John,
The 20% for '06 is for the Rams with the Hemi engine. The Rams will have the same MDS (Multiple Displacement System) that is used in the 300C/Magnum/Charger series.

MikeyB

 

yep, it is for the V8 hemi's only. It is called the Hemi 'C' for the Chrysler 300 car .

Wish they could do that with the Cummins, but shutting off cylinders would make it mechanically unstable. Only works with V-engines like V-6's and V8's and v-10's becasue the two sides of the engine share crankshaft positions. Ford and Chevy could do this with their diesels and increase milage. It is a briliant idea.

 

not really... all they would need to do is kill 3 cylinders at a time though... always the companion cylinder of the ones running...

so..
1 or 6
2 or 5
3 or 4

but it would need to be a rotating cylinder cut off though i think. so it would cycle which cylinders it had cut out while crusing. the engine will run fine on 3 cylinders, but it would just sound a little louder.

something different, at work on the ge fdl series diesels i work on that have EUP's on them, for emissions idle, it kills 12 cylinders out of 16.. makes the engine lope a bit

 

yea, you could be right, however a 6 cylinder engine would be unstable wouldn't it. Not sure how to properly word this, but with a 4-stroke 6-cylinder (like a Cummins or any other in-line 6 cylinder), there is a combustion stroke every 120 degrees (or 3 combustions per complete rotation).
If you cut down to 3 cylinders you would only have 1-1/2 combustions per complete rotation, or 3 combustions per every 2 complete rotations . Mecanically you create a slight vibration which could be destructive at higher RPM's, correct? Not sure how the Cummins handles this, but the Hemi still has 2 complete combustions per rotation with the HEMI C engine and is completely stable in doing so.

Does the Cummins have companion cylinders (cylinders that share crankshaft positions?) I thought each piston had it's own crank position (6 separate positions), but I could be completely wrong.

 

That would be very complicated on a I6 like the Cummins. The V8 is much easier. DC picked only 4 cylinders to shut down by turning off the injectors and parking the valves open. It's hard to tell when the event happens. I hear a slightly different exhaust tone when the computer switches to 4 cylinder mode.

MikeyB

 

On a I-6 engine, 1 and 6 cylinder, 2 and 4, 3 and 6 share crank positions sort of speak, although they are 180 deg out on combustion event.

So, 1 and 6 go up and down together except when 1 in under compression 6 is exhausting.

The firing order is "15's to young(1-5)36 is too old(3-6) but 24 is just right(2-4)....thats how i now remember it" (iker42)

 

true, but crusing speed with no load isn't really a high rpm. there are many 3 cylinder diesel engines around in industrial applications running pumps and generators.
they don't share a common journal, but there are companion cylinders. 1-6, 2-5, 3-4. when 1 is up 6 is up, when 2 is up 5 is up, when 3 is up 4 is up.
here is a link to a drawing of a inline 6 crankshaft. you can see the 7 mains and 6 pins...

i just remember it as 1-5-3-6-2-4..
6 is easy to remember...
16 is a little harder. on the emd engines at work, most are 16 cylinders...
1-8-9-16-3-6-11-14-4-5-12-13-2-7-10-15

 

I would think that the advanced timing would be more for the 610 guys to get back some of the lost fuel economy from the 555 engines.

You could probably get some improvement in your 555 engine, but not as much as the 610 guys could get.

 

You're probably right.
But I'm enjoying the extra low end grunt! Waiting for Quad to get the new timing only box on the market.

MikeyB

 

"That would be very complicated on a I6 like the Cummins. The V8 is much easier. DC picked only 4 cylinders to shut down by turning off the injectors and parking the valves open. It's hard to tell when the event happens. I hear a slightly different exhaust tone when the computer switches to 4 cylinder mode."


Errr.... actually it is quite easy to run a Cummins on 3 cylinders and actually, the ISBes do it under cold warm up operation. 3 cylinders running more fuel will warm up faster than 6 cylinders running less fuel. They don't park the valves open, but it wouldn't be hard to do so. Just override the rocker arm with an actuator, kind of like a Jake brake does, only differently, if that makes sense.

My source for this info is Quickserve. (The fact that ISBe warm up on 3 cylinders.)

Another 6 cylinder engine that does this is the Cat 3126.

Anyone got conclusive MPG numbers for the timing mod ?

 

Something doesn't add up here. Rocktech is claiming 2 degrees with 80 thou removed from the sensor. From what I can tell, removing 80 thou from the sensor is going to advance the sensor face 80 thou. 80 thou = 2mm. I'm assuming the sensor still sits flat in its holder and isn't pointing in a different direction.

