The new ford RAPTOR

GearHead_1 said:
This is perhaps a poor choice of words on my part. Some say direct port injection, that's what we've had for years. The newer term direct injection refers to injection that goes straight into the combustion chamber. Direct injection never sees the intake side of the valve, hence the problem. Because it is injected directly into the combustion chamber it never has a chance to "wash" over the valve. Add a supercharger or a turbo combined with normal blow by and you bake the blow by to the stem side of the valve. This is a problem industry wide with numerous fixes. I believe BMW actually has you pull the intake and use walnut shells to blast clean the intake side of the valve.
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Yep they do.

Some marketers are selling "catch cans' to try to abate it too. (at least on the vette forums)
 
Ronkh said:
Yep they do.

Some marketers are selling "catch cans' to try to abate it too. (at least on the vette forums)
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I was going to mention that. That's the market going old school to solve modern problems. I think most of the serious Mustang guys that supercharge the Coyote figure that's a no brainer. This isn't a DI solution in this case but the boost increases blow by significantly and you don't want all the oil being pushed into the cylinder. Tends to foul plugs. Back in the day they didn't even try to catch it, they just used a downdraft tube and let it hit the road.

Kind of makes you wonder how much more mileage they can get out of Techron and other fuel additives now that they can't keep the intake valve clean. :) My understanding is most of these additives burn to the point where they do little to help exhasut valves.
 
Ronkh said:
Yep they do.
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I believe I read that Lotus had service recommendations of pulling the head to clean at 40,000 miles to avoid the problem (maybe the S models). That can't be cheap. I think these things can get crudded up fairly quickly introducing stumbling/idle problems, reducing fuel economy and killing performance.
 
The EB has a special shaped piston that splashes fuel back onto the valve stem to reduce coking. There doesn't seem to be a lot of coking issues on the Ford truck forums. Roush has a tune that they sell for the EB. I suspect that the Raptor tuning will be similar.
 
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