STFC frequency seems high?

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delcowizzid
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Re: STFC frequency seems high?

Post by delcowizzid »

My vx uses 12L/100k uses a lot of water and oil too 540000+km. Egr is blocked off open loop tune no o2s no cat. My injectors are dirty and the fuel pumps tired adds a bit to the fuel use hasn't even had an oil filter or plugs in over 100000km haha the motor just won't die I have a low km one sitting here waiting need a box too I've never changed the trans fluid I'm the 2nd owner lol
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JohnDee68
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Re: STFC frequency seems high?

Post by JohnDee68 »

vlad01 wrote:I forgot I actually had a video demonstrating how much timing is affected by chain stretch.

This is on a high k engine I salvaged for parts and it's chain was quite sloppy. You can really see how many degrees of slop in the balance shaft at the start of the video, as well as lifter lift variation.


[youtube]https://www.youtube.com/watch?v=2oHX0t6hVDc[/youtube]
There isn't anything noticed like that in my motor. Though it is something I will take specific note to check next time the top is off.

Guys, at a 110kph, should the EGR Pintle Position be low or high? I presume high reading means more open which allows more or is it less exhaust back in to the inlet?
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delcowizzid
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Re: STFC frequency seems high?

Post by delcowizzid »

Higher steps should be more open. Mine partially blocked up the pipe and coated the manifold in lots of carbon possibly from being stuck open so I just unscrewed the pipe off the manifold and fitted a coin in there and did it back up and then disabled it in the tune haha
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Re: STFC frequency seems high?

Post by JohnDee68 »

delcowizzid wrote:Higher steps should be more open. Mine partially blocked up the pipe and coated the manifold in lots of carbon possibly from being stuck open so I just unscrewed the pipe off the manifold and fitted a coin in there and did it back up and then disabled it in the tune haha
So i presume the EGR is designed to open in sequence with the throttle to a point? so it diverts any excess "pollution" back t be re burnt and effectively reduce emissions out the exhaust end while likely decreasing performance also of the engine?
immortality
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Re: STFC frequency seems high?

Post by immortality »

It's not about recycling pollution, but rather about reducing pollution by adding a inert gas to the combustion chamber/process. SeeEGR it explains it better than I can.
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vlad01
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Re: STFC frequency seems high?

Post by vlad01 »

It has a few good advantages.

Reduces pumping losses. (efficiency gain)
Reduces combustion temps (less NOx)
Able to run leaner (due to less NOx and reduced temp) (efficiency gain)
Have more spark advance if advantageous (due to lower temp and leaner mixture) (efficiency gain)


Only real disadvantage in some cases is carbon build up if there is a lot of oil in the intake but that's usually only an issue with engines that have poor PCV.
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brindo
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Re: STFC frequency seems high?

Post by brindo »

A bit off topic but Perkins have a system where they kick the exhaust valve open again for their EGR. Does away with any choking of the intake manifold. And not something that can be deleted without a cam change.
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Re: STFC frequency seems high?

Post by vlad01 »

A lot of cars use cam VVT to get a type of EGR by increasing overlap at low rpms/loads to allow some of the exhaust gases to remain in the cylinder, this has been used for a good while now with DOHC engines.
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Re: STFC frequency seems high?

Post by JohnDee68 »

Thanks guys, all good knowledge.

Just researching how to check for a stretched or aged timing chain issue. Came across the concept of while the engine is off of course. Try to rock the crank shaft via the a harmonic balancer back and forth. Any free movement in this reflects the timing chain slop . do we agree to that method, as I think initially it is plausible.
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Re: STFC frequency seems high?

Post by immortality »

That would only really work with all the push rods removed otherwise the load from the valve springs will hold the cam somewhat.
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