More important in a direct injection engine...

[Jeff_in_VABch]

Originally Posted By: wallyuwl
I was reading about the 3.6L DI engines in the Traverse and was wondering something.

What do you guys think is more important in a direct injection engine (I have a 2.4L DI 4 cyl in 2010 Equinox), low Noack or a good cleaning oil in terms of dealing with intake deposits since the fuel doesn't pass by them with DI?



A low volatility and high, high temp viscosity oil would be good for these engines as they seem to run higher operating water and oil temperatures than previous GM engines. I havent checked what temperature thermostat they run, but I bet it is over 195F.

I have a 2011 Acadia with the 3.6 DI. Nothing special about it IMO except a lack of HP, torque OR fuel economy.

The intake deposit talk is mostly nonsense. It can happen, but it can also happen in a non-DI engine.

I built a DI 408 SBC back in the late 80s that never had a spec of combustion area buildup. Made 650HP too, amazing for the 80s.

http://www.christiani-tvet.com/pdf/71561_reading.pdf

 

[PZR2874]

^^Kind of weird considering the whole idea of DI is in fact, more power, economy, torque.

 

[Jeff_in_VABch]

Originally Posted By: PZR2874
^^Kind of weird considering the whole idea of DI is in fact, more power, economy, torque.


Exactly.

The Acadia does make a little power up near 7K RPM, but that's just not reasonable. When they use the VVT just for the sake of upping the extreme high RPM HP, it's crazy and just for marketing HP #s, which does sell the vehicle.

From a pure performance aspect, a DI race engine will make about 7% more HP than a carburated one and are incredibly responsive.

The Acadia style DI system, which I havent even looked at, is a GM "advance" to gain something, but it's not power or economy as far as I can tell. The whole Acadia powertrain control system is poorly programmed IMO.

-Erratic startup high idle speed
-Ocassional smoke of various hues on start
-low speed part throttle upshift way off
-coasting decel downshift points way off (this vehicle wont coast)

Mechanically, the Acadia is a conglomeration of flimsy angular stamped metal pieces with a nice looking body bolted to it with an oil filter you unscrew from the top side so the oil can flow over all those filmsy metal parts so they wont rust and fall off. End of rambling.

 

[PZR2874]

Almost sounds like my wifes' Murano and that goofy wannabe trasmission CVT.

Speaking of the oil (cartridge filter), GM is doing that is alot of cars... I noticed it with my 07 ION. My 07 speed3 is the same way, but from underneath.

 

[demarpaint]

Originally Posted By: Bill in Utah
Originally Posted By: Steve S
The most important thing is not to buy one untill all the bugs are worked out at other peoples expense.


Agreed. My family in the last 2 weeks just bought 2 vehicles that are available with DI motors or "normal" injection motors.

Even though the DI motors have 20-30 more HP and 3 mpg more on the EPA highway sticker both vehicles were bought with the normal motors.

I'll always take simple over complex. DI is something I do NOT want to deal with until I have NO choice.

Bill



I feel the same way Bill. In fact my plans were to buy new Jeep Wrangler in 2013, but now I'm seriously considering 2012 since the 3.6L Pentastar engine at moment is not DI. I have a feeling the 2013 version will be DI and then it will be Chryslers turn to try and de-bug them. If I could be 100% sure the 3.6L Pentastar will remain w/o DI I'd hold off..........These decisions kill me! LOL