Fuel Temperature

[Denton T. Young]

Could someone with a VAGCOM do me a favor and get fuel temperature readings after driving for 20 minutes/30 minutes. It would be nice if you live in a cold climate.

I'm curious because I've been using B100 lately. Lately, the morning temps have been in the teens. I wondering how long it takes for the fuel to warm up.

 

[MITBeta]

Straight B100 in the teens? How do you keep it from gelling?

 

[Denton T. Young]

How do I keep it from gelling?

I leave the TDI in the garage and I drive my Cherokee.

 

[jxpfeer]

nice. powerservice?

 

[Boundless]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Denton T. Young:
Could someone with a VAGCOM do me a favor and get fuel temperature readings after driving for 20 minutes/30 minutes. It would be nice if you live in a cold climate.

I'm curious because I've been using B100 lately. Lately, the morning temps have been in the teens. I wondering how long it takes for the fuel to warm up.<hr></blockquote>


Denton,

On the "Don't Lose Winter MPG's" thread, Aaron has done just that. An excellent graph along with explanation.

 

[GeWilli]

Denton,

the fuel temps get upwards and around 30 C - I've got a link or two posted in that thread I believe listed there by Boundless.

the coldest I have seen it after warm up and extended 117km/hr driving (vag-com numbers) was 28 C.

I believe sheilding the fuel tank and the lines that run under the car should do the trick. If you can preheat the fuel in the garage that would be the best - a nice low temp (25-30 degrees C) heat pad inside the insulation should be fine.

The stuff that Boundless reccomended for the engine (foam and aluminum foil insulation about $15 at Home depot for 15' of the stuff) should do the trick.

I wouldn't worry about the engine itself just the line exposed to air under the car and the fuel tank.

current numbers even as cold as it was are about the same - same rate of increase relatively

 

[Denton T. Young]

Thanks for the info. I re-read that long thread.

I won't worry about the bio-diesel gelling since my garage usually stays above 40 degrees. It takes about 30 minutes to reach the near zero temperatures of the high mountain passes. The biodiesel should be warm enough by then.

 

[GeWilli]

Denton,

I tried something different this morning and well - fuel temps were at 34 C before I got to the freeway a could 100% throttle accel (trying to get the car to duplicate a condition didn't do it but . . .) it was above 12 degrees C when I pulled out of the garage after idling for about 5 minutes or so and it was -2 degrees C this am.

The biggest problem you will have is keeping the lines insulated. The pump should put enough heat in the fuel filter but the lines running back to the tank will be problematic.

Last winter the dealership was having quite a few TDIs freeze the fuel in the lines when we got a very early wicked cold snap. The summer blend diesel was freezing solid in the supply and return lines. Not good. I don't think it would take much sheilding to prevent it - just remove it in the summer.

And Boundless, BTW, and i don't mean this to be taken as anything other than an observation, I have see 1 yes 1 truck in the 150 miles a day I drive on a trucking route with their grill covered. FWIW

 

[Boundless]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by GeWilli:
Denton,


And Boundless, BTW, and i don't mean this to be taken as anything other than an observation, I have see 1 yes 1 truck in the 150 miles a day I drive on a trucking route with their grill covered. FWIW<hr></blockquote>

GeWilli,

I don't think there will be many grills covered this "winter". I'm having near 50F weather here for the past two weeks and mid to upper 40s forecasted for the next week.... Rarely getting below freezing at night. Heck, last night or the night before it only got to 40F.

Winter has just never arrived this season....

The super cold arctic air is staying well to the north in Canada...

 

[VelvetFoot]

Don't a lot of trucks have that moveable grill cover over the radiator?

 

[GeWilli]

not to drag out the point but there have been a couple days with the temps in the teens (F) and they still weren't covered. < shrug >

but yeah

we have had one aweful winter if one is trying to prove a cold theory kinda thing

 

[Boundless]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by VelvetFoot:
Don't a lot of trucks have that moveable grill cover over the radiator?<hr></blockquote>

Yeah, it looks like the covers snap on/off.

A couple years ago when we had a wicked cold stretch, I used plastic trash bags held on with rare earth magnets on my LandCruiser to act as a radiator shield.

[ January 25, 2002: Message edited by: Boundless ]</p>

 

[Turbo Steve]

In addition:

Setting the Fuel Quantity Adjuster's value to a richer setting in the wintertime will result in higher Fuel Temps all around - even at idle, as confirmed via the VAG COM tool on several TDI's.

With the pump set on the rich side, it is cycling more fuel through the system and the increased heat from the load on the pump / injectors naturally transfers back to the extra diesel heading to the tank.

3.2 - 3.4 appear to be acceptable values to shoot for and 2.2 - 9.0 are the suggested ranges for adjustment.

 

[Turbo Steve]

P.S.

The reason why more power is readily available (when turning up the Quantity Adjuster cutoff sleeve position) is simply due to the pump having more "on demand" fuel available to instantly send to the engine.

This can result in a huge increase in go-pedal response or improvement in HP / torque, especially off the line and for midrange passing power. Those (risk-takers) wanting to break the TDI Speed Record on the Bonneville Salt Flats would be wise to shoot for maximum values, but not stick with them for longterm useage.