MAF Mod

[Hants]

All depends on driving style. Those that can keep out of it, won't see much of a change. Those who constantly drive WFO are more likely to see a gain. Closed loop operation is increased by the new MAF and, in theory, will maintain closed loop operation throughout a wider range of situations than before.

I think you may have just hit the nail on the head!

Since the MAF, I can no longer get into open loop unless I'm at WOT. Even just a smidge off of WOT under heavy load at altitude, it stays closed loop. The only other condition where I can force open loop is shifting into 2nd and holding high RPM at very heavy loads.

 

[corsair23]

You should have simply removed the vacuum line to the FPR, NOT plugged it.

The instructions say to pull of the vacuum line and plug/cap the ends that the line use to be attached to . Rick even includes the little caps, although they are way too long and need to be carefully and expertly trimmed down to fit...Just ask Matt

 

[Corbet]

I'd be very happy with 17.1. My "baseline" numbers are going to and coming back from Moab, where I'm typically in the 13.4 range.

I'm still stock height and tires. With a 4" & 35" I'm sure my 17+ would decrease.

Those that can keep out of it, won't see much of a change.

This probably explains most of it, however I'm constantly running wide open to get over the passes.

You should have simply removed the vacuum line to the FPR, NOT plugged it.

Do you notice difference when you're driving down the freeway?

I plugged them per instructions, you say no?

I have not really noticed real difference with how it drives freeway or city. I'd only say it "seems" a little more sluggish on the pass honesty.

Maybe I'll plug in my scanner on the way home to monitor some things.

 

[Hulk]

Mr. Corsair23 and I did my MAF mod yesterday evening. Not hard at all. The truck immediately ran better, just based on my own experience driving the truck every day. No hesitation off the line, smoother operation and shifting. Also, seems like it gained some power too.

I'm running 35-inch tires with 4.88 gears. No supercharger. It's a 1996. I stopped tracking mileage a few months ago, since my speedo is significantly off. I'll use the GPS to track mileage out to the Rubithon and get some numbers.

Honestly, I don't care about gas mileage in my 80 as much as I want more power. All the weight I've added to the truck has made it a beast. If I could find a supercharger, I'd probably buy it.

All in all, I think the MAF mod was worth every penny.

 

[Hants]

The instructions say to pull of the vacuum line and plug/cap the ends that the line use to be attached to . Rick even includes the little caps, although they are way too long and need to be carefully and expertly trimmed down to fit...Just ask Matt

My bad. Just checked -- mine IS capped.

There was a big discussion a while ago on MUD, and someone tried to deny LT's empirical results. I just mis-remembered which was which.

 

[Rzeppa]

I stopped tracking mileage a few months ago, since my speedo is significantly off. I'll use the GPS to track mileage out to the Rubithon and get some numbers.

I recalibrate mine every year driving to Moab. When I pass milemarker 100 on I-70 I write down the odometer reading. Then when I cross the Utah State line I write down the odometer reading. The difference between odometer readings from 100 miles becomes my new correction factor. Using so many miles gives very good precision. But then, I don't have a GPS

 

[nakman]

Overall, I'm fairly happy with the MAF mod. I'm not quite as blown away as, say, Nay is, but still this seems to make the truck run a little better. This morning going north on 470 between Morrison Road and I-70 I was able to hold that hill past Bandemiere, 70 mph without it shifting out of overdrive. Before to do this I would have had to have been in power mode, or turned O/D off. So I guess it's got a little more "stayin power..."

Looking forward to seeing some highway mileage next week.

 

[Nay]

I dig it. But...I run 5.29's and 35's, and NVH is way down at upper RPM, and it is shifting smoother at higher RPM's. It doesn't change the world, it's just enough with my *light* 80 that I'm in the left hand lane passing up Monument Hill vs. the right hand lane bogging. The rig feels right now, not supercharged or anything, but just more ready to pull, without the NVH, rather than always on that edge of bogging down, even with the low gears. That's a subtle change, but one for me that increases driving pleasure and makes me more willing to hit 3,500-3,700 RPM for brief stretches at 70 mph in 3rd vs. slowing down to that higher pass crawl.

IMO, very well spent $300...but...my 80 is a bit atypical (gear ratio/tire size, weight) so my experience may be outside the statistical norm. I do carry my whole family of six on long trips, and I'm pretty sensitive to NVH issues despite my tire choices , so this is a mod that hits home for me in the dual use arena.

 

[Hulk]

I have no idea what NVH is.

 

[DaveInDenver]

NVH usually means Noise, Vibration, Harshness.

 

[Hants]

Nevada Highway -- you're on one about now, aren't you?

 

[Hulk]

Nope -- leave next Monday. 5 days and counting.

