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

Amen to the Taco!

Cheers to the Taco Supreme!

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.

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.

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.

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.

Yes, but my source says aero parts are c-o-o-o-ollll and she know's best. If you want to know the "real deal" always ask the woman behind the scenes..........

damn. it was only a matter of time before your ex showed up again.

She likes the TACO and claims cabs are for girls.................

she's entitled to her opinion.

she is entitled to a shearing.

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

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.

Hot moist taco is always good. ...just not taco wing. <grin>

I don't care what Joel says. There will be no taco on my rear deck.

That's certainly true - I don't like the taco wing. Now, Ucube, have you modified the suspension at all? Have you noticed anything like what Joel has described?

Forgot to add. Another Rennlister added the Misha GT2 wing to his car after it was lowered with the X73 suspension and the car actually was MORE unstable. Needless to say, the wing came off immediately and went back to planted like on rails with the X73. Lowering is very important. That U.S. 4x4 ride height really screws up the aero stability of the cars at high speed.

Thanks for the info. Dell. This is a great discussion for me. Okay, so the message I'm getting is that I'm probably okay with the partial kit, but if I have any problems, then maybe I should opt for the X73 suspension, rather than a rear wing. Is that a fair summary?

If you plan on being at speed anytime then I would defintely go with either the RoWM030 or X73/74 kit (wide/narrow).

I haven't modified the suspension and don't plan to at the moment. Handling implications aside, I must be nuts to like the 4x4 look of the 911. The 911s of yore all have that 4x4 look, which has made such an indelible impression on me. I've completed the front bumper, and I'm hoping to finish installing the skirts this weekend, so I can't comment on the aerodynamic issues as described by Joel just yet. I'll take my chances.

Well, good luck. Let us know how it feels after you're done. I'm probably going to do exactly as you are doing, so it would be great to learn from your experiences and know what to expect in advance.

Hey everyone. I haven't been around for awhile. Hope all is well. How does Joel explain the 40th Anv 996 with the GT2 front bumper, skirts and no wing? Here is my understanding on this. Lift is generated at high speeds because the car is shaped like a wing so the air moving under the car has a shorter path than the air traveling over the car. Lift! The stock, retractable spoiler doesn't really create down force it just breaks up the flow of air over the car which reduces the wing effect and reduces lift. The reason the car is more stable at speed when it's lower is that less air goes under the car so there is less overall wing effect and less lift. The same result can be had by adding the front areo kit which does nothing more than reduce the amount of air that passes under the car. In the early days we actually used lawn edging to build an air damn on my 996 for track days and it had a huge effect above 140 or so. My conclusion is that there should be no problem with adding just the front of the MKII or MKI areo kit. Adding just a wing is a completely different story. It's a very bad idea. Jim

Well put Jim.

Nice info. Jim! Just the kind of ammo. I need in talking with these guys.

JimB: RE: How does Joel explain the 40th Anv 996 with the GT2 front bumper, skirts and no wing? The 04 40th anniversary 911 actually has a C4S front, the Mk2 aerokit (aka GT3) side skirts, and the usual Carrera wing that lifts at 75 mph and lowers at 37 mph. It also came stock with the US M030 sport suspension. I thought about this too because it obviously is not the full aerokit. Don't know what the aero impact the combo of the C4S front, side skirts, no elevated rear wing on a narrow body car is in comparison with the full aerokit package on an 04 Carrera. To Porsche obviously this combo was fine.. Regards, Marc

I love my taco wing, my neighbor was like "nice porsche! what kind of wing is that?" I said: "its called the taco wing." she replied "it does sort of look like a taco huh...!" anyways Ive noticed it really sticks to the ground after 85mph with the wing and it feels really stable and solid at high speeds which is a good thing! My car is lowered also, I want to say it feels like the car is sucked to the ground at higher speeds

Here's my take. I have the 996 Mk II Aerokit front and side skirts paired with the Misha GT2/GT3 wing. While I am aware that at least one rennlister has claimed this wing caused instability at the track, another rennlister has indicated that the aerokit/Misha combo worked well for him at the track. I can only speak to my experience with the product which has been good. While I have not run the wing up to 170 mph, I have had it well into the triple digits (at the track of course) with no problems or apparent instability. FYI, I do have the X74 suspension on my car that drops the ride height well below the ROW sport height. I believe this kit (X74) rides almost as low as a stock GT3. To answer your other question I believe the Misha is made out of fiberglass. In my opinion the quality of this wing is "good" i.e., it is better that the constuction of many other aftermarket wings I have seen, but it is not as well constructed as the Porsche OEM Mk I "taco" or Mk II wing. Good Luck.

FYI, regarding ride height. The factory measured ride height for the standard C2/4 is 46mm higher in the front and 23mm higher in the rear than the GT3. The C2/4 is a neutral rake (same height front to rear) while the GT3 has a forward rake (front lower than rear). If you add the X73/74 kit you will gain you that 23mm difference in the rear (maybe a shave more) but in the front you will still not be at the same GT3 ride height (close but still about 6mm short). What you do get though is a better rake similar to the GT3 and a ride ride almost the same as the GT3. If anything, that reduces wind travel under the car will aid in REDUCING lift. That is the stability you feel. Don't add the X73/4 and then go run with the replica wing and you will defintely feel the instability.

Dell, Have you honestly ever driven a 996 (stock ride height) with front aerokit spoiler and the Misha wing? Or are you just guessing about "definately feeling instability"?

Nope. Just documented accounts of others here with track experience and this very topic. Most noticeable account was from Chris in his C4S.

I'm rolling on a partial kit on my cab, not sure if i notice more instability with or without.

The taco rules over the aero kit II park bench!

Where would one eat the taco if there is no park bench? BTW, Good stuff guys... I want the X73 suspension. My psychologist said I might feel less instability if I got the X73 suspension.

It's fastfood, you stand up!

Well I dont have much to bring to the table but my car with the Mk I aero and US spec ride heigth feels very unstable over about 110-120 and up. Very floaty and light steering.

do you have the lower front lip installed?

Oreganet. I didnt see much difference in the silverstars, although I only replaced the two nearest to the bottom. Are these the secondary lenses, or do they both distribute even light. They are not the ultras.

To be honest I don't know. I replaced all 4 of my bulbs. If you look at them you should be able to tell the difference pretty easily in low light conditions. I couldn't tell the difference in daylight, but at night there was a significant difference.

BTW I found out by trial and error that you can also use a 5mm socket for the headlight assembly locks.

????