Third tank after the sensor mod (mix of interstate @ 70-75 and city). Ok, so I ran 8 tanks through towing my enclosed car trailer. Three non-towing tanks should be a good verification.

22.900 gal
462.9 miles
=
20.21 MPG

Best tank yet! I was getting around 17 to 17.5 before the mod.

Very, very happy

 

CalTom mine was advanced as far as it could be I think. I did grind the dowel pin hole and the bolt holes slightly. I've only driven it a few miles so far and the only difference I've noticed is lower EGT.

 

I got the Rokk sensor and also opened up the pin hole on the ring. I haven't gotten any knock so far, but I am not sure much has changed EGT or idle, take off wise... I will see about the mileage... I pretty much average 16.5-17.1 during my normal driving....

 

Without having to reread thru all these posts, is anyone seeing significant fuel mileage changes on a 555? or is this just working on the 600's? and with what modification, the rokktech sensor or the tone ring mod? I have a bone stock 555 and would like better fuel mileage.


Randy.

 

Ram04,
I filled up twice so far with the mod and both times I hand calculated 20mpg for around town driving. No straight highway driving yet. Before the mod I would usually see about 18.5mpg for the same driving conditions with my 555.

MikeyB

 

RAM 04 I tried the ROKK sensor will no success on my 555. I pulled the 5er with it and had about the same EGTs and mileage. Then, driving around town, my fuel economy went down almost 2 MPG. The truck was also harder to start. I took the modified sensor out and the truck is back to normal. Honestly, there was a little better low end response and the EGT may have dropped slightly (as seen on my post turbo pyro) but I couldn't accept the lost mileage. I always track my fuel economy both overhead and hand calculated. Some people are noticing the overhead reading lower with the sensor but hand calculating an increase. Things that make you go hmmmm...

 

I have been following this and have the rokktek mod but I think I might also ckeck the tone wheel. Forgive me but standing in front of the truck which direction should I move the whee,l clock wise or counter clockwise?

 

5. TIMING: Retarded timing will also enable your pistons to live longer. Do not advance timing in a Cummins engine. This was taken from this website :
http://www.dieselinjection.net/BRUCE/articles.html

I believe this was for building a 12 valve motor, but I was just wondering if this holds true for the 24 valves ??

 

I'm not sure but I think the tighter emmission standards led to retarding of the timing so the 12V and 24V are likely under different amounts of injection timing advance. Someone will likely verify or challenge this.

One other thing for people to check while doing this mod...when I was under mine I noticed some weeped oil on the timing gear cover. I initially thought this may be from a weeping front seal but it was actually coming from the cover gasket as some of the bolts were noty torques nearly as tight as they should be.

 

Installed the Roctek sensor last night. Not enough time to tell any mileage gains, however I noticed a significant drop in EGT's at highway speed (post turbo). No difference in start-up, however idle seems smoother. I Will be towing my CJ to Moab in a few weeks and will be able to tell more then. ie: EGT's, mileage,ect

 

Move the tone wheel clockwise.

MikeyB

 

So, I did the tone wheel mod this morning and it was so easy I was in disbelief. One hour from start to end, but I took my time to make sure I was doing it right. I ground off 32 thou. to give aprox 2 degrees according to superduty's calculations (thanks superduty for the great mod).

So far I love it, took a 20 mile cruice around town with some freeway and the overhead is reading 20.1 mpg. (I have never seen the over head over 17 mpg).

Idle smoother and better low end

Love it and it was free

 

Oh yea, thanks MikeyB for starting this thread.

 

So with the big decrease in EGT temps, is this going to still be enough to burn off the converter clean inside ?? Didn't know if this would cause the converter to clog up eventually, mine might fall off accidentally, I dont know.

 

I have run 6 tanks of fuel through since grinding the tone wheel. I always calculate the mileage by hand and combining all 6 tanks together my mileage has increased by .7mpg.
So I decided to do all the tanks separately. Best increase was 1.2. Worst was .3.
I am thinking of moving it ahead another degree and checking mileage again.