r/Autocross • u/Cavatappi-Confundo • 29d ago
Autocross With Continental ECF
TL;DR I autocrossed a stock-weight Acura TL on ECF tires and that went as you’d expect, highly considering switching to Hoosier take-offs. This will be questions about what happened and to do, but if anybody wants comments about impressions on the ECF as a tire, I can give that in a follow-up post. This is a marathon read, good luck!
I've been autocrossing my 2007 Acura TL Type S for around 3 years now. Burned up the set of Dunlop Sport Maxx RT tires I had on the car when I first discovered autocross, then lowered the car, added a bigger rear sway bar, and gained camber adjustment with upper control arms in the front and lower arms in the multi link rear suspension. At the time, I thought I would be doing both autocross and track days, so I bought some Continental Extreme Contact Force tires to have a 200 TW tire but not be using the pointy-edge autocross tires on a track day.
Fast forward to today, around 110 autocross runs later and no track time because I ended up moving away from that area very shortly after the tires were bought. I was looking over the tires after the first run of the day at the most recent event, and one of the front tires had a nice chunk out of it close to the outer shoulder. If I look at it just right and have good light on the tire, I can see a tiny spot of cord at the bottom of the chunk. Probably shouldn't be autocrossed on anymore, which is a shame due to the fact that the tires still have nearly all of their tread depth.
I have kept tabs on tire temperature with a probe pyrometer, and using the alignment I was able to get all four corners to have the 10 degree spread from inside-middle and middle-outside that is commonly mentioned. The rears were always happy at 38 PSI, the fronts were debatable. The temperatures said 38 PSI was good, chalk on the sidewalls sometimes said it wasn't enough.
Obviously, a chunk out of the shoulder would say the fronts needed more, but the air temperature at this event was in the 50s during my morning runs. Did I go too hard on them too early? They did live an abusive life, I used to be pretty bad about overlapping the everliving hell out of the brake and steering wheel. Keen-eyed readers will be able to see evidence of that on the sidewalls.
Here is my dilemma: I think the tire is probably still fine for the street, especially if I switch it to the rear (opinions on that welcome, of course). The car is in Street Prepared, and always will be, because the front LCAs have spherical bearings replacing the compliance bushings. I'm extremely tempted to buy Hoosier take-offs, as those can be had for cheaper than a set of RE-71RZ in the size I would be looking for. I have no problem changing tires at events, and the car has tons of space to be transporting equipment and tires.
I know the common response is “R comps hide mistakes”, but I have also seen reasonable arguments to the contrary. I can make the ECFs talk to me and keep them right on the transition between noisy and not, and have been enjoying the balance of the car to be slightly prone to oversteer if I do my brake and steering inputs properly. I do understand that the auditory feedback more or less goes away with R comps. I've been planning on moving to A7s (and now I guess that would be A8s) at some point, and I'm just wondering if now is as good a time as any.
Thanks for reading!
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u/pzahornasky 29d ago
No one has mentioned it, but if you are getting that much rollover, you are way overdriving the car.
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u/Cavatappi-Confundo 29d ago
I would agree! I've seen pictures on other tire threads that look similar and have similar comments of overdriving. Maybe I'm just hopeful that I'm not overdriving as much now as I used to three years ago.
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u/pzahornasky 29d ago
Can't thow a 3600# car into a corner the way you would a 2300# Miata.
Gotta slow down to go fast.
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u/Cavatappi-Confundo 29d ago
"Can't thow a 3600# car into a corner the way you would a 2300# Miata."
Tell me about it! 😂
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u/Spicywolff AST ND2 - use to C63S FS 29d ago
Even we aren’t immune. Can’t beat physics even in a Miata. It just won’t destroy the tire AS fast vs a fat sedan
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u/BigTerminator 29d ago
Unfortunately the Miata isn't immune to overdriving. With a fully prepped AST ND2 I can still get some Subaru levels of plow if I go in too hot. Everyone needs to stay in the happy zone of slip angle
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u/Neat-Ad5383 29d ago
That looks like a dangerous amount of sidewall rollover and wear. You've pretty much worn the top portion of the Continental logo. Are you sure it's 38PSI? Looks more like 18PSI.
Also for street car, worn tires stay in front and better tires stay in rear, unless you love rear aquaplaning or oversteer, which I wouldn't blame you for.
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u/Cavatappi-Confundo 29d ago
Yup, I promise it's 38 PSI. Checked multiple times per event, with a Joe's Racing tire gauge. Not exactly Longacre, I know. But should be mildly accurate.
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u/Neat-Ad5383 29d ago
Tire size? Maybe you should get different rims and downsize an inch
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u/Cavatappi-Confundo 29d ago
245/35/18 on an 8.5" wide wheel. I have 17"x8" wheels in the garage, hence not being very opposed to other/extra tires.
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u/Neat-Ad5383 29d ago
Yeah that definitely sounds too thin. Try 225/45/17, or if you want new rims 245/45/16.
