Started by SHOnUup, September 02, 2015, 07:45:18 AM
Quote from: SHOdded on September 02, 2015, 02:49:08 PMGDI engines can run quite lean compared to MFI or PFI engines, so the combustion process would create more heat. Add a turbo to GDI, and you can run even leaner, making the combustion gases even hotter. That's my theory and I'm sticking to it http://gf-6.com/sites/default/files/Turbocharged%20Direct%20Injection%20Is%20Engine%20Oils%20Next%20Big%20Hurdle.pdf
Quote from: FoMoCoSHO on September 02, 2015, 06:59:44 PMActually I've been studying egts and its not quite that simple.If you don't believe me let off the gas and put your car in decel fuel cutoff than watch your cat temps plummet. That is the leanest mixture you will see yet the lowest cat temps.
Quote from: J-Will on September 03, 2015, 07:09:07 AMQuote from: FoMoCoSHO on September 02, 2015, 06:59:44 PMActually I've been studying egts and its not quite that simple.If you don't believe me let off the gas and put your car in decel fuel cutoff than watch your cat temps plummet. That is the leanest mixture you will see yet the lowest cat temps.I agree, its not that simple. But I think the cat temp is the wrong metric in this case. The deciding factor for that is exhaust flow. During decel, RPMs are decreasing which means less exhaust gas is hitting the cat. I think that, because this is about engine oil, the graphic is referring to engine temperature.