12AutoX

iTrader: (7)

I have heard some good things lately about using wings and splitters on road courses. As for the current setup, my Z has a nearly stock motor, Cusco swaybars, and stock suspension. I have some wide Falken Azenis RT-615's.
I can't afford coilovers right now, and the OEM suspension is pretty manageable.

How much wing do I need? APR suggests having over 300hp to overcome the drag from their wing, but that wing is huge. C-West has some nice smaller aluminum wings for around $350. They are adjustable, and come in different sizes. They also make a CF wing with airfoil characteristics that change from the center of the wing to the sides. I don't really know what I need and how much I should be willing to spend to achieve my aim. (The wing should be functional and adjustable, but not create too much drag)
Then there is the splitter for the front. Is it ok to run a wing to generate rear downforce and leave the front end alone? Would this make the front end unstable in fast sweepers? Are there some splitters that work better than others? I would like something that is removable when I am not racing. Any recommendations?

betamotorsports

iTrader: (1)

What handling behavior are you trying to enhance or correct with aero? Do you need to increase rear grip? Do you need to increase front grip? At what speeds does it seem that grip is less then what you expect or need? Does the car's balance change at increasing speeds? Are pitch changes affecting grip? Is the chassis stable enough in pitch at speed to ensure aero mods will work?

In other words, do you have a goal for your aero modifications? Unless you know what you want to achieve with aero mods you are most likely going to make your car slower around a race track.

12AutoX

iTrader: (7)

I never really thought of it as addressing a problem. I was looking at it in terms of raising the upper performance limits. If I'm not at those limits and experiencing problems, maybe I should be more focused on reaching the existing limits.

I am a little concerned about what happens when I go to a bigger track than I am accustomed to (i.e. Buttonwillow) and what kinds of problems I will likely encounter. Maybe I should reconsider this issue after the fact when I have more data to draw from.

Thanks

knight_white99

iTrader: (5)

Hey John, I have to agree with John Coffey's post above. If you're not sure why you want the aero parts, maybe you don't need them yet.

I have gone and installed some aero parts on my car (and a "super secret" item will hopefully be on the car at the Redline Time Attack!), but I have specific goals in mind. And Buttonwillow is a track (as is Big Willow) were aero can make a difference if your car is fast enough.

I have enough power now to push a big wing on my car, and I wanted the extra high speed stability through the sweeper at Buttonwillow so that I can use as much power as possible with street tires. My issue now is balancing out front and rear downforce. I am also hoping to go over the Lost Hill at Buttonwillow without having to brake as much on the entrance, and carry enough speed (but not TOO much) over the top so that the aero parts will help to keep me on the track as I power out on exit!

Don't let Buttonwillow being a "bigger" track intimidate you. In fact, it is a really fun track! It is really not that high speed in the #13 configuration (in my opinion). It is longer than some, but handling is just as important as raw power there. Money spent on good rubber and suspension will likely gain you a lot more than aero parts will.

I'll let you ride with me for a few laps during Saturday practice for the Redline time attack if you like.

12AutoX

iTrader: (7)

Hey Steve, I was hoping to hear from you on this. I would love to ride along and see how you run the course. Maybe if you are agreeable you could do a few laps with me to offer advice. I have good rubber and am confident with the car. I am really looking for whatever I can do for under $1000 to improve my vehicle in a way that will shave down my lap times. The driver is the #1 mod, but I am kind of limited by my distance from any real track to practice.

Stack

Re-read what you wrote here... read it over and over... this indicates you've got some sense about you.

Use that $1000 to get as much track time as you can BEFORE adding aero, or anything else for that matter except high quality brake pads, fluid, HP street tires. Work on smoothness and consistency first. Until you can drive the same lap every time and not get anything else out of the lap without endangering yourself, you'll never know what your mods are doing, if anything other than reducing the amount of money you can spend on seat time.

Its not just about learning the course, its about learning how to get every ounce of performance out of what you have, then adding small amounts at a time to see what effect they have on the performance.

If you want to spend $1000 on something, buy a Racepak G2X datalogger. This will give you a tool to see some real numbers that will tell you what your car is doing, will show you what you can improve from lap to lap, event to event, turn to turn even.

And if/when you do upgrade anything on your car, you'll have some real data to look at to see where its helping you. For some examples of what it can show you, check these these pages out:

http://www.trackpedia.com/wiki/Butto..._993_Telemetry

The data looks daunting at first... but once you learn what its telling you, its a great tool.

Eagle1

iTrader: (2)

Three simple replies by John, Steve, and Stacy, and every one of them worth their weight in gold. Super solid advice.

