Autocross megathread

[12secrd]

For what it's worth, I am running 5mm spacers without thread engagement issues with my Apex setup. Not that I think 3mm will really make a world of difference.

What wheel spacer are using and how many turns on the lugs are you getting with the 5mm spacer?

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[ZeroGSR]

What wheel spacer are using and how many turns on the lugs are you getting with the 5mm spacer?

Akata and I want to say 10 turns, but I am not on OEM rims/lugs.

 

[optronix]

Took video this time out. I feel like I'm approaching the limits of the OEM tires; I'm still full pedal dance and Sport+, it was sunny and dry. Had to use a LOT of throttle discipline to avoid severe understeer on this course. I don't know exactly how I did as they killed the local wifi before I could see the results, but other than probably braking a bit too early on the straight (and not shifting into 3rd) I feel like I drove the course pretty well.

 

[chuuey]

Did my first HPDE and track driving ever this Monday. Learned so much about the car and driving in general. Already planning another.

Apologies for the wind noise and shaky camera. Gopro was freezing and Staff moved the day along really quickly so we had a ton of time on track and I did not have the time to set up proper mics.

My best run of the day was a 48.860 during the 10-minute heats where I seemed to get into a better rhythm. They did a solo timed stint at the end where I managed a 49.59. My buddy in front of me in the Black FL5 ran a 47.98.

 

[optronix]

Did my first HPDE and track driving ever this Monday. Learned so much about the car and driving in general. Already planning another.

Apologies for the wind noise and shaky camera. Gopro was freezing and Staff moved the day along really quickly so we had a ton of time on track and I did not have the time to set up proper mics.

My best run of the day was a 48.860 during the 10-minute heats where I seemed to get into a better rhythm. They did a solo timed stint at the end where I managed a 49.59. My buddy in front of me in the Black FL5 ran a 47.98.

Looks like a fantastic day and GOT DAM that R33 GTR!

 

[Victorofhavoc]

Took video this time out. I feel like I'm approaching the limits of the OEM tires; I'm still full pedal dance and Sport+, it was sunny and dry. Had to use a LOT of throttle discipline to avoid severe understeer on this course. I don't know exactly how I did as they killed the local wifi before I could see the results, but other than probably braking a bit too early on the straight (and not shifting into 3rd) I feel like I drove the course pretty well.

You lost a bit of time in the sweepers by staying so far out. You're smooth on your inputs, which is more of an HPDE or high speed track trait. In autox you have to be more violent about rotation start and then sort it out mid corner.

The understeer isn't really chassis understeer in your scenario but is power on understeer from lifting the front. Slow down a little and you'll go faster.

Combine those two and I can see almost 2 seconds.

Good work though! I especially like your inputs around the transition zone. I see good weight transfer, which is crucial to maintaining grip.

You're not missing a ton between the ps4s and a 200tw tire. The ps4s will peak at 1.01G roughly on a low speed round. That actually beats or matches most 200tw tires. The a052, hoosinental (only when hot), and re71rs are some of the few 200tw that can top it around the 1.03 to 1.05G range. It takes decent driver skill to notice that difference in raw time, but the slightly more grippy tires will mask poorer driving habits.

 

[optronix]

You lost a bit of time in the sweepers by staying so far out. You're smooth on your inputs, which is more of an HPDE or high speed track trait. In autox you have to be more violent about rotation start and then sort it out mid corner.

The understeer isn't really chassis understeer in your scenario but is power on understeer from lifting the front. Slow down a little and you'll go faster.

Combine those two and I can see almost 2 seconds.

Good work though! I especially like your inputs around the transition zone. I see good weight transfer, which is crucial to maintaining grip.

You're not missing a ton between the ps4s and a 200tw tire. The ps4s will peak at 1.01G roughly on a low speed round. That actually beats or matches most 200tw tires. The a052, hoosinental (only when hot), and re71rs are some of the few 200tw that can top it around the 1.03 to 1.05G range. It takes decent driver skill to notice that difference in raw time, but the slightly more grippy tires will mask poorer driving habits.

What fantastic feedback. The "violent inputs" is definitely something I need to work on. You're absolutely right; I kind of trained myself to smooth out my inputs, but first thing I noticed with an instructor driving my car during the auto-x school I went to in spring was that he was very violent compared to my inputs (but only in certain scenarios, e.g., slalom- but not always). I tried it and noticed instant results... but defaulted back to my old habits on this run, clearly.

