Originally Posted by AlG

The owners manual states very explicitly that one shouldn't drive the car over 62 mph if the spoiler does not deploy so the car must get "light" at that speed. Therefore I'm sure it has a use. The old Audi TT had that same problem. When they were originally built they didn't have that bar on the trunk but then too many people were losing control and Audi recalled all that were built until that time to retrofit them. The ones that were built after that time had them already on the trunk.

Originally Posted by apkano

Have you ever noticed how much the silhouette of the crossfire looks like an airplane wing?

If you're curious about it's effectiveness........disable the spoiler and go for a drive on the expressway at speed! You can feel the back of the car try to "hunt" around......it's a less than comforting sensation! Don't say I didn't warn you!

Originally Posted by Airscape

Very interesting post but now I have to ask about diffusers. I was under the impression that they helped with top speed by reducing drag but after reading all this I think I was wrong. Can somebody clarify for me? Now it seems that they would just reduce lift and actually cause more downforce, reducing top speed/increasing handling at high speed. In addition my brain might just be fried from reading this whole thing and consuming too much crown last night lol. Thanks for any info you can provide.

Originally Posted by chuck65

This tread has been a good example of intelligent conversation. What good information we have all gained. Thanks everyone.

The only thing that worries me is Franc driving 90 MPH, volunteering to be a test driver to see what happens when you drive without the spoiler being deployed. Who do you think you are Franc, Chuck Freaking Yeager ? No wonder your wife is balking at your getting a SRT6 .

Originally Posted by Airscape

Now it seems that they would just reduce lift and actually cause more downforce, reducing top speed/increasing handling at high speed.

Originally Posted by Franc Rauscher

Cathy likes it at 120 MPH.

Truth is the car is rock solid the faster you go. Without the spoiler it was just loose, like most any car. My 82 TA had a "spoiler" but it was more for looks than function. At 130 MPH the louvres would rattle and the rear was floaty. Spoiler was ineffective.

If it was just weight, I guess you could put 80 Lbs in the back, but I'm not going to test it.


roadster with a stick.

Originally Posted by Brent

Wings and spoilers function differently but the end result is the same. First a little background.

The shape of the Crossfire mimics a wing and as a result lift is generated. In order to have lift you must first have a high pressure zone and a low pressure zone. Obviously in the case of the Crossfire the high pressure zone is under the car and the low zone is above. Both zones are pushing against the car but the high pressure zone pushes with more force and lifts the car. The low pressure zone is not strong enough to counteract the high pressure one to push the car back onto the road. So how are these zones created? It's done by air being moved faster over the top of the car than the bottom. Look at the Crossfire in profile and mentally draw a line from the grill, along the hood, over the top and down the back. Now do the same except go underneath the car. Which line is longer? Since air molecules like to "hang together" those that go over the top of the car must move faster (since they have a greater distance to travel compared to those going under the car) so they can meet up with their respective drinking buddy molecules at the rear of the car. This accelerated mass of air has less "push" against the car compared to the air underneath. Another way of looking at it (and maybe easier to visualize) is that you have the same number of air molecules above and below the Crossfire. Since the molecules above have a greater area to cover (remember our mental line) they are spread out more and have less weight or push per square meter, foot or whatever the measurement of your choice.

What a spoiler does is to disrupt or kill the airflow over the top of the wing or Crossfire in our case. No airflow means that no low pressure zone is created.

Now I know that many members here already understand all of the above but I thought that those members not as knowledgable about aerodynamics would appreciate a basic primer.

How Chrysler determined the amount of downward force generated by the spoiler is beyond me. Part of the problem may be that it actually is a wing and is just misnamed. But from what I've seen of it I would call it a spoiler.

The gizmo on the back of the SRT-6 is a wing. It is shaped like a wing and is designed to allow air to flow over and under it.

Now for another basic primer on the SRT-6 wing. Imagine the Crossfire in profile in all it's lift producing glory. Now iimagine another profiled Crossfire except this one is little. Flip the little Crossfire over and stick it on the back of the big Crossfire. There's your wing. Just as air is pushing at the bottom of the big Crossfire, it also pushes at the bottom of the little Crossfire. And the push of the little Crossfire is what keeps the rear of the big one planted.

And why a wing on a SRT-6 and not a spoiler? I'll echo the thoughts of others that it is more effective for higher speeds and acceleration, and that it makes the SRT-6 standout more from the standard Crossfire. But I'll add that I think Chrysler went with it to keep costs down.