Direct Injection and the next gen Z
 

Well guys i was thinking about the next gen Z and i though that Direct Injection would have to be in the next Z because it allows you to make more power, and get better mpg(which is near impossible to do with a regular engine) so i began reading up about DI and what are both the good and the bad

well so far the benefits are amazing but the bads right now are something to be worried about

one of the biggest problems with DI engines today is that there is a carbon build up problem with these engines(some worse than others)

with VW's DI engines, there is a huge problem with the carbon build up that VW knows about but cant do anything to fix it because it has something to do with the way their emissions system is setup and modifying that will cause the car to fail sniffer tests but pretty much what happens is when carbon builds up, the engine loses power, and sometimes it gets so bad that parts have to be replaced because of it

ford and other manufactures who have direct injected motors also have this problem but its not as bad(not sure about nissan though)

so my question is...

what do you guys think about this?
would you want direct injection in the next Z if the car has this problem? and would you want to clean out the engine every so often because of the carbon build up?

i know i wouldnt want Direct injection in the next Z if carbon build up was a problem but if nissan could fix the carbon build up problem, i would be all for a direct injected engine

I have passed on Audi till they fix the problem. All of their DI engines have the problem. It's why I have passed getting an S5. Toyota has solved it using a set on injectors that are in the intake manifold that squirt when you first start the car to clean the valves. Hopefully Nissan will do the same before going DI.

Hm. I didn't know that was the reason (or at least a reason) for the port+DI system.

Notwithstanding this issue, I look forward to a DI'd boosted Z.

The only PITA is that for tuning you have to swap out the fuel pump on DI systems. If its a dual system, like Toyota uses, you can possibly get away with just having the port injectors pick up the slack.

Does Nissan (or Mercedes) have any DI engines on the market yet? That would be a good indicator of what's to come.

i believe the juke has a DI engine but im not sure

i dont think mercedes has any DI engines on the market though

Most of their engines are DI except for the AMG

I see Nissan going the same route as the Altima in the sense that... The Altima was purposely designed to be the most fuel efficient engine without the use of Direct Injection.
I believe the only reason why DI exists in the Juke is because the unusually small size of the engine and the amount of torque that was needed to make an AWD Juke. This called for drastic measures in order to pull out the smallest, most powerful AWD CUV in the market with the highest fuel efficiency for less than $25k
.
In the case of the Z. Going with a turbo 4 or NA v6 to make it fuel efficient or more powerful doesn't truely warrant the need for DI. Companies like Nissan that pride themselves on low-maintenence costs will ONLY add DI when it is cheap to do or has a outstanding benefit.
As it stands right now. DI is one of many methods to gain efficiency in cars. It just so happens to be what has been getting the most attention by the car mags. With more efficient upcoming engine designs and hyper-advanced future transmissions. DI will lose its weight in the auto industry. Its just a decent fix for keeping old technology up to date in gas powered motors in many cases.

The VW issue is caused by the EGR (Exhaust gas recirculation) system. It's really, really bad on the diesels. As you mentioned, you can disable it, but it may cause the vehicle to fail emissions tests.

To my knowledge, Mazda's Skyactiv engines don't have the problem nearly as bad, but it is still there.

Hopefully we will see some kind of fix as DI platforms mature.

What if the company's warranty included periodic carbon-cleaning of the engine ? ; but, like Unknown 370 said, Nissan pride themselves on low-cost maintenance . . . I assume cleaning carbon build up is an extensive process: not cheap -

The only thing they will flush is your wallet, they must not have offered you the fuel injectors cleaning service...

I thought the problem (or one of them anyway) had to do with the gas we get that now comes with 10% Ethanol in it?

I hate 10% Ethanol in my gas:shakes head:

I think there is only 1 Station around here that does not have Ethanol.

as far as i know, that isnt the case(well from what i have been reading)

most of the other forums state it has something to do with the emissions control systems, although i dont doubt the 10% ethanol plays a part in it, i feel its more cause of the exhaust recirculation than the ethanol

heres an idea how bad the carbon buildup can get on diesels

http://kansascitytdi.com/wp-content/.../image0011.jpg

pretty terrible

^ Wow! that's crazy! how does any emissions get through that pipe? I also had no idea that DI engines had this issue. I was always a little dissapointed the 370z did not come with direct injection but now I am glad it does not :)

EDIT: I can't read apparently!

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.