds nicer than the Audi R8's V10, too.

OK, so if you want to make an impression on (erm....or vaguely keep up with) a similarly powerful turbo equipped car you do have to keep the revs high.

I was quite surprised at how close it was to a friend's 500+hp M4, through a full rev 2nd gear comparison!

Sounded better, too....

Theone8181

482 posts

157 months

Friday 15th February 2019
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Tony B2 said:
Going from 2500rpm to 8400rpm in a single gear is one of the joys of the S65 engine. Likewise the S85

The ever changing intake and exhaust music and the ever increasing thrust is still a thrill after more than 10 years (jeez....) of ownership.

I think the S85 actually sounds nicer than the Audi R8's V10, too.

OK, so if you want to make an impression on (erm....or vaguely keep up with) a similarly powerful turbo equipped car you do have to keep the revs high.

I was quite surprised at how close it was to a friend's 500+hp M4, through a full rev 2nd gear comparison!

Sounded better, too....
That surprises me as I feel it's much slower than my old 996 turbo (which I thought an m4 would be similar in speed to).

Gouki

352 posts

209 months

Friday 15th February 2019
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After a impromptu trackday at brands hatch last year in my M6 (E65 S65) I was greeted by a 991 Turbo S on a derestricted dual carriageway.... It was behind me likely in the wrong gear, and I was eviscerated before the end of the straight. At least 5 car lengths behind before I backed off at crazy leptons.

Things have moved on somewhat in terms of performance!

Tony B2

752 posts

200 months

Saturday 16th February 2019
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Theone8181 said:
Tony B2 said:
Going from 2500rpm to 8400rpm in a single gear is one of the joys of the S65 engine. Likewise the S85

The ever changing intake and exhaust music and the ever increasing thrust is still a thrill after more than 10 years (jeez....) of ownership.

I think the S85 actually sounds nicer than the Audi R8's V10, too.

OK, so if you want to make an impression on (erm....or vaguely keep up with) a similarly powerful turbo equipped car you do have to keep the revs high.

I was quite surprised at how close it was to a friend's 500+hp M4, through a full rev 2nd gear comparison!

Sounded better, too....
That surprises me as I feel it's much slower than my old 996 turbo (which I thought an m4 would be similar in speed to).
Yes - I was surprised too. The M4 was quicker, but the gap was not as much as I thought it would be, having spent 100+ miles as a passenger in it.

The almost instant wallop and surge of torque does make the M4 (standard or tuned) feel mighty quick, and the same is true of almost any turbo engined car these days.

Subjective feel is a strange thing.

I must stick the performance box on each car and see what the real measurable gap is, over a speed increment - 30 to 70 is legal, so that might have to be the benchmark.

ocrx8

893 posts

221 months

Saturday 16th February 2019
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Prinny said:
True, but... 5th gear from 30mph going all the way to the limiter in the M6 doesn’t get old, and the changes in tone, as the cams come in, the heady rush to the red line, it’s intoxicating - though admittedly it’s not something you can do in the UK (legally).

It’s actually more ‘fun’ than 2nd/3rd, etc - you get to experience something special. The only thing I’ve driven that did similar was the DB7 vantage. The car’s likely coming over to NL with me soon, so when I do, I’ll have to take a side trip to DE and get a dashcam video of it.
Thank you for posting this. It inspired me to try the same in 3rd in my S54 tonight. Great fun! A prolonged surge that gets more intense the closer you get to the red-line.

AW10

4,648 posts

274 months

Sunday 17th February 2019
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ocrx8 said:
Thank you for posting this. It inspired me to try the same in 3rd in my S54 tonight. Great fun! A prolonged surge that gets more intense the closer you get to the red-line.
There's no doubt that the M2 is the quicker car but I do miss the more characterful sound of the S54 in my old Z4M. That engine had a lovely blend of induction, exhaust and mechanical noises that got a nice hard edge as the revs climbed. The M2 sounds OK but a distant second.

Wills2

28,570 posts

200 months

Sunday 17th February 2019
quotequote all
Tony B2 said:
Going from 2500rpm to 8400rpm in a single gear is one of the joys of the S65 engine. Likewise the S85

The ever changing intake and exhaust music and the ever increasing thrust is still a thrill after more than 10 years (jeez....) of ownership.

I think the S85 actually sounds nicer than the Audi R8's V10, too.

OK, so if you want to make an impression on (erm....or vaguely keep up with) a similarly powerful turbo equipped car you do have to keep the revs high.

I was quite surprised at how close it was to a friend's 500+hp M4, through a full rev 2nd gear comparison!

Sounded better, too....
Agreed Tony, the long legs of the S65 are fantastic to experience it's what it's all about to me anyway.



tigerkoi

2,927 posts

223 months

Tuesday 19th February 2019
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S85. You need to push on. 70-130+ mph. Blitzkrieg.

Tony B2

752 posts

200 months

Friday 1st March 2019
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Absolutely! I regularly go to the Ring with a friend in his E60 M5, and also occasionally to southern Germany.

That top-end rush is a joy on the autobahn.