Piston Star Patterns - continued - Discuss - PowerStrokeNation : Ford Powerstroke Diesel Forum
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post #1 of 87 (permalink) Old 08-27-2009, 06:24 AM Thread Starter
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Piston Star Patterns - continued - Discuss

Quote:
Originally Posted by Powerstroke Racer View Post
You can run a 350cc injector if you want just limit the fuel in the programming.
If the tuner of choice knows anything about how the HEUI sytem operates, the injectors are not the problem, the method of achieving the fuel delivery is the problem.
A competent tuner should know how an injector fuels for it's cc capacity and nozzle size, that comes from experience.

I can pretty much dial a truck in over the phone if I can get good feedback from the customer, Now lets take Sun for example, he wants to run a big charger and big injector yet have it respond instantanously like a stock truck with a chip, guess what that's not ganna happen. Anybody wanting big horsepower is going to have to learn how to drive it. Which brings up another point, the owner/driver is usually as much to blame for blown engines as a bad tune vs injector setup.

even my tuning with a set of B codes can dump enough fuel at 1800 RPMs to do serious damage if the engine is lugged and all of a suddened floored.
There is a good reason why the factory doesn't offer high horsepower trucks, you can imagine the idiots out there that would destroy them then wonder why. We all laugh at the stories of the Darwin awards, well guess what there are more of those people out there than you think including a bunch on this forum.

Now back to what I think is the actual culprit vs everyone claiming too much timing. The problem is too much fuel too soon not an actual WOT timing figure. If you load the cylinders up too low in the RPM band you are putting incredible forces on the rods and bottom end.

I have seen a lot of tunes over the years and yes very recently and the practice of using the EOT table to get the fuel is still going on. Ford put a Fuel Deliver Command Signal table, aka Pulse width in the PCM for a reason, to control fuel!!!!!
You take that table and combine it with the ICP table to get mass fuel desired which is translated in to a PW signal.

The EOT method is an easy way to get the fuel but at what expense?

Touchy throttle, excessive lowend fueling and limited top end fueling as it follows the factory curve which is rarely modified to any extent.
A good program should have a little power for a little throttle and go up in fueling, timing and power as the throttle voltage goes up not the opposite where the throttle comes on hard then dies off on the top end.
Ever wonder why people say it runs better when you back off the throttle there is reason for that.
as an example My tunes keep pulling till you either run out of fuel, ICP or injector.

This post was not meant to offend or point fingers at anybody rather point out the obvious. I promise you if Ford themselves put out performance tunes it would not be using the EOT method.
Quote:
Originally Posted by Powerstroke Racer View Post

This is not rocket science here, Bill posted the position of the piston at various RPMs, the tables in the PCM use various injections for guess what??? RPM.
Use them, that is why Ford put them there.

Everybody take out a sheet of paper, now lay it sideways. Now starting at the lower left corner(idle)draw a line of what you feel in the throttle toward the right side of the sheet(WOT) and post what you drew.
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Originally Posted by Tom S View Post
I thought this was worth a quote with some highliting

This also was on my mind so I am going to post it. Is it for certain that the tables in the various tuning software packages are labled the same way. Is there any posibility that there are some differences in the tuning software that results in one tuner ending up with a different end result even when they thought they provided the same input as another? I bring this up because of what David posted that he still sees tuning based upon the older method of EOT Comp but is the person that made that tune also seeing EOT Comp or did they think they made changes else where?
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Originally Posted by bbbxcursion View Post
Thanks for the derail guys. If there will never be an answer to those marks I'd rather close the thread. Too much bashing, a $hit ton more than I was expecting.
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Originally Posted by Powerstroke Racer View Post
DID YOU NOT READ WHAT I POSTED?????
I think this needs a bit more disscussion

Quote:
A good program should have a little power for a little throttle and go up in fueling, timing and power as the throttle voltage goes up not the opposite where the throttle comes on hard then dies off on the top end.
So, David, you are saying proper timing but too much fuel down low will give you a star pattern too?

aka - Grumpy .. aka - Bubba Grump .. aka - Bubba .. aka - Grumpy Old F... . . A "slow" fatass 9K Dually.
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post #2 of 87 (permalink) Old 08-27-2009, 01:49 PM
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Re: Piston Star Patterns - continued - Discuss

I've said it a million times..... so what's one more....


