ACR front splitter question - 56k warning

[Cop Magnet]

Take a look at the front splitter in these pics. It seems to me the splitter should be deflected slightly downward, or neutral at best. I know this is only two pics, but I have many more from various angles that seem to show the same thing, i.e., a slight upward deflection. Without measuring actual forces, are these photos convincing enough to let some slack out of the adjustment cables to get a downward deflection or am I letting some optical illusion mess with my mind? Seems the splitter would push down no matter what? The car is set up with the rough track alignment. The center track extension is in place.

P.S. photo's are by Sideline Sports from Autobahn a few weeks ago. Check out the heat signature from the back of my car in the 2nd pic

 

[johniew398]

That looks about the way my splitter is set up.

 

[white out]

I really could care less about your splitter. Those are some GREAT overall pictures!

The splitter is probably designed like that so when it hits something it goes up & over vs. direct impact and being destroyed.

Nick

 

[JackDud]

I can definitely help you out with your inquiry if given more picture to analyze the situation.

(NOTE: I'm lying. JUST POST MORE PICS =D)

 

[plumcrazy]

a guy i know has the aero setup on his and i noticed the same thing the other day on his.

 

[Chuck 98 RT/10]

When the car brakes the nose tilts down changing the splitter angle and increasing the downforce on the front. At high speed straights a downward pointing splitter would cause too much downforce. Pointing slightly upward pushes some air out of the way and channels the remaining air underneath (hence the diffuser and underbody panels) on the straights.

I'm no aero engineer but that's the way I understand it.

And then of course there are different tracks, conditions and driving styles to determine settings.

 

[Cop Magnet]

I really could care less about your splitter. Those are some GREAT overall pictures!

The splitter is probably designed like that so when it hits something it goes up & over vs. direct impact and being destroyed.

Nick

Thanks, that was the other reason for posting
I don't think that's why the splitter looks like this. The splitter is held "up" by two cables (you can see them behind the grill in the pics, but you can't tell if they are taught, of course). The cables allow the splitter to "ride up" a little, and also adjust tension downwards.

 

[Cop Magnet]

When the car brakes the nose tilts down changing the splitter angle and increasing the downforce on the front. At high speed straights a downward pointing splitter would cause too much downforce. Pointing slightly upward pushes some air out of the way and channels the remaining air underneath (hence the diffuser and underbody panels) on the straights.

I'm no aero engineer but that's the way I understand it.

And then of course there are different tracks, conditions and driving styles to determine settings.

I like this answer, up to a point. All the pics I have are on the gas. Any on the brakes either don't show the splitter well enough to determine angle of attack, or are from the rear quarter.

If this is correct, and downforce on the front changes based on gas/brake, then the rear wing makes unopposed downforce on the straights. Check the 'Ring video, and you will see that rear wing downforce is proportional to speed. This variability in downforce balance doesn't seem right--half a ton of rear downforce on the straights would tend to lift the front end.

Perhaps the front splitter still makes considerable downforce when it looks like it's angled "up". Or maybe mine is whack. Any other ideas?

 

[redtanrt10]

It may be more of an optical illusion. The splitter is set up to be level, when you loosen the cable supports it adds flex, the splitter then deflects downward further as it catches air. Here's mine under fairly heavy braking with the nose of the viper pushing downward, splitter entension looks level but is really isn't.

 

[Boxer12]

Front deflection is a function of two things...splitter adjustment cable loosening and rear wing adjustment for front downforce (less wing). If you go with 6 mm deflection (setting the fr splitter cables) and P1 on the rear splitter, then brake and turn in at 150 mph, you will see the evidence of splitter deflection as wear marks on the bottom of the splitter...I have some pics of this in my gallery.

 

[02 Graphite GTS]

It may be more of an optical illusion. The splitter is set up to be level, when you loosen the cable supports it adds flex, the splitter then deflects downward further as it catches air. Here's mine under fairly heavy braking with the nose of the viper pushing downward, splitter entension looks level but is really isn't.

Nice picture !!!!!!!!!!!

 

[Cop Magnet]

Front deflection is a function of two things...splitter adjustment cable loosening and rear wing adjustment for front downforce (less wing). If you go with 6 mm deflection (setting the fr splitter cables) and P1 on the rear splitter, then brake and turn in at 150 mph, you will see the evidence of splitter deflection as wear marks on the bottom of the splitter...I have some pics of this in my gallery.

