Dirt or carbon buildup above exhaust outlet.

[FreshDonuts]

Hey guys,

I recently purchased a sedan wrx and it seems like dirt/(carbon?) likes to build up above and around the two exhaust outlets on the back bumper. The dirt/(carbon?) seems to scratch off with my finger nail but there must be a better way to go about cleaning it. The pressure washer does not take it off! Any suggestions? It is white so it is easy to tell.

Thanks for your time,

Luke.

[Trinidrift3]

claybar may do it

[Heide264]

Your car may be running overly rich too. May want to check into that to prevent the issue in the future.

I dunno if a clay bar would take it off. You can always try - might mess the clay bar up pretty badly... but that is what it is there for in the first place I guess. I'm assuming you've tried scrubbing it with car wash with a firmer sponge? Maybe some tree sap/bug gut remover - doubt that one but never know.

[Sugar]

This happens on my lancer and suprisingly mothers aluminum polish removes it. Don't ask why I tried it, but it worked

[borrracho]

u can try to use a plastic razor blad and spray like a window cleaner to lubricate it but i would use either clay first or a wax and try to wipe it off first.

[pepe8892]

i read on of the forum here that running rich will cause carbon build up in pistons/valves? does fuel injector cleaner will help to break down those carbons?I am on stage 2 last spring and i just notice now that my lunch in 1st gear and 2nd gear is not the same as before when i just install it, however it will kick on 3rd gear once it reach 3000 rpm. would that be the carbon building on my engine? i'm also hearing a rattling noise before i do the stage 2 and its kinda getting a little louder now would that be the rocker arm? tnxs a lot

[Bash1288]

Try this stuff Engine Cleaner - Cleaners - Car Washing - Car Care - Griot's Garage all there stuff works as stated i use there stuff all the time and works well

[GarrettKoonsman]

a small amount of build up over time is normal. If you have any way to datalog do so and check your AFR's. My guess is your running at a normal AFR level and thats just from being Stage 2 and the normal buildup that occurs. The difference in feeling is probably just you getting used to the car, it happens to all of us, but some good datalogging would help. As for the rattling, that could be a huge number of things from a loose heat shield to the transmission dipstick hitting the heat shield to severe engine issues. More specificity and an idea of where exactly it is coming from would be helpful.

[pepe8892]

I was thinking of some additives to the gasoline than can clean the pistons, blocks, valves and injectors like lucas or dura lube? Any suggestion on these guys just for maintenance purpose?
Garret your maybe right about the feeling maybe am just get used to to the car, coz every time my wife is riding w/ me she always tells me to slow down lol. Does AFR stands for air/fuel ratio? am still catching up w/ the acronyms here hehehe. I am using GP moto elbow for my intake any input on my AFR? About the rattling noise, it is coming on the driver side, I can hear on idle and when i rev it a little bit, mine is 54,000 miles. tnks guys for the reply I appreciate it a lot :-)

[Trainrex]

Simple Green will clean the soot off the bumper. DO NOT take a razor blade to your bumper.

[KronosPerformance]

Pre-Wax does it everytime.

[GarrettKoonsman]

I wouldn't use any gas or oil additives. Most of that stuff is junk and even the few that aren't will never go into my motor. At that few of miles you shouldn't have any buildup that is worrisome as long as you keep up on your maintenance. What oil and filter are you using and how often do you change it? AFR is air to fuel ratio, yes. A tactrix cable can be bought for $100-$200 either used or new and the software to datalog is free. Check out tactrix.com for all the info you need on that. Or you may be able to find a local member that can help you out, where are you from? The rattle is interesting but still could be anything. If you let the car idle can you hear the noise when standing in front of the car with the hood open or only when sitting inside? How loud is the noise, is it still there at idle after driving for a while and warming the car completely up or only on a cold start?

[EJ257]

AFR is air to fuel ratio, yes. A tactrix cable can be bought for $100-$200 either used or new and the software to datalog is free. Check out tactrix.com for all the info you need on that. Or you may be able to find a local member that can help you out, where are you from?

And a wideband O2 sensor

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[GarrettKoonsman]

And a wideband O2 sensor

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Definitely doesn't hurt, I don't have one and have done okay with datalogging

[pepe8892]

I am in baltimore, I alternately use synthetic mobil 1 and castrol filters vary from K&N, Bosch or Fram depends on what goes on the sale oils. Do I still need tactrix even i am using Cobb AP for data logging? About the noise, it is more audible when I am sitting inside like you where hearing a loose rocker arm, but barely can be heard in front when the hood is open. The noise actually goes on & off (cold start or after driving it for awhile). Thank you..