MPG fooler - Design phase

[JOHNFAK]

I think so... But now I want to play with the value a bit more and see about tuning in a good general value as a start off... .

[SASQCH]

Mike,What wattage resister are you using? 1/4 watt 1/2 wattI'm planning on setting up 2 dpdt toggles so on the first toggle I can switch fron IAT to other dpdt toggle and then set that up to have 2 resisters so I can have a choice of resistance.

[ISX]

ok - to play devils advocate ......

How come with the IAT/timing fooling and full advanced timing we (you) still can't get anywhere near ISX's 28mpg ......... I mean thats a 40% better MPG than our vp44's .........

[Mopar1973Man]

ok - to play devils advocate ......

How come with the IAT/timing fooling and full advanced timing we (you) still can't get anywhere near ISX's 28mpg ......... I mean thats a 40% better MPG than our vp44's .........

[JOHNFAK]

Well if I drove to Whitebird, ID I could hit 27-28 MPG... It all down hill... Seriously for all my test I've been trying to be fair but travel the same amount of distance up and down so the numbers will average out. So like a normal day of shopping would include a climb up Goose Creek Grade which has a speed limit of 45 MPH and corners of 20-25 MPH.

Yeah - no I think this is awesome. But since you and ISX talk alot by phone I wanted to add this in. I know he gets 28 driving all around his place (pretty constant elevation) in winter or in summer. Now this IAT fooling looks like its doing a great job of increasing your mpg for winter - but its not going to do anything for summer right - as the IAT's will already be high. So we VP44's seem to max out at 20-21 mpg. He gets 28 all day long - how come ?? A few things spring to mind 1) Whats the weight of your truck ISX - with those tires it just looked smaller than mine - but maybe it was just the tires ? 2) Is his 28mpg due to the smaller tires -> either a small calculation error with larger distances due to smaller tires - or the tires themselves ? He doesn't have a scanguage to adjust his tire size right ? 3) Something else outside of timing/IAT ........ as he doesn't have it yet still gets good numbers. I mean he's pretty much stock in those terms and still getting good numbers. If we we stock we would be only 17mpg highway. etc

[Mopar1973Man]

Few other factors...

[*]24V 98.5 to 02 have the lower compression ratio ever in all Cummins ISB engines. (16.3 or 17.0) Where the rest of them ar 17.5 and up... ISX knows the numbers.

[*]VP44 has dynamic timing that will constantly change to road load, temps (IAT) etc. Where Ppump is static and never changes.

[*]I think ISX truck is a bit shorter in height and weight a few thousand pounds less (Guessing here).

[*]MO. Is for sure more flat than ID. is...

[*]Fuels could be a factor I'm not certain if ISX's winterized fuels are as aggressive as up North.

[ISX]

Well the 1-2 off onw I contribute to the fact...

[*]I'm running all petroluem lubes so they are thick in the cold temps longer.

[*]Cold air is more dense so there is a taste more drag.

since your a 2WD ISX I think you frontal area is a bit less than my truck being I'm nearly 7 feet to the roof of the truck where 2WD are typically a foot or so lower to the ground.

But my summer typical has usually ranged about 20-21 MPG this last summer.

What's funny is in the summer when I got the same mileage, that was with amsoil.. Now it's winter and running conventional premium blue I get the same numbers.

I got my winter results at the same freezing temps so that throws that out.

Frontal area might be something but I have a big brush guard and towing mirrors to add to it.

Yeah - no I think this is awesome. But since you and ISX talk alot by phone I wanted to add this in. I know he gets 28 driving all around his place (pretty constant elevation) in winter or in summer. Now this IAT fooling looks like its doing a great job of increasing your mpg for winter - but its not going to do anything for summer right - as the IAT's will already be high. So we VP44's seem to max out at 20-21 mpg. He gets 28 all day long - how come ??

A few things spring to mind

1) Whats the weight of your truck ISX - with those tires it just looked smaller than mine - but maybe it was just the tires ?

2) Is his 28mpg due to the smaller tires -> either a small calculation error with larger distances due to smaller tires - or the tires themselves ? He doesn't have a scanguage to adjust his tire size right ?

