Post your DIY aero pics
08-03-2013, 07:04 PM
#508
So from the subframe to a 3.5" leading edge, you have a bit of upward rake? The bottom of the front subframe seems to be the lowest point on the whole car. I'm considering less underneath coverage so I can get the front closer to 4" while maintaining level to the ground.
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08-04-2013, 01:15 AM
#510
Less crappy cel phone pic from ACS today
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08-04-2013, 01:47 AM
#511
OK - thanks. I was going from the bottom of the subframe which is costing me almost an inch. I'll have to see what clearance I have to the steering rack mounted FM oil cooler. I'll probably need to finish the season with my low clearance and hope I don't have a nasty off. I'll redesign everything from scratch over the winter. 
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08-05-2013, 08:43 AM
#512
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Well, unfortunately, I didn't get much data with the splitter setup as pictured compared to the COT splitter.
Right out of the gate on Saturday, my time with the new setup was good for two seconds over my best time with the COT splitter. Understeer was gone, handling was neutral with the slightest hint of the back stepping out in places. I never bottomed out with the COT splitter, but was making contact several times here and hitting the bumpstops (also confirmed by a few fender marks on the front tires). I didn't want to stiffen the shocks up without more than one run to base it on, but sadly, during run #2, a bump in turn 17 unloaded the suspension, and a slight offroad excursion and contact with a wall and huge tree branch result in the splitter and mounts getting annihilated.
I really would have liked to see what it was capable of. I finished up the weekend using just the air dam and rear wing, and the first run had so much understeer it was terrifying. I ended up with the front Konis nearly full loose, and the rear shocks at about 3/4 stiff, and finished the weekend slipping and sliding my way to about 4 seconds quicker than my best time. I'm confident that I could have bested that time with the splitter had I been pushing as hard as those last couple banzai runs.
I think I will likely go with something comparable to this setup with the spill plates next year, just need to come up with a better mounting solution for getting on and off the trailer with the new nose.
Right out of the gate on Saturday, my time with the new setup was good for two seconds over my best time with the COT splitter. Understeer was gone, handling was neutral with the slightest hint of the back stepping out in places. I never bottomed out with the COT splitter, but was making contact several times here and hitting the bumpstops (also confirmed by a few fender marks on the front tires). I didn't want to stiffen the shocks up without more than one run to base it on, but sadly, during run #2, a bump in turn 17 unloaded the suspension, and a slight offroad excursion and contact with a wall and huge tree branch result in the splitter and mounts getting annihilated.
I really would have liked to see what it was capable of. I finished up the weekend using just the air dam and rear wing, and the first run had so much understeer it was terrifying. I ended up with the front Konis nearly full loose, and the rear shocks at about 3/4 stiff, and finished the weekend slipping and sliding my way to about 4 seconds quicker than my best time. I'm confident that I could have bested that time with the splitter had I been pushing as hard as those last couple banzai runs.
I think I will likely go with something comparable to this setup with the spill plates next year, just need to come up with a better mounting solution for getting on and off the trailer with the new nose.
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08-05-2013, 12:31 PM
#513
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Join Date: Mar 2012
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Bear in mind I am a complete amateur and have no aerodynamics experience, I am in no way trying to **** on your design.
If the purpose of the sills in to keep more air on the splitter and in turn more downforce, do the sills need to be so large?
Gurney lips on rear wings have been used for decades. It keeps more air on the wing for longer, would something on splitter edging not work similarly?
If a 1/2" lip on the side edging of the splitter, where you have your sills now, could keep air on the splitter longer, as opposed to spilling off the sides. And without creating the drag the large sills do between them and the front bumper/fender.
Just a
If the purpose of the sills in to keep more air on the splitter and in turn more downforce, do the sills need to be so large?
Gurney lips on rear wings have been used for decades. It keeps more air on the wing for longer, would something on splitter edging not work similarly?
If a 1/2" lip on the side edging of the splitter, where you have your sills now, could keep air on the splitter longer, as opposed to spilling off the sides. And without creating the drag the large sills do between them and the front bumper/fender.
