Partial Aero Kit
10-30-2006, 10:21 PM
#1
Nordschleife Master
Thread Starter
Partial Aero Kit
We have had a fair amount of discussion about aero kits over the last week.
I have been starting shopping for a partial aero kit and have been talking with various people about it. Dell is a tremendous help and guide.
I thought the group would be interested in seeing the a posting today from Joel Reiser of the PCA on the subject of installing the aero kit bumper and side skirts without a rear wing.
Subject: 996 Partial Aero Kit Installation
At 170 or 180 mph, aerodynamics are tremendously crucial. This is a typical takeoff & landing speed for airplanes. Incorrect aerodynamic packages on cars can cause the former instead of the latter. With our cars we want downforce, not lift, but lift occurs naturally due to the shape and contours of the cars. If you add much downforce (or reduce much lift) at only one end of the car, you have upset the balance, and the car will be wickedly unstable.
Do NOT run top speed, or frankly much above any posted US speed limit with a partial aerokit in any way shape or form.
Additionally, in my opinion, all versions of the 911 at US ride height become unstable at those speeds. This is a key reason why I recommend lowering all of the cars to the Euro & ROW (rest of world) ride height, which also changes the rake or slope angle of the car to the ground, from front to rear. Due to the geometry of lowering, the toe settings are changed and thrown well out of spec, so the car must then get a 4-wheel alignment.
At 65 mph, the aerokit parts do not make nearly as much difference. By around 80 or 90 it starts to really matter, but so does the ride height.
You have a purely personal choice on your hands. If other people do something in numbers, that does not make it safe. I don't think you are going to find the opinion in writing for the reasons above. There may be other subtle aspects to this as well that I am not thinking of at this moment, so feel free to follow up with me by email.
For example, worn out shocks can cause a partial lowering of ride height, and typically not the same amount at all four corners. Tires which are low on air pressure will do the same. It is normal for tires to leak 1 psi per month. Now add back a partial aerokit and reconsider the complete package -- not good, not safe.
So, quoting Yod a, "try not; do or do not". Either put in the complete aerokit, or lower the car correctly, or both, but I don't recommend anyone going part way in between.
Joel Reiser - PCA WebSite - 10/30/2006
I have been starting shopping for a partial aero kit and have been talking with various people about it. Dell is a tremendous help and guide.
I thought the group would be interested in seeing the a posting today from Joel Reiser of the PCA on the subject of installing the aero kit bumper and side skirts without a rear wing.
Subject: 996 Partial Aero Kit Installation
At 170 or 180 mph, aerodynamics are tremendously crucial. This is a typical takeoff & landing speed for airplanes. Incorrect aerodynamic packages on cars can cause the former instead of the latter. With our cars we want downforce, not lift, but lift occurs naturally due to the shape and contours of the cars. If you add much downforce (or reduce much lift) at only one end of the car, you have upset the balance, and the car will be wickedly unstable.
Do NOT run top speed, or frankly much above any posted US speed limit with a partial aerokit in any way shape or form.
Additionally, in my opinion, all versions of the 911 at US ride height become unstable at those speeds. This is a key reason why I recommend lowering all of the cars to the Euro & ROW (rest of world) ride height, which also changes the rake or slope angle of the car to the ground, from front to rear. Due to the geometry of lowering, the toe settings are changed and thrown well out of spec, so the car must then get a 4-wheel alignment.
At 65 mph, the aerokit parts do not make nearly as much difference. By around 80 or 90 it starts to really matter, but so does the ride height.
You have a purely personal choice on your hands. If other people do something in numbers, that does not make it safe. I don't think you are going to find the opinion in writing for the reasons above. There may be other subtle aspects to this as well that I am not thinking of at this moment, so feel free to follow up with me by email.
For example, worn out shocks can cause a partial lowering of ride height, and typically not the same amount at all four corners. Tires which are low on air pressure will do the same. It is normal for tires to leak 1 psi per month. Now add back a partial aerokit and reconsider the complete package -- not good, not safe.
So, quoting Yod a, "try not; do or do not". Either put in the complete aerokit, or lower the car correctly, or both, but I don't recommend anyone going part way in between.
Joel Reiser - PCA WebSite - 10/30/2006
10-31-2006, 08:50 AM
#4
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that article makes me wonder. i want to buy the cargraphic front lip (or the mashaw gt3 front lip), aerokit side skirts, and the rear wing and seeing as how the cargraphic is different then the normal aerokit front bumber then would this upset the balance and make the ride a lot worse at high speeds? Also since the mashaw front lip is just that a front lip you attach to the bottom of your none aerokit bumber and then it looks like it is an aerokit would that help or hinder the way the car behaves at high speed? any help would be appreciated and thanks in advance.
10-31-2006, 11:07 AM
#5
Nordschleife Master
While I agree with Joe to an extent he is off base on the complete aerokit respnse toward the end of his response. On the CAB the "complete" aerokit is basically a partial aerkit and small fixed wing that is roughly the equivalent of your retractable rear wing replaced. The taco is a comelptly different ballgame. It can be installed in a coupe but it is also stated in the tsb that the wing adjustment should NOT be changed in a manner that is condusive to increased downforce in the rear. in otherwords the wing should be flush and not adjust on a tilt.