You can call it whatever you want, but to much fuel, too soon is the culprit. Whether people want to dissect it into a million different things or not is immaterial.

Everyone wants to take the word timing as only being relevant to the start of the event. But the over-riding concept of fuel timing is the time relative to crankshaft rotation where the fuel is injected. Injection timing does not only deal with the point in time when the injection starts. It deals with the entire fuel charge, and the time when it enters the cylinder relative to crank angle.

The over-riding concept is as follows...

For any given fuel quantity, the timing of that charge is the window relative to crank, within which that event takes place. It is only in the fact that the word timing is most commonly associated only with the start point that the true breadth of the concept is usually lost.

Whether you alter pressure, start point or orifice size, the net effect is a change to the timing of the fuel charge relative to crankshaft rotation.
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post #3 of 87 (permalink) Old 08-27-2009, 03:58 PM
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Re: Piston Star Patterns - continued - Discuss

^^^^^^ I think everyone understands that the star pattern is what Charles has described.

But here's the problem that no one wants to address:
Quote:
Originally Posted by aggie
I have seen a bone stock motor with marks outside the bowl, no chip or anything. Not NEAR as apparent as that, but ive seen it.
Quote:
Originally Posted by stroked
i have also seen that on a bone stock 7.3 came out of a small e-350 van/bus
Quote:
Originally Posted by Swamp
On bone stock engines that never even had a chip on them, the injector spray pattern on the pistons looks like it is 1/2 out of the bowl on top of the pistons.
So if this is happening, why do we still play the finger pointing game? (yes, the game that everyone knows what I'm talking about)

A novel idea, let's figure out why it's possible that we can have a star pattern on a bone stock truck to begin with. After all, just about every tuner out there (regardless of brand) is adding fuel in one program or another. So if the damn engine is already spraying halfway out the bowl to begin with, we can all figure out what happens when we make it worse with a chip or programmer, and start throwing more fuel into the mix.

So with that said, let's go back to Charles' post: "too much fuel, too soon is the culprit". I think that couldn't be any more true. We'll call this "The Charles Equation" . If the timing is already there, all the chips and programmers are now just completing the first part - too much fuel. From that point on, it's just a waiting game.

We've all seen posts where stock PMR motors are chunking rods at 300 hp (stock truck with nothing more than a chip or programmer), and it's even been done with some of the "big brands" like Edge, Banks, Hypertech, etc, as well as a few of our PSN local favorite brands. Heck, we've seen the occasional post in the past about forged rods taking an exit at 300 hp. And there's even the occasional engine that blows up without a chip or tuner.... just bone stock as the day it was brand new.

So, is timing a problem that's causing the star pattern? Yes, we can all agree on that. But Charles nailed it with including the fueling part too, as that's what's going to determine what breaks, and what stays alive. So now we aren't looking at timing in regards to tunes as the problem, but instead (and here's another novel idea), let's look at the fueling! OMG, that was so difficult!

For example... a customer orders a chip, and they tell their favorite tuner that they want smoke, lots of it. So the tuner obliges to the customer's wishes and makes a tune that will blot the sky. Well, the timing issue already exists, and now we are adding huge gobs of fuel...... Then the customer goes out, and proceeds to kill every living polar bear and penguin he can find, continuously dumping lots of fuel, unknowing to him he has timing issues straight from the Ford factory, and thus he has successfully completed "The Charles Equation".

The point of my post is that people are still trying to point the finger and play the blame game, without sitting down and figuring out exactly what's going on. So, let's discuss it, and see if we can figure out why some people have found a star pattern on a bone stock motor with bone stock Ford programming. If we can figure that out, then everything will be come clear.

