timing and higher rpms...

[GOT-Torque]

Just curious if you had an engine with enough fuel and air to make decent power, and a 5 gsk in the pump, will the timing actually prevent spinning high rpms?

I am assuming that as you add more and more timing you are generically speaking (lots of variables here) moving your hp/tq curve to the right on the graph (moving the peak to a higher rpm). However, will low timing actually prevent the engine from turning higher rpms?

Same engine on the street in direct gear (5th on a six speed, but doesn't really matter), pedal to the floor, what rpm will it hit?

if the engine is static timed at 15 degrees, 20, 25, 30, 35 degrees?

Or does timing have little to no impact, only the gov. springs setup, and the timing only determines how much power you make at max rpm?

 

[zstroken]

You are dealing with static timing. There are the physical properties of how long it takes for the mechanical events to happen. Plus the slow rate of diesel burn. Think of it as you bring the RPM up, you have to anticipate the injection event. Basically you bump the timing up to overcome the physical properties of the injection cycle.

I notice that the charger is harder to spool as the timing moves up, and it gets to the point that the truck likes a shot of ether to start.

 

[GOT-Torque]

I understand what you are saying and agree.

I'm just curious if a truck with 15 degrees timing can even spin 4500 rpm? Or will the combustion event become so late in the power stroke that the force on the piston isn't enough to keep accelerating the crankshaft and raising rpms? Will the rpms hit a ceiling of say 4000 rpms?

I can understand it getting harder to spool a turbo with high timing since at lower rpms, some of the energy of the combustion is actually acting on the piston before it gets to TDC (which is wasted) and is then not available to act on the turbine impeller. Hence the loud noises you hear on a truck running alot of timing at lower rpms (especially under a load)

 

[stock600]

Good question, not really sure of the answer myself either. I do know that going from 18* to 25.5* i noticed no EGT cooling, trap E.T., or mph? No harder to crank either but im not running a dodge starter so that might have some to do with that? At some point they get harder to crank like zstroken said, but at 25.5* id say i have not been there yet. But ive had issues with 5K kits not turning the rpm for sure, i have the great CDS in it now but have not yet got to test them, ive wondered myself if static timing could be part of it? Because i know its not the other obvious things like fuel pressure, and gov. set up ive been all over that..... where is your timing now?

 

[GOT-Torque]

stock600, I've been following your other posts and was hoping to hear your opinions on the CDS springs...

I'm at 20 degrees now on my truck. I've also got 5k springs in my pump, not sure what it will spin to yet. Still breaking everything in... I was just thinking today about this subject and thought I would ask everyone on the forum what they thought.

 

[Rods]

One thing I noticed with a bore scope that when using stock washers and timing close to 30 deg it wasnt were it needed to be in the bowl and my injectors has around 3deg inward cut, even on a VP with a timing box I'v seen quit a few that the spray pattern is getting wide

 

[GOT-Torque]

Rodney, do you happen to know the angle of the spray pattern in degrees for stock 24V injectors?

 

[Muddin_dude06]

It will still rev that high but you can tell it doesn't like it. For my truck the timing is around 17*-19* but once it gets to 3500rpm or so it really doesn't want to climb much higher, I need to bump it up to 22*-ish and give that a try...