Can the mph that raises the rear spoiler be changed?

[KRAM36]

Can the mph that raises the rear spoiler be changed? If possible I'd like to change it to 100 mph before it raises.

Thanks!

[Redboxs]

Porsche says that the car becomes unstable and dangerous without the added down force from the spoiler over 75 MPH. So I doubt that there would be an easy way to do this.

[JayG]

Originally Posted by Redboxs

Porsche says that the car becomes unstable and dangerous without the added down force from the spoiler over 75 MPH. So I doubt that there would be an easy way to do this.

On the Boxster it is a spoiler, not a wing. It does not produce down-force, it disrupts the airflow over the car and reduced the tendency of the car's aerodynamics to act a wing and lift.

A wing will produce down-force and actually push the rear of the car down. This needs to be co-ordinated with the suspension

[Redboxs]

Originally Posted by JayG

On the Boxster it is a spoiler, not a wing. It does not produce down-force, it disrupts the airflow over the car and reduced the tendency of the car's aerodynamics to act a wing and lift.

A wing will produce down-force and actually push the rear of the car down. This needs to be co-ordinated with the suspension

Ah! I see! I havn't ever really researched it. Just what I've read in my owners manual. Thx!

[thstone]

IIRC, it is hard coded into the ECU to deploy the spoiler at 75mph.

So, my best guess to work around this is either modifying the speedometer input to trick the ECU that 100mph was 75mph (without screwing up the speedo displays in the cluster) or modify the ECU code itself.

Maybe someone else knows more and will jump in...

[linderpat]

why does it matter at what speed it raises? You can't see it when it's up from inside the cabin.

[KRAM36]

Originally Posted by linderpat

why does it matter at what speed it raises? You can't see it when it's up from inside the cabin.

Because it creates unnecessary drag on the car, plus I don't really care for the looks of it in the up position. It doesn't go back down until you slow to 50 mph. It's easy to hit 75 and then travel a long distance at a lower speed and the spoiler stays up for no reason. Yes I know about the manual raise and lower button at the fuse panel door, but that's PITA.

I'd rather it not deploy until I hit 100 mph or even 85 mph. Was hoping maybe the Durametric could set this function.

Guess I could buy one of these. http://www.ebay.com/itm/261698591779



.

[j.fro]

Even with the switch, once the spoiler has been automatically deployed I don't think You can override the function.

[JayG]

Originally Posted by KRAM36

Because it creates unnecessary drag on the car, plus I don't really care for the looks of it in the up position.

It keep the car from lifting at higher speeds. Probably does add some negligible drag, but that is what it is supposed to do.
Porsche put it there for a reason!

Why are you concerned with drag anyway? Are you trying for a high speed record?

In any case, if you don't want the spoiler to deploy, you probably could get inside it and disconnect the gears and while the motor would still work and therefore no CEL, it would not move.

There probably are alternate methods as some have added fixed wings and disconnected the spoiler and have no codes.
Do some searching here, on boxa.net, boxster register and rennlist boxster forum

[KRAM36]

Originally Posted by JayG

It keep the car from lifting at higher speeds. Probably does add some negligible drag, but that is what it is supposed to do.
Porsche put it there for a reason!

Why are you concerned with drag anyway? Are you trying for a high speed record?

In any case, if you don't want the spoiler to deploy, you probably could get inside it and disconnect the gears and while the motor would still work and therefore no CEL, it would not move.

There probably are alternate methods as some have added fixed wings and disconnected the spoiler and have no codes.
Do some searching here, on boxa.net, boxster register and rennlist boxster forum

I want the spoiler to come up, but I don't think it's needed at 75 mph.

Why am I concerned with drag? Because this is my DD and that causes fuel economy to go down and drag isn't the only thing, I think it looks tacky when deployed for no reason.

I rarely hit 85 mph, but 75 mph is easy when the highway speed is 70 mph and you need to get around another car. So here is this spoiler up for no reason and doesn't come back down until 50 mph.

[Porsche9]

For safety reasons raising the speed at which it goes up is risky. My thought is that instead the speed at which it drops back down be changed. Instead of 50 let's say 65 or maybe even 70. I always thought the 25 gap was a bit much.

[JayG]

Originally Posted by KRAM36

I want the spoiler to come up, but I don't think it's needed at 75 mph.

