adding CAC to existing dt466 motor

[hemivolvo]

well i decided to go one more 1/2 turn , i got about one more lb of boost to a solid 14 the temp went to 1175 maybe 1200 but not over, seems the boost came on a little quicker but not much different. seems funny to me the first two adj really made a noticable difference, and not much change on the last try. not sure if i should go back down 1/2 turn and call it good
any advice? dont think im going to adj the govenor seems much better the way it is now

VERY cool how much better it runs now made this project worthwhile

thanks again for all the help

[hemivolvo]

i was reflecting on my progress today and had a thought --major difference on first two adjustments , then not so much. i have done so much reasearch the last week or two ,it dawned on me the ambac model 100 is good to [if i remember corectly ] 120hp and the inline pump is good to 150hp, i think its possible i hit the limit of the pump at the second 1/2 turn, thus not much increase on the third try. am i on the right track? think ill go back down 1/2 turn and check the milage in the next day or so. i need to go 100 miles or so to get a good average, the way its running im excited to give it a test
thanks for any help or ideas

[drcampbell]

Save yourself the hundred-mile trip. An add-on charge-air cooler is a power-increasing device, not a fuel-economy device.

The highway mileage will be essentially the same, unless:
> You feel so comfortable with the additional power that you're driving faster, which will consume more power (and fuel) via aerodynamic, tire & bearing drag; or
> You've turned it up a little too far and you're getting some black smoke from running a richer-than-stoichiometric air:fuel ratio. (which may or may not be visible - a Diesel engine has a very large volume of exhaust flow for it to get lost in)

The city mileage will probably be slightly worse.
Chances are, you'll be taking advantage of the extra power to get from stoplight to stoplight in less time and using the brakes (or engine braking) more.

Originally Posted by hemivolvo

... not sure if i should go back down 1/2 turn and call it good
any advice? don't think im going to adj the governor seems much better the way it is now ...

In my profession, there's a relatively famous adage:
There comes a time during the development of every new product when becomes necessary to shoot the engineers and begin production.

If you like the results, maybe it's time to stop tweaking and enjoy the ride.

[hemivolvo]

thanks for the reply DR but i did not ever think my milage would go up. i increased the air volume and turned up the fuel three times,, it only stand to reason the milage would go down, the question is HOW MUCH. it runs SO much better what ever the loss it was WORTH it. i can now cruise on the interstate and maintain my speed which is what i was after from the beginning, cant tell you how much better it goes through the gears, used to drop RPM on every shift now just shifts and climbs to next shift. this is no speed demon it is 38 ft long and weighs in at 25000 lbs it just fells more like it is running with a new found eficency, so far im very happy, just interested how this will effect my fuel bill on long trips, most trips are between 500 and 1000 miles ill just have to adj to the increase in cost but ill be smiling while im going down the road

[fireguywtc]

I don't think you are going to lose any milage as you are just cruising down the highway. You will still be using the same amount of HP to keep you moving, whatever that might be to move your given amout of weight about 25k. You may loose some with a heavier foot in city or in the hills, but if you can maintain a higher gear in the hills that may help.

Don't expect any significant loss or gain imo and only time will tell with your mpg as your figure it over several trips. BTW, my most siginficant gain on mpg (1mpg) when I built up my 97 psd came from adding an intercooler. Finally, enjoy the fruits of your labor!!

[hemivolvo]

well i drove 80 miles today and the thing runs great loys more power and just sounds more efficiant, hard to get real accurate measurment as it has a 70 gal tank, ifilled it this morn untiil it just ran out the fill tube, did my drive went back same pump same level ground came with 9 miles to gallon i squeezed one mor gal in which put me at 7.6 mpg I WAS GETTING 8mpg before pretty consistintly, im so happy only time will tell over several long trips.


thanks for every ones help i really learned a lot in the last couple weeks, after being the gas guru for 40 yrs diesel was a change ill just drive this now and get back to hot rods

[Evel486]

Your minimal boost increase on the third try may be due to the fulcrum lever now hitting on the max speed screw. I would suggest at the very least you adjust your max speed screw to get 3100 rpm with no load. This will insure you get full fuel at 2600 rpm & will probably feel much better driving.

