Just thought I'd share this with you, it made me chuckle - unless I'm mistaken?

My employer sent me on this course this morning, aimed at reducing my fuel consumption. These courses come round every few years, and I'm always happy to cut my motoring costs if possible.

My instructor was quite insistent that driving too close to the car in front was bad because the turbulent air remained turbulent through the air filter and was bad for the engine - giving reduced fuel economy!

Even when I questioned it, he was adamant that this was the case - "that's why racing cars don't get too close to the car in front". It made me chuckle, please tell me that this man had no possible scientific basis for these comments?

It's all about drag IMO. Too close = less drag = easier work for the engine = less fuel used.

Exactly why close racing cars go faster and when I get behind a lorry in the Greenline II I use noticably less fuel.

One word...NASCAR

This man should never again be allowed to present a training course. He has no understanding whatsoever of his subject matter.

That's how come F1 cars can get "tows" down straights by tucking in and drafting the car in front.

You're letting them do the work by punching through the air, you tuck in behind and reduce air resistance conciderably.

Even if there was "turbulance" entering the airbox, im sure once it's gone through the air filter which would effectively act as a damper and associated pipework there'd be absolutely no difference.

You'll always get better economy if you draft a lorry on the motorway..

What a load of waffle!

In the motorsport world, there's talk of driving in "hot dirty air" when following another vehicle closely but my limited understanding (based on Mr Brundle's ramblings) is that the effect is more in terms of loss of downforce than significant inefficiences in the engine, otherwise there'd be no slipstream overtaking.

Of course, driving too close to a vehicle can wipe out any efficiencies gained by "drafting" if it forces you to drive on reactions (because you can't see what's going on beyond it) rather than being able to manage speed changes with better forward planning

Turbulence is to be encouraged in the inlet because it helps mix air and fuel ... combustion chambers are specifically designed to promote it.

Haha. I would have just laughed in his face!

Had something similar. A driving simulator designed to help with awareness of how to drive more efficiently.

It didn't take into account being able to let go off the throttle/change down and have the fueling cut (no fuel being burnt), pulse and glide was a no etc etc.

Phil

In the motorsport world, there's talk of driving in "hot dirty air" when following another vehicle closely

I remember F1 commentators saying about engines potentially overheating because they're not getting any cool air when following very closely for extended periods.

In the motorsport world, there's talk of driving in "hot dirty air"

Plus engines run better/with more power on colder air (I think?).

Edited 22 February, 201214 yr by TriggerFish

Guys, there are huge design differences between an F1 airbox and a road car one. Taking the F1 car vs a production Skoda, the F1 flows somewhere between 3.5 and 7 times (depending on model) air at peak power revs, the F1 doesn't have a filter, the F1 airbox is designed for peak flow rather than partly as a noise damper...

As I understand it a moving car will leave behind in the airflow a pattern which ( particularly on flat back vehicles ) circles back in on itself ( causing drag and explaing why transits and trucks are best to slipstream, that and there size of course) this pattern is beneficial to someone travelling behind if they are close enough, Driving very close will allow this slipstream effect and will reduce your fuel, however you would then be perhaps too close for safety. If you drive a little further back still, the pattern will be turbulent and have more resistance than normal airflow, meaning lower fuel economy, further back still the air pattern will return to normal.

If you stand on a platform as a high speed train passes, as it immediately passes you will be pulled in towards the back of it, and then pushed back again a short time later, which demonstrates this airflow, F1 cars are designed to minimise drag and so this effect is less apparent, jets suffer strongly from it.

To drive very close is beneficial ( and suicidal ) a little further back worse for fuel, a little further back still safer and better economy.

It is very hard to quantify these distances as it depends on the amount of drag generated by the vehicle.

To drive very close is beneficial ( and suicidal ) a little further back worse for fuel, a little further back still safer and better economy.

It is very hard to quantify these distances as it depends on the amount of drag generated by the vehicle.

Mythbusters did an experiment for this - results are quite interesting...

http://green.autoblog.com/2007/10/28/mythbusters-drafting-10-feet-behind-a-big-rig-will-improve-mile/

Chris

This man should never again be allowed to present a training course. He has no understanding whatsoever of his subject matter.

Agreed ! +1

JRJG

He should have just said tailgating on the roads is for ignorant retards that is why we don't do it.

 

There would be a point in what he is saying at a certain distance perhaps but there is a difference between following the vehicle in front tailgating and 10cm from bumper in front slip streaming for a similar wake vehicle. He has prob done some course himself where something 'along' those lines was said and he has taken it a bit too serious. Or perhaps he just uses that line with people in the hope that fuel economy saving might make them think more than the risk of killing people line, with the best of intentions and just met his match when questioned lol