I've been working on getting the front end of the tC a little more planted during on-track high speed straights + long corners and have come to the aero section to gather input and conversation about improvements. Sticker tires and better suspension have increased the speeds achieveable in the turns, but have also made the shortcomings that much more visibile. I currently run a front splitter set at a near horizontal (parallel to the ground) angle with elevated section in the middle to hopefully push air to the center of the car and away from the turbulent wheels, but am still finding the front end a little too pushy and willing to skip and lift at higher speeds especially in long corners. I've beefed up the rear sway bar, run wider front tires and skinner rear tires, but am looking for more.

Next on the list in my quest for front end stability is likely going to be a set of wide front canards as well as a front air dam that will sit between the the bottom of the OEM bumper and the splitter so I'm hoping to see if anyone else has run simliar set ups.

Regarding an air dam: There appears to be a huge amount of space between the bottom of the OEM bumper (including the splitter) and the ground - with a 1.5-1.8inch lowering via suspension - so I'm looking to retard or redirect some of the airflow underneath with the use of an air dam. One of the problems with this is that I'm not sure how to connect said dam to something strong enough to support potential downward forces as well as keep the splitter mounted securely enough to the bottom of the dam. Has anyone played around with anything like this?

Regarding canards: Some of the things I'd be interested in hearing about are any experiences (or potential theories) with the size of canards people have run, the angle of attack(s) that people have tried, and what materials people have used to make them or connect them reliably to the car.



>> This conversation is strictly for on-track/closed-course racing and HPD situations. This conversation is not about looks, it's about theoretical and practical applications. <<

 

Here's your answer:

 

pretty much. where are you driving the tC and how much power are you putting down that you find it is in need of more front end grip? i've driven my tc countless miles on the highway, and even supercharged, it wasn't about to lose control on full throttle. lol

 

The situations that I'm feeling this on are when I'm on the race track. I go to Pacific Raceways in Kent,WA which is about 40-50mins south of Seattle.

All of the mods I've chosen are focused on stability, handling, saftey, and braking. I've not yet touched the motor, so I remain at stock power output until I've found my limits as a driver.




The biggest problem I have in front end grip is in the long sweeping left of a relatively long corner (Turn #2) at the end of a very long kinked straightaway. At the end of the straightaway a tC is around 115mph at about 6,000rpm in 4th gear. Through Turn 1 you're decreasing speed to the 90's and then brake decently hard into Turn 2 with maintenance throttle all the way around it until you hit your exit points to set up for Turn 3a.

Overall, I think there's a lot of room for the tC to get some more front end stability through downforce causing aero, but this -again- is only in regards to track speeds.

I personally would love to have a front wing setup like Rado's car and the old Can-Am cars back in the day, but I am unfortunately not able to create or run something like that right now. Maybe someday.

 

ACK stole my answer.

 

I realize it might be a separate issue, but with you mentioning grip in the long sweeping turn, do you have an LSD?

 

I don't have one yet, although it is in the planned future list. I didn't bring that up in this thread because I am hoping to have the aero discussion here.

Even with the LSD I'd still be interested in maximizing front grip via aero downforce though.

 

i don't know, the way the tc understeers, i strongly doubt you'll be white knuckle handling the tc to keep stabil on the track around those sweepers (also, i'm pretty sure 4th tops out at 104 mph, i'll have to double check) but on that sweeper it doesn't seem to me like the kind of turn that even a lightly modified tc would have a problem with and need aerodynamic enhancements to keep the car planted. the sweeper seems wide enough that you could easily take it at WOT once the car is positioned, the tighter turns look like a great place to use lift throttle oversteer and power out of and at those speeds aerodynamics wouldn't be a huge factor.

if anything really, going through all that power would probably just increase drag so much on the car that you hurt your top end speed because unless you windtunnel test those parts you really don't know whether you're helping or hurting yourself.

 

What suspension/chasis mos do you have? I am up north of you and would be interested in working on this with you as well! If you have adjustable suspension (coils, sways, camber, etc) I would reccomend stopping by speedware in Redmond and asking about corner balancing and explain the problems you are having. They are good guys and i am sure could help get you on the right track. You are not running stock tires are you? Might be a good place to start...

 

115 was the last number that I saw on the speedo before I entered turn 1 (still on throttle so I probably ended up going slightly faster as 1 goes downhill). Keep in mind this was just the displayed speed from the speedo (so there's probably a 3-5% fudge room) so I suppose -for arguement's sake- you could say I was going about 110, but I can very much assure you I was still in 4th gear at the time.

[Side story: on one of my passes with a driving instructor ride-along he had asked me to call off what speed I was at a few heartbeats before the turn-in to Turn 1. I mentioned I was at 110 and then he promptly messed his pants as I very very stupidly lifted off throttle going into Turn 1 and the rear end got squirrely. That was exciting, to say the least. ]

I can see what you're saying about the turn looking wide and long enough to stay WOT, but I can very much assure you that trying to go WOT around that turn will very quickly put you into the outside wall as the front end just walks away.

As it is now, the car feels a little flighty and you can tell it wants to understeer if you get anywhere near the throttle once you find the limit of your line at the time. What I'm aiming at here would be to keep the front end pushed down and remove the inclination for the nose to lift as I throttle on (or stay at maintenence throttle) around the curve.

Getting the car to a neutral balance in most of the other corners actually isn't too hard so long as you are smooth with your throttle applications and drive a very brake-early / FWD-friendly line on this course. More stability over the nose would just help in tightening the line to a more AWD-ish line hopefully.