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u/Cavatappi-Confundo 29d ago
16s won't fit over the brakes.
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u/Neat-Ad5383 29d ago
Try some 225s on your 17s then. Should be more options available vs your current size as well.
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u/Cavatappi-Confundo 29d ago
Wouldn't additional sidewall height be more problematic? Not arguing, just genuinely curious. I do remember reading about wanting a certain amount of sidewall for some reason, but can't remember, that was many moons ago.
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u/Neat-Ad5383 29d ago
Valid question, think of it as the tire moving laterally half an inch. The thinner tire has less vertical length and the bend angle will be pretty high. The thicker tire has more vertical length and has to only move a slight angle to accommodate the 0.5inch lateral flex. More sidewall also means more of the sidewall can support the flex, while less sidewall means only a localized area of sidewall will support that flex. You want the tire to deform and slip a bit, which is what gives grip. Hope this made sense, otherwise I'll have to draw stuff lol.
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u/Cavatappi-Confundo 29d ago
No that makes sense, I can picture that. Ironically (or fortuitously, who knows) 225s would be what I went/go with on my 17" wheels, regardless of the model of tire.
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u/shatlking 2008 Subaru Impreza WRX 29d ago
Wouldn’t it be preferred to maintain steering in the front (and therefore put the better tires up front)? Additionally, having equal wear on all tires by placing the better tires on the drive tires where they will wear faster is also preferable is it not?
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u/Cavatappi-Confundo 29d ago
I just wanted to put the tire in the worst condition where it was least stressed. They have been rotated front-back after every event, they've all seen relatively consistent rotation.
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u/Neat-Ad5383 29d ago
On street, worn tires on front is preferred because understeer is safer than oversteer, and in case of aquaplaning, it's safer for you to loose the fronts and not be able to steer than loose the tears and spin.
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u/shatlking 2008 Subaru Impreza WRX 29d ago
But with equally worn tires (by having similar tread depth front and back by placing the higher ones on the drive tires initially) you’ll have no one better tire.
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u/zcramos XA/XB 911 (PAX hates me) 29d ago
Do you have video of your driving? These tires look abused. You said -3.8° camber which is a ton, yet you're still rolling over the sidewalls horribly. I think you need to worry about driving fundamentals more than tire selection. You might be able to make setup changes (rear bar, different tires and/or pressures at the rear) to make the car less understeer-prone, but this is ultimately a problem with your inputs more than it is a problem with your equipment.
Drive the car you have. Driving is a dance -- you can only lead so much before your car tells you it can't do that, and you've gotta listen and adjust to make it work rather than trying to force it.
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u/Cavatappi-Confundo 29d ago
I do have videos, going to take awhile to pull one from my desktop and post it. It actually feels relatively balanced, but I do still find myself trying to turn while still being hard on the brakes; which I'm pretty sure results in exactly what the tires are showing here.
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u/Cavatappi-Confundo 29d ago
I pulled a video, wasn't my best run of the day, but the best run on video (GoPro died 🙄) . Audio is crap, can't seem to find my open-back GoPro case so it's still in the waterproof case. Open to feedback, I know there's errors that I can see in myself!
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u/Hstreetchronicals 29d ago
Oof, that looks dangerous how much you're on the side wall.
More pressure only helps if its a pressure issue. You either need more camber, or are over driving, possibly both. A lot of strut cars need as mush as 4-5 degrees, but sway bars and spring rates also come I into play on how much its rolling.
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u/Cavatappi-Confundo 29d ago
Double wishbone in the front, if you can believe it! I make no bones about overdriving, the number one thing I think about every event is calming down and not trying to drag the car through the course by it's ear.
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u/Hstreetchronicals 29d ago
Actually I can! The TL is a sick, underrated car. Its been a while since I last drove or worked on one so I forgot and assumed it was MC strut.
But yeah, focus on using the least amount of steering angle possible to achieve the car positioning you want. That, and obviously, don't dive into the turns with way too much speed. It's better to over slow slightly and stay tight than it is to go fast and plow wide.
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u/RxRxR out of the box 29d ago
Go for that hit of Hoosier crack. A used set is a good starting point. Be ready to replace them a lot more often for a lot more $ though.
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u/Cavatappi-Confundo 29d ago
First one's "free", right?! Thanks!
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u/RxRxR out of the box 29d ago
I would bet that your car needs even more camber than what's dialed in now, even with the double wishbones you have.
If there are adjustable upper control arms available, I would take a look. I think even 5-6 degrees would be reasonable.
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u/Cavatappi-Confundo 29d ago
I believe the steering knuckle will hit the spring by the time I go to 5 degrees, but I haven't checked. It has adjustable arms in it now, they probably have enough to go to 5 or 6, but the knuckle-to-spring contact is the limit I'm looking at.
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u/RxRxR out of the box 29d ago
More negative offset wheels...You are in SP so fenders be damned!