Cool pics. Looks like you are getting this on the front edge, not as a function of turn in, i.e., outer edges of rub strip? Also, are you using the smooth track setting, which is lower than mine?

 

[Chuck 98 RT/10]

I like this answer, up to a point. All the pics I have are on the gas. Any on the brakes either don't show the splitter well enough to determine angle of attack, or are from the rear quarter.

If this is correct, and downforce on the front changes based on gas/brake, then the rear wing makes unopposed downforce on the straights. Check the 'Ring video, and you will see that rear wing downforce is proportional to speed. This variability in downforce balance doesn't seem right--half a ton of rear downforce on the straights would tend to lift the front end.

Perhaps the front splitter still makes considerable downforce when it looks like it's angled "up". Or maybe mine is whack. Any other ideas?

There isn't much need for a lot of downforce on a straight. Cars today have plenty of high speed straightline grip. I've had both my GTS and RT/10 over 170mph many times and they both felt solid to me and neither of them had any aero parts.

Air doesn't always act like most people initially think it will. Some folks forget that air compresses as it hits the front of a car. Aerodynamics tries to utilize that energy. Slight changes in body contour can have strange and varying results at different speeds. It would take someone with a lot of aero and windtunnel experience to just look a style and make a decent prediction as to what would happen.

The best thing to do is go out and test it for yourself. If you are a consistent lapper and can get some clean laps the difference in splitter angle will show up on the stopwatch. That's what makes it all fun anyway.

 

[fireball]

I went and looked at some track pitures of my car and I see exactly the same thing.

This might be a good question for the Grail Keeper.

I know that my shock settings were all over the place from the factory so maybe the dive plane settings are not that consistant either.....

Greg

 

[Cop Magnet]

There isn't much need for a lot of downforce on a straight. Cars today have plenty of high speed straightline grip. I've had both my GTS and RT/10 over 170mph many times and they both felt solid to me and neither of them had any aero parts.

Air doesn't always act like most people initially think it will. Some folks forget that air compresses as it hits the front of a car. Aerodynamics tries to utilize that energy. Slight changes in body contour can have strange and varying results at different speeds. It would take someone with a lot of aero and windtunnel experience to just look a style and make a decent prediction as to what would happen.

The best thing to do is go out and test it for yourself. If you are a consistent lapper and can get some clean laps the difference in splitter angle will show up on the stopwatch. That's what makes it all fun anyway.

I understand and agree there would not be a lot of call for downforce at straight-line high speeds. But there IS still downforce on the rear, and it goes up the faster you go. My comment was about this being unopposed downforce, which seems like a bad idea. 1200+ pounds on the rear only is palatable if you have some downforce on the front. Again, this impression was driven by your comment that the angle of attack created downforce on the front during braking, when the splitter would be "pointed" down. The same is not true for the rear.

 

[Chuck 98 RT/10]

I understand and agree there would not be a lot of call for downforce at straight-line high speeds. But there IS still downforce on the rear, and it goes up the faster you go. My comment was about this being unopposed downforce, which seems like a bad idea. 1200+ pounds on the rear only is palatable if you have some downforce on the front. Again, this impression was driven by your comment that the angle of attack created downforce on the front during braking, when the splitter would be "pointed" down. The same is not true for the rear.

It is capable of 1200lbs, doesn't mean it should be set at 1200lbs or that there will ever be a track where it hits that mark.

On a short track with lotsa turns it might be best to set the wing at max downforce. Being a short track you'll never hit the 150mph/1200lbs.

On a fast track it might be best to back off on the downforce in which case you still wont hit 1200lbs but you will hit 150mph.

Fun topic.

 

[Boxer12]

Cool pics. Looks like you are getting this on the front edge, not as a function of turn in, i.e., outer edges of rub strip? Also, are you using the smooth track setting, which is lower than mine?

Look at the edges, you will see a lot more rub on one side than the other.\

Also, with reference to the downforce graph, did you guys notice there is only a 10% diff from H1 to H7 on the rear splitter? And that it says "front downforce" on the graph?

Also, 6mm, the max deflection of the front splitter is only about a half inch. Kinda hard top notice on a picture.

Here is why you don't want it too low...