Why am I concerned with drag? Because this is my DD and that causes fuel economy to go down and drag isn't the only thing, I think it looks tacky when deployed for no reason.

I rarely hit 85 mph, but 75 mph is easy when the highway speed is 70 mph and you need to get around another car. So here is this spoiler up for no reason and doesn't come back down until 50 mph.

Fuel economy, really? slow down a bit, that will improve your fuel economy.

I get around 27 mpg on the hwy doing 75-80, so I don't know what you expect. A Boxster is not an economy car and was not meant to be one
Besides the spoiler at worst has a negligible effect on fuel economy

The spoiler comes up at 75 for a reason. I am fairly certain that Porsche did a lot of wind tunnel testing and determined that 75 is where it is needed.
The spoiler is up FOR A REASON!!!

Basic aerodynamics are in play here. the shape of the car acts like an airfoil (wing). when air flows over the top of a wing, it moves faster than the air below the wing and creates a partial vacuum. this causes the wing to move towards the partial vacuum, in this case up. by disrupting that airflow over the top, it prevents the partial vacuum and therefor prevents the car from lifting. It is exactly how the wing on an airplane works and why they deploy spoilers on landing.

A proper wing on the back of a car is in fact inverted and the airflow is faster on the bottom, causing down-force. In a car you need to counteract that down-force with springs (adjustable coil-overs)to push up a bit

They probability have the down set at 50 so once it is up, its not constantly moving up and down

[Topless]

A little bit of science and aerodynamics:

https://www.youtube.com/watch?v=TKH1DyV9vNU
Pickup Truck Tailgates | Fuel Economy - Consumer Reports News

[JayG]

Originally Posted by KRAM36

I want the spoiler to come up, but I don't think it's needed at 75 mph.

Why am I concerned with drag? Because this is my DD and that causes fuel economy to go down and drag isn't the only thing, I think it looks tacky when deployed for no reason.

I rarely hit 85 mph, but 75 mph is easy when the highway speed is 70 mph and you need to get around another car. So here is this spoiler up for no reason and doesn't come back down until 50 mph.

I realize you have now seen the light and understand that the spoiler goes up and down at a specific speed for a reason and does not lower mpg as that was your concern. So if getting better mpg is your concearn, why are you looking at increasing HP with a bunch of engine mods in another thread? That will surely decrease MPG. The easiest way to increase MPG is to slow down a bit, especially if you are going 70+

[Nine8Six]

Originally Posted by KRAM36

Can the mph that raises the rear spoiler be changed? If possible I'd like to change it to 100 mph before it raises.

Thanks!

Just cut it off from the Porsche's system and built your own. Hardware: Arduino + automotive 12vdc relay ($20). Hand code one simple condition in your arduino backend (e.g. if >150mph then PIN#HIGH else PIN#LOW end)

The speedo analog signal can be tapped from the OBDII harness, and so its ground.

But you knew all about Arduino did you? If not it takes a day to learn on their site (ask their million-members-forum for support if you ever need lol)

[Nine8Six]

Dynamic: air speed, wind force, direction, turbulence, density....

I think spoilers are a scam LOL great marketing none the less

[JayG]

Originally Posted by Nine8Six

Dynamic: air speed, wind force, direction, turbulence, density....

I think spoilers are a scam LOL great marketing none the less

LOL, until you design and make some super duper cool illuminated one

Next project????

[madmodz]

You can bypass the oem system and use and two relays and a Porsche window switch and manually control the wing. The wing motor wiring works the same as a window regulator. It has 2 wires on the motor -up and down. Reverse polarity to move in the other direction. I have also in the past used dei window controllers to wire the wing to alarm remote controls. Your sitting having some coffee when some people come to admire your Porsche. You hit your remote switch and the wing goes up.

[particlewave]

Wow...what happened here?

I really don't want to end up having someone mad at me, but one person is absolutely 100% correct and the other is absolutely wrong.
Let's just say that Porsche did their homework and a spoiler is called so for a reason.
Aerodynamics affect a car differently at different speeds, hence the reason for a speed activated spoiler

[KRAM36]

Topless, apparently my thinking is incorrect. You are correct in this on the way our spoilers works.

I'll no longer worry about the spoiler causing a drag on the car and lowering the mpg.

I am grasshopper. Thanks for the lesson learned.