Most responsive RWD 6 cylinder car

[ewenm]

kambites said:

ewenm said:

Next year's Exige V6

Will presumably be the same as this year's Evora?

Presumably, but in a lighter package one would hope.

[kambites]

ewenm said:

Presumably, but in a lighter package one would hope.

Which doesn't make much difference to throttle response.

Besides, Lotus already buggered up the throttle response of the Elise once, I don't see any reason to believe they wont do so again.

[RobM77]

Zwoelf said:

300bhp/ton said:

Not really. I know the OP said 6 cylinder, but they also seemed to fail to add why or what they where looking at. From what I've read in the rest of the thread it seems to actually be a what car for a car with really good throttle response.

Suspect something like a AJPV8 Cerbera would be a good bet.

He also asked what others are as smooth. A TVR V8 (either flat-plane or cross-plane) is nowhere near in the same ballpark of smoothness as an inline or flat six. From a technical point of view - they simply can't be, although some flat and inline 8s can. As can a V12.

Wiki article on engine balance said:

There are four different forces and moments of vibration that can occur in an engine design: free forces of the first order, free forces of the second order, free moments of the first order and free moments of the second order.

The straight-6, certain straight-8, flat-6, flat-8 with 180 degree firing, flat-12, flat-16 with 90 degree firing, V12, V16, and W16 designs have none of these forces or moments of vibration and hence are the naturally smoothest engine designs. (See the Bosch Automotive Handbook, Sixth Edition, pages 459-463 for details.)

flatline84 said:

what about the S50 and S52 engines, in the E36 M3s? Do they also have throttle delay?

UK E36 M3s only had S50 engines in B30 (3.0) and B32 (3.2 "Evo") forms. The S52 was a North American engine and quite different in design and power output.

S50 uses six individual throttles, connected by cable to the pedal just as previous Motorsport sixes all did, the S52 uses a single throttle on a more standard BMW 1 into 6 inlet manifold. M52 sixes 1995-2000 use cables, M54 sixes 2000-2005 use "drive by wire" electronic throttle modules, so there's no longer a physical connection between the pedal and the throttle, it's entirely electronic. (S designated engines = Motorsport engine, M or since 2001 N designated engines = standard production series engine)

The S54 six as used in E46 M3, M3 CS and CSL, along with late Z3 and all Z4 M Roadsters and M Coupes (earlier Z3 Ms used S50 B32s) shifted from cable to electronic throttle operation (which meant those cars could then be equipped with DSC). However there isn't the response delay of the vanilla M54 family owing to the fact that S54s are still equipped with six individual throttles rather than one as in M54s.

Some people have found ways to modify their S54 to use a cable throttle, the main difference then being the "weight" of the throttle pedal, electronic ones don't have any real weight to them as they're not physically operating the throttles, whereas in all previous BMW sixes, they did. It's quite easy to feel the difference by driving an E46 328i and 330i back to back.

Edited by Zwoelf on Tuesday 11th October 19:42

Thanks for a good post. This may just be semantics, but when talking about the S54 did you mean 'there isn't as big a delay'? There's definitely a delay in the E46 M3.

[Zwoelf]

RobM77 said:

There's definitely a delay in the E46 M3.

Then you've keener senses than I.

[RobM77]

Zwoelf said:

RobM77 said:

There's definitely a delay in the E46 M3.

Then you've keener senses than I.

If you look at the Z4 Coupé video I posted earlier in this thread, the E46 M3 lag is a little longer than that. On a good note though, I've tried the new M3 (E90/92), and couldn't detect a delay in that at all. What worries me is that the 135i is terrible for this problem (throttle delay, not turbo lag), and the new M cars are all going turbo as well.

[Monty Python]

NSX V6

[RenesisEvo]

Wiki article on engine balance said:

There are four different forces and moments of vibration that can occur in an engine design: free forces of the first order, free forces of the second order, free moments of the first order and free moments of the second order.

The straight-6, certain straight-8, flat-6, flat-8 with 180 degree firing, flat-12, flat-16 with 90 degree firing, V12, V16, and W16 designs have none of these forces or moments of vibration and hence are the naturally smoothest engine designs. (See the Bosch Automotive Handbook, Sixth Edition, pages 459-463 for details.)

This is to me, rather too simplistic a view...

Firstly, there must be higher order forces - third, fourth, and so on - like any harmonics/vibration, it will approximate something like a Taylor series, and the higher order terms have probably been discarded because they will result in neglible magnitude forces. So I think it's a little bold to simply state there are four forces/moments - a lot more happens than that.

Also, it's not that the configurations listed magically don't have those forces. It's because, with the right firing order it is possible to exactly counter the otherwise uneven force impulses applied to the crankshaft by each combustion, thus there is no net force or moment - given the impression of a balanced, ergo smooth, engine. A flywheel can help counter-act lower order forces, but if you do the maths on an engine with a net first order imbalance, the resulting force even at modest rpms is surprisingly large - it would not be feasible to use a flywheel to sort it out without having an incredibly unresponsive engine (tadaa - neatly back on topic). Then one needs to consider axial or longitudinal vibrations (e.g. the crankshaft vibrating like a skipping rope), which will also vary according to firing order.

All this is from memory btw, so feel free to correct me.

[twizellb]

Speed Six is the most reponsive I've driven/had.

[Tyson1980]

Jimmy No Hands said:

Whats this supposed throttle delay? The 3.0 I6 in my Z is glorious.

Same here...

