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Carbon build up is a serious issue on today's direct injected engines. Our injectors don't squirt fuel onto the backs of the intake valves like the previous generations of V8s. That fuel would typically keep the valves clean. How much does the carbon build-up on the backs of the intake valves affect performance?
I have a 2015 Z51 Manual with 35,500 miles and the following modifications with no tune:
When I installed the MSD intake manifold at 22k miles, I had noticed asignificant amount of carbon on the backs of the intake valves. 13k miles later, I finally decided to do something about it.
I bought a can of the Seafoam intake cleaner spray that you can purchase for$12.99 from any auto parts store. I made sure to get a base dyno pull first,then ran the seafoam through the intake. Seafoam wants you to spray the cleaner directly at the throttle plate, but I cheated a little by removing the MAF sensor from the AFE intake tube and inserted the provided nozzle into the MAF hole. The directions on the can of seafoam are very straight forward. Let the car heat soak, then go out and "drive aggressively" to clear out any remaining carbon deposits, etc...
After running the cleaner through the engine, I changed the oil and put the car back on the dyno. The results are very impressive. I re-gained 20 horsepower and 26 ft-lbs of torque!
Dynocom Dyno with calibrated load. 80 degrees. 60% Humidity.
My engine runs noticeably smoother now and I can feel it pull harder on the top end. I also noticed a 3-4 mpg increase. I t ought I was getting crappy fuel mileage before because of the modifications.
Keep in mind, I do not run top-tier fuel and I do not have a catch can. I plan to run the seafoam intake cleaner spray every 2-3 oil changes from now on.
I also added motor honey and put a can of NOS in my fuel tank. Numbers don't lie and carbon is real. I wouldn't post this if I didn't think it was worth it.
A few months back I did the CRC intake valve cleaner in my 14 z51 manual with 14k miles. It worked great. Not a miracle but smoothed out the idle a little and I could feel slightly better throttle response. Or maybe it was the placebo affect. Nonetheless I got one can free. It worked wonders on the mower, and my daily driver with 145k miles. I am sure the stuff works.
I also added motor honey and put a can of NOS in my fuel tank. Numbers don't lie and carbon is real. I wouldn't post this if I didn't think it was worth it.
At 8,000 miles my 14' Z51 had noticable carbon build up. I wish it was as easy as running Sea Foam but I can't believe that would eat this burned on crap. I am going to pull the heads at 20K and get them cleaned...
Trying to load a photo but my Photo Bucket is not working...
It would be nice to see some before and after pic's of the intake valves.....I thought the seafome was for the gas tank not an intake spray. I know CRC has a intake spray for GDI motors.
I heard from the "expert" on here that these cleaners do more harm than good. Because it breaks off pieces of carbon. That carbon ends up in places it shouldnt. i remember reading about a guy on the truck forums that had to get a new cat because carbon bits were on them. He used seafoam.
think about it, if you have carbon on the valves. where does the carbon go after you spray cleaner ?
I think the safest method is manual cleaning, because you take the carbon out.
I heard from the "expert" on here that these cleaners do more harm that good. Because it breaks off pieces of carbon. That carbon ends up in places it shouldnt. i remember reading about a guy on the truck forums that had to get a new cat because carbon bits were on them. He used seafoam.
think about it, if you have carbon on the valves. where does the carbon go after you spray cleaner ?
I think the safest method is manual cleaning, because you take the carbon out.
But maybe it wouldn't do much are any damage if you do it like every 2k r 3k is way wouldn't be but very little build up on any thing. But then again just thinking out loud on this.
But maybe it wouldn't do much are any damage if you do it like every 2k r 3k is way wouldn't be but very little build up on any thing. But then again just thinking out loud on this.
This is a good point, and something I already thought about.
I actually ran this cleaner (CRC intake valve cleaner)through my engine at 6k miles. I was planning on doing it every oil change. But i got scared about possible problems when i started getting into the higher mileage.
The direction i am taking is waiting tell i get higher mileage, and doing a manual cleaning when more data on the LT1 is out.
I was joking about the motor honey and NOS by the way. If I experience any problems in the future, especially related to catalytic converters or O2 sensors, I'll be sure to let you guys know.
The CRC and Seafoam intake cleaning sprays are probably exactly the same. I opted for the Seafoam spray because it mentioned it was "O2 sensor safe." This product is different than the normal seafoam that some of you are familiar with. This is an actual spray can.
If I had a bore-scope I would have taken pictures. When my intake was off at 22k miles, the build-up was substantial. The fact of the matter is that I have dyno-proven results that show how much carbon build up affects performance. It feels great to have that 20 horsepower back where it belongs.
Some people have used ground walnut shells blasted directly into each intake port to clean off the carbon. This is what BMW required when their intake valves carboned up. If the spray dissolves the carbon, don't see how it could affect the cats unless the solvent itself would damage them if it didn't burn up completely in the engine. In a non-DI engine, the same amount of carbon is still being created, but it gets cleaned off (mostly) by port injection fuel.
While a scope can be used to take pix, when the intake manifold is removed, you can see the tops of the intake valves.
I'm blown away by the power loss due to the carbon deposits. I hope that the manufacturers come up with corrective action in the future.
I'd also be very curious if a catch can would really make any difference?
I know that Toyota is running 2 injectors in some motors to solve this very issue, one port injection and one DI.
EcoBoost DI engines in Fords have a built-in catch can on one of the valve covers. It is my opinion that catch cans help all engines. I have them on my 2 G8's as well as my Z51 A8. It's amazing how much oil is collected which would otherwise go into the intake manifold. Also, I was spraying methanol early on in my Flex TT and it did a great job on cleaning the intake valves, but eventually would have damaged the cats. Don't think an occasional can of cleaner is going to affect a Vette unless you drive 30K a year and keep it forever.
3M also makes an intake cleaning kit that includes a can of spray that you use thru your TB.
The newly re-designed Ford EcoBoost 3.5 used in new Ford GT, 17' Raptors and 18 F-150's has both DI and Port injection, which helps this somewhat, but most importantly provides the needed fuel at WOT.
I'm betting that GM also does this sooner than later.
09-14-2016, 02:56 PM
Carbon Cleaning Dyno Results
I also added motor honey and put a can of NOS in my fuel tank. Numbers don't lie and carbon is real. I wouldn't post this if I didn't think it was worth it.
But maybe it wouldn't do much are any damage if you do it like every 2k r 3k is way wouldn't be but very little build up on any thing. But then again just thinking out loud on this.
