2016 Silverado Refresh

[Darkanion]

No, not yet. Should start soon after the gas mileage and performance goes to shit due to the intake valves coking up from direct injection.

Just keep sucking that dirty crack pipe of hate.....

 

[Black02Silverado]

Haters gonna hate, but I like it.

 

[PenguinLTZ]

I like it, at least the painted front end.

 

[1BADSS396]

No, not yet. Should start soon after the gas mileage and performance goes to shit due to the intake valves coking up from direct injection.

Just keep sucking that dirty crack pipe of hate.....

Yep, I hate DI and will not buy a engine with it until they figure out how to prevent it. Nobody has yet.

It's another dumbass CAFE bullshit feature.

It's a big reason I would buy a Ram with a 5.7 Hemi right now. No fucking DI yet.

I would at the very least put a catch can on that engine if I were you. And run some Seafoam through it at least once every oil change. Or you can just pretend it's not an issue. your call.

 

[DV2000NJ]

Yep, I hate DI and will not buy a engine with it until they figure out how to prevent it. Nobody has yet.

False.

Some manufacturers are running multiple injectors (such as the BRZ/FRS, I believe it's Toyota's system). They have a large direct injector, and a smaller port injector to handle idle/low load situations and valve cleaning.

It's another dumbass CAFE bullshit feature.

Bull.Shit.

DI allows an engine to produce more power while consuming less fuel. That's literally the furthest thing from a "bullshit feature". That's what every engine deveolper has been finding ways to do since the beginning of the internal combustion engine.

Does it have issues? Yes. Mainly valve buildup. But that can be remedied the way Toyota/Subaru have done, and the benefits of DI can't be denied. Unless you don't like more power from less fuel.

 

[1BADSS396]

Yep, I hate DI and will not buy a engine with it until they figure out how to prevent it. Nobody has yet.

False.

Some manufacturers are running multiple injectors (such as the BRZ/FRS, I believe it's Toyota's system). They have a large direct injector, and a smaller port injector to handle idle/low load situations and valve cleaning.

It's another dumbass CAFE bullshit feature.

Bull.Shit.

DI allows an engine to produce more power while consuming less fuel. That's literally the furthest thing from a "bullshit feature". That's what every engine deveolper has been finding ways to do since the beginning of the internal combustion engine.

Does it have issues? Yes. Mainly valve buildup. But that can be remedied the way Toyota/Subaru have done, and the benefits of DI can't be denied. Unless you don't like more power from less fuel.

Yes, it adds efficiency and some power...but at a cost. Cost to build and a cost to maintain. It's to help satisfy CAFE....period. They try to sell it has a performance feature...Bullshit. You can believe that if you want. There are better/cheaper/more reliable ways to increase power.

Yes, there are ways to help minimize them, but to date, nobody has solved the issues completely.

More power from less fuel? Sure...for a while.

 

[mr_bots]

I'm with Dan, it's just a method to allow higher compression are more advanced timing. The basic driver for power and efficiency and basically what every upgrade ever done to the internal combustion engine has tried to accomplish. By that reasoning, if it wasn't for CAFE we'd all be driving cars with a round filter on top of the engine sucking in hot air with fixed valve timing, carbs, and the horrendous heads and manifolds they used for decades with 2 or 3 speed transmissions.

I haven't heard of any issues on Toyota's D-4S system. Yes, it increases cost and complexity but you get the cleaning effect of port injection with the cooling effect and better atomization of direct injection. Some times it uses one injector or the other, some times it uses both.

 

[1BADSS396]

Ask An Engineer: GDI Problems In A Nutshell - The Truth About Cars

Even though every other car nowadays seems to offer gasoline direct injection (GDI), Mercedes-Benz was the first to exploit this technology in the 1955 300SL. But it wasn’t until the mid-1990’s that other automakers started to use GDI in mass produced vehicles. GDI promises marginal increases in fuel economy (3% reduction in BSFC ) but its real benefits include reduced cold start/low load emissions and higher power outputs. While the technology offers engineers incredible flexibility from an engine design perspective, it is not without faults. As with any new technology it is important to understand both the positives and negatives before you choose, say a compact car with GDI or one regular fuel injection. If you want to keep your car for a long period of time, the long-term reliability of a GDI engine is an important factor.

The effect of increased percentages of ethanol on injector longevity.

The percentage of ethanol in gasoline at the pumps is steadily increasing. Ethanol has a tendency to increase the corrosion rate of the various metals used in an engine. Add this to the elevated fuel pressure and the fact the injector is directly exposed to in-cylinder combustion events, and you have a recipe for a recall. Furthermore, these injectors are very sensitive to fuel quality due to outrageously tight tolerances. It is very important to use high quality fuels and keep the filters clean.

Higher pressures in general.

GDI requires significantly higher fuel inlet pressures than port injection. This puts a great deal of strain on every piece of the fuel delivery chain. This is not a problem on a new engine. 50,000 miles down the road, and it may be. Manufacturers have been relatively proactive in this department by specifying robust, stainless steel fuel lines and connections. That hasn’t stopped fuel pump recalls from already occurring

Carbon buildup on intake valves.

This is the big problem with most current GDI engines. Due to modern unburned hydrocarbon (UHC) regulations, vapors from the crankcase are usually vented into the intake stream in order to prevent oil droplets from escaping through the exhaust. In a port injection engine, these droplets are ‘washed off’ the neck of the intake valve by a relatively constant stream of gasoline droplets. In a GDI engine, the gasoline doesn’t touch intake side of the valve. As a result, the droplets have a tendency to bake onto the valve and significantly reduce performance. To add to this effect, many advanced GDI engines also include exhaust gas recirculation in order to lean out the combustion mixture and reduce in-cylinder temperatures for certain combustion modes (reducing NOx emissions). Since GDI combustion has the ability to produce far more soot than premixed combustion (port injection), the problem is magnified.

Even more alarming is that these deposits can dislodge and damage other downstream components (turbochargers, catalytic converters, etc.). Manufacturers have added systems to capture these oil droplets and particulates, but no system is 100% effective. As a result, there are many disappointed early adopters with large repair bills. Even diesel engines haven’t been immune to these issues.

The reason these issues have slipped through to production is that they won’t show up in a 500,000 mile torture test. These types of issues will appear after years of short trips (preventing the engine from reaching operating temperature), bad batches of fuel, etc. As we approach the efficiency limits of the internal combustion engine, the engines themselves (and associated support systems) have become more complex. As with the transition from carburetors to electronic fuel injection, there will be some overlap between relatively bombproof port injected engines and the unproven, first-generation GDI engines.

 

[1BADSS396]

There several reports of C7's on CorvetteForum that are reporting coked intake valves and drastically reduced power and fuel economy...with less than 50K miles on them.

You can believe what you want.

 

[1BADSS396]

And if DI adds sooo much more power, how come the LT1 6.2 in the C7's only produces 24 more HP than the port fuel injected LS3 in the C6's? And the LT1 also has VVT, which likely accounts for most of that 24 HP increase.

Pretty sure my tune covered that spread.

Oh, and it only gets about 1 MPG better hwy FE. (30 vs 29) with AFM.

Are the DI issues really worth it in the LT1 vs the LS3? Hell NO!!!!