Quote:
Originally Posted by GTO The marketing spiel would have us believe that decarb is indeed a magic solution that'll make our engines run smoother, faster and more efficiently. Personally, I think it’s all rubbish. Shom, |
I honestly feel this thread needs to be revived.
Decarbonisation is not a myth. Ofcourse its not needed in older engines, just use of good fuel and timely change of engine oil will keep the engine in good condition.
But the the new Direct injection engines especially all the european engines, decarbonisation is a must IMO.
Quote:
Originally Posted by DrANTO Interesting post. This is the first time I am hearing about something like this. But still I am in dark about the actual theory behind this; I am not sure whether the effect will last longer than a few thousand kilometers. |
The theory is very simple, In older engines (port-injected engines), air and fuel are mixed before entering the combustion chamber. So the fuel kind of acts like a cleaning agent for the intake valves.
This is not the case with DI(Direct injection engines), where fuel is pumped into combustion chamber directly via another entry. Blowbacks from combustion chamber result in escape of vapors to the back of intake valves and get deposited there periodically.
As the carbon deposits increase the air flow is not optimum. The ultimate purpose of Direct Injection is defeated, as now the fuel and air mixture is not optimum. Sometimes the intake valves are not closed properly and in the worst case, result in more wear and tear of piston rings.
Symptoms are reduced performance, poor fuel economy, engine knocking etc.
which engines are effected?
All German manufacturers. If I'm not wrong VW till date has not put anything in place to address this. Hyundai GDI engines also work the same way. Not sure if this is updated in newer engines though.
Toyota is the only company I know of which didn't have this problem as they used both port injection and direct injection.
Always remember Japanese are the best period.
What are the preventive measures?
IMO, nothing can be done to fully prevent this issue.
Italian tuneup kind of helps as the air intake is more in spirited driving. (Heavy foot helps)
Catch Cans are also useful, but its hassle to install and regularly change the cans.
What needs to be done.
No chemicals/additives can remove these deposits. They don't touch this area.
Best way is to manually clean the intake. Walnut blasting is the most preferred way. Of course this needs to done be with utmost care. Any muck if seeped into the combustion chamber will result in a total loss.
I'm not sure if FNGs do these.
This is the best example in our forum to depict this.
Quote:
Originally Posted by ACM
As per the service centre guys any Diesel BMW would have significant carbon deposits given the condition of fuel in India.
Since mine had a new engine at 90,000kms the current engine and gearbox are only 40,000 kms and hence this is a good reflection of the condition of most new cars in less than 2-3 years of running.
BMW claims their expensive fuel additive helps in reducing this. I frankly used a lot of it and this was the condition.
|
This is just plain wrong. Higher octane fuel helps to some extent but cannot prevent the build up completely. Even if we go to germany, you will find BMWs having this issue. All blame should go to the decision of not having port injection. And as said no additive helps.
30-40K kms is good enough time interval to do this manual process.