Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.
Aerodynamic drag and why a coupe is better
-
- Member
- Posts: 272
- Joined: Sun Oct 20, 2019 6:38 pm
Aerodynamic drag and why a coupe is better
If on the rare occasion I use my car for work, I tend to drive it exactly the same, regardless of roof up or roof down. Not heavy driving, but not dithering about either.
Same round trip with the roof up, just under 1/4 of a tank,
Roof down, just over 1/4 of a tank
It works about at just under 2 Litres of burn difference across the two comparisons over 150 mile round trip.
It might also be worth noting that if I don’t have the roof down, it’s usually because it is a lot cooler, or raining, and both of those factors will only make a petrol engine run better, so not entirely down to drag in my case.
Same round trip with the roof up, just under 1/4 of a tank,
Roof down, just over 1/4 of a tank
It works about at just under 2 Litres of burn difference across the two comparisons over 150 mile round trip.
It might also be worth noting that if I don’t have the roof down, it’s usually because it is a lot cooler, or raining, and both of those factors will only make a petrol engine run better, so not entirely down to drag in my case.
2013 Z4 20i sDrive.
Remapped, and currently “interior” rattle free.
Early midlife crises and so far loving every minute of it!
Remapped, and currently “interior” rattle free.
Early midlife crises and so far loving every minute of it!
- srhutch
- Moderator
- Posts: 26959
- Joined: Tue Jun 19, 2007 1:22 pm
- Location: East Sussex, UK
- Contact:
Aerodynamic drag and why a coupe is better
I bought a roadster because I could put the roof down, not so worry about how much fuel I'm using.
You can't put a price on a nice summers night drive with the roof down. An experience a coupe driver can only dream of.
You can't put a price on a nice summers night drive with the roof down. An experience a coupe driver can only dream of.
- Mr Tidy
- Legend
- Posts: 23789
- Joined: Wed Jul 02, 2014 12:18 pm
- Location: North West Surrey
Aerodynamic drag and why a coupe is better
Well now I know another reason to stick to Coupes! Must be why my MC is currently showing 26.9mpg average, although that may be more to do with being gentle with it for now as the bearing shells have only just been replaced.
As for driving with no roof the only sort of dream that conjures up for me is a nightmare.
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
- Stevo1987
- Senior Member
- Posts: 1203
- Joined: Sun Nov 17, 2019 11:08 pm
- Location: Breckland, Norfolk
Aerodynamic drag and why a coupe is better
I don't make a point of monitoring my fuel consumption. It is not the reason I bought the car. Average is maybe 25 mpg. I did notice a few weeks ago that on a trip down south to my brothers new gaff I went through half a tank which worked out to roughly 37 mpg. I think for most of the tie the roof was down. Now, the caveat is Mrs Stevo was accompanying me and she adopts the brace position whenever I change down a gear so I was being extremely gentle. Suffice to say on to returning to the homestead I made an excuse to pop to the shop for something medicinal and blew the snot out of it.
2014 Z4 e89 35is in mineral grey.
2012 Audi TTS in Ibis white.
2012 Audi TTS in Ibis white.
- BMWZ4MC
- Lifer
- Posts: 6342
- Joined: Sun Sep 13, 2009 4:24 pm
- Location: Back in the sunshine
Aerodynamic drag and why a coupe is better
Mine is showing an average of 18 mpgMr Tidy wrote: ↑Thu Sep 10, 2020 7:50 pmWell now I know another reason to stick to Coupes! Must be why my MC is currently showing 26.9mpg average, although that may be more to do with being gentle with it for now as the bearing shells have only just been replaced.
As for driving with no roof the only sort of dream that conjures up for me is a nightmare.
Thanks for the interesting article Pbondar
Z4MC - heavily fettled for track use
Lotus Exige - sensible daily driver on the mods slippery slope
Westfield SEiW - in hibernation
Modified RS4 Avant - back in Blighty
S2000 GT - gone
Aerodynamic drag and why a coupe is better
Your welcome..the original point if the article was not to justify or not the extra cost of roof down motoring simply to rationalise in part differing fuel consumptions...plus the confirmation that wind deflectors and some spoilers have a benefit for top down motoringBMWZ4MC wrote: ↑Fri Sep 11, 2020 7:14 amMine is showing an average of 18 mpgMr Tidy wrote: ↑Thu Sep 10, 2020 7:50 pmWell now I know another reason to stick to Coupes! Must be why my MC is currently showing 26.9mpg average, although that may be more to do with being gentle with it for now as the bearing shells have only just been replaced.
As for driving with no roof the only sort of dream that conjures up for me is a nightmare.
Thanks for the interesting article Pbondar
-
- Lifer
- Posts: 4034
- Joined: Sat May 25, 2013 8:27 pm
- Location: Stourbridge
Aerodynamic drag and why a coupe is better
It was said the Princess was more aerodynamically efficient going back wards, at least until the steering ball joint broke off!
- R_P_M_
- Member
- Posts: 109
- Joined: Tue Jun 09, 2020 6:34 pm
Aerodynamic drag and why a coupe is better
This is what you get when you spend the first 1000 miles of ownership warming her up and driving your favourite b roads
Last edited by R_P_M_ on Sat Sep 12, 2020 9:58 am, edited 1 time in total.
Current - Z4M Coupe, Ruby Black, Extended amarone, Copper bronze 224s, Eventuri carbon intake, BC Racing Coilovers, OEM strut brace, top spec including digital TV
-
- Senior Member
- Posts: 2809
- Joined: Sun Nov 20, 2016 2:49 am
- R_P_M_
- Member
- Posts: 109
- Joined: Tue Jun 09, 2020 6:34 pm
Aerodynamic drag and why a coupe is better
that's what you get using the car as intended on b roads.
Current - Z4M Coupe, Ruby Black, Extended amarone, Copper bronze 224s, Eventuri carbon intake, BC Racing Coilovers, OEM strut brace, top spec including digital TV
-
- Member
- Posts: 488
- Joined: Sat Nov 11, 2017 10:42 am
- Location: Wokingham
Aerodynamic drag and why a coupe is better
It’s about as high as I get. Normally it’s mid to low 20s.
Z4 S-Drive 35i
Audi TT S-line
Mazda MX5 Mk2.5 (for sale)
Wokingham Berkshire
Audi TT S-line
Mazda MX5 Mk2.5 (for sale)
Wokingham Berkshire
-
- Senior Member
- Posts: 2809
- Joined: Sun Nov 20, 2016 2:49 am
Aerodynamic drag and why a coupe is better
Yes, your 17.5 mpg is at an average of 34.9 mph, which in reality is quite quick on B roads over the given 53 miles. That said, my global figure is 26.4 mpg at an average of 30.1 mph.
Vidi, vici, veni