I'll give it a shot as I'm heading back out this Saturday, again with the stock setup. I'll have a little more camber after getting springs installed but that won't happen til next week.

 

[chuuey]

Looks like a fantastic day and GOT DAM that R33 GTR!

We jokingly gave him a hard time given everyone in our group was driving a type r/s. That car is really sorted and has some time with Misha on the ring. He was in a 550 whp setting, which was impressive because the integra was more car than I was driver, so I can only imagine how that felt.
It is running a G30 900 and 800 wheel on full kill. He ran a 49.38.

For posterity:

 

[optronix]

We jokingly gave him a hard time given everyone in our group was driving a type r/s. That car is really sorted and has some time with Misha on the ring. He was in a 550 whp setting, which was impressive because the integra was more car than I was driver, so I can only imagine how that felt.
It is running a G30 900 and 800 wheel on full kill. He ran a 49.38.

For posterity:

I just love the R33 in particular. Gives me all kinds of 90s-era JDM goosebumps.

I figured his license plate implied a built engine (RB28).

 

[chuuey]

I just love the R33 in particular. Gives me all kinds of 90s-era JDM goosebumps.

I figured his license plate implied a built engine (RB28).

You and me both- R33 is my favorite. And your assessment is correct it is a 2.8L.

 

[Victorofhavoc]

What fantastic feedback. The "violent inputs" is definitely something I need to work on. You're absolutely right; I kind of trained myself to smooth out my inputs, but first thing I noticed with an instructor driving my car during the auto-x school I went to in spring was that he was very violent compared to my inputs (but only in certain scenarios, e.g., slalom- but not always). I tried it and noticed instant results... but defaulted back to my old habits on this run, clearly.

I'll give it a shot as I'm heading back out this Saturday, again with the stock setup. I'll have a little more camber after getting springs installed but that won't happen til next week.

Did you pull the pins to get more camber up front?

Not sure how much you care or your region does, but springs put you in a different class in autox. My region is super strict so they follow every rule to the T.

I haven't been out in autox in like 4 years now. I won the midyear divisional conference in my gti day one in the wet and then day 2 in the dry. 2s faster than 2nd place (group of 14 iirc) and 3rd overall pax (140+ drivers)... I got bored after that and started doing more high speed stuff, lol. You guys are making me want to go out again now. I bet the stock width wheel in an 18" could stuff some fast rubber in 285 and be very competitive in it's class.

 

[optronix]

Did you pull the pins to get more camber up front?

Not sure how much you care or your region does, but springs put you in a different class in autox. My region is super strict so they follow every rule to the T.

I haven't been out in autox in like 4 years now. I won the midyear divisional conference in my gti day one in the wet and then day 2 in the dry. 2s faster than 2nd place (group of 14 iirc) and 3rd overall pax (140+ drivers)... I got bored after that and started doing more high speed stuff, lol. You guys are making me want to go out again now. I bet the stock width wheel in an 18" could stuff some fast rubber in 285 and be very competitive in it's class.

I haven't pulled the pins yet; I may have mentioned in another thread that my local shop seemed reluctant to do that because they felt like it could introduce some sort of liability. I may just have to pull them myself before taking it for springs install/alignment next week. If they do give me a hard time I will be forced to find another shop for this kind of stuff. Which sucks, because they're close... but between the implication that pulling the strut alignment pins could be "unsafe" to not wanting to install H&R springs because they're not specifically made for the DE5, I'm getting really skeptical. Could be they've been burned by shitty customers in the past... or could be they don't know wtf they're actually doing.

All of it makes me want to just build out my garage and do this shit myself, but that requires more effort and funds than I'm prepared to devote to this hobby right now.

I do not care about classes. I'm just trying to embarrass Porsches at my local PCA events right now. Definitely no desire to take on the workload that competitive racing entails, at least not at this point.

I do also want to get back into higher speed stuff too, but only in small doses. I'm the guy who generally is satisfied after two sessions and leaves early; I only need 1-2 HPDE events per year to get my fix, but I haven't been to one this year and I probably should have been by now. There are some things going on in October but that's a busy month for me. I'll see what I can do.

