Well gang... I've been playing with theories and ideas for long enough now its time to put them into a design and see if it actually works. We all know the 24V's seem to take a good tumble in MPG's as the winter sets in well ISX proved that with the 12V engines with static timing that MPG's don't change. Well if you look at it the only thing that could be tossing this out the window is the IAT sensor on the 24V is changing the VP44 performance. Most know that colder air produces better HP/TQ because colder air is denser and requires more fuel to keep balanced. Well if you reverse this and warm the air (in theory) the VP44 should retune and burn according to the manifold temp. So what I've done tonight is fished through my resistor pile and found 3 I'm going to use for test candidates. Orange - White - Red - Gold = 3.9K Ohm = 116*F IATRed - Violet - Red - Gold = 2.7K ohm = 132*F IATRed - Black - Red - Gold = 2.0K ohm = 148*F IAT So now tomorrow I'm going to pull 3 test runs on the same piece of highway... Seeing if the highier the IAT temp increases the MPG or not... I'll can give you something to think about... Grid heaters are NOT controlled directly by the IAT... With the 2.7K Ohm resistor in place before even starting the grid heater still where hitting as normal. So there is more to the grid heater that the IAT temps... ... On the cutting edge again...

OK, I'm confused. I used a Radio Shack DPDT switch. I thought all such switched the active contacts were opposite the toggle position. When I soldered the wires on, it seemed according to the multi-meter that the active contacts were in the same direction as the toggle. Which is it?

  flagmanruss said:

OK, I'm confused. I used a Radio Shack DPDT switch. I thought all such switched the active contacts were opposite the toggle position. When I soldered the wires on, it seemed according to the multi-meter that the active contacts were in the same direction as the toggle. Which is it?

The DPDT switches I have used had 6 solder contacts on them. The two in the center were the common contacts and switched to the two on the right when the toggle was moved left and switched to the left when the toggle was switched to the right. I suppose that the one you have could be built so it switched to the left when toggled to the left and to the right when switched to the right, not seen one like that yet though. Check it out with the meeter and believe what the meter tells you. Jim

Hi Guys,It's not all that cold out. Outside air temp 50-60, not appreciable wind, down to sea level, uphill coming back, some hills. I have my IAT fooler installed. I had to make the same route yesterday & today. Reset my overhead (still running stock mode) was AVERAGING 16.8 with about a 1 mpg dive on each the cold start & local miles (1 start to go there, sat all day, 1 start to come back)... about 100 miles for the day. Today with the IAT fooler on, the average only dropped .2 on the cold start & local roads & without resetting the overhead brought the AVERAGE up to 17.4 for both days (100 miles + 100 miles). Not only was it better than yesterday but it improved the average for both days. Mathmatically, to bring up the 2 days average by that amount, it has to be a 1 mpg improvement... but it is still a small sample.

Well I made my run down to Boise ID/Ontario OR and pulled roughly 12.8 MPG with the MPG fooler in place and set for 140*F. Not to mention having the water tank on the trailer loaded both directions (466# more). Now I know most of you can pull better number with +15,000# GCW but here in Idaho everything is up and down hills and twist and turns. So I'm tickled to death to pull this much weight and get nearly 13 MPG going from as low as 1,500 feet to as high as 4,800 feet in places. I would like to say thanks to Caj... Another secret... Set a high mark boost limit and hold to it. Like I know I can set my cruise for 60 MPH and climb iany grade I want. Boost will nearly smack the pin at 32-33 PSI. Like Caj told me be nice to your ride and limit you climbing boost to 20 PSI. Well I tried it and you climb most grades in a grade lower but pyrometer temps are roughly 300*F cooler and fuel usage is less. Like Midvale grade climbing over it I'd drop from 5th gear to 4th (direct 1:1) and run it up to about 1,900 which in turn puts me at 45-50 MPH and it just walks right on over the grade. Now mind you. All this travel I've done with my Edge Comp on 5x5 which even says is too mach and will cause pyormeter problems or clutch problems. None of the above... Ran great and never had a problem with pyrometer heat at all if you use a 20 PSI boost limit. Now just pouring the fuel it by the time I get to 4th gear I'm heading to 1,000*F once I get to 5th I can push that pyrometer as far as I want past 1,200*F but that's just plain wasteful. So letting it sag back 1 gear and climbing in 4th is excellent. Funny part is I get people whizzing around me like I'm a big semi truck. I drive this way because fuel is expensive and it sure nice to be able to go farther with less fuel... So you have to use the slow lane... So what... So people get a bit impatient with you holding up traffic... so what... But it's priceless to haul that much weight and do it for less...

Nothing wrong with the right lane... I only get frustrated if the truck is struggling. As long as we're getting down the road, getting better mpg / saving money can be it's own reward! Takes a whole lot of the sting out of being passed.

