Active Spoiler vs MPG

Yep I'm very curious tonight. Has anyone ever measured the affect disabling the active spoiler has on a Supra's fuel consumption?

Funnily enough......

No never.

It must add drag...

But probably not as bad as driving with your window open.

Or on a treadmill...

My active spoiler is currently sat in my living room and I've not noticed it change the mpg of the TV

Or on a treadmill...

Funnily enough, I once did.

Leeds to London at a steady 80mph with the spoiler up used more fuel than the same journey back with the spoiler down and me occasionally 'having fun'.

Not much help really!

On a serious note, I've not noticed a change in fuel consumption without mine - it's been off the car since last summer.

It must add drag...

On a serious note, I've not noticed a change in fuel consumption without mine - it's been off the car since last summer.

I reckon that you'd only see an improvement in MPG over very long distances and if you avoid getting your boost on. I expect that Toyota designed it to be pretty slippery.

If one did see an improvement specifically after removing it then you have to apportion some of that to the weight saving.

Further more, I always felt that the car felt wrong at speed with the spoiler up.

I watched an episode of mythbusters where they did a test with a pick up truck with the rear door open and the rear door closed. It was actually more efficient with the door closed as it caused a vortex effect forcing the air over the cab at the back rather than down in to it.

Perhaps the AS does a simliar thing forcing the air over the top of the car more efficiently ?

There we go, my curiosity has been satisfied.

I can't say as I'm the lightest person with my right foot though

I reckon that you'd only see an improvement in MPG over very long distances and if you avoid getting your boost on. I expect that Toyota designed it to be pretty slippery.

 

If one did see an improvement specifically after removing it then you have to apportion some of that to the weight saving.

 

Further more, I always felt that the car felt wrong at speed with the spoiler up.

Long distance motorway runs (~250 miles) used about the same fuel before and after I removed it.

How do you mean by the car "felt wrong"? I haven't noticed any difference really, but I tend not to chuck the Supra around too much at speeds where the spoiler is down.

Perhaps the AS does a simliar thing forcing the air over the top of the car more efficiently ?

Doesn't it direct airflow up into the engine bay more efficiently than without it? So if you're hooning it around on autobahns at 150+ all day, it helps keep things a little cooler than they might be. I always figured that was why it came as standard on UK cars, same as the bonnet scoop and rear diff cooler.

Whatever the affects I wouldn't imagine it'd be any worse than having an aftermarket front on a Supra.

I thought the Active Spoiler was there to create a massive low preasure zone under the nose/engine bay to cause downforce to the front of the car? I doubt the spoiler or it's mounts are strong enough to give primary downforce by air direction alone.

Doesn't it direct airflow up into the engine bay more efficiently than without it? So if you're hooning it around on autobahns at 150+ all day, it helps keep things a little cooler than they might be. I always figured that was why it came as standard on UK cars, same as the bonnet scoop and rear diff cooler.

As for the UK bonnet scoop, according to the same document it "...directs cooling air through the exhaust manifold to improve fuel consumption at high speeds". I think I'll start a new thread to discuss that one though.

According to the official brochure "Front and rear spoliers counter lift, using the air-flow at high speeds to create downforce. The front spoiler deloys automatically at speeds over 50 mph"

Well that would explain why mine used to feel odd at speed with the spoiler up. However, my spoiler only came down at 60 mph which I thought was standard for all of them. I take it that it's only JDM cars that are set to 60?

However, my spoiler only came down at 60 mph which I thought was standard for all of them. I take it that it's only JDM cars that are set to 60?

my JDM used to at 60 too, consumption was generally worse with it down I found, especially when on the boost, but it felt too light with it up!

my JDM used to at 60 too, consumption was generally worse with it down I found, especially when on the boost, but it felt too light with it up!

I think the on boost part explains the drop in mpg.

I think the on boost part explains the drop in mpg.

hehe true, but I meant that I'd see a more noticable difference in consumption on boost with the spoiler down, rather than on boost with it up if that makes sense?

hehe true, but I meant that I'd see a more noticable difference in consumption on boost with the spoiler down, rather than on boost with it up if that makes sense?

hehe true, but I meant that I'd see a more noticable difference in consumption on boost with the spoiler down, rather than on boost with it up if that makes sense?

I can't see how? Doesn't the boost drop off when you are at a steady speed? On long m-way drives I always found that the boost (or seeing that I didn't have a boost gauge, the turbo sounds) dropped away only returning if going uphill or me putting my foot down.

Is a stock TT on boost at 90mph even if you are driving steadily?

Nope, no boost while crusing...

I spotted that too. I'm sure Genna's UK doesn't deloy the spoiler until 60 MPH either.

My (UK spec) spoiler deploys at approx 60mph too