GDI discussion

[GJEMD]

I recently traded a 4.6 MPI for a 3.8 GDI. I have shared in some question
about GDI long term reliability ie intake valve deposits and future power loss.
BMW Mercedes had early issues and now Ford is in big trouble with their version.

I could not find any discussion of Hyundai having issues. 2012 may not have accrued sufficient miles It appears they are all in on this technology.

I researched this topic generically and learned the following.

Intake deposits are a combination EGR oil vapor and the trajectory of the Direct Injector. It Seems Turbo GDI is a Super heated version making it more trouble prone.

Traditional Techron gas treatment or BG injection service will not effect the problem. In fact BG service has burned up the Turbo Chargers on the Ford 3.5 Ecoboost . Right now Ford is replacing the heads and have new baffling on the valve covers to disperse the EGR oil vapor. They don't allow BG service.

Only other approach is removing the Intake plenum and blasting the underside of the intake valve.

It appears the OLD EGR technology is not compatible with GDI. Catch cans
are limited in effect.

It seems the latest GDI engineering is to abandon EGR for a NOx cat converter.

I could not find any specifics regarding current Hyundai version of GDI.

Question is EGR still used on these Hyundai Engines?

 

[GRIFF]

I think that all the manufacturer's using GDI engines, including Ford, Mazda, Hyundai, GMC, Corvettes, ..... decided the increase in power and gas mileage would result in an increase in profits (along with a means of meeting the ever increasing mileage requirements) as compared to the down-side risks are simply worth it. I wonder what percentage of owners keep using a vehicle long enough for the intake deposits to become a problem.

I have never heard of any engine problems with a Hyundai yet. Friends of mine with GDI engines have had the valves cleaned (GMC trucks an vettes) but it was a fairly inexpensive fix that did result in noticeable improvement to engine performance - service was performed around 40,000 miles in all cases.

Interesting to note that Honda and Toyota (Toyota uses a modified GDI engine with some gas still injected over the intake valves) are not using full GDI technology as of yet and I believe Honda probably builds the best engines.

Griff

 

[Mark_888]

I think that all the manufacturer's using GDI engines, including Ford, Mazda, Hyundai, GMC, Corvettes, ..... decided the increase in power and gas mileage would result in an increase in profits (along with a means of meeting the ever increasing mileage requirements) as compared to the down-side risks are simply worth it. I wonder what percentage of owners keep using a vehicle long enough for the intake deposits to become a problem.

Manufacturer's are only concerned whether owners keep the car long enough for it to become a warranty problem. Even with Hyundai's 100,000 mile drivetrain warranty, since the engine performance only becomes "degraded" and the engine does not actually "fail" when the problem occurs, Hyundai can claim such performance degradation is "normal" and therefor not covered under the extended drivetrain warranty.

 

[GJEMD]

There are a number of drive ability issues poor idle etc. that might give manufacturers issues.
So, my question is , has Hyundai moved away from EGR to NOx cat. on the 3.8. This essentially removes the source of deposits??

 

[GRIFF]

The deposits come from the crankcase via the positive crankcase valve and the recycling of these gases into the intake manifold - common to all GDI engines.

 

[Mark_888]

The deposits come from the crankcase via the positive crankcase valve and the recycling of these gases into the intake manifold - common to all GDI engines.

Except "maybe" for Toyota's engine which is hybrid GDI and EFI, specifically to address these concerns.

 

[Gunkk]

There are a number of drive ability issues poor idle etc. that might give manufacturers issues.
So, my question is , has Hyundai moved away from EGR to NOx cat. on the 3.8. This essentially removes the source of deposits??

Quick search on Jim Ellis parts site says there's a PCV value, but I couldn't find any entries when searching for "EGR".

http://www.jimellishyundaiparts.com...2/Genesis/VALVE---PCV/3355491/267403C200.html

and based on the parts diagram for the exhaust, there is no air inlet on the cat (28950), so it appears it is only 2-way.

 

[fiveoh]

Early GDI systems did not take into account the presence of hydrocarbons (combustion byproducts, oil vapor from PCV, and exhaust gasses coming from the intake tract), and did not account for the cleaning that a constant fuel stream provides. Welcome to engineering, shit happens.

The latest GDI platforms have re-timed the intake valves AND the exhaust valve, addressing most of the swirl issues (basically, the intake valve is closed well before combustion, and the exhaust valve is timed for maximum scavenging, so that when the intake valves are opened, very little (if any) remnants are able to migrated behind the intake valve).

If someone could actually show an intake valve out of a later production GDI motor (either the GDI 3.8 or the 5.0) and show a substantial carbon buildup on the stem, then it's worth worrying about.

Otherwise, there's a better than average chance Hyundai addressed at least the valve timing issues, and are at worst, left with the PCV gasses causing minimal buildup. At best, the PCV was re-designed to mitigate the issue. Other platforms have addressed the carbon buildup issue in different ways, Hyundai just hasn't been very vocal about their engineering efforts except to say GDI resulted in a more efficient, more powerful power delivery system.

 

[GRIFF]

No evidence that Hyundai engines had yet had any problems, but previous threads on this have resulted in several individual installing in line filter on the GDI 5.0 engines to help clean up the PCV valve air stream.

The only pics I have seen are on the Vette forums.

 

[zielritter]

No evidence that Hyundai engines had yet had any problems, but previous threads on this have resulted in several individual installing in line filter on the GDI 5.0 engines to help clean up the PCV valve air stream.

The only pics I have seen are on the Vette forums.

Actually there is evidence on this very forum that has been presented showing build up on the 5.0's valves. Someone actually took the time to remove the heads and show us. Whether it had a noticeable impact on performance is another question, however.

I installed a catch can very early on my 3.8 and it catches a significant amount of viscous blow back in between oil changes. I get a bit of relief knowing that crap isn't going back into the engine.

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