Lost Bottom End With The 6x.16's

[RSWORDS]

My bottom end and turbo spool up has really sufferd from when I had my POD's to now with the 6x16's. The amounts of smoke is leading me to belive that I am just over fueling to the point that is is putting out the fire. I'm running about 3/16" timing over stock and know that these large injectors like alot of timing so I'm planing on bumping it some more. But I have read that the incressed timing will hurt my spool up... I DONT WANT THAT!

The spool up is so bad that I catch hell trying to build boost for a 4wd launch, and It does not mater if I roll into it or if I floor it, it is VERY slow to build boost.

I have read about milling 2mm off the timing advance piston and that will allow me to run a stock timing setting on the pump (after jumping a tooth) but still have plenty of advance up top to burn all the fuel. Sound like a good idea for me?

Any other thoughts?

[Crossy's son]

This is weird because the same thing happened to BC847...

HIs truck ran better with DDP4's

[seeker1056]

wierd cuz when i switched from PODS to 6 x 18's it was nite and day better

[RSWORDS]

This is weird because the same thing happened to BC847...

HIs truck ran better with DDP4's

Mine feels a little stronger on the top but I think over all the truck was faster with teh POD's/ I'm sure it is just in teh "tune"

[Richie O]

I have stock timming with my 6x16's and it spools my 60 mm h1c quick. Why don't you try stock timing and see if it gives you some bottom end back.

[BC847]

Bobby, you (we) need more advance (static or dynamic).

Perhaps 16*BTDC total.


Where can we find an inexpensive timing light for a diesel? I've seen the $200 adapters.

[Richie O]

Alright, I guess I need more schooling. How does advanced timing help bottom end? With my VERY limited experience advancing the timing hurt my bottom end. That was with my 89.

[BC847]

As I understand things, in the case of over-fueling, one will get better fuel combustion by adjusting the timing such as to better place the fuel in the piston bowl. This might be thought of as re-establishing the timing baseline, then fine-tuning from there.

In the case of a more proper fuel/air ratio, dinking with the timing will shift HP/torque values as we typically see.


So say the voices in my head.

[Richie O]

OK,

I understand.

Now, advancing the timing. Does that not put fuel in a wider spray pattern? If you go to far, does it not spray in the " BOWL"?

[BC847]

The fuel spray angle and pattern is defined by the nozzles (assuming they get the required volume of fuel at the right pressure).


Dinking with the injection event timing alters where the event starts relative to the piston position relative to TDC.

Keep in mind also that piston position relative to the top of the combustion chamber (on the compression stoke) effects things such as "squish", "quench", and "swirl". These influence how the actual combustion occurs (flame propagation, etc). Squirting the fuel in at the right time relative to these things matters as well.



I think . . . . .. .

[RSWORDS]

So David we are correct then in thinking about shaving 2mm off teh advance piston then setting the base timing at idle to a stock setting. Hopefully the modified advane piston will allow for a greater advance and get the full advance up around the 16* mark... Correct? Or am I still asleep?

[BC847]

The machine work is not required to do what is needed now.

But advancing the pump a tooth to put us more in the range of a good starting point would be in order.



Let me get to where I can write . . ..

[RSWORDS]

But by advancing a tooth wont I kill my bottom end more? I'm going to sell the 1st gen and buy another programmer for the 3rd gen... it so much easier.

[Ace]

Have you considered testing the theory by turning the fuel screw out a bit?

[BC847]

But by advancing a tooth wont I kill my bottom end more?

In a more correctly fuel truck, . . . yes.

We are over-fueled and that needs addressing first. Once the injection timing baseline is re-established, then tweak as needed.

As I understand it.


Having gotten the fuel to burn better, the added fuel (over your PODs) now should produce enough heat that you shouldn't necessarily see a drop in boost. Even with more advance (as compared to before).



Ace, in my mess, backing out the fuel screw a good two or three turns only made less smoke (and slower track times).



I'm still working on my mess . . . . . . . . . . .