Tidbit of playing... I've now tuned down to 110*F as the weather warmed up and gaining even more MPGs... Like I said this only the design phase I'm playing with the temp setting and see the result differences... I'm closer to 23.5 to 24 MPG making a trip to New Meadows, ID to get propane. No topper! Winter fronts are now off for the season.

It there a socket that could be soldered to the switch which would accept a resistor? Do you feel that the 140 resistor would be better winter setting over the 110?

Don't jump yet... I'm playing with different values and check to see the results of each. Then I might even try plugging the sensor back in and try that too... Got a funny feeling that will reduced the number slightly when the sensor is cold.

  mrtowman4u said:

I got the mpg fooler in and installed that I got from Winslow! Was working on some numbers for a 3500 truck, but all that got cancelled due to my tranny going out! Going to take the tranny out prolly tuesday and see if the dude is going to replace it! After that I will get some numbers!

Any luck yet??

The beauty of haviing the IAT fooler on a switch is that one can throw the switch & return to the sensor. It might well be that fooling is only useful to beat the warm up cycle, but once the engine temp is normal switch back to the OEM sensor. While we are talking about air temps... as I was working on this, I got in a position where I could see under the back edge of the hood. I'd always "assumed" that the rubber piece on the cowel edge contacted the hood forming a gasket seal. It does not on my truck. I think it's more of a dam/diverter to keep water from getting on to the engine, electronics, components (also the lower edge fiding the various unsightly harnesses). If there is a gap here, hot underhood air will exit, perhaps de-icing the windshield. Then again it exposes the cowel air inlet to fumes from under the hood... Just an observation...

Actually is was to keep the engine fumes from entering the cab more so. Like I'm still starting my morning temps at 35-40*F but getting to a daytime high of 60-65*F. Thats one of the strange things of Idaho the night time lows rarely get above 55-60*F but the daytime highs can be near 85-90*F here at the house. This is a annoyance to me because it always cold enough to trip the grid heaters every morning. Thing is it still runs through my head that none of the 12V engine had any IAT control for the injection pump only for the grid heater. The injection pumps have a static timing (p-pump). So trying to follow ISX truck for MPG's and performance. It's possible to reduce the loss of MPG during cold weather.

Well, the p-pump had no variable timing and the VP44 does. So we have to tell the VP to do something. I imagine it has a default setting if the input is lost & almost certainly it's not what we want! I can't help but think that the electronic injection adjustment is as much about SMOG as it is about effiency. We want to flip this priority!

I remember when the smog sniffers first came out, a guy who owned a garage put his 64 Chevelle 6 cylinder on the sniffer even though it wasn't required. The 6 cylinder Chevy was almost unmeasurable, compared to the (then) latest smogged engines. What have we gotten for all this "smogged" engines, detuned, loss of power & efficiency... an energy crisis!

It seems to me (my fogged brain)... that an efficient engine is not incompatable with "clean". I don't want to pour my $4.29 a gallon fuel into the atmosphere... I want to do the job I bought it for, without wasting a drop of it.

OK, somebody help me down off my milk crate before I fall down...

Russ

--- Update to the previous post...

Jim,

You made the comment, that the trigger for the timing is 130 degrees IAT. I am very interested in if this figure is reliable & if your data source is something we can access? It might save us a lot of trial and error!

Russ

  SASQCH said:

I think that Mike has proven that with the IAT fooler. With colder intake temps the ECM advances the timing in an effort to warm the engine (combustion occurring earlier causes the engine to fight the compression stroke and retain more heat). When the fooler comes into play and feeds the ECM info that the intake air is over 130 degrees the ECM retards the timing giving better winter mileage.

Jim

Jim is actuall on to something because as winter fuels are used the cetane is increased slightly to about ~45 cetane. This means the fuel ignites at a lower temperature easier. So with over advancement it would be like Jim is saying it would fight the pre-ignition more so. (heavy rattling noise). So using the theory of the +40*F offset to the 2nd Generation 24V engines this would give... Outside Temp - IAT Temp 30*F - 70*F40*F - 80*F50*F - 90*F60*F - 100*F70*F - 110*F80*F - 120*F90*F - 130*F100*F - 140*F I know the IAT temp to outside is NOT linear rise like I'm showing actually around 30*F there is a +50*F offset and round 90*F there is a +30*F offset. But I agree with you Russ the VP44/ECM is programmed for smog emissions. So it a matter of fooling the ECM it the direction that is the most efficent for us as owners. I really can careless about emissions because knowing I'm using less fuel I know that I'm creating less emissions too. Emissions can't be created from thin air... (Giving Russ a hand off his milk crate)

I just got my high idle/mpg fooler modified to where I wanted it. The four controls on the right are for the mpg fooler using 2 momentary swithes to activate a DPDT relay which puts the 5k pot inline instead of the IAT sensor. (the black one activates it and the red one is to cancel it. It cancels when the ignition turns off) The bottom right is the 5k POT and the top right is an indicator light for when the fooler is active. The 2 toggles in the middle are for the high idle. I used one DP3T switch to replace the 2 that previously controlled the IAT fooling. Then the 2 on the left are my mystery switch with the top one being an indicator light for when it is activated. I know the labeling looks pretty tacky for now but I'm thinking about how to improve that. I can post up the wiring diagram if anybody is interested. Got the wiring diagram attached here now.

