Most of the GDI intake valve deposits are a result of oil seeping past valve seals and the balance from the PCV/vacuum system. Some engines like the earlier Audi V8s had huge issues resulting in significant performance loss and even class action law suites. BMWs are also prone but to a much lesser degree. Fuel additives do nothing, repeat, nothing for the intake valves because the fuel does not contact the back of the intake valves like a port injected engine. Mechanical cleaning is the only way to remove the deposits effectively. These intake sprays may help a tiny bit but they may do more harm than good. Low SAPs oil and oils with low volatility will help a bit. A baffled catch can on the PCV system will help a bit. The amount it helps will depend on how bad the stock PCV system is. Nothing can eliminate the valve seal seepage and it gets worse with age, other than replacing them in an older engine. Toyota/Lexus got it right with both port and GDI but this is obviously a more expensive and complicated set up that most mfgs would avoid.
Additive to help with direct injection carbon B/U?
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I've heard of secondary port fuel-injection system used to get the spray on the valves. There supposed to be a little bit of the fuel spray that makes it to the valves with DI, but obviously it's not misting the valves with fuel.
Weren't some carmakers adding some sort of coating to the valves?
I guess another way would be to run it at higher RPMs periodically to heat up the valves.
Weren't some carmakers adding some sort of coating to the valves?
I guess another way would be to run it at higher RPMs periodically to heat up the valves.
Originally Posted By: FranzX3M
Most of the GDI intake valve deposits are a result of oil seeping past valve seals and the balance from the PCV/vacuum system. Some engines like the earlier Audi V8s had huge issues resulting in significant performance loss and even class action law suites. BMWs are also prone but to a much lesser degree. Fuel additives do nothing, repeat, nothing for the intake valves because the fuel does not contact the back of the intake valves like a port injected engine. Mechanical cleaning is the only way to remove the deposits effectively. These intake sprays may help a tiny bit but they may do more harm than good. Low SAPs oil and oils with low volatility will help a bit. A baffled catch can on the PCV system will help a bit. The amount it helps will depend on how bad the stock PCV system is. Nothing can eliminate the valve seal seepage and it gets worse with age, other than replacing them in an older engine. Toyota/Lexus got it right with both port and GDI but this is obviously a more expensive and complicated set up that most mfgs would avoid.
Good post, just wanted to mention that Ford is using the port/DI scheme on their updated 3.5l Ecoboost. I read previously that this scheme was patented by Toyota but they have offered it royalty-free to the industry, sounds a bit too generous to be true to me but I suppose it's possible.
Most of the GDI intake valve deposits are a result of oil seeping past valve seals and the balance from the PCV/vacuum system. Some engines like the earlier Audi V8s had huge issues resulting in significant performance loss and even class action law suites. BMWs are also prone but to a much lesser degree. Fuel additives do nothing, repeat, nothing for the intake valves because the fuel does not contact the back of the intake valves like a port injected engine. Mechanical cleaning is the only way to remove the deposits effectively. These intake sprays may help a tiny bit but they may do more harm than good. Low SAPs oil and oils with low volatility will help a bit. A baffled catch can on the PCV system will help a bit. The amount it helps will depend on how bad the stock PCV system is. Nothing can eliminate the valve seal seepage and it gets worse with age, other than replacing them in an older engine. Toyota/Lexus got it right with both port and GDI but this is obviously a more expensive and complicated set up that most mfgs would avoid.
Good post, just wanted to mention that Ford is using the port/DI scheme on their updated 3.5l Ecoboost. I read previously that this scheme was patented by Toyota but they have offered it royalty-free to the industry, sounds a bit too generous to be true to me but I suppose it's possible.
I didn't realize Ford was doing this as well. Every mfg uses port injection or DI so I don't understand a patent to use both. Makes no sense.
Originally Posted By: FranzX3M
I didn't realize Ford was doing this as well. Every mfg uses port injection or DI so I don't understand a patent to use both. Makes no sense.
Most patents are evolutionary rather than revolutionary. If you ever have a look at a patent filing, there will typically be several previous patents referenced that the "invention" builds from. A combination of multiple older inventions could be patented.
As far as not charging for use of a patent, that's not unusual. Someone at Daimler-Benz came up with the crumple zone, but they never charged for its use by other automakers.
I didn't realize Ford was doing this as well. Every mfg uses port injection or DI so I don't understand a patent to use both. Makes no sense.
Most patents are evolutionary rather than revolutionary. If you ever have a look at a patent filing, there will typically be several previous patents referenced that the "invention" builds from. A combination of multiple older inventions could be patented.
As far as not charging for use of a patent, that's not unusual. Someone at Daimler-Benz came up with the crumple zone, but they never charged for its use by other automakers.
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