boomn29

iTrader: (47)

Been researching aero (canards, front splitters, rear wings, diffusers, etc) myself. Everyone I've talked to (including EVOlutionary btw) says that if you add a front splitter to our cars, you had better add a larger aftermarket wing to the car as well. The reason - just like quoted above. If you add a good deal of extra downforce/grip to the front of the car, then the rear will become light and loose!

Do others agree that to run a front splitter than you essentially need a bigger rear wing to balance the downforce front/back (ala rake balance with aero)?

george3

iTrader: (39)

Agreed. I use a custom made corrugated aluminum front splitter which goes half way under the car and protruded 3.5" past the nose of the front bumper, 3.5" off the ground. It has a custom bolt-on / bolt-off cover to facilitate oil changes. Four adjustable splitter braces. The APR CF splitter I was using before just had way too much flex. Nice for bling.... useless on the track.

The stock rear wing was replaced with a 61" APR GTC 300 CF wing, with extra pedastal risers to get the wing height about even with the roof line. Don't forget to reinforce the mounts under the trunk deck lid. There's a lot of force here.

Depending on the track, I was using between 7.5 to 8.5 degrees AOA (Angle of Attack) and my rear was always firmly planted.

Think of your car as a see-saw, with the front splitter and the rear wing as the weights. The goal is to balance the car to your driving style, track, suspension setup, tires, camber, etc. It's not an easy formula, but it's not that complicated either. Shown here running 18x10 wheels with 285 series Kumho V710 R-Compound tires.

My car has gone through quite an evolution..... no pun intended (!)

EvolvedMR

iTrader: (14)

Did you ever sell this car george?? oops sorry for the jack...

Bueller

iTrader: (1)

If you want to ask me i would tell you to ask me towards the end of next year. Right before 2010 NASA Nationals, we added an APR splitter that we have mounted to the chassis. And we coupled that splitter with an APR GTC-200 wing. I can give you some feedback now, but i will know better in a year. As you know, it takes time to figure things out. I would like at least 1 season of racing and test days to get things started.

Edit: So some people dont get confused, for those of you who dont know, that GTC-200 wing is the STi version. Its my friends wing off of his STi. He gave it to me for Nationals to help me save money. The wing itself is identical to the Evo version. The only features that are different are the end plates and the mounting brackets location.

Ludikraut

iTrader: (17)

Depending on how much DF your splitter is generating, a Vortex generator combined with a gurney flap on the stock wing might be enough. However, if you're serious about aero, then I would look towards getting an adjustable wing and an adjustable splitter.

l8r)

jid2

iTrader: (62)

1.5"-2.0" of splitter is about the max the stock rear wing can cope with, with a gurney etc. My 5.0" splitter was WAY too much for my stock wing with gurney and vortex generator - that's why my car was always wicked loose in the back end with that setup. It was crappy. The big wing now balances 5.0" of splitter nicely.

EVOlutionary

iTrader: (38)

And if you run a properly designed 3D splitter/undertray with even an average wing you will be hating life in the corners! Just think of the square foot difference between a wing and a full splitter/undertray.

Cheap/small splitter vs. a well designed one is similar to the difference in running a flat rear block off for drag racing, or a full rear diffuser like the one on CBRDs TA Evo.

boomn29

iTrader: (47)

Sounds like there's a general consensus on this one.

My next question:
If we're adding an aero package to the vehicle, should we look into a stiffer suspension setup? For example, stiffer springs and/or stiffer anti-rollbars?

Balrok

iTrader: (15)

Well ya generally, it's all gotta work as a system right. I don't believe your running any super soft setup so you should still be good with the standard splitter/wing combo from what i've seen. Each shock absorber is gonna have it's own valving/spring requirements aside from tire compound, weight, etc. Tuners worth their salt will be able to serve up the right combo that can be fine tuned by you/us/them at the track.

boomn29

iTrader: (47)

^^ I'm pooling together resources and parts from several different companies! lol... Which is why I'm asking.

Suspension from 1 company - setup/alignment from another - aero (if applicable) from another - power from another. Driven by me.....

I guess you could say it'll be all new from the ground up with regards to suspension and possibly aero. Trying to think outside the box as I'm going with some setups that haven't been tracked together on an Evo that I know of. At least not in the 5-10 us of on here that actually thrash the car like me and likewise post up and share.

Balrok

iTrader: (15)

Haha, Indeed, just couldn't pass it up bro.

So to this thread's topic, on front bumper C's, i don't think they'd do enough to justify using a stiffer suspension. To that note, I don't think the basic splitter/wing combo's really justify stiffer springs at the 8.7 power level. I've never read nor heard from the big players engineering around this.....with the exception of SSE/CBRD and up from there that have uber aero. Cooooould it benefit from stiffer springs from the normal track setup...in a well thought out design yes, but my opinion is it would complicate the system more in a way that we wouldn't find that 0.1 sec to justify the research.

george3

iTrader: (39)

Yes. Absolutely. These are only the basics. This is the type of topic that books are written about.

It sounds like you're just in the early phases of building your car. The ideal track suspension setup will be different for everyone, because of the type of components on the car, tires, driver skill, track & track conditions, etc. You should speak with other Evo drivers at the track and ask which components have been successful for them and which were a waste of money.

If you haven’t done so already, you should have added front & rear strut braces and replaced the front and rear anti-sway bars with stiffer versions. Change out all your suspension bushings, motor mounts, add a bump steer kit, etc. for better responsiveness and “feel” of the car. Do a professional track alignment and corner balancing on your car... something along the lines of: -3.0F / -2.0R.

After a lot of research, my choice were the KW ClubSport’s with 10K front and 12K rear spring rates. (These spring rates are not ultra stiff, but still not recommended for inexperienced drivers.) I keep the adjustable rear bar set to full soft in the wet, and either medium or full stiff in the dry. I like my car to rotate easily and quickly in the corners, so mine is on full stiff when conditions are warm and dry. This has worked out beautifully for me.

Keep in mind that each aftermarket component change will affect two or three other components. Therefore, many of your parts will need to be upgraded in order that everything works together well as a “system.”

When you get it right, your car will sing in the corners. And all races are won in the corners.

EVOlutionary

iTrader: (38)

Sounds like you may not know Nathan He has his car well set up already and is a track record holder at multiple tracks in various NASA HPDE classes.

I think he's just looking at adding aero to an already spectacular package. . .

Nathan - email me if you want to discuss spring rates outside of the forums.

george3

iTrader: (39)

.


...ooops

my bad

EVOlutionary

iTrader: (38)

No problem, it is still wonderful information. It doesn't hurt anyone to hear some of the basics over and over again. When I was in HPDE2 I still sat through every download session after each time on the track and listened to the same lectures many times so I could get it ingrained into my brain. Others got bored listening to the same thing for the 3rd time in 3 days, but I enjoyed it.

I specifically like the reminder about how changing just ONE part can affect the performance of 3 or 4 other parts. . . I think we often forget about this.

Speaking to the topic at hand - adding canards in the front will not only add more downforce in the front - but it also can REMOVE downforce in the rear - so just a couple well placed canards on the right car can have a fairly dramatic effect to the whole car's balance. . .