Economy tune/timing question

secondarychaos · #1 Wed, January 28th, 2009, 07:43 PM

Hello,
I've got a question about Economy tunes. there was some debate about economy tunes and "ventilated" blocks

My question is this: what in the Economy tune is suspect to causing this Rapid remodel of the engine compartment? Some seem to think it was the timing causing too early or too high of a pressure spike. Does this sound accurate?
I understand that this was mostly on heavily modified or PMR trucks, but I like to know all that I can, and may modify my truck heavily some day

and dont want it to

Thanks,
Dan

***Power Hungry*** · #2 Wed, January 28th, 2009, 08:23 PM

There is still speculation as to what EXACTLY was the issue. I have found a specific set of problems that related to calibrations done for the PMR engines that weren't exactly related to the tuning, but were an actual error in the file itself. The tip-off on that was the fact that people were experiencing problems switching levels when they shouldn't have been. Even with that, the Econo files looked like the timing was more aggressive then it needed to be and that may have been a contributing factor to the failures.

In general, the consensus is that timing helps improve mileage by keeping as much heat energy in the cylinders. This would be immediately recognizable by the lower EGT and boost levels at cruise. Unfortunately, this also contributed to the now infamous "Death Rattle" which would cause engines to pop. I've not seen this with stock injected engines so there must be something specific to the Stage 2 injector setup that simply doesn't like timing.

Tuning with the timing tables is a bit of a fine art. Watching boost, EGTs, and even listening to what the engine is telling you can be an indication if you're going too far. Of course, using cylinder pressure test equipment is the final answer to all of life's mysteries (in relation to how your tuning is going), but at $7000.00+ it is out of reach of most people.

roosterdiesel · #3 Wed, January 28th, 2009, 11:32 PM

I only have one thing to add...the CP testing equipment needs the addition of knowing when SOI is commanded by the PCM.

My CP setup consists of a 2 channel oscilloscope from SnapOn and a custom pressure transducer from Kavlico. I'm sending them a glowplug and the are making one that will read the same pressures that the cylinder head surface and valves do. I will only test one cylinder with 2 variables consisting of SOI, TDC #1 and cylinder pressure to choose from.

For economy I will test crusing down the highway @ 65mph.

bbbxcursion · #4 Wed, January 28th, 2009, 11:39 PM

Both my popped engines had stage 2's.....and 80E. If I did it again, I'd go hybrids.

bbbxcursion · #5 Thu, January 29th, 2009, 12:34 AM

I'm not sure if it was the 80e program on my truck that did it. It was 2 different versions of the program and the last engine was live tuned. Maybe there was a flaw in the 1st program....But even in the 2nd live tuned one? I don't know. I drove it like I stole it, and paid the price.

bbbxcursion · #6 Thu, January 29th, 2009, 01:00 AM

Normal just cruisin down the highway. The noise still haunts me. Now no matter what I drive, I'm waiting for that BOOM to happen again. I know Bill's been around and I know your history with DP. No secrets on this end. I respect Jody for what he does and how he runs the buisness with his wife. I wish I had a better story with my truck, but I guess that's life. The first engine was cruisin at about 65 mph. The second was about 45 mph. The only load on the engine was just to maintain the speed I was at. When I think about the noise, my heart starts racing really fast every damn time. My workers said my skin was pale white when the 2nd engine popped. Man have I had bad luck!