3) Something else outside of timing/IAT ........ as he doesn't have it yet still gets good numbers. I mean he's pretty much stock in those terms and still getting good numbers. If we we stock we would be only 17mpg highway.

etc

I will have to run into town at night where they leave the scales on at this one place and see what I get.

Tires are the stock 245/75's.

Few other factors...

[*]24V 98.5 to 02 have the lower compression ratio ever in all Cummins ISB engines. (16.3 or 17.0) Where the rest of them ar 17.5 and up... ISX knows the numbers.

[*]VP44 has dynamic timing that will constantly change to road load, temps (IAT) etc. Where Ppump is static and never changes.

[*]I think ISX truck is a bit shorter in height and weight a few thousand pounds less (Guessing here).

[*]MO. Is for sure more flat than ID. is...

[*]Fuels could be a factor I'm not certain if ISX's winterized fuels are as aggressive as up North.

Now throw into the equation that Thracing gets 22 at 60-65 with his 4.10 Dually In canada's cold and his is a 24V.

I need to get Guesswho to test everything since his truck as identical to mine in every way and we see about the same temps and terrain.

As for timing. I made this. Basically I enter a baseline which if stock is 13.5 and we have a range of about 700-3000RPM, then you can average that out to 1850, use the time it has to go from 13.5-TDC as a baseline time, and figure out what timing would have to be at at all other RPM's to equal the same time. Pretty interesting.

On the left it shows all the specs of 1850RPM at 13.5* Timing and the "Injection to TDC Time" is what the very right column matches. The 2 columns to the left of the very right are actual times if the engine was at the baseline timing the whole time (like 12V's are).

[JOHNFAK]

Few other factors...

[*]24V 98.5 to 02 have the lower compression ratio ever in all Cummins ISB engines. (16.3 or 17.0) Where the rest of them ar 17.5 and up... ISX knows the numbers.

Didn't know about the compression ratio - how come ??

[*]VP44 has dynamic timing that will constantly change to road load, temps (IAT) etc. Where Ppump is static and never changes.

Any way to mimic this for vp44 ? I thought even though his timing was static - it was still not fully advanced.

[*]I think ISX truck is a bit shorter in height and weight a few thousand pounds less (Guessing here).

Yeah I am curious on this one also ... common fella - give us the facts

[*]MO. Is for sure more flat than ID. is...

Have you ever got a run on cruise control over some distance thats relatively flat ? I see most VP44's maxxing out at 21mpg and a couple 12v's have said 26-28mpg - various countryside north and south

[*]Fuels could be a factor I'm not certain if ISX's winterized fuels are as aggressive as up North.

Yeah - but plenty of MO people driving vp44's and I never heard above 21 ...... and then we are comparing apples/apples .... its just the vp44/12v thats the difference then.

Some thoughts

[ISX]

Some thoughts

It has been down to -2F and the fuel didn't gel or anything, I don't add any additives. I have gone from here to detroit at 70, got 21mpg. Here to Denver at 70, got 21mpg. Here to Nebraska at 70, got 21mpg. I seem to get 21mpg at 70 Cruise was set going to detroit.

[AH64ID]

Interesting read. The couple thoughts I have are the reason for the boost difference is timing. Advanced timing makes less boost that retarded timing for the same fuel. But the interesting thing on that is advanced timing makes more power, and thus better mileage. So I wonder if your going past the most advantageous timing with the quad box and the fooler?

Few other factors...

[*]24V 98.5 to 02 have the lower compression ratio ever in all Cummins ISB engines. (16.3 or 17.0) Where the rest of them ar 17.5 and up... ISX knows the numbers.

These are the numbers I have found.

89-93: 17.1:1

94-98: 17.5:1

98.5-02 SO: 16.3:1

98.5-02 HO: 17.0:1

03-07: 17.2:1

07.5-curr: 17.3:1

[ISX]

Interesting read. The couple thoughts I have are the reason for the boost difference is timing. Advanced timing makes less boost that retarded timing for the same fuel. But the interesting thing on that is advanced timing makes more power, and thus better mileage. So I wonder if your going past the most advantageous timing with the quad box and the fooler?

