Think I surprised an M4 driver.......

[stuartinzg]

And now add over-boost into the equation:

I've only got a partial curve for that because you need an up change with the throttle in kick down.

Are you sure you only get overboost with kick down? I thought it was full throttle regardless of kick down?

 

[techathy]

Not on mine, older cars maybe.

 

[stuartinzg]

Not on mine, older cars maybe.

That sucks, that means I can't get full power unless I use the kick down... which I don't like doing.

Can you still control gear changing at WOT ?

 

[techathy]

In M with selector to the left my box doesn't change down until I tap the left paddle. In S or D it does.

 

[stuartinzg]

In M with selector to the left my box doesn't change down until I tap the left paddle. In S or D it does.

Even when you engage kick down with the button? Mine will always kick down, that's why I leave it full throttle without the click. I'll do some more research because it will be a bit odd just to work with the "click" ...

 

[R.E92]

The kickdown switch isn't actually a real switch, it's just a setpoint on the position of the accelerator pedal. I believe the pedal goes from 0.5-4.5v, the kickdown activates at 4.3v.

In stock form your accelerator pedal hit's max torque request at 41% of the pedals travel. Any more than that is just dead space. Not an ideal situation if overboost requires you to hit the end of the travel before activating. Doesn't exactly aid in smooth power delivery.

It would be easy to test using MHD. Just log two pulls, one with kickdown and one without and look at the boost. Standard boost on the 35is is 11.5PSI, overboost is 14.5PSI.

 

[techathy]

In stock form your accelerator pedal hit's max torque request at 41% of the pedals travel. Any more than that is just dead space. Not an ideal situation if overboost requires you to hit the end of the travel before activating. Doesn't exactly aid in smooth power delivery.

41% of travel or voltage? I ask because I'd agree with this when in sports mode, there's a huge gap before you hit kickdown. However, this is not how it feels in comfort there's a fairly small gap between reaching maximal acceleration & the kickdown resistance point.

 

[techathy]

In M with selector to the left my box doesn't change down until I tap the left paddle. In S or D it does.

Even when you engage kick down with the button? Mine will always kick down, that's why I leave it full throttle without the click. I'll do some more research because it will be a bit odd just to work with the "click" ...

Yeah. My car has a different kickdown behaviour to a 35iS demonstrator I drove which rolled off the production line 1 year earlier than my car.

Remember all of this behaviour is software not hardware so it's more than possible BMW have changed behaviour.

 

[stuartinzg]

In M with selector to the left my box doesn't change down until I tap the left paddle. In S or D it does.

Even when you engage kick down with the button? Mine will always kick down, that's why I leave it full throttle without the click. I'll do some more research because it will be a bit odd just to work with the "click" ...

Yeah. My car has a different kickdown behaviour to a 35iS demonstrator I drove which rolled off the production line 1 year earlier than my car.

Remember all of this behaviour is software not hardware so it's more than possible BMW have changed behaviour.

Well I have my logging cable so I'll go datalog a run with and without kickdown and report back

 

[R.E92]

In stock form your accelerator pedal hit's max torque request at 41% of the pedals travel. Any more than that is just dead space. Not an ideal situation if overboost requires you to hit the end of the travel before activating. Doesn't exactly aid in smooth power delivery.

41% of travel or voltage? I ask because I'd agree with this when in sports mode, there's a huge gap before you hit kickdown. However, this is not how it feels in comfort there's a fairly small gap between reaching maximal acceleration & the kickdown resistance point.

In comfort mode it's more like 60% of voltage, but it varies on revs in that mode.

 

[techathy]

That perfect!

At 100kph the 335d needs to be in 3rd whereas the 35is is still holding 2nd and producing a shed load more torque to the wheels thanks to the gear ratio.

That's actually N thrust per kg of mass. It's basically a CdA (& calculation) away from an acceleration graph. :lol:

 

[techathy]

In comfort mode it's more like 60% of voltage, but it varies on revs in that mode.

Yeah, noticed the varies bit but still 60% movement seems a little further away from the resistance point.

 

[jimmybell]

Anyone else surprised to hear a Z4 E89 in any guise would even trouble an M4?

Just doesn't seem realistic to me. M4 is lighter, newer, more powerful and probably better setup for the power than the z4 is.

I don't doubt it happened, just very surprised - and threads like this always make me chuckle when you read about a forum car 'beating' other cars. Usually it's 'RS/M/AMG/ST/etcetcetc forum owners car beat a <insert supercar that clearly wasn't racing>'

 

[Jasey]

Public road racing only proves which driver is more willing to lose their licence

But the stories are often amusing

 

[Axelf]

If you read my signature you will see I have had all the new M range so yes I know how they behave... And also if you read my post it will say there was no other traffic and never went over speed limit... You telling me you have never put your foot down just to get to the sped limit... I don't think so

 

[R.E92]

Public road racing only proves which driver is more willing to lose their licence

But the stories are often amusing

Just reminded me of this video

It's not a race, it's a rallye!

https://youtu.be/xhu4dzC0vrw?t=195

 

[jimmybell]

If you read my signature you will see I have had all the new M range so yes I know how they behave... And also if you read my post it will say there was no other traffic and never went over speed limit... You telling me you have never put your foot down just to get to the sped limit... I don't think so

Your signature is a car dealership's dream customer!

I don't think anyone said they disagree with what you said, i just found it unlikely that at max chat a 35is would pull away from an M4. On paper, at least, it should be no competition in the M4's favour. In my experience of both i'd of agreed with the paper expectation too.

 

[Jasey]

If you read my signature you will see I have had all the new M range so yes I know how they behave... And also if you read my post it will say there was no other traffic and never went over speed limit... You telling me you have never put your foot down just to get to the sped limit... I don't think so

Your signature is a car dealership's dream customer!

I don't think anyone said they disagree with what you said, i just found it unlikely that at max chat a 35is would pull away from an M4. On paper, at least, it should be no competition in the M4's favour. In my experience of both i'd of agreed with the paper expectation too.

Especially between 30 and 70.

I reckon an Octavia vrs could keep up with the M4

 

[Axelf]

 

[R.E92]

If you read my signature you will see I have had all the new M range so yes I know how they behave... And also if you read my post it will say there was no other traffic and never went over speed limit... You telling me you have never put your foot down just to get to the sped limit... I don't think so

Your signature is a car dealership's dream customer!

I don't think anyone said they disagree with what you said, i just found it unlikely that at max chat a 35is would pull away from an M4. On paper, at least, it should be no competition in the M4's favour. In my experience of both i'd of agreed with the paper expectation too.

Especially between 30 and 70.

I reckon an Octavia vrs could keep up with the M4

Only if it were a diesel. We all know how much torque those have