Former VWDieselParts.com Forum

Just for fun I thought I'd share that I've been running grease in my Jetta TDI for about 8k miles so far. I also decided on an exhaust gas temperature gauge instead of a veg oil temp. gauge. I could have done both or like most folks, just do the veg temp. gauge.

My biggest reason for the EGT is that it monitors combustion quality. A vegetable oil temperature gauge is a great tool to have, but there's many dissenting opinions on how hot the oil needs to be pre IP, and it doesn't tell you if that's enough to burn the fuel completely in the combustion chamber.

The EGT gauge tells you how hot your exhaust is on WVO, therefore letting you make comparisons to what it reads when you're on diesel fuel.

The A4 TDIs are known to drop combustion temperatures at idle, so I try not to sit in traffic longer than I have to on WVO, but generally I get the same readings on WVO as I do on diesel. Usually at idle on either fuel, the temps. are anywhere from 300 to 400 degrees. Highway or intown driving gets the same readings also.

Anyone else using one of these? It's really cool to be able to make comparisons.

sounds confusing, but combustion temps. dropping means exhaust temps. rising. hotter egt's=incomplete combustion as the fuel has not burned all the way in this instance.

I run wvo and I ordered an EGT gauge yesterday. Didn't think about this use for it when I ordered it, but it will be something to watch. Thanks!

>sounds confusing, but combustion temps. dropping means exhaust temps. rising. hotter egt's=incomplete combustion as the fuel has not burned all the way in this instance.<

the TDI burns very lean and even leaner at idle ... uses just enough fuel to do its job and produces very little excess heat, so it cools down at IDLE..... they even install glow plugs in the water jacket to increase the block temp if it gets too low (and helps with cabin heat)

if a diesel gets too much fuel, it picks up engine speed or gives off black smoke if it can't burn it (diesel fuel doesn't ignite or burn in the exhaust pipe)

so too much fuel in the TDI engine = hot engine with hot exhaust ( like under high boost )
too little fuel = cold motor and cool exhaust

gasser with too much fuel = cold engine and really hot exhaust
too little fuel = hot motor and colder exhaust

diesels are the opposite of gassers.

Just hit 20k miles since the veggie conversion.

I've been buying my oil. Way better than collecting and filtering it! Such a PITA...and still less than half the price of D2.

It is a hastel gathering and filtering your own vegy,.. glad you found a place to buy it.