Zygrene goes off at Laguna Seca in his stock ITS

[optronix]

Very, very interesting video. Also for anyone even remotely interested in taking their ITS to the track, you should already be following Zygrene as I think he's going to end up with the absolute most relevant ITS content on YouTube moving forward.

Case in point, he's had his ITS out to the track at least twice now virtually bone stock. In this one all he's done is front pads.

I know he gets into reasons he had his close call (i.e., tires), and yes it's interesting to see how his tire folded in like that... but personally I see two problems here:

1- it's probably unreasonable to expect a bone stock ITS to stand up to 4 full sessions at a track like Laguna Seca

2- I've been following his channel for a while and he drives so many other cars, including full race-prepped vehicles- and jumping back into a stock ITS it seems like would be so easy to go beyond the limits just from sheer muscle memory.

In any case I see other YouTube vids posted here, this one definitely deserves a watch and FOLLOW HIS CHANNEL so we can keep getting more relevant ITS content.

Sponsored

 

[StingertimeNC]

I saw this. I had the ITS at VIR a couple weeks ago and it was a blast. Dialing in air pressure was tough on these skinny wheels. In my third session I essentially started in the 28/29 lb area and simply couldn't get the tires up past 32-33 lbs after 25 minutes of driving. Previous session I had hit 39/40 in the front and was assuming that was just past were I want to be. I think you just have to accept 40 psi in the front and 35 in the rear just to be safe.

In any case, it's really made me start to think about getting dedicated track wheels and tires. Something with a little more sidewall might be the way to go.

 

[optronix]

I saw this. I had the ITS at VIR a couple weeks ago and it was a blast. Dialing in air pressure was tough on these skinny wheels. In my third session I essentially started in the 28/29 lb area and simply couldn't get the tires up past 32-33 lbs after 25 minutes of driving. Previous session I had hit 39/40 in the front and was assuming that was just past were I want to be. I think you just have to accept 40 psi in the front and 35 in the rear just to be safe.

In any case, it's really made me start to think about getting dedicated track wheels and tires. Something with a little more sidewall might be the way to go.

Yeah unfortunately this may be the case. I'm pretty sure my tires were rolling onto the sidewall too, just from looking at them now. It felt pretty good for me, but it was probably a warmer day then you experienced... I was out there it was at least ~75 degrees ambient temperature. My PSI was ~34-36 hot and they felt pretty good until towards the end of my last (2nd) session. VIR is surely a way faster track than Dominion Raceway too.

In any event I would never expect them to hold up to 10/10ths driving on a track like Laguna Seca or VIR. At the very least I'd go with a 200 TW tire in OEM sizes if I wanted a full day of 3+ sessions... apparently he's typed in his comments that he was at Thunderhill yesterday (man it must be nice with all those west coast tracks...) and the mods he did transformed the car. I expect some really great feedback in his next video, where according to this one he should have Ohlins and 18s with 200 TW tires on it.

Sigh... I just wish 18s looked better. I guess I just need to make sure I get the right wheels... I actually really liked the way the TE37s looked on that Apex Blue that AHC did originally...

 

[NoelPR]

Not saying that it was the case but the manual mentions a different tire PSI rating for those who race.

 

[optronix]

Not saying that it was the case but the manual mentions a different tire PSI rating for those who race.

This is a great point actually, and one I had forgotten about. I think it's pretty rare for a manufacturer to specifically state what PSI to run dependent upon use case... this actually seems like a bit of a liability waiver doesn't it?

Zygrene also mentioned in his comments on this video that he thinks the tire de-beaded before he went off. That is super interesting indeed.

 

[LiquidCarbon]

Too low of tire pressures. Way too low. On what planet would anyone run lower than stock tire pressure on a track? Must be some new internet “science.” Even autocrossing, you generally run higher pressures than stock, especially on the front of a FWD car.

 

[LiquidCarbon]

This is a great point actually, and one I had forgotten about. I think it's pretty rare for a manufacturer to specifically state what PSI to run dependent upon use case... this actually seems like a bit of a liability waiver doesn't it?

Zygrene also mentioned in his comments on this video that he thinks the tire de-beaded before he went off. That is super interesting indeed.

Note that it says “COLD” tire pressures. Running on a track, the pressures will be much higher when you are running.

 

[RamVA]

Too low of tire pressures. Way too low. On what planet would anyone run lower than stock tire pressure on a track? Must be some new internet “science.” Even autocrossing, you generally run higher pressures than stock, especially on the front of a FWD car.

In a 20-30 minute track session, the tire is going to gain 8-10psi of pressure. I start my track car at 26-28psi cold, depending on the ambient temps, and aim for 36-38psi hot. It's not the same as autocross.