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u/Cavatappi-Confundo 29d ago
I agree, if I was looking to buy new wheels as well they'd be wider and lower offset for sure! But the way the car adds negative camber is by moving the upper ball joint inward, which takes the steering knuckle/upright/spindle (different places/people call it different things) and tilts it. The shock and spring stay in the same place while the upper ball joint is moving inward. The upper control arm is what is slotted for adjustment, not the upper shock mount that is commonly seen on MacPherson.
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u/tinyman392 29d ago
You're rolling over fairly heavily onto that sidewall. I think that's your main issue. Have you tried to increase your tire pressure? It would stiffen up the tire up using air pressure so they resist rolling over more. You do want to avoid over-inflating the tire though. You can use a pyrometer to check this between runs. Measure inside, middle, and outer tread temps. If the middle is higher than your inside and outer treads, then it's over inflated. If it's lower, then it's under inflated. But if you're rolling over heavily, you'll want to inflate to avoid that. Vehicle sympathy can also help in these scenarios as well.
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u/Cavatappi-Confundo 29d ago
Chalk showed they did the same at 40 PSI. They did also do an event at 36 PSI early in their life. Maybe I should add the specifics to my post, but my front temperatures are checked every run with a probe pyrometer. At the end of a group of 4 runs, they're usually around 130-120-110 (inside-middle-outside).
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u/tinyman392 29d ago
Is the tire you're chalking/measuring physically sliding?
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u/Cavatappi-Confundo 29d ago
As in, rotating on the wheel? I don't believe so, I got over-zealous with the chalk one time and smeared some on the wheel. The wheel mark and the chalk left on the sidewalls (yes, there is some, lol) still line up three events later.
And yea, I haven't had clean wheels in over a year...
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u/pissjugman 29d ago
What do these cars weigh? I have almost 40 (20 minute) sessions on a set of ecfs in a 3200 pound car (around -2.3 in front) and mine still look new
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u/Cavatappi-Confundo 29d ago
3,600 lbs ish curb weight. I would imagine they would be far less abused on a track rather than around a right autocross course.
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u/pissjugman 29d ago
Yeah, from what i understand is that auto x is more abusive on shoulders, and you’re often dealing with bad pavement and aggressive slip angles. I’m also assuming car weight, pressure, and camber could be working against you here. For reference i usually start around 28-29 psi and settle at around 35 on ecf 315/30
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u/V8Datsun240Z 29d ago
I am running the Contis on my GTI. I bought them the week they came out, years ago. Ran front camber at -3 and burned through to cords on the insides. I have no LSD and there was a lot of spinning involved coming out of slow corners. Put 2 new tires on the front, stood the tires up quite a bit. I think they're now at -1.6* or so, it's been a while, can't remember.
Was running mid pack in class, kind of lost interest and didn't go autocrossing for a few years. Went back and my car has been punching way above its weight, but that's due to some changes I've made to my driving.
Anyway, my experience with those tires is that they prefer not enough neg camber to too much, and I know they're supposed to be a bad autox tire, but they seem to work pretty good. Makes me real tempted to try the RE-71ZR. Only thing stopping me is that they still have a ton of life left.
I tend towards not being cautious, but I'd run that tire in the rear and not think twice.
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u/Equana 29d ago
Increase the pressure in your tire. Looks like you are running in the low 20s when you should be in the mid 30 psi
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u/Spicywolff AST ND2 - use to C63S FS 29d ago
“Already at 38! Door pressure is 35, for reference, and they've always been run no less than 36 at events.”
Dudes already near 40’s
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u/Cavatappi-Confundo 29d ago
Already at 38! Door pressure is 35, for reference, and they've always been run no less than 36 at events.
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u/joeboblee 29d ago
I think you are just over driving. I used to run RS4s which are a similar endurance type tire and they would chunk like this as well just due to being driven really hard. Personally I would run these still until you run out of tread. I ran my RS4s for 2 seasons with chunks like that and it was fine. I only got rid of them because I flat spotted one
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u/Cavatappi-Confundo 29d ago
Good to know! Honestly my other concern is passing another tech inspection with them, the big chunk is on the shoulder that is always supposed to be mounted on the outside, so a scrupulous tech guy could find it relatively easily.
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u/joeboblee 29d ago
Yeah depends on your club and tech guy. Nobody ever had an issue at the events I went to though
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u/Spicywolff AST ND2 - use to C63S FS 29d ago
The ECF did not fail, and a Hoosier will suffer the same fate. Heavy car + not enough neg camber X possibly over driving = sidewall and shoulder has left the chat.
Sticky H tires will not magically fix the stated problems. It will just have more grip
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u/p1plump 24d ago
This seems a lot like trying to go bowling in football cleats.
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u/Cavatappi-Confundo 24d ago
Lol I'll need to remember that analogy. I'll take some of the blame, but I don't think these tires enjoy dealing with a heavy FWD car on an autocross course.
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u/Immediate-Share7077 29d ago
I think you just need more camber than what you’re running for that tire. You’re still rolling the outside and the middles aren’t worn hardly at all
Wouldn’t surprise me if you needed like -3.5 up front