Just a
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08-07-2013, 12:26 PM
#514
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Bigger is better. Any two things that operate in completely perpendicularly different directions of airflow, such as a gurney flap and a splitter endplate are two things that are so different they probably shouldn't even be mentioned in the same sentence. A smaller lip would help when compared to none at all, but a bigger one will create a larger build up of pressure and therefore downforce than a smaller one. At some cost of drag of course. I have some theories about how that can possibly be minimized while still using a large endplate though.
-Ryan
-Ryan
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08-07-2013, 12:49 PM
#515
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Gurney lip is used loosely. I was picturing something quite a bit larger, maybe 5-6" tall, but is a fender height side plate really needed?
I think the tall side plate sealed to the bumper/fender at the rear edge would create way too much drag.
But I don't have 400hp pushing me along either.
I think the tall side plate sealed to the bumper/fender at the rear edge would create way too much drag.
But I don't have 400hp pushing me along either.
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08-07-2013, 12:59 PM
#516
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It's going to produce more drag than without it. "Way too much" depends on a lot of other factors. We know for certain that there are cars for which the benefits of this feature greatly outweigh the drawbacks. Knowing whether it's right for a certain car takes only a bit of real-world testing.
-Ryan
-Ryan
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08-08-2013, 04:36 PM
#518
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Gurney lip is used loosely. I was picturing something quite a bit larger, maybe 5-6" tall, but is a fender height side plate really needed?
I think the tall side plate sealed to the bumper/fender at the rear edge would create way too much drag.
But I don't have 400hp pushing me along either.
I think the tall side plate sealed to the bumper/fender at the rear edge would create way too much drag.
But I don't have 400hp pushing me along either.
Really ought to spend the bucks on some wind tunnel time next spring up in Mooresville...
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08-24-2013, 11:20 PM
#519
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Nope, the car was actually nicely balanced once I had the sway bars set up right. It's got a flat undertray in the nose and a decent splitter. The canards make a noticeable difference as well. Obviously, I needed a lot more wing for that last corner...
Since there have been no pics in the thread. All this stuff is DIY at home. Well, the wing mounts were laser-cut, but since I made the first set at home I'm still taking the points for them
Wing is a COT on FM-style mounts, a bit taller than the production ones.
Canards, splitter and wheel spats. I did do some before/after on the canards, they work.
Splitter without the other bits. The cables allow it to flex up if necessary but they'll take a significant amount of load. I forget the rating, something like 400 lbs each. I also modified the eye bolts to improve their rating.
Under the nose with the splitter removed.
You can tell the splitter's working, the cables are taut! They've got a bit of slack at rest.
Since there have been no pics in the thread. All this stuff is DIY at home. Well, the wing mounts were laser-cut, but since I made the first set at home I'm still taking the points for them
Wing is a COT on FM-style mounts, a bit taller than the production ones.
Canards, splitter and wheel spats. I did do some before/after on the canards, they work.
Splitter without the other bits. The cables allow it to flex up if necessary but they'll take a significant amount of load. I forget the rating, something like 400 lbs each. I also modified the eye bolts to improve their rating.
Under the nose with the splitter removed.
You can tell the splitter's working, the cables are taut! They've got a bit of slack at rest.
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08-25-2013, 12:14 AM
#520
"So resistant" is being a little overdramatic. I've never said anything against it. I just haven't done it on my car.
Although plucas's simulations would disagree with your statement. My setup (#4) is considerably more efficient than a flat nose without a splitter (#5). Note both the lift numbers and the drag between those two.
Since I have a little more horsepower than most, drag is not as much of a concern to me as it is to cars like Crusher. And I'm learning more by playing with canards and splitter depth than I would by simply copying other setups. That's important. It's also a setup that I can easily revert to full rally spec if required as well - this is a multi-use car.
Although plucas's simulations would disagree with your statement. My setup (#4) is considerably more efficient than a flat nose without a splitter (#5). Note both the lift numbers and the drag between those two.
Since I have a little more horsepower than most, drag is not as much of a concern to me as it is to cars like Crusher. And I'm learning more by playing with canards and splitter depth than I would by simply copying other setups. That's important. It's also a setup that I can easily revert to full rally spec if required as well - this is a multi-use car.
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