Author Topic: Diesel noob questions.  (Read 5536 times)

June 03, 2011, 08:07:17 pm

meanvw

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Diesel noob questions.
« on: June 03, 2011, 08:07:17 pm »
83 rabbit.  1.6 non turbo.  I rebuilt everything.  I have a 160 mile per day commute.  Been running a Scirocco gasser I built for a few years on this commute.   now time to run this rabbit.

Today was most I've run it since rebuild, put on 170 miles today.

Some questions I could not find answers for:

Even when it's colder 50 degrees, my engine starts without pulling the timing advance.  Should I use the timing advance always when starting cold?  How soon after it's running should I push it back in? Gradually push it in over the course of a few miles, or just push it in?

Shift points.  I have a .71 5th gear FN code 020 transmission.  There are little dots on the speedo.  One dot at 20 mph, 2 dots at 40 mph, 3 dots at 65 mph.  Do these mean something?  I have no tach, so what would good mph shift points be for each gear.  I've been running it out to 45mph before grabbing 5th gear.

Last question of today .  Better to fill up diesel at truckstop or at a gas station that has diesel nozzle on gas pumps?  I filled up at big truckstop and was surprised how fast those pumps go.  30 seconds and car was full.  Diesel any better/different between truckstop and smaller (for cars/trucks) gas station?

On fresh motor and this transmission, 65 mph felt good.  What is top speed on these just as a curiosity.  I sometimes go into Indiana and other states that have speed limit higher than 65.
« Last Edit: June 03, 2011, 08:09:35 pm by meanvw »

Reply #1June 03, 2011, 08:36:36 pm

RabbitJockey

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Re: Diesel noob questions.
« Reply #1 on: June 03, 2011, 08:36:36 pm »
Some questions I could not find answers for:

Even when it's colder 50 degrees, my engine starts without pulling the timing advance.  Should I use the timing advance always when starting cold?  How soon after it's running should I push it back in? Gradually push it in over the course of a few miles, or just push it in?

50 degrees really won't require the cold start, usually after a minute or 2 i can push it in and it will stop missing.  i try to push it in right after i start my car and its running properly, otherwise i forget and drive all the way to work with it pulled.  i have heard people say; in the very cold, crank the engine till it starts to sputter then pull the timing advance its really something you gotta play with to get right.  but being that you just rebuilt your engine, you shouldn't have much to worry about

Shift points.  I have a .71 5th gear FN code 020 transmission.  There are little dots on the speedo.  One dot at 20 mph, 2 dots at 40 mph, 3 dots at 65 mph.  Do these mean something?  I have no tach, so what would good mph shift points be for each gear.  I've been running it out to 45mph before grabbing 5th gear.

sounds quite mild and a good way to get good mileage to be in fifth by 45mph

Last question of today .  Better to fill up diesel at truckstop or at a gas station that has diesel nozzle on gas pumps?  I filled up at big truckstop and was surprised how fast those pumps go.  30 seconds and car was full.  Diesel any better/different between truckstop and smaller (for cars/trucks) gas station?

i have never noticed any difference between stations, some have bio diesel mixed in, which should add some lubricity to the pump, but honestly i can never tell the difference, like u can on a gas car when u switch stations and grades.

On fresh motor and this transmission, 65 mph felt good.  What is top speed on these just as a curiosity.  I sometimes go into Indiana and other states that have speed limit higher than 65.

u just gotta floor it and find out, i believe my top speed was 90 some with my 81 na rabbit, on my old td i did 120,  honestly tho with an na engine its hard to cruise above 75, the power just isn't there like on a td


01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #2June 03, 2011, 08:48:29 pm

wdkingery

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Re: Diesel noob questions.
« Reply #2 on: June 03, 2011, 08:48:29 pm »
I hit 5th religiously @ 25 mph, and don't more than 50 mph if I can help it.. just clocked 54 mpg because of it. Cold start I just push in immediately, only use it to start

Reply #3June 03, 2011, 09:03:26 pm

ORCoaster

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Re: Diesel noob questions.
« Reply #3 on: June 03, 2011, 09:03:26 pm »
I thought we were supposed to rev these little buggers up to shifting points.  25 in 5th?  That's lugging it for ya.  I generally shift at the 15,25 35 and 50 points. I too have the .71 fifth gear and I don't have much trouble getting 47 mpg out of a tankfull running at 65 mph.  I do add wax in the ratio of 2-3 ounces per 10 gallons.  Going to start with some ounces of oil as well for better lubricity. 