The dia of the tone wheel is 210 mm, so the radius is 105mm. The advance in degrees is thus

sin(adv) = o/h = 2mm/105 mm adv = asin(2mm/105mm) = 1.09 degrees

To get 2 degrees of advance, we would need:

sin(adv) = o/h o = sin(2degrees) x 105mm = 3.66mm or 144 thou.

Now, people slotting the tone wheel dowel:

sin(adv) = o/h o = sin(2 degrees) x 22.5mm = 0.785mm = 31 thou.

The easiest way to do this exactly might be to measure the dowel pin hole and then carefully drill it 62 thou oversize. 31 thou is not much material. Judging by the comments the tone wheel people are making (more rattle) compared to the sensor mod people, I'd guess that they are advancing the timing more.

I find it interesting that there is play in the dowel hole. If I had a truck that was getting poor fuel economy, I'd advance my tone ring as much as I could.

One mroe thing: there are 60 teeth on the tone ring. That means that each *tooth and space* is 6 degrees and if the tooth and space distances are equal, each tooth is 3 degrees wide, as is each space. Thus to change the timing 2 degrees, the sensor would have to move 2/3rds of a tooth.

I think the Rockteck sensor is actually advancing the timing by 1 degree.

I think I'm going to adjust my tone ring for fully advanced timing with the stock dowel pin hole and then mod my sensor to advance the timing by 1 degree. I don't want a rattly engine.

Can someone give me good, conclusive MPG or EGT numbers ?

 

One more question: is Rocktech removing the whole O Ring groove on the one side or are they going deeper than that ?

This picture seems to suggest they remove the whole groove and then some.
https://www.dieseltruckresource.com/...sort=1&cat=500

 

Superduty,
From what MikeyB said, the Rokktech sensor pivots on a central point and the 80thous. of material removed is around halfway from the pivot point to the actual crankshaft sensor tip. So, the sensor tip is adjustable to about double of the 80thous., which in my calculations is approximately 2 degrees of movement.

BTW - My truck rattle is only slightly louder when cold starting it and is completely gone after about 2 minutes of driving. My truck would rattle before anyhow when cold, which I guess is the forged pistons needing to expand into their cylinders.

Mileage Report!!!

So, I have burnt through my first tankful and engaged in typical driving that I would encounter with my truck. This included local stuff, stop and go LA traffic and towing a 2000lb boat for 1/4 of the tank. Lastly, I was still my ol' leadfoot self periodically with continuous jaunts at 80mph+ (sometimes the flow of traffic in SoCal!)!

Once the truck goes into O/D and the torque converter locks up, I can now definitely feel the benefit of this mod as the truck doesn't need as much "go pedal" as before, and like I already said, it just feels alittle bit more spunkier. I reset the overhead mileage indicator at 19.1mpg before I filled up, and last night I pulled in with it reading 22.0. Now, I'm not going to say I got a 3mpg improvement at this point as I really need to do the hand calculations as the overhead display is known to be in-accurate. However, I'm pretty confident that I will consistently have at least a 1.0mpg increase if not more.

Since this mod was essentially free with only an hour of my time in opportunity costs, I'm actually making money with this! If only life was this simple.......

MikeyB,
Did your friends do the tone wheel mode yet, and did they notice any difference?

 

"From what MikeyB said, the Rokktech sensor pivots on a central point and the 80thous. of material removed is around halfway from the pivot point to the actual crankshaft sensor tip. So, the sensor tip is adjustable to about double of the 80thous., which in my calculations is approximately 2 degrees of movement."

I get it now. The sensor bolt is the pivot. The place where the material is removed is about 1/2 to where the sensor area is, so the move distance isn't 80 thou, but the multiple of it due to the swing of the sensor on the pivot bolt.

How do you get 22 MPG driving 80 MPH and towing ? That is incredible. Is a good part of your city driving at loafing speeds, like 45 MPH ?

If you drove the same, the 3MPG improvement should be pretty accurate because both the 19MPG and 22 MPG numbers are inaccurate by roughly the same percentage.

It sounds like this is worth doing.

Any EGT numbers ?

 

Superduty,
So far my EGTs dropped about 100-150 degrees with my 555. Last weekend also noticed that my boost has dropped at highway speed cruising. At 70mph boost is holding steady at about 5psi, before the sensor mod it was around 8psi. That 3psi drop means I'm burning less fuel at that speed.

SoCal,
Not yet. They are waiting for me to do it for them. Might do my buddy's 555 next month If can find the time.

MikeyB