Can the mph that raises the rear spoiler be changed?

[j.fro]

Fwiw, I picked up 1-2 mpg by going to an underdrive pulley.

[KRAM36]

Originally Posted by j.fro

Fwiw, I picked up 1-2 mpg by going to an underdrive pulley.

That's already on my to do list, didn't know it helped mpg though, thanks.

I need to change out the metal impeller water pump I installed when in a pinch last summer. So I'm going to do the UDP and Low Temp Stat at the same time.

[woodsman]

Hey don't mess with the 'active aero' man. That's right folks our cars were SO ahead of their time- so be proud of that sweet little, variable flap!
Kram- just think about what those huge GT2 air suckers are going to do to your aero...How about rigging up some slides that limit airflow through them above say, 50 MPH?

[KRAM36]

Originally Posted by woodsman

Hey don't mess with the 'active aero' man. That's right folks our cars were SO ahead of their time- so be proud of that sweet little, variable flap!
Kram- just think about what those huge GT2 air suckers are going to do to your aero...How about rigging up some slides that limit airflow through them above say, 50 MPH?

The bumper replacement is on hold. http://986forum.com/forums/general-discussions/55530-goy-my-new-front-rear-bumpers-wheels-way.html#post433870

You do make a valid point on that, but the cooling benefit would be worth it, plus it looks sweeeeeeet! The rear spoiler sticking up doesn't look sweet to me, but yes it's a nice and needed feature. I believe the slots in the upper portion of that front bumper would allow the air to escape and give front down force too. So that would probably reduce mpg too, not sure at what speed that would come into play though.

Like I said, this is a DD mostly, but I do take her out to some nasty fun twisties now and then. Hence the lager wheel and tire upgrade and ROW M030 suspension.

The rear spoiler isn't just about mpg, I think it looks tacky when up and I only want it up when needed. Seems the dash button control would be my best option.

[Topless]

Yaaa, I kinda like the function of the spoiler even if it is unattractive. It "spoils" both lift and drag in the rear which keeps the car planted at speed and also improves mileage. If it ain't broke, don't fix it. I can't even see mine while driving so it doesn't bother me at all.

[KRAM36]

Originally Posted by Topless

Yaaa, I kinda like the function of the spoiler even if it is unattractive. It "spoils" both lift and drag in the rear which keeps the car planted at speed and also improves mileage. If it ain't broke, don't fix it. I can't even see mine while driving so it doesn't bother me at all.

Can you explain more how the extra drag the spoiler puts on the car actually improves mpg?

Seems I'm not the only person to think about this.

http://rennlist.com/forums/987-981-forum/624522-anyone-ever-disable-their-rear-spoiler.html

Interestingly in that thread it says the Durametric can disable the spoiler. Will have to dig into this some more, would be nice if it could change the speed settings too. Crud, just realized the person said Durametric Professional and I have the Enthusiast.

Byprodriver even posted in that thread he wished his spoiler raise speed could be changed to 80.

[Topless]

Originally Posted by KRAM36

Can you explain more how the extra drag the spoiler puts on the car actually improves mpg?

Seems I'm not the only person to think about this.

Anyone ever disable their rear spoiler? - Rennlist Discussion Forums

Interestingly in that thread it says the Durametric can disable the spoiler. Will have to dig into this some more, would be nice if it could change the speed settings too. Crud, just realized the person said Durametric Professional and I have the Enthusiast.

Byprodriver even posted in that thread he wished his spoiler raise speed could be changed to 80.

It's a physics thing. By breaking the lift it also partially diffuses the aft vortex behind the car. A major source of drag. The same is true in a standard pickup truck. All the homies drive around with their tailgate down thinking it will improve gas mileage but it has the opposite effect. Having the tailgate in place creates a pressure zone known as a separated bubble that significantly improves the aerodynamics. Both concepts were proven in the wind tunnel.

[JayG]

Originally Posted by KRAM36

The bumper replacement is on hold. http://986forum.com/forums/general-discussions/55530-goy-my-new-front-rear-bumpers-wheels-way.html#post433870

I believe the slots in the upper portion of that front bumper would allow the air to escape and give front down force too. So that would probably reduce mpg too, not sure at what speed that would come into play though.

You need some kind of an airfoil to get down-force. Again, it's aerodynamics/physics. I don't think air flowing through those vents will give you down-force.

[KRAM36]

Originally Posted by JayG

You need some kind of an airfoil to get down-force. Again, it's aerodynamics/physics. I don't think air flowing through those vents will give you down-force.

Sure they can. Why do you think Porsche added them to the GT2 and GT3 cars? The new Z06 does it with vents on the hood.

[Topless]

Tailgate Up or Down

[JayG]

Originally Posted by KRAM36

You don't need a dyno to figure out mpg.

I couldn't find anything the aerodynamic of racing link showing that having the spoiler up would increase mpg. It did mention drafting would cause the car in front to have less drag.

I was being sarcastic about the butt dyno
The problem is that to calculate MPG, you need to have constant conditions, speed, etc, so using a dyno actually would be a good way to get a good caculation

as far as less drag via drafting, again it comes down to aerodynamics and physics. Drafting produces a partial vacuum and effectively sucks the car behind in. Please someone correct me if I am wrong

Originally Posted by KRAM36

Sure they can. Why do you think Porsche added them to the GT2 and GT3 cars? The new Z06 does it with vents on the hood.

Sorry, but the front vents are for cooling the brakes and radiators, they don't produce down-force. The front apron/lips generates down force, not the vents. I would guess the same is true for the Vette, cooling. I could be wrong, maybe someone can comment differently

[JayG]

Originally Posted by j.fro

Fwiw, I picked up 1-2 mpg by going to an underdrive pulley.

Was that using your butt dyno?

[KRAM36]

Originally Posted by JayG

Was that using your butt dyno?

You don't need a dyno to figure out mpg.

I couldn't find anything the aerodynamic of racing link showing that having the spoiler up would increase mpg. It did mention drafting would cause the car in front to have less drag.