DLC coated lifters, dry lub film bearings

[tirod]

Unlike composite lifters, DLC coated lifters are made by plasma deposition of a hard diamond like carbon ion spray - on a stock lifter. They are already in production http://www.huliq.com/32228/nissans-hydr ... meti-award and in use on race cars. DLC coatings can also be used on many other engine components.

Dry film lubricated bearings are another coating tech applied to engines. They are showing up in top fuel dragsters and going years - yes, that's YEARS - of use on the strip. They just don't dry scuff and fail.

Read up on Jack Raby's aircooled engine tech and you'll also discover some folks are TEFLON coating intake runners and manifolds on fuel injected cars. Obviously, this goes beyond a nice polish, which actually hurts a carbureted application. Dry air fuel injected manifolds apparently not only tolerate it, but make horsepower.

Food for thought.

[tirod]

Edit to add: Clevite has announced 7 July the addition of coated bearings (suffix "K")for engines - and listed by Jeg's, etc. Availability of 4.0/258 bearings? Hyundai is offering stock DLC tappets now, and the industry is gearing up. Even motorcycle inner forks are getting DLC.

[SilverXJ]

So.. who does this? All I have found are the two below:

http://www.extremeion.com/

http://performanceresearchinc.com/pages/products.html

Also, what to get coated? I have heard of people coating there bearing, crank, cam lifters, etc. If you coat a lifter, will there be any benefit to coating a cam? Or the opposite?

[1bolt]

Very interesting Tirod you got any links for the teflon intake runners? I read some SAE stuff a couple years back where GM teflon coated a throttle body and got 25% more airflow at part throttle, but I've done a lot of research and found a lot of info that suggests a teflon coated surface wont really do anything significant for air in a port or runner, only to areas where high friction exists such as in the boundary layer (on the wall of the runner, or at the throttle blade,) so in practice no substantial CFM increase is found...

Guess it would be easy enough to test.... just take the wifes teflon cookie sheet cut it up and roll it up on a piece of tubing and run it on a flow bench against a plain piece of metal sheet with the exact same diameter, or maybe sand blast a piece of aluminum sheet with black beauty (really coarse) to get a cast texture and roll that into the same diameter... ... Hmmm man my Wife would be pissed if my flow bench wasn't in pieces... hahah

[SilverXJ]

Not that easy. There are coatings that oil will stick to and ones that it won.. like car wax.. beading vs. sheeting.. IIRC even Teflon comes in those two types.

LOL... know you were joking though

Coating have been long used in engines.. some have been adopted by OEM some not. Would be nice to have something with proof that it works though.

[1bolt]

well yes and no, OEM's coat the TB blades to keep them from sticking sometimes, but as far as coatings for ports and runners pretty much nadda on the domestic front, at least none that I've heard about, maybe the Japanese do? Basically coatings on a port only reduce the Reynolds number (the friction) of the wall, this supposedly has very little effect on the bulk of the air flowing through, it basically just acts like increasing the cross section of the port or runner a tiny amount. Appearently (from my understanding of the subject anyway) cast Aluminum already has a pretty good texture for a fast moving boundary layer.

(that's one of the reasons Teflon non stick surfaces are usually textured similarly)

I wasn't entirely joking, I'm just geek enough to want to test teflon versus cast texture on my flow bench, and easily poor enough not to want to spend hundreds to get an intake coated without knowing the results before spending the cash.

As I noted I have seen a few discussions about this but never any testing. So I could be entirely wrong. I've litterally spent hours searching speedtalk to find racers talking about air flow oriented coatings, there's surprisingly little.

[the_wrench116]

hey im dumb enough to bite. if you want to be a test dummy i would contribute 10$ any other takers. and if it is worth 5 horse well then hot damn and if not im out 10$.

[1bolt]

just guessing but the kind of specialty house that could teflon coat the inside of an intake, is going to take nearly a hundred similar donations to pay for not that I don't appreciate the offer, just don't think it'll happen, I'm pretty sure the results wont make it worth the trouble...

Anyone think of anything that is inexpensive, tubular, slightly convoluted (a 90* smooth bend would be ideal), and is teflon coated on the inside? that would make a good test subject? I realize there are different teflons/processes as well so that would have to be considered... It wopuld have to be cheap enough that I could destroy the coating after I measured the flow, so I could measure the flow without teflon.

With something like that I could very easily come up with a Flow coefficient that I could plug into Engine Analyzer Pro to get an estimate of the effect on performance. It would be fairly accurate and not cost much.

[5-90]

The latter point in the OP makes sense.

It's long been known that the intake runner surfaces can be made "too smooth" in carburetted applications - the slight turbulence and disturbance of laminar airflow is actually necessary to keep the fuel droplets in suspension in the intake airflow. NB: This also applies to throttle-body injection - the basic mechanism differs very little from a carburetted intake, and both intake systems are "wet".

Improvement of laminar airflow with "dry" intakes will indeed assist in making power, simply because it improves airflow efficienty. Since there is no fuel in suspension in a "dry" intake, laminar airflow efficiency improves volume airflow - which is key.