I have to pull the start lever out to get my Rabbit to start most cool mornings.  Once it smooths out I push it in and drive on.  It doesn't matter if you drive with it out once the RPMs are up the advance you gave it from the lever is long since over ridden by the dynamic advance of the IP pump. 

Runs of 225 miles between work and home twice a week is my route.

Reply #4June 04, 2011, 06:34:36 am

wdkingery

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Re: Diesel noob questions.
« Reply #4 on: June 04, 2011, 06:34:36 am »
Wax? What is this wax you speak of.. surely you don't mean you melt a candle and add it to the tank??  I'm interested to hear yer reply to that!

Yes I lug the piss out of it.. I try to get @ least one good smash in there per tank tho. I don't know if luggin will hurt it or not.. don't think so.  I don't know what trans I have

Reply #5June 04, 2011, 08:55:11 am

mac.man25

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Re: Diesel noob questions.
« Reply #5 on: June 04, 2011, 08:55:11 am »
Just because you have power there doesn't mean you should use it.  Below 2k RPM the oil pressure in these engines is below 25PSI, and when you're asking for power that low, you're squeezing the oil out of the bearings and it's not getting replaced.
'83 VW Pickup, Getting the AAZ.
86 BMW 325es.

Reply #6June 04, 2011, 09:08:28 am

wdkingery

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Re: Diesel noob questions.
« Reply #6 on: June 04, 2011, 09:08:28 am »
Oooo that seems logical.. but I don't like to push the skinny pedal! Hmm

Reply #7June 04, 2011, 09:43:54 am

Quantum TD

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Re: Diesel noob questions.
« Reply #7 on: June 04, 2011, 09:43:54 am »
Wax? What is this wax you speak of.. surely you don't mean you melt a candle and add it to the tank??  I'm interested to hear yer reply to that!

Yes I lug the piss out of it.. I try to get @ least one good smash in there per tank tho. I don't know if luggin will hurt it or not.. don't think so.  I don't know what trans I have

He's talking about parrafin wax to thicken the fuel. The result is more dynamic timing advance, better MPG.

Reply #8June 04, 2011, 09:46:40 am

R.O.R-2.0

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Re: Diesel noob questions.
« Reply #8 on: June 04, 2011, 09:46:40 am »
Wax? What is this wax you speak of.. surely you don't mean you melt a candle and add it to the tank??  I'm interested to hear yer reply to that!

Yes I lug the piss out of it.. I try to get @ least one good smash in there per tank tho. I don't know if luggin will hurt it or not.. don't think so.  I don't know what trans I have

He's talking about parrafin wax to thicken the fuel. The result is more dynamic timing advance, better MPG.

i made up some diesel once upon a time, out of filtered waste oil, kerosene, and some white gas to thin it out. i could tell the difference when my car was running that stuff. it really does give you more dynamic timing.. cause its harder for the thicker fuel to get out the out bolt, so more pressure gets built..
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Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #9June 04, 2011, 05:48:22 pm

ORCoaster

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Re: Diesel noob questions.
« Reply #9 on: June 04, 2011, 05:48:22 pm »
Parifin wax also adds a bunch of cetane to the fuel.  Something they decided to take out when they started making low sulfur fuel.  I cut it up into thin 3/4 inch by 1/4 by 3/4 pieces and dissolve them in a small one gallon plastic jug.  I usually keep it in the back of the car and it gets warmed in the sun.  Before heading to the diesel pump I pour it in the tank and then refill it with straight diesel when I fill the rest of the tank.  Makes a big difference in the MPGs and it runs so much better.  Once I get the fitting I need to monitor the pump I am going to pop a thread on here that shows the before and after pressures at idle and at 65 mph with and with out the wax.  Also the miles per gallon.  Should be entertaining.
« Last Edit: June 04, 2011, 09:30:08 pm by ORCoaster »

Reply #10June 04, 2011, 07:58:00 pm

CRSMP5

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Re: Diesel noob questions.
« Reply #10 on: June 04, 2011, 07:58:00 pm »
truck stop fuel used to be bad.. and from those experiances i still will not use them.. use a real station fo rit..

with todays low sulfur crap.. no idea what truckstops have.. so cannot say..


