Bio and EGT's

[250downunder]

I have just returned from my first trip hauling 6000lbs running 100% Bio and noted a definate reduction in my EGT's - in the order of 100 deg.
Have others noticed similar reductions?

[magnumpeei]

yet another reason for me to buy a pyrometer

that makes sense, seeing as biodiesel has more lubricating properties it probably soaks up a far bit of heat as it travels through the exhaust system. That's my take on it - I could be way off base though

[morebiodiesel]

Originally Posted by 250downunder

I have just returned from my first trip hauling 6000lbs running 100% Bio and noted a definate reduction in my EGT's - in the order of 100 deg.
Have others noticed similar reductions?

Hmmm Biodiesel contains more oxygen so theoretically your combustion temps should be higher. It's possible that due to fuel viscosity differences your injectors may be delivering less fuel and thus lowering EGT.

I'm just guessing.

[Clay Henry]

i thought Bio-D had a lower cetain value making it burn less hot?

[magnumpeei]

nope BD has a higher cetane value, but I thought it also has a higher flash point.

[morebiodiesel]

Surmising here...

BioD has more O2 which results in a hotter burn but has a higher viscosity which is going to delay injection which will appear to retard timing.

Could the change in timing due to BioD increased viscosity be lowering the EGTs?

Viscosity as seen here:
Biodiesel Viscosity...

[sea71]

Dont really understand this, but you fellas might. I copied and pasted this from JTF concerning your auto and bio.

Optional: Retard the injection timing by 2-3 degrees -- this overcomes the effect of biodiesel's higher cetane number. The engine loses a little of the extra power you get with biodiesel, but it runs quieter and the fuel burns cooler, reducing NOx emissions. (See also NOx emissions and biodiesel.)

[morebiodiesel]

The original poster said his EGTs had dropped while running BioD. BioD should produce higher EGTs so we were trying to figure out why it would be cooler.

I was thinking the viscosity might be naturally retarding the timing depending on what the feedstock for the fuel was.

[250downunder]

Maybe the reduction I saw was more related to low ambient temperatures than to the fact that it was the first trip on Bio. We have had pretty cool weather lately. I do this trip frequently so I will see what happens when the weather warms up.
The maximum temp I saw was 1000 deg. on a moderate climb without backing off. Normally on this climb I see 1100 deg. which is my back off temp.

[mako314]

Biodiesel has about 10K or 12K less BTUs than petro diesel, and a cetane # of about 58 to 65 most ulsd has a cetane # of about 47- 50 the bio doesn't burn as hot as petro thus the minute decrease in power. I run B100 in my 2001 work truck and have noticed a 100-150* dcrease in egt and a large swelling in my wallet from the savings