Nice looking set up, VW!I admit I'm confused by the IAT temp offset business. I don't know what parameters beyond the IAT that the ECM uses to adjust the timing. I'd like to find a single IAT value so I could use a single IAT fooler. Life should be so simple. This is a long thread with a series of small experiments. I was reviewing these several tests but the conditions vary so it's hard to draw overall conclusions beyond the immediate experiment. A basic of the "scientific method" we all learned in school, is to only vary one factor at a time. But if the environment changes (Winter into Spring) then that changes a second factor. So what caused the change in the results? Is the MAP sensor or the Coolant temperature a factor? On another note, I have tried to research the Quadzilla XZT+. I don't know with a certainty if the economy mode affects the overhead MPG averages, but the power setting does according to posts. So I've got to hand calulate mpgs now. Russ

MAP sensor and Coolant temperature both have bearing on the VP44.

MAP sensor is going to be a measure of how much fuel to boost pressure. Once again it varies for me because my Edge Comp has the final say in way the boost pressure does in relation to the VP44 fueling map. The amount of boost is going to relate to the amount of lead in your boot and how fast your traveling like me with my 55 MPH habit now I typical see about 1-4 PSI of boost on flat ground. So boost is rather meanless to me too. Now the picture changes for me towing trailer now I'm 8-20 PSI.

Coolant Temperature also has a effect with timing with a cold engine too. But if everyone is using a stock 190*F then the value is rather meaningless because this is where it matches. Typical engine temperature will vary about 193-197*F regardless of weather. It's just the cold start that is different.

So now the only sensor IAT that floats around to relationship to outside temperature that weather DOES effect directly. But the funny part now going back to the old 12V days now those pumps had no relationship to coolant temperature or manifold temperatures. They just pumped fuel regardless of what the weather is so being we can gain control directly of one sensor and fool the ECM into thinking its summer why not... The coolant temperature is the same summer or winter (except for cold starts). So now everything should act like a 12V in theory.

Like here in Idaho I'm still seeing snow in the high country (>5K Feet) I'm still seeing temps as low as 36-38*F in the morning but seeing high temps of 65*F now. So I'm seeing spring but my mornings are like winter time but my day is like late spring.

Night time lows (May 2011)

Daytime Highs (May 2011)

Here is a slightly off topic, but relevant, tidbit of info. I recently learned the Quad max mileage module for the 3rd gens is an IAT fooler that adds up to 3° of timing advance...The only thing I don't like about the IAT fooler is the IAT's are no longer accurate on the SG, and I watch them like I do boost/EGT's.

Thanks guys for the enlightening discussion.

I have noticed via the overhead (when stick & with XZT set to 'off')... I keep the display set to AVERAGE. On a cold start, the AVERAGE would drop ~1 mpg (one whole mpg) for the stock engine & no IAT fooling. With the IAT fooler only activated, the cold start drop is .1-.2 (one tenth of one mpg) So it is having an immediate effect. If there are some other factors they are relatively minor.

My temperature gauge runs slightly left of the centermark unless I'm towing... but without a scan gauge there's no way to confirm the exact calibration of the dash gauge. But once warmed up, the engine coolant temperature is almost a constant value.

AH, That is an interesting point about the Quadzilla Mileage Max (#rd Gen) being a IAT fooler. One might conclude that the other Quad products like the XZT+ would likely incorperate the same technique. Is it unnecessary & maybe counter productive to run an IAT fooler if one has an XZT+? I have sent a querry to Quadzilla... I'll let you know what I learn.

"I have sent a querry to Quadzilla"Good idea, I'd bet that the R&D people at these tuner companies may have done a lot of the leg work on something like this for us. We may find that some milage specific tuning boxes do something like this already.

To: Jeremy McCann, Quadzilla

Jeremy,

I have a question on my new XZT+. I have been running an Intake Air Temperature fooler, a resistor which minics a warmed up engine which improves mpg on a cold start. I am wondering if the XZT+ also fools IAT if so I'm thinking that both should not be run together.

Please advise.

Thankyou for your assistance,

Russell

reply:

Russell

The XZT+ does not fool the IAT in any way.

Jeremy McCann

Quadzilla Tech

1-888-842-6572

jmccann@quadzillapower.com

www.quadzillapower.com