Reply #11June 05, 2011, 03:25:57 pm

R.O.R-2.0

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Re: Diesel noob questions.
« Reply #11 on: June 05, 2011, 03:25:57 pm »
Parifin wax also adds a bunch of cetane to the fuel.  Something they decided to take out when they started making low sulfur fuel.  I cut it up into thin 3/4 inch by 1/4 by 3/4 pieces and dissolve them in a small one gallon plastic jug.  I usually keep it in the back of the car and it gets warmed in the sun.  Before heading to the diesel pump I pour it in the tank and then refill it with straight diesel when I fill the rest of the tank.  Makes a big difference in the MPGs and it runs so much better.  Once I get the fitting I need to monitor the pump I am going to pop a thread on here that shows the before and after pressures at idle and at 65 mph with and with out the wax.  Also the miles per gallon.  Should be entertaining.

mk2 n/a pump out bolt pedestal.. drill and tap the side of it..
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #12June 05, 2011, 09:11:40 pm

ORCoaster

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Re: Diesel noob questions.
« Reply #12 on: June 05, 2011, 09:11:40 pm »
Drill and tap may get done next weekend but I hate to take the pump off and apart to do this when a simple extension would do the job.  I liked Andrews solution with the drilled and tapped extension.  Although the side port area would be more protected between the IP pump and the engine.  I would likely through on a 90 degree elbow and route the tubing up and along the incoming fuel line to the pump.  There is already enough junk hanging off the drivers side on my engine.  As I found a center console and added some gauges this weekend.  Two oil pressure, one VDO temp, volt and amp gauge.  Now I just have to figure out the OUT pressure from the IP and I can see where I am at both at idle and Cruising. 

Ran most of the way up to Portland with 70 lbs on the engine oil.  Starts at 80 and when I hit the rest areas it was down to 40 at idle when up to 90 C on the temp gauge.  Have an issue with the lighting.  It drops the voltage from 13.6 to just under 12.  Pulled it off and the charging system and electric temp gauge are steady now, they were bouncing all over the place.

Getting all the mechanical systems ironed out then going for the interior and the paint job later this summer I hope.

Reply #13June 05, 2011, 09:51:40 pm

Quantum TD

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Re: Diesel noob questions.
« Reply #13 on: June 05, 2011, 09:51:40 pm »
Post updates. Would love to see real-time pressure readings. I though about plugging in a VDO 0-10 bar sender from a Porsche and running it on a dash gauge to see what the curve was doing. I still may do it, rather than bang on the pressure regulator at idle. I dig the paro-wax idea. But the overall plan is to run blended veggie oil w/kerosene and cetane boost. I'm hoping it will compensate for my long-out-of-date pressure setting on my home-rebuilt pump. I'm getting 37-39 MPG out of my caddy with a heavy foot. Kinda blows.





Reply #14June 07, 2011, 05:27:54 pm

meanvw

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Re: Diesel noob questions.
« Reply #14 on: June 07, 2011, 05:27:54 pm »
First tank of fuel on new motor=48mpg.
Mostly 65mph steady on freeway, but probably 10% of it is in town or stop and go traffic. 

2nd fuel up was at a BP regular gas station.  Will see if this next tank gets better mpg.

Planning on 1st oil change at 1000 miles.  This engine is new rings/bearings/everything.  This a good time to do oil change or run it out longer?

Also used Delvac not synthetic as the break in oil.  Was planning on running one complete oil change 5000 miles on regular oil before going synthetic.  Good plan?

Always buy filters from Vw dealership for my gassers, still good plan for the diesel?

Yes, I need to do some searching and reading .

Pretty stoked.  I do 160 miles a day, and my scirocco gasser got 33mph, so 48mpg is 1.5 gallons less fuel per day.  Plus scirocco had supercharger and needed premium fuel or it would knock.  So something like $6.25 per day in fuel savings...