My AutoX journey

[mrmatto]

I almost forgot -- In a test to see if I could keep my FMIC from getting quite so heatsoaked between runs, I left the car running longer between runs with the hood open and the AC on. This forced the fans to come on and pull air in from the front of the car and over the IC a bit (then out the top of the engine bay). Even with 7 runs, I never felt any obvious power loss from heat, so maybe it worked.

I'm still interested in trying a light water spray on the IC between runs, but I'm nervous that it will cause water to accumulate on the splash guard right under the IC and then drip out as I approach the starting line. Gonna test that at home first.

 

[GTIfan99]

I almost forgot -- In a test to see if I could keep my FMIC from getting quite so heatsoaked between runs, I left the car running longer between runs with the hood open and the AC on. This forced the fans to come on and pull air in from the front of the car and over the IC a bit (then out the top of the engine bay). Even with 7 runs, I never felt any obvious power loss from heat, so maybe it worked.

I'm still interested in trying a light water spray on the IC between runs, but I'm nervous that it will cause water to accumulate on the splash guard right under the IC and then drip out as I approach the starting line. Gonna test that at home first.

Leaf blower. It's what all the cool kids are doing.

 

[mrmatto]

Leaf blower. It's what all the cool kids are doing.

You're not wrong. I do think a spray of water and a leaf blower would be ideal, actually. Working with what I have, for now. If/When that stops working, you'll see me with all the things spraying all the things

Edit: There you go

 

[GTIfan99]

You're not wrong. I do think a spray of water and a leaf blower would be ideal, actually. Working with what I have, for now. If/When that stops working, you'll see me with all the things spraying all the things

Edit: There you go

But that IC is so small, you could spit on it to cool it down.

Even the upgraded one is tiny.

 

[krs]

I almost forgot -- In a test to see if I could keep my FMIC from getting quite so heatsoaked between runs, I left the car running longer between runs with the hood open and the AC on. This forced the fans to come on and pull air in from the front of the car and over the IC a bit (then out the top of the engine bay). Even with 7 runs, I never felt any obvious power loss from heat, so maybe it worked.

I'm still interested in trying a light water spray on the IC between runs, but I'm nervous that it will cause water to accumulate on the splash guard right under the IC and then drip out as I approach the starting line. Gonna test that at home first.

I can't speak to the OEM IC or tune, but last summer I did a very non-scientific test with 90°+ days, hood open, hood closed, spray water in the front over the course of a handful of events.

My determination is it was a waste of my time. Things still get hot sitting there, things are still hot while on course, sure IAT temps drop after a few seconds of movement, but my focus should be on the course as any minor reduction in power over 45-60 seconds is negligible. I'd rather spend the time doing something else, or nothing, than worrying about a temps under the hood.

 

[mrmatto]

I can't speak to the OEM IC or tune, but last summer I did a very non-scientific test with 90°+ days, hood open, hood closed, spray water in the front over the course of a handful of events.

My determination is it was a waste of my time. Things still get hot sitting there, things are still hot while on course, sure IAT temps drop after a few seconds of movement, but my focus should be on the course as any minor reduction in power over 45-60 seconds is negligible. I'd rather spend the time doing something else, or nothing, than worrying about a temps under the hood.

Broadly speaking, you’re correct, which is why I’m just using what I already have today and not buying anything new. But for me, there was a perceived difference with getting the fans running. I didn’t measure it because IAT’s don’t truly measure what the IC is doing, but I did feel it. Very non scientific but isn’t must of this stuff?

 

[GTIfan99]

I can't speak to the OEM IC or tune, but last summer I did a very non-scientific test with 90°+ days, hood open, hood closed, spray water in the front over the course of a handful of events.

My determination is it was a waste of my time. Things still get hot sitting there, things are still hot while on course, sure IAT temps drop after a few seconds of movement, but my focus should be on the course as any minor reduction in power over 45-60 seconds is negligible. I'd rather spend the time doing something else, or nothing, than worrying about a temps under the hood.

Yeah, I'm giving up a couple seconds to a professional driver in the same car, with same limitations. I've got more things to worry about. Lol.

 

[enobiko]

That being said, these tires have been disappointing on the street. They’re decent and acceptable, but the tradeoff for the trackability is a rough ride and more refinement on uneven roads. I can easily see after this season getting a dedicated track tire/wheel set so I can run nicer summers for daily driving.

I read the reviews and got a set of Michelin PS 4S tires, and have been happy with them. I read the tire tests at Car & Driver and Tire Rack... The PS 4S had the best combination of trackability and livability. BTW, I ran mine at 38 psi cold for one autocross, and found they rolled a bit too much to the side, I asked a knowledgeable competitor and he recommended another pound and a half, so next time I went 40 psi all around... and that seems to work with these tires. I have an RSB and run zero toe at all four corners (full disclosure, in case that makes a difference). I think you can run lower pressures on tires with stiffer sidewalls, such as trackday tires.
What am I giving up with the PS 4S tires? My understanding is that my fastest run of 46.401 seconds could be reduced by a fraction of a second. I was 1.9 seconds behind the guy in first place, I was 2nd, the best tires would not close that gap. If you are in my shoes, having fun, learning to lower my times, I think a set of summer tires makes sense. They will last longer than a set of 200tw tires, and be more livable on a daily basis. Should I get much, much better, and have a chance at being really competitive, I might consider more aggressive tires. But... I understand they run the PS 4S on the 'Ring and get more laps than they would with the Cup 2, which helps keep costs in check, or saves money that you could be using on other mods. (I run in the GS class, so fewer mods... but shocks are next, and those are expensive.)
OTOH, I could use all-seasons for my daily, giving and acceptable daily driving experience (but not up to the PS 4S), and get a set of track day tires used only for autocross. Maybe when I get better, but I've been doing this 4 years, I'm finally getting it down.

