Improve mileage 350 with Quadrajet

[motornut]

glad to see you got it all cleaned up
don't think those are the same rads in those pics lol
on the right the cleaner one has a high solder drip i don't see in the other(middle right)
and the outline of the metal contours of the rad don't look the same

[kikkegek]

Originally Posted by bctom

I found this short article on spark advance at this link:

http://www.rasoenterprises.com/index...-advance-curve

Dual Fuel Advance Curve
Sunday, 18 January 2009 13:20

When running a dual-fuel setup, ideally you should have both a gasoline advance curve and a propane advance curve. For older vehicles, Dual Curve makes a dual advance curve ECU for these applications under PN 40622. I contacted Dual Curve about the operation of their 40622 ECUs and they gave me the following response:


Regarding timing advance, the PN40622 is designed to give an additional 8-10 degrees of advance, after the distributor is recurved.

Please refer to the PN40622 instructions pg. 2:

“The Timing Recurve will electronically delay the factory set timing signal 15 degrees. The user must mechanically move the distributor timing ahead or advanced 15 degrees. Add 15 degrees to the original factory gasoline set point. With the 15 degree delay for gasoline, the Recurve can then provide timing advance for the higher octane LPG/CNG fuel. At idle on LPG fuel, only 10 degrees (CNG fuel, only 13 degrees) additional advance will appear on your timing device. The other degrees (5 LPG or 2 CNG) of timing are used to compute a smooth, accurate timing for RPM changes. After the (gray wire loop) fuel timing program is set-up and selected. The fuel selector switch will select the proper timing program via the yellow wire.”

You can use this ECU for straight LPG or CNG applications too. I believe the reduced timing advance when on LPG at idle would make the engine easier to start, which would be the main advantage for installing it on a straight (or dedicated) propane vehicle. However, I found that I have not had any starting problems with the advance curve used at the top of this page.

It was on this web site: http://www.rasoenterprises.com/index.php

There are also articles here on rejetting the carb, ignition and spark plug changes that are necessary in dual fuel conversions . They also state that your vacuum advance should definitely be hooked up. You might find the 195 degree thermostate too warm in the summer months. I don't have any experience running these engines at sea level, and I'm not sure how hot it gets in Holland in the summer time, so you will know better than me.

he man!
thank for the info.
the dual curve product dont seem to be sold anymore. "Obsolete" says the website, just leaving the instructions.

Where are those articles on dual fuel? ca you point then out to me?

[kikkegek]

the thermostathouse is leaking. should I use teflontape or something on this plueg on top?

[motornut]

does it not tighten up and seal?
but the teflon should work

[kikkegek]

checked my cooling fluid again today and it is staying nice and clean...wich makes me very happy.

I usually get a mileage of 7,5 MPG
today we got gas and I calculated a mileage of 8,2 MPG

[283nova]

somethingsw gotta be wacky, what gears are in the truck and what transmission?

my 80' was de-emissioned has 3 inch exhaust 350 q-jet 4 speed stick, and get 12-14 hwy.

[kikkegek]

Originally Posted by 283nova

somethingsw gotta be wacky, what gears are in the truck and what transmission?

my 80' was de-emissioned has 3 inch exhaust 350 q-jet 4 speed stick, and get 12-14 hwy.

hi there, my Burb has a TH400 and 4.1 gear ratio. We drive about 55mph on the highway.

[283nova]

that would explain it mine was a 3/4 ton 4x4 4 speed with a 342 or something close rear gear. real highway friendly

[kikkegek]

connected a tach tonight...

my car makes about 2800 rpm at 55 mph. is that a lot or normal?

I have 4.1 gears.

[kikkegek]

I also replaced the vacuum advance. I thought it wasn't working. So I checked. It did work, but the replacement I got from somebody had a longer path, so more advance at high vacuum.

could this improve the mileage on the highway at low throttle?

I also replaced the front brakes that were old and rubbing the discs constantly because the brake cilinders were stuck.

My mileage improved from about 6 mpg to about 7 mpg...still not very good...but improvement...I wonder if I'll see the same mileage when I get gas the next time.

[motornut]

hi kikkegek.I noticed the other day the 78
totally diff trucks but @80 km/hr(about 50mph) i was running 2000 rpms

[dos0711]

Change out the tranny to a 700R4...the overdrive will help on the highway...

[kikkegek]

Originally Posted by dos0711

Change out the tranny to a 700R4...the overdrive will help on the highway...

it is a 4WD is that even possible?

[motornut]

Yup i believe my gold burb had one
[size=1]Posted via Mobile Device[/size
And so did my 87

[erikgto]

Talking about being on a different playing field;

Yours has a 3 speed automatic with 4.10 gears and 2800 rpm @ 55
Mine has a 4 speed autom / overdrive and 2.73 gears.... no tach, but I guess 1.400 rpm or so at 55....... just a bit above idle.

You need an overdrive and I'm better off keeping it out of OD with my gears

erik

[kikkegek]

Originally Posted by erikgto

Talking about being on a different playing field;

Yours has a 3 speed automatic with 4.10 gears and 2800 rpm @ 55
Mine has a 4 speed autom / overdrive and 2.73 gears.... no tach, but I guess 1.400 rpm or so at 55....... just a bit above idle.

You need an overdrive and I'm better off keeping it out of OD with my gears

erik

can you mount just an OD then?

[motornut]

may have to change a housing/tail

[kikkegek]

he John,
I am a complete noob for trannies, can you explain a little more on that?

[motornut]

what i understand is the tranny size is diff
the two wheeler has a longer tail housing,cause in the 4 wheeler it has the tranfer case to bolt up to
and being computer controlled,you need some sensors.....
not sure why erik,wouldn't want to use the OD
My 87 i drove in it all the time

[kikkegek]

alrighty, here we go again.

Today I got my radiatorcap with thermometer in through the post from mr. gasket. really cool device.

Now I can check the temp right at the core. And what do you know. It's exactly the same as my meter in the cockpit (of wich I wasnt certain).

Just 150F....isnt that extremely cold for an engine to run well?

The thermostaat is 195F....but I can drive on the highway or city for miles and the temp will not go over 150F...

what to do?

here's two pics of the cap:

[dos0711]

Replace the thermostat...sounds like it's stuck open...

[motornut]

nice cap hadn't seen one like that
how cold out was it was the heat on
he just changed it the stat
if thats the case i would go back to your summer at this point
i never change it i always just cover the rad
incase we got a warm spell i can just rip it off

[kikkegek]

Originally Posted by motornut

nice cap hadn't seen one like that
how cold out was it was the heat on
he just changed it the stat
if thats the case i would go back to your summer at this point
i never change it i always just cover the rad
incase we got a warm spell i can just rip it off

its pretty good over here now...about 50-60F...and the heat was off...

I probably wanna check the thermostat...in a bowl of water and check when it opens....with a thermometer...

[kikkegek]

I took of the hose from the thermostat houding 2nite to feel if the thermostat is tight in position., And it is. no movement.

I also then checked with a cold engine if there was flow of coolant through the radiator with the cap of.

I started the engine and looked, but when I raised the throttle a little, I definately saw water flow and when increased the throttle more it got more turbulent.

shouldnt there be absolutely NO flowif the engine is cold? and the thermostat closed?

[motornut]

I'm guessin you have a small pipe from the intake to to waterpump or threw the heater core
(need pics)
the pipe will bypass the stat = heat sooner inside