I actually was kind of bummed that I didn't get to use lift throttle (FWD's secret weapon, haha) as much as I thought I was going to. Most of the tighter corners are actually lower speed corners which have enough forward run that you can go a little wide and, with some trail braking, rotate around so that you don't need to reposition the nose with lift throttle. Slowly peel off the brake while you're adding more and more throttle past apex and into the run-up for the next corner entry and then repeat.

The point where I've found lift throttle oversteer the most useful is in Turn 9 almost exactly at the apex, surprisingly. It's a decently fast run up to the corner, but if you try to keep on-throttle you just drift wide and will scramble to get far enough left to get into 10 but it's a terrible setup for the corner and a really really really long slow drive down the straightaway. Ask me how I know.

To a degree I understand what you're getting at about the windtunnel testing, but it's similar to me saying that you don't really know if you're helping or hurting yourself by changing out the suspension of your car unless you're taking each setup to a shock dyno. (Weak analogy I know, but I hope you catch my drift) At higher levels of the sport where we'd be trying to shave .10s of seconds perhaps the windtunnel testing is necessary, but otherwise a good application of the theories and principals available in automotive technology and aerodynamics design books will hopefully be sufficient to get the basics in place.

As for top end speed, I've already consigned myself to knowing that a 140-ish HP car isn't going to win any drag races down the front straight. On the PR course that I linked above, there are really only two places that I'm reaching points where I need top end speeds. The: end of 5b-6-7-8 series and then the 9-10-1 series. (3b-4-5a looks long and straight, but is hilly and the picture doesn't do justice to the curve of turn 4). Yes it'll suck to lose the top end go and get rolled on the straight, but I'll be happy to make it up in a solid entry and follow through for turn 2 and have me be ready for the car/my strong sections of: the end of 2-3a-3b and 4-5a-5b-start of 6.


I'm looking to make incremental steps to getting the front end stable. Using tried and true methodology for implementing air dams and canards should yield similar results on my car that they yield on cars that have done similar things in the past. Yes I'll likely lose my top speed (which is admitedly low for this course anyway), but I'm content with that if I can improve the speed and smoothness I'll get into Turn 2.

Does that help? I know this seems like a lot of work for not a whole lot of easy to see benefit for most people.

 

Hi Kanchi,

I'm actually a member of Balliztik PNW so if you've been to some of the car shows around here you'll likely have seen some of the guys/girls from my club.

I've been to SpeedWare and talked a bunch with them originally about suspension setups, but I'm actually working with the guys at Cantrell Motorsports over in Kirkland to see if I can get a half-cage fabbed up by them. Both garages seem like they've got super nice guys working for them and they've been pretty willing to answer my sometimes stupid questions.

As for suspension, I run full coilovers and have the uber-light-weight and very sexy Dan Gardner Edition RPF1s with BFGoodrich TA KDWs. 245/40/17 front and 225/45/17 in the rear.

I've pasted my list of upgrades from a different post in the Autosports & Technique section. Otherwise, I'd love to meet you and chat about this stuff. I'm always looking for car people and tC owners always make me happy.

 

yeah, i'm just applying what i've learned from autocross (low speed) and drag racing (high speed) and seeing what i can apply here.

yeah, a good front end splitter is always good for aerodynamics up front. and then maybe put some vents in the rear bumper to help reduce pressure build up at higher speeds which would hold the car back at higher speeds.

i also know that rear spoilers on front wheel drive cars can be functional as they can sort of reduce drag by creating a more gradual slope for the air pattern to follow over and behind the car. so they reduce drag instead of generating more downforce.

 

Yea, hopefully with a font air dam and the splitter there will be a controlled low pressure zone of air underneath the car, but it'll need to still be able to move and I want to make sure I control its movement to the back of the car. I've been toying back and forth with the thoughts of fabbing up some underpannels for the car as well as a diffuser for the back end, but I've not gotten very far as this will be after I develop or source a front air dam.

I've considered also a rear wing, but haven't come to a final conclusion. The rear wings with adjustable elements for sale all seem to connect to the trunklid which isn't really helpful to me. I'd be looking to get something that I could connect to the frame of the car or to the chasis itself and in my admittedly short research trips I've not quickly located one that I think would be useful for the tC in its current form.

To your last point, you've got most of it right, but anytime you add something to the outside of the car you're adding an element of drag. Your point about changing the slope of the air pattern is the part that's the most useful for FWD cars (in my opinon). When you change the way the air flows over the back of the top of the car you're changing the way the air flow seperates from the hard surfaces. If you look at a the results of a wind tunnel test (the graphic map) you can see harsh seperation points cause turbulent patterns which generate unstable characteristics and general drag. The spoiler (and those vortex generators you see on some car's roofs) adjusts those seperation points and in theory calms the turbulence created by the passing of the air over your car. The drag is still there (and probably more of it), but it's more controlled and adjustable.

I'm sure once I sort out the front aero I'll need to take a look at the rear of the car to figure out what I'll need, but for now I'm just hoping to stick to the front and increase what I can down there.

Has anyone run canards on their track tCs? I'm curious to see if anyone has played with the angle of attack they've used.

 

I just re-read your post and realized that I had misunderstood. I thought you were saying the rear wing added no drag not that it just reduced it. Sorry, ignore my 3rd paragraph it's just a reiteration of what you said.

 

you could also put covers over the back wheels to reduce drag! LOL