Grumpy

8.5:1, barrier coated pistons, 4.1L, v6, mild cam,

Map
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95100Rpm

80 80 80 80 80 80 80 80 74 68 68 68 68 68 68 68 68; 400
80 80 80 80 80 80 80 80 74 68 68 68 68 68 68 68 68; 800
68 68 78 68 80 80 80 80 74 68 63 63 63 63 63 63 63;1200
68 68 68 68 74 78 87 90 81 74 74 74 74 74 74 74 74;1600
68 68 68 68 74 78 87 87 87 87 84 84 84 80 80 74 74;2000
68 68 68 68 74 78 87 90 90 87 84 84 84 80 80 74 74;2400
68 68 68 68 74 84 87 87 84 77 74 74 74 74 71 71 71;3200
68 68 68 68 68 68 68 68 68 68 68 68 68 68 68 68 68;4000
68 68 68 68 68 68 68 68 68 68 68 68 68 68 68 68 68;4800

To get the approx timing in degrees divde by 3.
Yes, this is a low timing chip, and get great gas economy, when not in boost.


To get the approx VE divide by 3.

Map:
30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 ; RPM:
86 86 86 86 88 96 98 100 100 100 100 100 100 100; 400
86 86 86 89 94 96 98 100 100 100 100 100 100 100; 800
105 120 125 130 135 150 160 160 160 160 160 160 160; 1200
120 135 135 135 135 140 150 160 170 170 170 170 170; 1600
120 130 130 132 135 143 145 160 165 170 175 180 180; 2000
115 120 130 130 133 143 143 152 155 160 175 180 180; 2400
110 115 125 125 125 135 140 140 155 160 175 175 175; 3200
90 90 110 120 130 130 140 140 155 160 175 175 175; 3600
90 100 110 120 125 125 155 155 165 170 175 175 175; 4000
90 100 120 120 125 125 155 155 165 170 175 175 175; 4400
90 100 120 120 125 125 155 155 165 170 175 175 175; 4800

In the interest of not boring folks I cut out every other rpm row, and the low K/Pa region of the VE table.

Will do 25 PSI on 93 Octance no intercooler, no alky injection.

The boost multiplier table however is classified.....

While others have taken to lean with alot of timing, to get decent mileage, I've gone the other way. Tad rich, without much timing, and it also works, at least for me.

JPrevost

So you like the coated pistons . I'm sold on them but the combustion chamber is a different story.
Just curious, what stall TC do you have? I've found that with my rear gears and high loose stall TC that I can't tell the difference between slightly rich and less timing vs lean and more timing. On the highway it gets the best milage with 6 degrees less timing than it's capible of handling (knock sensor) which I just accept as good enough.
What's the mild cam grind? If you don't want to release exact specs then could you compare them to stock (ex. more dur on in, higher lift, etc).
I'm excited about your ride. Is the cost still a quarter?

Grumpy

Pistons domes, chambers, and exhuast ports if you want the fine details.
It's about 3,000 stall. With TCC.
Least amount of timing with max results is, IMO, the rule.
206/206, at 050, .~.510 lift.
Maybe up to 30 cents due to the rising fuel costs. With Alky on possible 33 cents.......

RednGold86Z

iTrader: (1)

Hey Grumpy,
Haven't done a search to see what the answer is, but I was just wondering what your theory as to why less timing equals higher mileage.

My theory: Don't tune part loads for near knock. The way an OEM should and does calibrate is for MBT, or Minimum Best Timing (or torque). There's a curve where the same (about the same, cresting over a curve) torque can be produced from a varying amount of timing, and beyond the curve (more advanced) you'll reach knock (except WOT, where often, the engine is knock limited so more timing is good until knock).
Other than that, I can't seem to comprehend how less timing equals more mileage. I definitely don't think there's a rule of thumb where you can simply reduce timing to increase mileage, do you?
Just picking your brain and trying to get the board filled with good stuff.

jeepguy553

I'll second this one! I am about to get into upper end tuning on the Jeep and this is precisely what I want to see. If I can tune the upper end stuff for max performance while keeping the mileage down low, I'll be a VERY happy camper...or Jeeper.

Grumpy

This whole theory about being knock limited goes back to the days of the Flat Head Fords, and running 60 Octane gas, IMO. As well as cold engine temps..

You can get really good performance out of 87 octane, and running a 180dF thermostat. The ONLY reason I use the higher octanes is for the better additive package. ie less carbon build-up.

Interestingly enough, Hot Rod TV, made mention of the fact that the flat head fords, would make lots of power with a coolant temp of 146dF, and then severely detonate at 148. And I'll venture a guess, that's where alot of the colder is better theory started. While yes, in some cases you can go faster with a cold thermostat, it's not for the reasons, suggested, IMO.


MBT holds true for everything.
I've been saying that for eons.


Way too often folks get into the trap of the thought of being knock limited so the always just automatically go to that region, and it's easy to tune there, all you have to do is run against the knock sensor. And if you have enough fuel, you can even start changing the acoustic signature of the engine to fool the knock sensor. So then the motor winds up with so much fuel the compression ratio is even increased, and with all the timing it feels responsive, so the tune is considered good, when in fact, it's hammering the bearings out of the motor. Watching one's oil pressure can be a godd indicator of how hard your actually working the oil. The chamber temps., to some degree are passed into the crankcase thur the piston dome, also.

I tune for min TPS and highest oil pressure when in light load conditions, and so far, it's given the best results. I'm blind to the amount of timing I'm giving the engine, and just when I'm done, look at what the actual amounts are. IMO, you just have to really do the Zen thing, and give the engine what it's telling you, without trying to force it to do what you think it should be doing.

Now, with all that said, you do first have to make sure the engine is peak condition. ie, no blow-by, or if there is, then use a GOOD oil vapor/ air seperator, and details like that. And a Zero cracking check valve in line with the PCV valve on any blown application is a must.

It's details, details, details, that get the tune right.
While folks often mistake my trying to impress the details end if things as me having an attitude problem, it's not. Watch folks like George Bignotti, or the winning engine guys at Indy, NASCAR, or the NHRA guys away from the track, and you'll see what details are really about. I say Indy engine guys, meaning back when they actually did engine work, rather then just swapped the engine out as a component.

You can tell a winning, Tuner, Engine Builder, Body Guy, by the way they work. It's a thought process. First about what the desired result is, and then how to achieve it. Then one works on how to impliment things. Tuning isn't just about tuning, it's about the discipline that goes with doing it. Well, if your after peak results.

Well, sorry to get side tracked.........

CrazyHawaiian

That was awesome.

yager

Excelent comments... this deserves a bump....

my new searching strateogy is <topic> and user = grumpy so far its giving the best results... Thanks !!!

Any other good milage tuning threads out there?

or possible some new ideas?

JPrevost

https://www.thirdgen.org/techbb2/sho...hlight=mileage

DM91RS

Since you are sidetracked have you ever heard of Jim Ruggles?

Grumpy

Yes, I've heard of him.

I friend cross town has one of his engines in his GN.

Grumpy

SEFI, and being able to control the injector timing. It beings tuning to a new level. It's amazing how it effects AFRs, and EGTs.

DM91RS

Ruggles shop used to be within shouting distance from where I used to live. Went there one time with a bud and bought some sort of oil pump plate for a Buick V6. Seen a twin turbo 275ci. on the dyno. 1200 hp.

Shop was full of Nascar Busch V6's week after week at this time.
He got a new Grand National every year back then.

Several people from his shop came to work at my employer after Buick pulled out and he folded.

Later DM