 

[mrmatto]

I read the reviews and got a set of Michelin PS 4S tires, and have been happy with them. I read the tire tests at Car & Driver and Tire Rack... The PS 4S had the best combination of trackability and livability. BTW, I ran mine at 38 psi cold for one autocross, and found they rolled a bit too much to the side, I asked a knowledgeable competitor and he recommended another pound and a half, so next time I went 40 psi all around... and that seems to work with these tires. I have an RSB and run zero toe at all four corners (full disclosure, in case that makes a difference). I think you can run lower pressures on tires with stiffer sidewalls, such as trackday tires.
What am I giving up with the PS 4S tires? My understanding is that my fastest run of 46.401 seconds could be reduced by a fraction of a second. I was 1.9 seconds behind the guy in first place, I was 2nd, the best tires would not close that gap. If you are in my shoes, having fun, learning to lower my times, I think a set of summer tires makes sense. They will last longer than a set of 200tw tires, and be more livable on a daily basis. Should I get much, much better, and have a chance at being really competitive, I might consider more aggressive tires. But... I understand they run the PS 4S on the 'Ring and get more laps than they would with the Cup 2, which helps keep costs in check, or saves money that you could be using on other mods. (I run in the GS class, so fewer mods... but shocks are next, and those are expensive.)
OTOH, I could use all-seasons for my daily, giving and acceptable daily driving experience (but not up to the PS 4S), and get a set of track day tires used only for autocross. Maybe when I get better, but I've been doing this 4 years, I'm finally getting it down.

No doubt those are great tires. I didn't want to risk getting the Michelins due to all the reports of people seeing terrible shoulder chunking after getting them too hot. A few laps is probably OK, but it seemed after repeated laps they would get too hot and start to fall apart. I couldn't stomach risking a $900 set of tires. These Yoko's have held up great and I drive the piss out of them -- they've been good enough that I will likely buy another set of these. Definitely still happy to run sticky summers vs. dedicated track tires.

 

[GTIfan99]

The Michelins don't chunk with proper inflation. The issue is they heat cycle out with half the tread left. Just a miserable combination of understeer on entry and oversteer on exit in my old NC. This was MPSS on a 2400lbs car, but I've heard the same complaint with the MPS4S.

 

[enobiko]

I saw that on the Nurburgring, Apex Taxi gets 120 laps out of a set of PS 4S tires... See here at about the 11:40 mark:

Yes, I've heard complaints about this or that tire... I take 'em with a grain of salt. I only run autocross, not a full track day, so I don't cook my tires like some might. I think the 'Ring might get them hot, but apparently the hold up very well.

 

[mrmatto]

Run em til you can’t!

 

[GTIfan99]

I saw that on the Nurburgring, Apex Taxi gets 120 laps out of a set of PS 4S tires... See here at about the 11:40 mark:

Yes, I've heard complaints about this or that tire... I take 'em with a grain of salt. I only run autocross, not a full track day, so I don't cook my tires like some might. I think the 'Ring might get them hot, but apparently the hold up very well.

Where do you autocross that your tires don't get as hot as tracking? Are you new to autocross and just don't drive hard? Seriously curious. My tires get hotter autocrossing than on track.

And it's the number of hear cycles and or overheating them that kills them, and a FWD GTI overheats the tires when driven hard.

 

[enobiko]

I never get out of 2nd gear in autocross. I'm thinking that braking from high speed adds heat that spreads to the tires, and long curves would heat up the tires more than a quick sweeper and slalom.
Then again... my local track is Nelson Ledges, "...One of the fastest circuits in America, with an average speed of 97 mph (156 km/h)". I've never raced there, but it seems like the
Then again... I'm in NE Ohio, it seems hot when I'm doing coursework in the afternoon, but maybe the parking lot isn't as hot during my morning runs? Honestly, this is all based on guesswork on my part. But, my last finish I concentrated on "slow in, fast out" rather than overcooking it coming into the corner then plowing wide while scrubbing off speed. (That would heat up my tires!) I thought I did well... actually driving less hard. But, faster, cleaner. (There's still room for improvement! I came in 2nd in the GS class.)
I do see people spraying their tires between runs. Why would your tires get hotter autocrossing than on a track? Seriously curious. I've always thought (guessed) otherwise.

 

[SouthFL_Mk7.5]

AutoX abrupt changes in braking and lateral forces and rotating the car really heats up the tires…. Especially if running fun runs back to back.

Brakes get much hotter at the track vs Autox from my experience.