 

[Victorofhavoc]

I haven't pulled the pins yet; I may have mentioned in another thread that my local shop seemed reluctant to do that because they felt like it could introduce some sort of liability. I may just have to pull them myself before taking it for springs install/alignment next week. If they do give me a hard time I will be forced to find another shop for this kind of stuff. Which sucks, because they're close... but between the implication that pulling the strut alignment pins could be "unsafe" to not wanting to install H&R springs because they're not specifically made for the DE5, I'm getting really skeptical. Could be they've been burned by shitty customers in the past... or could be they don't know wtf they're actually doing.

All of it makes me want to just build out my garage and do this shit myself, but that requires more effort and funds than I'm prepared to devote to this hobby right now.

I do not care about classes. I'm just trying to embarrass Porsches at my local PCA events right now. Definitely no desire to take on the workload that competitive racing entails, at least not at this point.

I do also want to get back into higher speed stuff too, but only in small doses. I'm the guy who generally is satisfied after two sessions and leaves early; I only need 1-2 HPDE events per year to get my fix, but I haven't been to one this year and I probably should have been by now. There are some things going on in October but that's a busy month for me. I'll see what I can do.

I recall that you mentioned that now.

Yeah it's funny they'd say that when literally almost every other car on the road only uses 3 bolts to secure the strut mount and no floating pin, lol.

You'll find that additional camber up front is pretty huge for grip. Even half a degree total more is a massive grip change.

You'll also find that lowering springs will often make mcstrut cars understeer more. You need exponentially more front bar, rear spring, and/or rear bar to balance it out. Usually higher spring rate is preferred.

If anyone is up for a technical read, here's a wonderful article that goes deep into detail: https://nasaspeed.news/tech/suspens...-track-performance-for-strut-suspension-cars/

Tldr; stop dropping cars and band-aiding with rear bar. Front bar is what a mcstrut car needs.

 

[RamVA]

[/QUOTE]
Tldr; stop dropping cars and band-aiding with rear bar. Front bar is what a mcstrut car needs.
[/QUOTE]

I'm not sure that's right for a FWD car. For a BMW or a Porsche it makes sense, and you can happily three-wheel through corners, but I think with FWD a stiffer front bar is going to cost you traction on exit. I could very much be wrong.

I'm not for or against dropping the car, but the easiest way to get the balance right (on a FWD car) is to change the rear bar, do an aggressive front-end alignment, and possibly stiffen the shocks.

Just my opinion.

 

[Victorofhavoc]

Tldr; stop dropping cars and band-aiding with rear bar. Front bar is what a mcstrut car needs.
[/QUOTE]

I'm not sure that's right for a FWD car. For a BMW or a Porsche it makes sense, and you can happily three-wheel through corners, but I think with FWD a stiffer front bar is going to cost you traction on exit. I could very much be wrong.

I'm not for or against dropping the car, but the easiest way to get the balance right (on a FWD car) is to change the rear bar, do an aggressive front-end alignment, and possibly stiffen the shocks.

Just my opinion.
[/QUOTE]


Take a read through that article. I know it's super long and technical but it's well worth it.

ALL fwd modern mcstrut cars are designed with a softer bar up front for comfort because of all the front weight. They balance this on more performance oriented cars with softer rears and a bit more bar. In almost all cases the rear end is typically pretty sorted and the front is where the performance gains can be had because that's where 80% of braking/rotation happens.

The reason people typically do rear bar is because it's a 15min job. The front typically requires dropping subframe or a lot of of other effort to finagle a bar in with all the tight packaging. On a mcstrut car, both will increase oversteer tendency of the chassis and yes, they CAN counteract each other.

Important things to know about mcstrut and bars in general:
An anti roll bar on non-mcstrut works by REDUCING the grip across the axle - add more rear bar to reduce rear grip because it's multilink back there

On mcstrut, camber increases positively as the suspension compresses past the pivot point of the lower arm outer ball joint to lower arm pickup point on the subframe, which means when a car is lower its more likely to get to positive camber sooner so more static camber is needed to offset this - adding more front bar prevents the roll, which reduces the compression of the strut, thereby reducing the angle of the control arm and keeping the camber from gaining positive degrees.

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