I know i have started a thread about this before, but never got into details about my setup. As many may know I have a 2022 lexus rcf fuji, with oem titanium tips, from factory the exhaust tips are blue and the blue extends till the inside of the exhaust tips. I have not exposed the exhaust to any harsh chemicals or harsh polish, over time I have noticed the exhaust tips blue colour start to discolour, and well as the inside of the exhaust Turing yellow.

my current setup is PPE EL headers, custom midpipe ( straight setup not catted) and kept the oem axel back oem. I just ordered and amuse R1 titan midpipe noncated, I am thinking of adding HFC option to it hoping this may fix things, not sure if it's worth it if it won't fix things. So could the discoloration of the tips and yellowing of the inside be due to My setup ? If anyone can chime in that have any idea or experience with titanium even on other cars. I read that wd40 can clean the carbon build up but I'm hesitant to use that. More over do you guys know if the titanium on lexus exhaust is idonized or burnt to achieve that look. Appriciating any help as this is driving me crazy.

 

The discoloration is for sure coming from the headers, my exhaust used to stay clean as can be until I got my headers installed. Now after 1 drive it’s turning yellow. After a weekend of driving with the friends it’s got brown soot inside of the inter tips and the outer barrels are yellowing. As far as cleaning them when I had my J’s Racing titanium exhaust on my s2000 I used to use metal polish on it and metal wax. It only brightened and made the coloration look better. However that more thank likely will not be the case in this scenario.

I’d try the wd40 method.

 

You could try P21S Polishing Soap if the other methods don't work, I'm installing headers soon and plan to try this stuff out.

 

Going non-catted is the root cause of the discoloration. All those exhaust oxides will end up reacting with surfaces. The yellowing also occurs on your paint usually evident when you have a white car.

I remember some well known YouTuber discussing the impact it had on his car-paint around the bumper-trunk area and saying his only regret was going non-catted with his exhaust system which had headers. If he was to do it all over again he would be sure to put cats on. Actually on this particular YouTube video he was advising a friend who was about to install new headers on his Porsche to put on catalytical converters to avoid the same issues with yellowing and discoloration.

Having cats will reduce the discoloration

 

I second konichiwa3 that the non-catted exhaust and the EL headers is the root cause of the discoloration.

I have the same setup as you (PPE EL headers and decatted exhaust system), and I had the same issue with my exhaust tips discoloring. I used to use wheel cleaners, spray them on the tips and let them sit for a while and then wipe and rinse, which did the job and used to restore the shine and the color for a very few days.

Eventually, I did install 2 HPCs (GESI 50025) in the mid pipes for emission purposes, to remove the smell, and I was also hoping to bring the volume of the exhaust down a little. Once the HPCs where installed, the yellowing decreasing to almost gone.

 

Thank you all for the feedback, so if I install HFC on my midpipes, that will eliminate the yellowing as well as the smell

 

My STi has a catless tubo back exhaust. The back bumper where the exhaust comes outo is yellow/carbon. If you run no cats you will get this. There is no way around it.

On top of that being catless stinks. I like it but I don't anymore. You need to have somem type of cat to eliminate the odor smell.. even then if you get a super high flow cat and depending on their size it might or might not be as stinky.

15 years ago I was OK with catless, now I just find that it stinks too much and when I start my car I feel like the exhaust smell attaches itself onto me, and that's all I smell for the next couple hours. It's annoying...lol

-Nigel

 

it did the trick with mine for both the smell and the discoloring.

 

I just reached out to R1 titan and they are able to add resonators to My midpipe order, mu question is is it a matter of too little too late, I feel as my tips have discolored not sure if it's permanent damaged as well as the inside of my tips are yellowed out for reference this is the pics of my tips before when they were normal

 

Polished them out with mothers metal polish to remove current burn effect and burn the tips again with a torch. It's very easy to do and lots of videos out there.

 

Thanks to @JT2MA71 I remember the YouTuber I mentioned earlier. Here is the video, jump to 3:27 where he specifically mentions the yellowing issue going catless. I believe there is another video where he talks with the Porsche owner and goes over the same issue. Enjoy! It's a great video all the same

 

Thank you all of the feedback and advice, I will go ahead and add a resonator option to My midpipe to reduce everything as well as will go with the amuse axel back I think that my tips are permanently damaged

 

Have you even tried cleaning the tips yet? It seems like you’ve been given suggestions and have not said if anything has worked yet. When washing my car I use the same car shampoo on a microfiber and clean my exhaust with it and the yellowing goes away.

Either way just curious as I’m sure eventually others will have this question and we have no answer on what worked for you or didn’t work for you yet.

 

I tried cleaning it but havent given it a hard scrub I will try that next and give my feedback

 

If only they invented something to prevent this from happening...like, a catalytic converter.