[hemivolvo]

thanks for reply evel486 the pump is located in such a way i cant get a GOOD look at the back bottom side, was looking for the ''plug'' to get to the screw not quite sure where it is so far today is COLD and raining i would have to access this from underside first chance i get ill take a closer look, thanks for the tip exactly what should it look like?

[Evel486]

The screw you are looking for is actually a stop for the throttle lever. It's at the rear of the pump just below the fuel hose connection. The lower screw is the low idle stop. The upper is the max speed. It will have a locknut and an acorn nut. It may have a wire seal- if so remove it, Remove the acorn nut, loosen the lock nut and turn the screw out to increase rpm. I believe the nuts are 3/8" or maybe 10mm wrench.

[hemivolvo]

thank you evel468, with info this was very easy, i took of the acorn nut and adj to 3000, took it for a drive. IM BLOWN AWAY, what a difference, took it up the big hill and got my 15lbs boost temp went to 1250, i tryed it a couple times same result very impressive change. i went out on the interstate and was able to go approx 9 mph more than ever before, if i really pushed it boost went just over 15 temp went higer approched 1350 so i backed out right away, i drove quite a ways and was able to hit the high temp a couple times but if i just drove and didnt over push it just ran so well cruising speed is up about 5mph witch is perfect did not really slow down on small hills this is what i was after.
thank you so much for the help, i am planning a good cruise for the week end if i see the higher temps im gonna turn down the pump 1/4 turn so as not to hurt any thing from what i understand 1250 to 1300 is ok just not above is that correct?

my motivation for trips in the bus can be seen in the attatchment, i try to spend about 100 days a year on the water this state has a lot of GREAT fishing this 14lb brown trout was caught and released in late oct this year.

once again thank you for your help

[Evel486]

Now that's a fish! We do get rainbows up here in northern Canada that big (though not often) and the char can be monsters.
Glad I could be of help. Hope you're happy with your "new" motorhome. Enjoy

[drcampbell]

Originally Posted by hemivolvo

... i went out on the interstate and was able to go approx 9 mph more than ever before ...

If you're getting 14% more speed, you're getting 40% more power. (and 40% more fuel burn per hour) Power is proportional to the third power of velocity, and fuel flow is proportional to power.

Originally Posted by hemivolvo

... if i see the higher temps i'm gonna turn down the pump 1/4 turn so as not to hurt any thing from what i understand 1250 to 1300 is ok just not above is that correct?

I don't know if 1300° Fahrenheit is the right number but it sure sounds like you're on the right track.
(I've heard 1200° more often)

Keep in mind you're testing & calibrating in November. When summer temperatures return, everything will be 50° hotter - the turbo will be drawing in 50° hotter ambient air, the charge-air cooler will have 50° hotter ambient air flowing over its fins to cool with, ...

[Evel486]

EGTs are exhaust gas temps. With intercooler, ambient temps will have minimal effect on EGTs.
40% more fuel burn per hour? I don't think so. He only turned up the max fuel. He may even possibly improve his overall mileage a tiny bit.
BTW- 14% more speed does NOT equate to 40% more power. 40% more power does NOT equate to 40% more fuel burned.

[444-4D]

Originally Posted by Evel486

EGTs are exhaust gas temps. With intercooler, ambient temps will have minimal effect on EGTs.
40% more fuel burn per hour? I don't think so. He only turned up the max fuel. He may even possibly improve his overall mileage a tiny bit.
BTW- 14% more speed does NOT equate to 40% more power. 40% more power does NOT equate to 40% more fuel burned.

The positive thing about a post like this is it usually results in the poster learning something.

[LMJD]

The positive thing about a post like this is it usually results in the poster learning something.

Right, what's that saying, a guy with experience beats a guy with a theory every time?