That’s interesting as there was a 765LT at COTA back in November, they did have an issue but it was not cat related. they got that issue sorted and he was going the rest of the day without a hiccup

 

Change the cats, stock cats are too restrictive and retain a lot of heat. go 300 cell and you are good

 

well this was annoying. Starting to get pace in the car and did a PB but the car would overheat the cat and warn about the engine and slow the car down.

Surprised the LT would do this. Any other track rats have this happen yet?
It was a super cold day in Texas 35-40 degrees.

If so would anyone do the high flow cats? or no cats with the O2 (cat sensor) to prevent a CEL?

I didn't have any issues before, but I went with Fabspeed and their 200cell HJS-Sportcats solution. No CEL, nothing, some extra HP and some extra sound. Now it's fine.

 

Yep was thinking about it. Had the same on the 720

 

If you choose to go catless I have downpipes in stock.

 

Speculating here, but it's reading the cat temp off the O2 sensors. Perhaps you're getting a faulty reading off an O2 sensor.

 

correct. I dont think the cat could have clogged at only 900 miles and just the last 20 of them being track miles. So I imagine maybe the O2 sensors or something else. I was surprised how much gas I was using. Usually I can do more than one session before refilling. But after one session I was down almost 3/4 of a tank...so maybe I am running rich and fouled the sensors?

 

This is part of the response I got from a contact at McLaren. Make of it what you will.

"We are well aware that there were a couple McLaren retailers that were allowing some cars to slide by with modifications. However, we feel we have done a pretty thorough job of cracking-down on these particular retailers in the last year and flagging numerous cars, but if you hear of any instance that we should take a closer look at, please do let me know. We do everything we can to ensure that any modified or abused cars be flagged and that any new potential owners be informed prior to their purchase of those cars whenever possible. Obviously we can’t catch them all, but we will always investigate every situation and do everything we can to protect new owners and the reputation of the McLaren brand."

 

after market cats will void your factory warranty no matter what your dealer tells you,even in writing!

 

Exactly but then you may be able to make a claim on the dealer when HQ washes their hands of the problem. Unfortunately this could end up with lawyers at 10 paces!!

 

Update**: just got the car back from the post track inspection and service and the service center said the cat warning was because I was behind on software updates?....so interesting. Hope that fixes it. Might try to get to ECR on Sunday

 

I've gotten the "catalytic converter overheating" or somesuch message, too, at Chuckwalla Valley Raceway, but the message always goes away before I can get back to the pits to write down the exact message. Now also dealing with a Check Engine Light and code P0492, and a melted plastic fastener on a hose, causing a vacuum leak. Dealer is fixing it for a second time under warranty. 2019 570S. Car's holding up pretty well, but it's a little annoying when it shuts me down on a track day.

 

Well that didn’t work. Got the catalytic converter overheat again and pulled power. There is another owner here we said he hasn’t run into the issue. Recommend I try to run higher psi 31 in tires abs street mode and adjust the drift mode.

 

That's a weird recommendation. What would tire pressures have to do with it? Or drift mode for that matter?

I got this warning again as well as having another melted connector on a related pipe on my 570S. The dealer diagnosed the problem as, yes, in fact it was a catalytic converter problem and replaced one of them under warranty.

See this thread for more info:
2019 570S Check Engine Light (CEL) and code P0492

 

Out of curiosity, are your underbody strakes intact? They do effect engine bay cooling.

 

Either one of your catalytic converters is going bad, or more likely an O2 sensor is bad. Just curious, have you ever run race gas through it or octane booster, or anything like that in the past?

 

Nope! No race gas just standard 93. All strakes intake.

car is at the dealer for them to look. Surprisingly they said the control arm bushings are tearing so they are replacing those.


Sent from my iPad using Tapatalk

 

so a follow up to this. Still getting this warning after bringing it in again after a long offseason. Drove it on a cold day and still got the warning. This is the most recent response.

Kinda frustrating. Isn't the car built to go fast?


Unfortunately, we did not find an issue with the catalytic converter, we spoke with McLaren engineers, and they informed us that this could be a normal warning that the vehicle is being pushed a bit too hard. It is normal for these messages to come on during hard/strenuous track sessions.

They emphasized the importance of properly letting the car cool down, time in between sessions and cooldown laps to assist in this.

 

That's some BS. At least change the sensor!

 

there is another guy with a LT that goes faster than me and hasn't had it. So weird

 

small little things can be impacting things . Follow the owners manual very carefully . Make sure the oil and engine temps are black before getting on the track before any session (I tend to drive around the paddock before any session before getting on the track ).

If possible then on a cool down lap I go into non active mode and let the car do the final lap in 7th gear (auto shifting ). If not possible then I’ll drive around the paddock after getting off the track for a few minutes . Once in my park position then I’ll leave it running for 2 minutes in neutral before shutting down the car . (I’ve seen too many people turn off the car right away ).

I rarely do more than 15 minutes in a session (including out and in lap). My track days have max 20 minute sessions

 

It will not be an oxygen sensor, they really do not fail often and is rare. The main explanation for it really is the cats being blocked/Damaged, this causes excessive temp build up. Unfortunately McLaren's do not actually use EGT sensors, they use MODELED EGT via the lambda sensor. It works well still... I guess...