Need exert advice

[DuramaxOnTheBrain]

I think I'm gonna try that mod out.

[Hook'em_Horns!]

Rather makes one think that GM didn’t want it to breath. New motor in old body style (’05 got a taller hood) and they closed off the holes in the previous fender design? I wonder who got the bonus in Detroit for that idea.

Friday, pulling thru the hills on a run with a total weight (truck, trailer, cargo) in excess of 29k lbs and 100+* outside, that was the first time since the mod was done that the fan was back to screaming. Other than that, it's been pretty quiet.

Tranny temps were running 210, with the D-max spikeing to 205.

[DuramaxOnTheBrain]

Those temps dont really sound too bad to me. Was your gas mileage still good?

[Hook'em_Horns!]

Originally Posted by DuramaxOnTheBrain

Those temps dont really sound too bad to me. Was your gas mileage still good?

Those temperatures are with 21k lbs hooked on while pulling steep hills, WOT and the fan screaming (8.7-9.0mpg).

The temperatures are usually much lower with less fan activity after the mods…with engine just under 200 and the Allison just under 200 with occasional spikes to 205 pulling moderate Interstate hills with 25k lbs hooked on (10.5mpg).

Just trying to emphasize that only under an extreme load, in extreme outside temperatures, with steep hills did it revert to the old howling like a Freightliner since the completed modifications.

[DuramaxOnTheBrain]

roger that!

[Hook'em_Horns!]

Originally Posted by DuramaxOnTheBrain

I just came in from dremel grinding my turbo inlet. Hopefully that will help some.

Brain

Interesting, I just wanted to add that Killerbee found during his research that some of the mouthpiece inlets he removed had already been ‘Dremeled’ from the factory.

GM did in fact realize their design flaws and modified the pieces for production vehicles. At what stage of the LLY production this was done is not known. This disparity explains why some LLY’s have more serious overheating problems than others do.

While this ‘Dremel Fix’ does reduce turbulence, it far from eliminates the total problem caused by this bad design.

And while modifying the exhaust to lower EGT’s has positive results to counter the effects of this Thermal Feedback, it is much more costly and it doesn’t correct the real source of the problem.

I’ve got some free time tomorrow, going to the parts house to compare the mouthpiece dimensions from the LLY versus the LBZ, for a possible adaptation without exchanging the complete air intake setup... hey, I’m a tinker-er. Come Sunday, we may be 'Dremel-ing' a bit here also, or at least find out if GM already did it, as this 05's production date was late in the year.

[DuramaxOnTheBrain]

That would be some great info. I took mine off and It did seem to have a pretty sharp angle on that inside corner so I took the dremel to it and got a nice pile of plastic dust on the floor. It's not the prettiest dremel job but the corner is now smooth and rounded. It feels MUCH better to the touch inside there now. The only thing I have noticed so far is MAYBE a slightly better throttle response and a much louder and cooler sounding turbo whistle. Even better than when I just had the plug in. I haven't pulled yet but I am going camping soon so I'll report from that trip.