S'vette

I was just wondering how bad carbon build up is in ls3s and what is the best way to clean it out? I have 30K in my vette in a yr and a half so would I have a bir of carbon build up by now?

MisterMidlifeCrisis

No real way to know without looking. Not having a catch can and running the engine hard, particularly getting off the throttle with the engine at high RPMs, will cause oil ingestion that will cause carbon buildup. Using gas that does not have detergents, basically any gas that isn't a top tier gas, will also contribute to deposits.

Don-Vette

Use Top Tier fuel,it has detergents to prevent this.That said,every oil change I put a bottle of Lucas injector cleaner in my gas tank.

Wayne O

I wouldn't worry about carbon buildup adversely affecting performance. As others have mentioned use quality fuel with cleaning additives and IMO once or twice a year add a bottle of Techron. Don't always drive like you're in a funeral procession.

S'vette

Well I never drive like that. Im not always on it eaither but Im a bit heavy footed on the pedal and use the gas from the base mostly, hope they have top tier gas. Ive heard putting seafoam in th gas and just before an oil change is good or some say use BG44K. I dont know.

SG4206

I agree with the good fuel usage and gas additives to minimize carbon build up ; however , I personally don't mind a little build up across the piston or valve faces. This only decreases chamber size.
I don't want build up on the back side of the valves ; that decreases flow and promotes guide wear.

I doubt a 30,000 mile engine will look tooo bad having normal oil changes and average fuel used.

Larry/car

Don't worry about it, not a real problem. Drive and enjoy.

S'vette

Im only wondering cause I have seen a 1 or 2 mpg drop on a road I drive all the time so it got me wondering.

Rocket-J

Cool winter weather will get you less fuel mileage. EFI measures the O2 comming into the engine and adds fuel to it to keep the proper Fuel/air ratio. Cold air is rich in Oxygen and needs more fuel (makes more HP too) so mileage goes down. Summer hot air, less O2, needs less fuel, better mileage, less performance.

mikeCsix

You might live in one of those areas of the country that uses a winter blend of fuel by adding ethanol and switching to straight gasoline during the summer months. Ethanol reduces my mileage by nearly 10%. Alcohol simply does not have the btu content gasoline has.

RO55

LDB

If it's a seasonal effect, butane is a more likely explanation than ethanol. Winter gasoline vapor pressure is about 12psi, vs 7psi in summer, which translates to about 10% added butane, which is about 5% on mileage. Ethanol swings can cause variations that large, but since way back in the 90's when there were a few such rules in high altitude areas like Denver, I don't think any areas still have ethanol variations related to winter/summer.

Jaxxx

Drive it like you stole it and carbon wont be an issue!!

S'vette

Thats about 45% of my driving and as a DD car.

redls3

its called an Italian Tune up... do a couple brisk runs of 100 +mph(of course on a closed course road) and you wont have to worry about carbon buildup.

Ketchum

Put a can of SEAFOAM in the tank once a year or so. Its a de carbons. Buy it at most auto parts stores. http://www.seafoamsales.com/

S'vette

I actually just did that a few days ago and will put some in the oil just before my next change. I wont do the vacum line one as I dont feel like going thru the process of doing it muself and dont want to pay someone to do it, atleast for now.

Silver Raptor

Just drove back from Cocoa Fl. to New Jersey.when I fill up in Cocoa fl my fuel range reads 400 or so here in Jersey it reads 300 or so whats up with that?