 

[LiquidCarbon]

Why do you aim for such a low pressure? Are you running dedicated race tires or the tires that came on the car? Tire Rack recommends 40 to 45 psi for FWD. Do you mark your tires to see how far they are rolling over? Do you measure the temperature of the center of the tire vs the outer edge? The guy in the film is complaining about understeer. More front pressure reduces understeer.

 

[RamVA]

Why do you aim for such a low pressure? Are you running dedicated race tires or the tires that came on the car? Tire Rack recommends 40 to 45 psi for FWD. Do you mark your tires to see how far they are rolling over? Do you measure the temperature of the center of the tire vs the outer edge? The guy in the film is complaining about understeer. More front pressure reduces understeer.

Yes, you measure the temperature on the inside, outside, and center of the tread, and aim to have them equal. If it's higher in the center then you have too much pressure, and vice versa if it's lower. If it's higher on the outside than the inside, you need more negative camber. Doesn't matter if it's a street tire or a dedicated track tire. It's not about the sidewall rolling over, it's about using the whole contact patch, and managing the fact that the tires are going to get to 160+ degrees.

I have not tracked the MPS4S, though I have had it as street tire on a few cars. I have tracked the predecessor MPSS, and they want to be at 38psi hot. Same with the one before that, the MPS2.

 

[LiquidCarbon]

So you are saying that 35 to 38 psi gets you even temperatures across your tires? Hard to believe for street tires. I run higher pressures driving to get lunch. Marking the tires to see if the sidewall is rolling over is what you do if you don’t measure the temperatures. The tires that you are running will definitely change the pressures that you will use.

 

[RamVA]

So you are saying that 35 to 38 psi gets you even temperatures across your tires? Hard to believe for street tires. I run higher pressures driving to get lunch. Marking the tires to see if the sidewall is rolling over is what you do if you don’t measure the temperatures. The tires that you are running will definitely change the pressures that you will use.

In my experience, the MPSS and MPS2 are happiest at 38psi hot (+/-) on track. So that's my best guess for the MPS4S. I'm sure it doesn't matter what pressure one runs to get lunch.

EDIT: I've found the same for Michelin Cups, though I have not run the Cup 2.

 

[LiquidCarbon]

I will take that as a no, you haven’t measured the tire temperatures.

 

[optronix]

Christ, take it to PM.

It does appear that the consensus is he ran his tire pressures too low, overdrove the car, and the PS4S is not an adequate tire for hard track use.

 

[StingertimeNC]

Christ, take it to PM.

It does appear that the consensus is he ran his tire pressures too low, overdrove the car, and the PS4S is not an adequate tire for hard track use.

Agreed.

In my case I am not over-driving the car, not even close as I'm not that good a driver. Car And Driver got the CTR to a 2:58 at VIR's Grand Course on Sport Cup 2's. I was running the ITS at 3:32. (I'm just not that good plus traffic)

I think the PS4S on the ITS is capable of at least a 3:03. I have lots of room to grow. I only track the car 4 days a year, so it's hard to justify dropping 5k on a proper wheel/tire set-up, especially when I'm not fully using what I have.

That being said, as soon as these tires wear out I'll likely get sport cup 2's. I'm lucky in that I only drive about 3k miles per year, so Sport Cup's will still last me at least 2 years, including the track time. If I had 5k to spend I would get forged wheels and go to a 200 TW tire.

With my old car I was running the same size wheel on the back, 19x9.5 (RWD) with a 275/30 rear, and 19x8.5 with 245/40 front, with Pilot Sport 4S tires. Car weighed in at 3800 lbs or so. Tires held up great. Again, not pushing them anywhere near their limits.

I also experienced the same type of pressure issues. For instance, showing up to the track with temps in the 30's, car at normal cold temps, I would pick up 5-7 lbs of pressure in a 30 minute session. As the day went on, ambient temps would go from 30's first session to 60's last session, each time I would drop the pressure a few lbs, always searching for that max 38 lbs, and typically by the third or fourth session, I would have taken out so much air that the tires would only come up to 35 or 36, then I had to add air again. Same thing with the ITS. Would have been so much easier to manage if temps were steady throughout the day.

It's a learning process. I'm definitely going to just let the fronts get up to 39 or 40 from now on.

At least with 30 sidewalls. I may go ahead and add some meat and go with 265/35 19" and just deal with the fact the speedometer is off a couple mph. My last car was reading about 2mph slower than actual at 60 mPH. I just adjusted my speed on public roads accordingly.

Sponsored