When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I thought I was going to be able to run my set of BFG R1's, but when I went to load them in the car last night, it turned out I only had 3 mounted! Whoops! So I ran the R888's which are very very beat up. Played with the car a bunch, and I have a couple tweaks to make, and I really need to get on good tires to do more testing.
Anyways, very fun day. Here are a couple laps before the tires totally fell off and got really hairy (aka wanting to drift every corner rather than stick... kinda fun in the slower ones, not so good in the high speed ones!!)
Also took out a spectator, Carly, who was there with her brother in his Audi A3. Very cool people and I always enjoy taking out passengers! Closing comments from her were "this car definitely slides the most" in comparison to others she's been out in (E36 race car, 2016 A4, and 2011 R8). So I'll take that as a compliment to my car control skills
Cracked a rear rotor and managed to use up every last bit of rear track pad! Fortunately I come prepared and had spare rotors with me. And brake pads. And lots more stuff
The aero is good - I had limited mechanical grip yesterday due to tires, but as speed built, I did feel a difference. The car did feel more planted at higher speeds.
Looking back at video footage from my fastest laps there show that my speeds in high speed sweepers is only slightly lower (3-4 mph) vs the slow speed corners where I was as much as 10 mph lower. This is highly indicative of downforce at speed leading to more grip which inspired me to push harder.
So yes, there is a difference. I really need to get on R1's or R7's which have the huge "mechanical" grip to get a real indication of how much the aero improves lap times. I'm thinking about 2 seconds at Palmer, where I was yesterday. At a minimum, the improved feel of the car is worth it though as it feels more locked down at high speed, which is really really nice
Last comment in regard to "locked down" - under hard braking at the end of the main straight, there was a lot less drama. The rear did not get nearly as light as it would previosuly, and braking was done later, harder, and without the "wiggling" of the car. So again, confidence inspiring
That all said, the difference is not night and day - it's a difference, but it's not like driving a totally new car. Next up will be playing with sway settings, suspension, and wing angle to dial it all in (with Hoosiers or R1's )
I did some testing of the wing at two different angles of attack (AOA). First was 5 degree AOA, which is what I ran this past week at Palmer. I then adjusted to AOA of 12 degrees, whcih is probably about as high as I can go before getting significant separation (which needs to be tested still with some flow visualization).
Anyways, resulting data is plotted up to around 100 mph and interpolated beyond that based on a 3rd degree curve. I'm glad I'm getting some decent downforce, but I want significantly more, so the next version of the wing will be wider (probably 70-72" width) and with a longer chord length (13" vs 11" at present) which will increase total surface area and also get a significant portion of the wing into the free stream, away from the car centerline.
So I did some data assessments following the last track day with aero. I ran the same track in the same conditions a couple months back, on the same tires. So excellent apples to apples data.
Low speed corners:
Without aero, but with new tires grip maxed out at 1.2 g's lateral.
With aero, but used up tires, grip maxed out at 1.14 g's lateral.
- This aligns with what I felt in that the car didn't have the same mechanical grip, irrespective of any impacts aero modifications were making. Speeds were a couple mph lower in slow speed corners on the "heat cycled out" tires. Not surprising
High speed corners
Speeds were the same or slightly higher. This is of interest because the low speed corners showed that mechanical grip was down, however as a result of the aero, I was able to make up for the lack of "mechanical tire grip" with the downforce being produced. Clearly indicative of effective downforce
Braking
I noted previously that braking from high speed felt much more controlled. The data actually backs this up too.
Without aero: Max braking g's are 1.02 g's, and the car would get "squirrely" at this level, with the rear feeling very light.
With aero: Max braking g's are 1.12 g's, and as previously noted the car felt much more planted. The higher g's are a result of aero drag as well as more traction, largely rear traction, which allowed me to hit the brakes harder before engaging ABS
- Also worth noting, again, is the tires had less capability on the day I drove with aero, so despite less traction, I still pulled 0.1 g's more in braking!
These numbers may not sound like much, but they are very significant at a track day. You feel the difference of 0.1 g's - it's not insignificant.
Good to see my data backing up what I felt!
I'm hitting Palmer again in a couple weeks and I'll be using the wing at the max angle of attack (AOA) which roughly doubles the wing downforce compared with the first outing with aero.
More to come! Also, I'll be able to run some real slicks next outing... I have my BFG R1's mounted up and I'm taking delivery of some Hankook C51's as well which will join me for the event! Should be some good videos and more good data soon!
. . .
I'm hitting Palmer again in a couple weeks and I'll be using the wing at the max angle of attack (AOA) which roughly doubles the wing downforce compared with the first outing with aero.
More to come! Also, I'll be able to run some real slicks next outing... I have my BFG R1's mounted up and I'm taking delivery of some Hankook C51's as well which will join me for the event! Should be some good videos and more good data soon!
Interesting data! What fun . . .
Are you going to the Northeast Track Days event at Palmer; or is there a different one coming up? I am planning on the NTD event on October 18; need to decide if I'll sign up as novice to get an instructor for the whole day, or intermediate and borrow an instructor for a session or two.
I'll likely make a diffuser over the winter. That'll be a challenge largely based on the attachment I think. But yes, definitely looking at that!
If you can make the diffuser use the GT500/CS/Boss attachment points, that might help. The back side of the bumper is pre-marked by Ford as to where you need to cut and drill.
Are you going to the Northeast Track Days event at Palmer; or is there a different one coming up? I am planning on the NTD event on October 18; need to decide if I'll sign up as novice to get an instructor for the whole day, or intermediate and borrow an instructor for a session or two.
Yup, that's my next outing at PMP. I'll see you there! I have a student already for the day, but could probably hop in with you for a session if you wanted to. I think my friend will be in the intermediate group, but I'm not sure yet.
If you can make the diffuser use the GT500/CS/Boss attachment points, that might help. The back side of the bumper is pre-marked by Ford as to where you need to cut and drill.
Oh really? I was not aware of that... yeah that would help! Any idea if there are pics online of other attachment points? That would make it a lot easier...
Good data D!
My lat figures are somewhat similar, in the 1.12 to 1.2 range max, but my decel values are typically much lower at 0.8 to 0.9. Of course R- comps make a huge difference too.
But you're spot on, 0.1g at the track is very noticeable in the seat of the pants sensor. I sometimes get the rear end squirelness while braking you mentioned too. Not a confidence inspiring feeling. The wing definitely helps there as te locking pressure in the rear increases by probably 20-30 Bar or so. That translates to more brake torque and thus more decel. So it makes sense!
9/12/16, 07:26 PM
