Author Topic: wideband on diesel? (Read 6806 times)

boostaholic · « **on:** January 06, 2008, 10:47:43 am »

so i'm not sure if this is possible or not? but can you hook up a wideband on a diesel? maybe hook a 02 in the downpipe or something.. for the wideband.. i notice alot of people are running egt's but my expierence is the reading of a EGT gauge can be slow and the damage could already be done.. just curious?

jimfoo · « **Reply #1 on:** January 06, 2008, 10:53:53 am »

The Aircraft Spruce thermocouple reacts almost instantaneously, so others have said. Even mine reacts fairly fast as far as I'm concerned. I have a hard time thinking the turbo would heat up faster.

vanagonturbo · « **Reply #2 on:** January 06, 2008, 01:46:20 pm »

slow response from an EGT probe is usually due to poor placement in the manifold. Usually damage from high EGTs is from sustained driving with high temperatures. The pyrometer is pretty quick responding. I have Egts go from 1400 to 1000 in a matter of about 3-4 seconds on my vanagon. The scirocco is slightly slower, but I think thats because of the charge piping and intercooler making it take a little longer. But its still pretty fast to respond.

vanagonturbo · « **Reply #3 on:** January 06, 2008, 02:02:25 pm »

Hmm, interesting. That makes sense though.

also interestingly enough is that I had one car in the shop that we had placed the thermocouple directly in the exhaust stream right before the turbo flange and it responded quite quickly. We also had a car in the shop that someone else had installed the thermocouple indirectly in the exhaust stream and it responded very slowly. Both gauges and thermocouples were the same model and brand.

RabbitJockey · « **Reply #4 on:** January 06, 2008, 06:52:24 pm »

a wide band won't really tell you anything pertinent anyway since there is no specific air fuel ratio u want

QuickTD · « **Reply #5 on:** January 06, 2008, 07:07:16 pm »

A wideband O2 meter will always read deadly lean on a diesel. Since there is no air throttle, the fuel air ratio on a diesel is directly controlled by the pedal position and varies from more than 100:1 at idle to probably around 20:1 at full power. Well out of the range of any wideband sensor and, as was said above, not pertinant info anyway.