Weird thing is that when I advanced my timing, I could get 3-4psi more out of it. The advanced timing gives it more power up high, when I put it back to stock I had a big bump in low end power that I hadn't realized I lost.

As for compression. Those numbers are all over the place on the net, not sure how they always end up so skewed. According to cummins quickserve, the SO 24V is 16.5 and the 94-98 is 17.9. I don't know if the 1st gen's are any different, I need an engine number to look them up.

[AH64ID]

As for compression. Those numbers are all over the place on the net, not sure how they always end up so skewed. According to cummins quickserve, the SO 24V is 16.5 and the 94-98 is 17.9. I don't know if the 1st gen's are any different, I need an engine number to look them up.

I just noticed a typo in what I wrote. I have HO 98.5-02 at 17.0:1. The HPCR and 98.5-02 numbers came right out of the OE service manual. I don't recall where I got the others, but I try to remember.

[ISX]

I just noticed a typo in what I wrote. I have HO 98.5-02 at 17.0:1. The HPCR and 98.5-02 numbers came right out of the OE service manual. I don't recall where I got the others, but I try to remember.

I don't know what to believe with compression ratios since everyone is posting different numbers all over the place. I am just gonna have to measure it some day. The OE service manual also says max fuel pressure of 25psi for my truck which is a load of crap.

[AH64ID]

Yeah its a bummer they have so many errors. My 05 SM shows my truck as making 600 ft/lbs at 1400 rpms, when really its 610 @ 1600.

[guesswho512]

isx...what do you need me to get for you?

i thought the 24 valves had different pistons.

Information obtained from TDR issues and Chrysler Master Tech No 2 February 1998.

[*] New piston design features a symmetrical combustion bowl

[*] (combined with vertical centered injector and higher injector pressures) for improved power, fuel efficiency and oil control

[*] New vertically housed thermostat is easier to access for service and has fewer leak paths for improved in-cab heating

[*] New electronic fuel system improves engine control, driving performance, engine cleanliness and provides engine/vehicle diagnostics

[*] New Bosch VP44 Electronic Fuel Injection Pump has higher injection pressures, electronically controlled timing and fueling for precise, instant control. The pump is driven at half the engine speed by the front gear train to reduce operating noise

[*] New engine-matched Holset turbocharger is custom-designed for high-speed ratings and wastegated for improved engine performance at all speeds

[*] New fuel filter has an integral water separator and water-in-fuel sensor. An environmentally friendly cartridge is rated at five microns

[*] New 24-valve cylinder head produces improved air and coolant flow, more torque over a wider range and improved fuel economy with reduced emissions

[*] New valve train has wider lobes on the tappet face, on the cam, and longer push tubes.

[*] To reduce camshaft wear, an electric lift pump eliminates the need for a mechanical lift pump lobe.

[*] The 60 pound standard valve springs are compatible with engine braking

[*] New single-piece valve cover allows faster access and easier servicing

[*] No-adjust overhead has improved lubrication and requires its first check at 96,000 miles to reduce scheduled maintenance

[*]The EGR valve (CA) and catalytic converter are eliminated.

[ISX]

isx...what do you need me to get for you? i thought the 24 valves had different pistons.

[guesswho512]

I need to get Guesswho to test everything since his truck as identical to mine in every way and we see about the same temps and terrain.

[ISX]

this is what i was asking what i need to get for you i think a quadzilla adrenaline is in my future, assuming the VP44 doesn't dive on me

[flagmanruss]

I'm 01.5, SO, automatic... I guess I got screwed on compression. Or does that mean I just NEED to buy a bigger turbo to compensate?? LOL!! I've NEVER seen 20 mpg with my 4:10 gears. Not even running empty, babying it... I'd sure like to keep summer MPGs all year long.

[Rogan]

12v and 24v pistons are almost identical, with exception to bowl shape and size. The latter one has a centered bowl with an angled dome in it. A 12v has an offset bowl to account for injector placement, and it's center dome is ramped on one side where the injector sprays. Cr I don't know.