Aero is not only important to address a handling challenge, but it varies from track to track, just like suspension settings, so it gets a bit complicated. If you dial in the downforce that you want to improve cornering velocities, it will cost you on the straights. A mediocre approach does not give you enough added performance in the corners, costs you in the straights, and as John points out, you overall go slower than if there was no wing at all. A good rear wing setting at Buttonwillow #13 config will pay big dividends in the Riverside sweeper, the turn at the end of the esses at the front straight, (or the end of the front straight going to the esses, depending on which way you run the circuit), the kink at the Dogleg, and basically any high speed (over 60mph) turn. But on the straights it will slow you down like you are dragging all your laundry out the back window. So what would be ideal there at Buttonwillow as settings, would probably just ruin you at Big Willow Springs, where instead of 23 turns you have only 9 of them and some blazing fast straights. A rear wing would help at Big Willow (especially in the carousel and turns 8 and 1) but the setting is going to be much less than Buttonwillow, and you are really going to want to keep that front end down to dial out the understeer (triple digit velocity entry to turn 9 and its diminishing radius with understeer would be "bad"). If you run Streets of Willow or the 3.5 mile config at Spring Mountain Pahrump, you probably are not going to have enough speedy turn sections to make a wing worth fussing with compared to other handling tweaks, at least in our class of cars. In a Radical or Chiron or Ariel, different story of course. IF you go to Cal Speedway with the Roval........well rats you have some interesting challenges making aero choices there. The infield has a couple of pretty fast straights, but not corners that you are taking at 60mph+ if you noodle through the set up carefully. Then you have that awesome dash down the full length of the banked front straight and then through the banked Roval of turns 1 and 2. The car is going to be taking some serious downforce as a function of the 14 degree banking, and the setting of that rear wing when you are doing 135-145mph without aero gets to be serious business...you don't want to be losing front end adhesion with high speed and walls in the equation.......so interestingly enough, that is a track that probably will warrant "less" wing than Buttonwillow.

So let's retrace our steps now that we are using our noggins together as a team and go back to John's comment....in essence what are you trying to do?
The answer is always going to return to the fundamental, and that is "Safely go faster". The first word is safely. So that means really know what you are doing BEFORE you do it.

Thus my two cents contribution to this thread is.....you should not be fussing with aero until you are WAY down the line on reaching the limits of your stock car, or modified car, with other changes, and your own driver abilities are well honed with this car so that you know what it is telling you sufficiently to be confident about dialing in downforce balance front and rear. Otherwise you could really mess yourself up. How can you be adjusting the balance of front and rear unless you take a lap and KNOW what it is doing, separately from all the other elements working on your handling? You already allude to the next step in your own post..........the driver is the #1 mod. I would invest in a race driver school experience. Some of those are a bit more that a grand, but still I would save up and take the course with Russell or Skip Barber. In particular the Barber school has a car control clinic for one day that really gets you tossing the cars around on skid pads and modified auto cross type layouts (Dakota truck, neon, viper and formula dodge platforms are all used) so you get the feel of spin and recovery, dramatic illustrations and feel for under and over steer, and then transferring weight to load and unload the springs with throttle, brake and steer to set the car to take a turn, essentially to get the transfer of weight to where it is maxed for that particular turn and you can power through it with confidence at higher speed, etc. Then when you have that lesson down and work at it on your own car....you will be ready for the difference the wings and splitters bring to you and be SAFE. The problems of adhesion loss with wings will be, by definition, coming to you at higher, and sometimes dramatically higher, velocities. Best to have a real solid understanding of what the car is telling you at lower speeds, and how to recover when you don't listen closely enough, before going to aero and confronting the problem at say an additional 15mph with much less margin for error.

Of course, as Dennis Miller tells us, that is just my view.............I could be wrong.

You are asking GOOD questions and thinking this through. I strongly applaud your intelligent and reflective approach.

Stack

Well said... something has to seperate us from the all teh ricers out there right?

12AutoX

iTrader: (7)

Wow, you guys should write a book... oh nevermind, you already did

Seriously, this is exactly the kind of input that I needed, and the reason that the internet can be a great learning tool (if you listen to the right people).
That datalogger looks like a sound investment. It's not hard to read at all- no different than doing free runs on video games and comparing entrance and exit speeds from turns when taking alternate lines and varying braking points. In another game I can see how efficiently I am using my available traction. In this case, I can get real data from real racetracks and my real car. Good stuff.
That comment about consistency is another good point. I was joking with an instructor a couple months ago about how my racing line constantly varied around a pothole on the track. Very telling of work that needs to be done.
Now if I only lived within two hours of a racetrack!

HyperSprite

iTrader: (6)

And if you are still interested, this article here has some interesting information http://www.tprmag.com/issue/13/13_aerodynamics.shtml

Chris

betamotorsports

iTrader: (1)

One of my favorite sites that has a lot of aero examples: http://www.mulsannescorner.com/

And an aero experiment I tried on my racing 240Z that ended up creating lift at the front of the car. The splitter was not close enough to the ground to work properly (as a splitter).

merlot350Z

iTrader: (3)

We run a SCCA T-2 car with the current cams and intake, the full suspension package including JRZ canister shocks and the car hits about 140 mph on a long straight. We dont even have the standard spoiler in the rear but we do have the under body air deflectors recommended by Nismo. We havent experienced any rear lift at all. The wings and spoilers you are talking about will only slow your car down. Put you effort and money into some SCCA lega motor changes like the 2006 intake and cams, the Nismo bars and spring kits and as a starter buy a set of shocks from TC Kline in Hilliard, Ohio. TC has a licence from Koni for some shocks for the Z that he designed and we used them all last year except at the runoffs. When you get your car up to 160 or so then look into wings and things.