direct "ignition" is something different from direct "injection" yes the 370
does not have direct injection.

:rofl2: lol apparently I can't read! I totally over looked the ignition part and took it as injection, my bad! :ugh2:

No problem :)

I've always had a distaste for EGR in general; the Chevy 4.3L Vortech is a very good example of why, and those weren't even DI. For those not familiar, the electronic valves would clog up constantly from carbon buildup, throwing engine codes, failing smog, and running or idling terribly.

The good news is that today's VVT/VCT technologies do a lot to remove the need for an EGR Loop. I'm not famliar with VW engines, but my first thought would be to assume they're not using this tech on those engines having the buildup issues.

I have to admit that I was mildly disappointed after learning that the 370z does not feature DI (because of the immense tuning potential on boost), but if the DI systems currently out there are having a significant impact on component longevity, then I'm all too happy to go without.

Unfortunately, DI carbon buildup spans many different engines and manufacturers. Some are better than others, but many DI engines from Audi, Mazda, BMW, and others still require carbon cleaning due to the nature of DI setups.

In the video below, it shows how gas flows over the intake valve into the cylinder before firing. With direct injection, there is no gas moving over that valve. Modern gasoline blends contain detergents (like Techron and the like) which clean these valves and keep carbon from building up.

Some manufacturers have included supplemental port injection of gasoline with their DI engines for the sole reason of combating this issue.

https://www.youtube.com/watch?v=aOksuRwfovw

EGR is the root of the problems, and will be in more and more modern gasoline cars to reduce emissions and meet new federal mandates. Diesel engines have had EGRs for much longer because of their pollution issues, I have read/watched alot about the ford truck diesels and their issues. The solution to the carbon issues in diesels has been to just disable the EGR, install an oil catch can for the PCV, and mod the ecu. This won't pass an emissions check but it will keep the motor reliable. The other option is to inspect and service the EGR system early and often.

https://www.google.com/url?sa=t&rct=...68235269,d.b2k

I hope that link works, youtube blocked here@work.

daaaaaaaamn... looks like my arteries after eating a hamburger from five guys

I'm not sure how accurate that statement is. EGR has been around a while now, and - at least in ford vehicles - is now being largely phased out in favor of systems that utilize variable timings in both intake and exhaust, as well as Direct Injection. In many of those applications, emissions were lowered enough that EGR was not needed at all in order to pass emissions testing. Add mild boost on top of that (as with Ford's EcoBoost line) and emissions are cleaner still.

EGR IS a large part of the problem on vehicles that still have it, but I believe we'll be seeing it less in future engine designs while companies perfect the ability to leverage DI more efficiently, and hopefully with greatly reduced carbon buildup.