Very responsive in my 3.0i Z4 with the CDV removed

[RobM77]

Tyson1980 said:

Jimmy No Hands said:

Whats this supposed throttle delay? The 3.0 I6 in my Z is glorious.

Same here...

Very responsive in my 3.0i Z4 with the CDV removed

See the You Tube video of the Z4 Coupé 3.0si earlier in this thread. Although the delay is tiny, there's a definite delay there and it's enough to get in the way of attempts at decent throttle control.

On a seperate note, I expect that removing the CDV would be a very worthwhile mod - the CDV made the car unbelievably hard to drive smoothly at low speed.

Without those two 'features', I think the Z4 Coupé would be the best car I've ever owned; it just did everything so supremely well.

[pilchardthecat]

RobM77 said:

Tyson1980 said:

Jimmy No Hands said:

Whats this supposed throttle delay? The 3.0 I6 in my Z is glorious.

Same here...

Very responsive in my 3.0i Z4 with the CDV removed

See the You Tube video of the Z4 Coupé 3.0si earlier in this thread. Although the delay is tiny, there's a definite delay there and it's enough to get in the way of attempts at decent throttle control.

On a seperate note, I expect that removing the CDV would be a very worthwhile mod - the CDV made the car unbelievably hard to drive smoothly at low speed.

Without those two 'features', I think the Z4 Coupé would be the best car I've ever owned; it just did everything so supremely well.

Roof rack?

I agree about the 135i - i noticed the throttle delay (and turbo lag), but i do not notice any delay on the Z4M (which you might think is close to the e46 M3, but supposedly has a later/better engine management chip/software).

[bmthnick1981]

Alfa 75 3.0 V6, Glorious Alfa V6 and RWD

That or an E36 M3 Evo - less throttle delay due to throttle cable rather than drive by wire arrangement on E46 M3

• I might be drunk so this could be nonsense.

[Meoricin]

Grovsie26 said:

But the drivetrain of a car has no effect on how good an engine is.

Best at what? Power? Noise? Reliability? etc, etc.

Can't include the Skline GTR's then if it's only RWD for example.

The Skyline was RWD-only until the R32, even if you're ignoring the RWD models beyond that.

[Mr Dave]

The early E34 M5 has a great engine, very smooth, sounds great, responsive, that is a car that is serious fun to drive and still quick even today.

The later one I have no exeprience of.

The M50b30 in the early E36s is again a brilliant engine but I would say its slightly slower to spool up, the b32 is better. Again no throttle delay at all.

The M54 in the 330 is notorious for throttle delay but its not a deal breaker in my eyes, heavy flywheel too which kills some of the fun, so not really whats being looked at in this thread.

The 530d when remapped, has a pretty responsive engine for being a big oil burner, the one im building at the minute should be pretty quick to go with it. Id say its better fun to drive than a 330/530.

The M3 CSL however is the best car I have ever driven, it is very very responsive, didnt notice any throttle delay, the car can be balanced extremely easily on the throttle and I love them so much.

NSX is a good shout, very responsive engine, revs like a good un but the CSL is a better track car in my opinion, the NSX always made me want more from it, it needs more power to make the best use of the car.

[S3_Graham]

pilchardthecat said:

RobM77 said:

Tyson1980 said:

Jimmy No Hands said:

Whats this supposed throttle delay? The 3.0 I6 in my Z is glorious.

Same here...

Very responsive in my 3.0i Z4 with the CDV removed

See the You Tube video of the Z4 Coupé 3.0si earlier in this thread. Although the delay is tiny, there's a definite delay there and it's enough to get in the way of attempts at decent throttle control.

On a seperate note, I expect that removing the CDV would be a very worthwhile mod - the CDV made the car unbelievably hard to drive smoothly at low speed.

Without those two 'features', I think the Z4 Coupé would be the best car I've ever owned; it just did everything so supremely well.

Roof rack?

I agree about the 135i - i noticed the throttle delay (and turbo lag), but i do not notice any delay on the Z4M (which you might think is close to the e46 M3, but supposedly has a later/better engine management chip/software).

I've not noticed a lag on my 130, should I have?

[s m]

Meoricin said:

The Skyline was RWD-only until the R32, even if you're ignoring the RWD models beyond that.

Time for THAT video?

[roverspeed]

flatline84 said:

Too bad the cars connected to the engine is sub-par. Needs to be RWD to be of any interest. Which sadly excludes most of the Alfas too..

So I guess its a question of the most responsive BMW 6? Anyone ?

Real Alfa's are RWD

[OlberJ]

Meoricin said:

Grovsie26 said:

But the drivetrain of a car has no effect on how good an engine is.

Best at what? Power? Noise? Reliability? etc, etc.

Can't include the Skline GTR's then if it's only RWD for example.

The Skyline was RWD-only until the R32, even if you're ignoring the RWD models beyond that.

Yes but he clearly says skyline GTR's, not just skylines.

[s m]

OlberJ said:

Meoricin said:

Grovsie26 said:

But the drivetrain of a car has no effect on how good an engine is.

Best at what? Power? Noise? Reliability? etc, etc.

Can't include the Skline GTR's then if it's only RWD for example.

The Skyline was RWD-only until the R32, even if you're ignoring the RWD models beyond that.

Yes but he clearly says skyline GTR's, not just skylines.

Very responsive GTR

http://www.youtube.com/watch?v=EAXGuD_f3Kw

Fantastic

[flatline84]

roverspeed said:

Real Alfa's are RWD

I said most
Arent those gtv`s put together with stickers and gum though?