To say that you must NEVER drive above posted speed limts or you run the risk of aero imbalance if you only install the front and sides is just flat IGNORANT and misinformation. What he seems to forget is that you have increased downforce in the rear once you exceed U.S. posted speed limits (74 mph the rear wing deploys).
I can speak from experience (and agree with Joe) that ride height is almost more important than the aero components that increase downforce. Prior to any mods to my car I didn't feel stabel and secure at higher speeds (100+) on the track. Then when I added the RoWM030 to bring the car to RoW specs and lower the car roughly 20mmR and 25mmF I noticed a significant change in handling. Now with the aero (parital) on my car (front and sides) along with the retracting spoiler and RoW suspension settings I feel more stable than ever. Pushing 150mph at a track like VIR and feeling 100% stable and secure is not something I take litely. I 100% respect speed and will not push when I don't feel confident. Had it not been for the partial aero, retracting rear wing, and RoW suspension settings there is NO WAY that I would would be full throttle pushing 150 and feel safe.
Hope my experience can shed some light on the situation.
To say that you must NEVER drive above posted speed limts or you run the risk of aero imbalance if you only install the front and sides is just flat IGNORANT and misinformation. What he seems to forget is that you have increased downforce in the rear once you exceed U.S. posted speed limits (74 mph the rear wing deploys).
I can speak from experience (and agree with Joe) that ride height is almost more important than the aero components that increase downforce. Prior to any mods to my car I didn't feel stabel and secure at higher speeds (100+) on the track. Then when I added the RoWM030 to bring the car to RoW specs and lower the car roughly 20mmR and 25mmF I noticed a significant change in handling. Now with the aero (parital) on my car (front and sides) along with the retracting spoiler and RoW suspension settings I feel more stable than ever. Pushing 150mph at a track like VIR and feeling 100% stable and secure is not something I take litely. I 100% respect speed and will not push when I don't feel confident. Had it not been for the partial aero, retracting rear wing, and RoW suspension settings there is NO WAY that I would would be full throttle pushing 150 and feel safe.
Hope my experience can shed some light on the situation.
10-31-2006, 11:44 AM
#6
Three Wheelin'
Great post Dell. I'd read Joel's letter yesterday when it was emailed from PCA and thought the same as you. I wondered if he had neglected to account for wing extraction on speeds higher than 74.
10-31-2006, 11:58 AM
#7
Nordschleife Master
Sounds like it was a "cover our ***" in a legal way to repond to a honest question from a PCA member. You can respond in one way and feel another. I think his response was a mix of the two. If it wasn't then he really needs to get up to speed on aero properties.
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10-31-2006, 04:18 PM
#13
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I personally don't like the taco wing. If I were to add an aerokit to my 03, I'd use a GT2 style wing.
As for Joel's comments, he is basically saying what has been and will probably remain the concensus with regard to aeros - full kit or no kit. For the cost of the kits + installation + painting, you could really upgrade the suspension, ride height, etc.
Steve
As for Joel's comments, he is basically saying what has been and will probably remain the concensus with regard to aeros - full kit or no kit. For the cost of the kits + installation + painting, you could really upgrade the suspension, ride height, etc.
Steve
10-31-2006, 05:34 PM
#14
Nordschleife Master
Thread Starter
Nice posts.
I'll chime in on the side of Dell.
Joel's post made me seriously reconsider whether I should do the partial aero kit - it was a little alarmist. I also consider, realistically, when will I get to the speeds that it will matter?
I don't track the car and the fastest I've taken it on an open road is around <ahem> 110mph for a short period of time. I look at the other kits that people have installed and figure that they should be as bad or worse for downforce, but they don't have the rear wing.
I could take the tactic of installing the partial kit as I intended, then install a Misha GT2 wing should I need it at a later date. (BTW, what is that wing made of?) I'm still on the fence about that, as I do seriously love the mechanical wing and would hate to say goodbye to it.
This is an interesting topic and it's good to hear people's thoughts.
I'll chime in on the side of Dell.
Joel's post made me seriously reconsider whether I should do the partial aero kit - it was a little alarmist. I also consider, realistically, when will I get to the speeds that it will matter?
I don't track the car and the fastest I've taken it on an open road is around <ahem> 110mph for a short period of time. I look at the other kits that people have installed and figure that they should be as bad or worse for downforce, but they don't have the rear wing.
I could take the tactic of installing the partial kit as I intended, then install a Misha GT2 wing should I need it at a later date. (BTW, what is that wing made of?) I'm still on the fence about that, as I do seriously love the mechanical wing and would hate to say goodbye to it.
This is an interesting topic and it's good to hear people's thoughts.
Last edited by oreganet; 10-31-2006 at 06:03 PM.
10-31-2006, 05:35 PM
#15
Nordschleife Master
Thread Starter
Originally Posted by dallasboats
She likes the TACO and claims cabs are for girls.................
Hot moist taco is always good.
...just not taco wing. <grin>