whitt1

Sometimes a rod bolt fails due to stresses that have occured previously.The bolt could been stretched due to multible full throttle runs or overrevs and failed catastropicly when you backed off the throttle,luck of the draw stranding you on the highway.Sorry to hear you ruined the motor.

dewmanshu

iTrader: (4)

CHarris...how much does that beast weigh again? I bet (as whitt1) if you pull the oil pan and checked those rod bolt specs they would have been out. It was only time...those hard *** runs through tacoma and up that mountain finally got to her.

On another note, I couldn't imgaine how hard sd tuning would be if I had to tune for wot maf error AND pe. Thank GOD for hpt 2.0 and the histograms.

XLR8NSS

iTrader: (4)

Well, that sucks. High rpm decel is tough on those bolts, could've been a bad one from the factory or like Whitt mentioned above.

Make sure to put some nice ones in the 40Xci

CHarris

iTrader: (5)

You've already shown us... you posted right while I was making that comment...

"A wideband isn't going to do anything but tell you it's running lean. Once the MAF flatlines, PE enrichment also flatlines. As the RPM's raise, there's still more air coming in the engine than what says the MAF. There is no cmopensation made for this additional air coming into the engine, resulting in a lean condition."

Okay... so the MAF maxes out. Does this mean that fueling can't be tuned beyond the point the MAF is maxed. No. But you recognize this. You go on to explain your method for fueling past the MAF Max point....

"To tune for this, you mult by 3% at which point you begin to flatline. For example. If you start flatlining at 5600 rpms. You mult from 5600 up to the top by 3%. Go to the next cell and do the same thing. Do this until you get to the end. You can then go and make fine adjustments."

So you say that 3% pretty much gets you where you need to be. The only other tuning you do is fine adjustments. Why do you even toss this made up 3% number out there? 3% may or may not fix your AFR. All real tuners already know this. What you need to do is tweak the multiplier RPM by RPM until it is where you want it to be.

The table is supposed to work such that you set your multiplier based off of 14.7 to 1. So... whatever number is in the cell is dividing 14.7. So if a cell has 1.3 in it the formula is 14.7/1.3 = 11.3 for example. But this doesn't necessarily work. So you may need to use 1.35 to reach 11.3 AFR or you may only need 1.25. Every cell is tweaked individually based on what the engine needs.

Throwing out a BS "3%" answer is irresponsible for a moderator in my opinion.

CHarris

iTrader: (5)

I honestly don't doubt that it is a cumulative stress failure. Its the most reasonable answer in my mind. But the fact is that it happened to let go well after the peak stresses were encountered.

CHarris

iTrader: (5)

I'm glad to see we're (Jimbob, TwoFast, and I) aren't the only ones who've heard of this. It get sfrustrating explaining some of these things when so many are relatively "tech-light." Thanks for popping in!

CHarris

iTrader: (5)

It weighs about 6800 lbs with me and a 1/2 tank of gas. I have indeed abused this package and asked a hell of a lot from it. Some get more from theirs before they break... I didn't.

It may well have been a bad one from the factory... who knows... it failed and now its SDPC 402 time

CHarris

iTrader: (5)

I'll check back later to see where this goes... I've got a RADIX to pull tonight

dewmanshu

iTrader: (4)

I am certainly in the "tech light" department, but i thought it was common knowledge high rpm decel will kill a motor faster than accel. (give the accel is tuned right). That was one of the first things my highschool shop teacer told us.

TwoFast4Lv

iTrader: (8)

Dang I can't believe a Mod came in and threw his out in an area he had no clue about like that WTF?

What is this Tuning 101? Sorry that was far to long ago.

Cory addressed the MAF issue month's ago and I am sure the injectors were up to it...I talked him into getting the Motron/Siemens 60Lph injectors

The MAF Issue has been around AND addressed years before the LSx based GEN III was ever produced. It is NOT hard to tune around. It just takes time and experiance

Whitt1 pretty much nailed it. We have all seen it before. I knew before Cory even dug into the Engine it was rods. Not much else will let go on decel like that. It is the highest destructive load on a rod. Maximum Stretch just pull's things apart.

There is alot of experiance hanging around this area. Lets all put it to good use