Hey Nigel,
Do you by any chance know if you could put a "Adaptor" about 0.5" thick, between the exhaust header and header pipe? The entire exhaust sytem from the Invidia connection would be shifted rear wards by that 0.5". I'm being proactive as my - F might be one of those cars that just doesn't like the stock/Invidia connection and is determined to be a "Shop Queen". :>)
DR4

 

I have this exhaust mod to fit my gsf and got the check engine light. For me the bolts were loose because they were too short and you can easily see where it was leaking. I replaced the gasket with AIB2C gasket and the walker ring gasket to fill the recess on the downpipe . I noticed a few reviews used the AIB2C with q300 and suburu saying this one works. I will update if starts leaking I don't think the walker ring is needed but I put on since I had it. The vibrant mentioned in the forum about has too little width IMO.

 

Hi,
Thanks for the great pictures. I own a 2019 RC F and it looks like your exhaust manifold flange is different than the RC F's. From previous pictures in this thread (way back!!). That picture doesn't show a short piece of pipe extending beyond the flange. On the RC F there's a groove in the flange for the gasket but no short piece of pipe extending beyond the flange. In your case I'm surprised there was any leak at all with the short piece of pipe protruding into the SS after market (Invidia?) exhaust. Doesn't look like you felt the need for the sealant everyone else is using.Please keep us posred if the CEL pops up aga
Thanks again,
DR4

 

The main reason for my leak was that bolts came loose and this was because the bolts (I believe are the stock bolts) are too short. The nuts were not on fully on the bolts. I got longer grade 8 bolts from NAPA and cut two of them to about 1.5 inches otherwise hits the cat. I also used red thread lock locktite. I would not use any copper rtv, no need for it if you do it properly. I like those AIB2C gasket, they seem to be good quality. Also, last year I did go back to the exhaust shop after a track day for minor adjustments of the tips and he checked the bolts back them and it still came loose after that but he should have caught the bolts were too short.

 

Hi,
Well it the bolts were too short then that was definitely the problem. But sound slike you'r eon top of the problem. I'm pretty sure if the RC F's exhaust flanges wer elike yours the CEL problem would have never come to light.
As far as my RC F fix (stainless steel Grimms 3" gaskets with exhaust sealant by Permatex)...no CEL light and it's been 3 weeks now. I have not raced a car since auto-crossing my AH 300 with a 302 V-8 so the -F is having an "Easy life". Hopefully the CEL is a past issue.
Happy motoring,
DR4

 

So I got another CEL and sure enough my exhaust bolts were loose again. This time I tried Nord washers and locktite 271 (272 would be better but did not have). Hopefully no leak. For those not familiar with Nord washers here is a video or go to YouTube.
Nord washers $30 for this pack which includes shipping

 

Hopefully this solves your issue. I’ve had mine on for a little over 13 months/11,000+ miles and fortunate enough to have no CEL….yet. If or when it does decide to illuminate and say hello I’m thankful and grateful for this thread for the feedbacks from enthusiasts.

 

Those Nord washers are pretty cool. I'll use them when/if Mr CEL comes back to visit me on my .19 RC F. But I've been lucky so far (~2000 miles) with the gaskets and selants everyone else has recommended in this string. I also have a permanent ...hopefully...


solution in que using a flange that I'll just weld to the end of the Invidia flange then use the stock Lexus gasket or equivalent. I'll have to verify how this flange mates up with the stock header before I do any welding.
dagored.
.

 

I like the idea of welding those flange as I Don't like the slots on the invidia flange.