 

[Crash]

Drove to Leadville for dinner yesterday and got a good chance to work out the MAF modded 80 into major headwinds all the way up there. SOTP impressions are that power has been enhanced, the transmission is now smarter and thinks more like me, i.e. it downshifts when I think it should and manual downshifts aren't required nearly as often. This was with the power button NOT engaged. At the elevations west of Georgetown, the engine was beathing much more easily and revved more freely with less skinny pedal required to accelerate or maintain desired speeds. As the headwind was major, I didn't fret about mileage so power was what was tested and the Landtank MAF mod gets two thumbs up from me in that regard. Mileage will be the test target in a couple of weeks when I head to Kansas City and it will be reported upon at that time. However, even with the headwinds and large doses of skinny pedal, we drove 198 miles on half a tank of gas. The winds had died down by the time we returned to Denver so didn't have the tailwinds on the way home.

 

[Nay]

NVH usually means Noise, Vibration, Harshness.

Yea, sorry, noise, vibration, harshness. My stereo is much louder now, conversations with a bit quieter

 

[Hants]

Another update:

I live at about 7300ft. Just returned on a trip from Colorado Springs to Pagosa Springs, about 280 miles each way, and the resort is at about 7500ft. Between, lowest elevation is about 4700, and you go through a couple of passes at about 10000 (10,800 & 9,400).

15.4MPG going there -- best ever
17.2MPG returning -- unbelievable!

The only time I can get into Open Loop is at or above 3,550 RPM and significant engine load, or at WOT.

Held moderate grades very well without downshifting. Had power to pass (slowly) when I needed to.

Engine/tranny shifted very well. Sometimes I felt that it didn't downshift soon enough, but by watching the scangauge, it was doing VERY well at maintaining better mileage. In a couple of borderline zones, I forced a downshift and had an immediate drop in mileage (sometimes >5MPG difference).

There were a couple of spots where it was obvious that the cruise control was going to do its "cut out" game. In those spots, I put my foot back on the peddle, and manually turned it off -- waste of gas to try to re-gain speed on steep grades.

On the way back, I didn't force 60MPH in 2nd on the passes -- kept it under 3550RPM to stay in Closed Loop (about 1/2 throttle!). Historically, I'd keep at 60-62 on the steep grades in second (about 4200 RPM).

I think I only passed twice on the return, probably 6 on the way there. Passing was: time the oncoming traffic, WOT about 1 second before the oncoming car cleared me, hold it until passed+100ft, back on cruise control. Didn't really worry about grades (none were on steep down or up grades). Speed post-pass was generally 80+.

Had the cruise control set at 65 both ways. Stopped for lunch in Walsenburg both ways, and stopped at the Brewery in Alamosa (owner is a Cruiser dude -- don't recall his name) to fill up my growler both ways. Both trips started in the morning and ended in the late afternoon.

Setting the Cruise at 65 versus 75 makes a material difference in mileage, and doesn't add much time to the trip. Keeping the RPM under 3550 (staying in Closed Loop) adds another real kicker to the mileage.

Does anyone still have the stock MAF & 33's? I don't recall tracking which conditions caused open loop with the stocker; I just remember seeing it in Open much more.

 

[corsair23]

Does anyone still have the stock MAF & 33's? I don't recall tracking which conditions caused open loop with the stocker; I just remember seeing it in Open much more.

Snif...snif...yep

Want me to check on something before I get around to the upgrades? Of the new MAF and housing that is.

 

[Hants]

I'd be curious to know the following:

1. Set your SG to monitor LOD, RPM, OPEN/CLOSED, TPS
2. Monitor OPEN/CLOSED LOOP as you're driving
3. At what RPM/LOAD/TPS combinations does it switch to OPEN loop?
4. When do you hit those combinations?

I used to hit Open Loop merging onto the freeway and going up even moderate grades. Now, I only hit Open Loop going up steep grades at high altitude (and then, only when I force 2nd and keep the RPM too high).

 

[Hulk]

Jeff, I still have your Scan Gauge II. I'll bring it to the RS meeting next week, unless you want it earlier.

 

[Red_Chili]

Man, I gotta get me one of them SGs.
Right after all the other things I gotta get. Like a second job.

 

[Hants]

Man, I gotta get me one of them SGs.
Right after all the other things I gotta get. Like a second job.

At current (and future!) gas prices, it could pay for itself in a few tanks, if you can use it to increase your MPG.

Being able to monitor my instantaneous and "today" MPG is really useful. I use it to test various driving "habits". It allows testing over short periods of time, and getting immediate feedback. No need to wait for a fillup (and thereby accumulating confounding data).

It also allows before & after monitoring as you make mods (like LT's MAF).