Reducing carbon deposits on direct injection engines.
Discussion
Find out for what engine speed and load combustion is hottest? Then the heat may oxidise the build up. This is not the same as just thrashing it. I guess with something like torque pro on android you can try find the point at which peak exhaust manifold temp is reached? You need about 600 deg to burn soot, maybe more for different deposits.
Of course the engine management might not like that due to NOx production. But suck it and see?!
Of course for petrol this is all made much harder thanks to keeping to stoichiometric combustion. Ie no spare oxygen for this kind of thing. Best you can try is a drop to idle when running hot. The quick drop will suddenly give lots of free o2. Have to be careful though, you could damage a cat or something.
Of course the engine management might not like that due to NOx production. But suck it and see?!
Of course for petrol this is all made much harder thanks to keeping to stoichiometric combustion. Ie no spare oxygen for this kind of thing. Best you can try is a drop to idle when running hot. The quick drop will suddenly give lots of free o2. Have to be careful though, you could damage a cat or something.
Edited by Otispunkmeyer on Tuesday 29th July 23:26
AIUI the problem with DI is carbon build-up on the inlet valves, mainly the stems. This happens because they don't get cleaned by the fuel. The only viable preventative measure I have come across is to disable any exhaust and/or crankcase recirculation, which may be easier said than done.
El Guapo said:
AIUI the problem with DI is carbon build-up on the inlet valves, mainly the stems. This happens because they don't get cleaned by the fuel. The only viable preventative measure I have come across is to disable any exhaust and/or crankcase recirculation, which may be easier said than done.
This ....you can reroute the breathers into catch cans, fit water injection which will clean the valves or even meth injection to do the same, latest thing is walnut shell blasting every so often that cleans the carbon build up off the valves, no need to remove the head and around £200 every 40k or so.rigga said:
This ....you can reroute the breathers into catch cans, fit water injection which will clean the valves or even meth injection to do the same, latest thing is walnut shell blasting every so often that cleans the carbon build up off the valves, no need to remove the head and around £200 every 40k or so.
Where can you get this done for £200? Seems mega cheapActually having wrote the above a while back,a couple of month's ago I had my mini jcw blasted with soda powder to clean the valves, which upon inspection were pretty coked up at 55k and it cost me £150.
Was done by a mini specialist in nuneaton.
Car certainly feels a bit perkier, and for some reason is not now using as much oil as it used to.
Was done by a mini specialist in nuneaton.
Car certainly feels a bit perkier, and for some reason is not now using as much oil as it used to.
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