If we already have a pre-existing timing issue.... then the actual root problem is fueling.... wrap your collective heads around that concept, and let it sink in.

So now.... how many tuners were ever aware 2+ years ago of the possiblity of a pre-existing timing issue straight from Ford? My guess is not many. You wouldn't have discovered it until you see thread after thread of "star patterns", or done some extensive diagnostic work, or testing, etc. Even then, it might not have been apparent right away. So is it really the tuner's fault? After all, this whole timing thing has been the "flavor of the month" for a short time, and the star pattern issue has not really surfaced in any forum until recently. My point is, we have only recently discovered this, despite what everyone's ego wants to believe.

K, have fun shredding my post apart

Curtis
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post #4 of 87 (permalink) Old 08-27-2009, 04:32 PM
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Re: Piston Star Patterns - continued - Discuss

The point Charles is trying to make is that when the injection starts is not near as important as how much fuel is displaced into the motor at xx degrees btdc. The other important part is how burnable is this amount of fuel thats been displaced into the motor, and how fast is it going to start burning, and how is that going to be effected by even more fuel being injected.

A stock motor with no tune, running stock injectors at stock icp pressures, injects fuel very slowly and it does not build cylinder pressures very fast, comparatively. Now a higher injection pressure, with a rate 3 times that of stock, running the same start of injection timing, will have built pressure that much faster, and that much greater than the stock scenario. The idea is to get the cylinder pressure to peak at the right amount, at the right time to produce the most power at any given rpm. So if you have a motor that builds cylinder pressures slowly, it would make sense to start the injection earlier to give them the appropriate amount of time to reach the peak, where it needs to be.

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post #5 of 87 (permalink) Old 08-27-2009, 04:34 PM
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Re: Piston Star Patterns - continued - Discuss

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Originally Posted by 389SixPack View Post
I think this needs a bit more disscussion


So, David, you are saying proper timing but too much fuel down low will give you a star pattern too?
What is proper timing vs the amount of fuel being injected?

I think the biggest problem we have is that the concept of how our engines operate is a mystery to most people on here and evidently a few tuners
You tune by RPM, so if you inject a large quantity of fuel too soon while the piston is down where does the fuel end up???
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post #6 of 87 (permalink) Old 08-27-2009, 04:55 PM
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Re: Piston Star Patterns - continued - Discuss

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Originally Posted by Powerstroke Racer View Post
What is proper timing vs the amount of fuel being injected?

I think the biggest problem we have is that the concept of how our engines operate is a mystery to most people on here and evidently a few tuners
You tune by RPM, so if you inject a large quantity of fuel too soon while the piston is down where does the fuel end up???

On the ground from the whole in the block???
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post #7 of 87 (permalink) Old 08-27-2009, 05:04 PM
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Re: Piston Star Patterns - continued - Discuss

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Originally Posted by aggie View Post
The point Charles is trying to make is that when the injection starts is not near as important as how much fuel is displaced into the motor at xx degrees btdc.
Quote:
Originally Posted by Powerstroke Racer View Post
What is proper timing vs the amount of fuel being injected?
With these two statements, one might ponder something: There might be nothing wrong with having a star pattern on the top of the piston. Heck, if it's evident on a bone stock motor, maybe Ford did it intentionally? Maybe it's for emissions, advance the timing to burn more complete and reduce NOX emissions. Maybe it's for EGT control, if you advance the timing a bit, EGT's will drop. After all, they tried to make the engine dummy proof so people wouldn't melt pistons driving around towing loads that exceed the rated capacities, driving blindly without pyros, etc. I dunno, just throwing that out there. Ford engineers do strange things at times

Then we come along and jack up the fueling....

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post #8 of 87 (permalink) Old 08-27-2009, 05:06 PM
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Re: Piston Star Patterns - continued - Discuss

Curtis
your logic is being flawed by the 3 post you quoted, 3 examples that were most likely due to bad EOT sensors are hardly a dilemma that is the cause of all these engine failures, That said I have yet to see any stock engine with any star pattern.


I asked the question in the other thread, how many people have made a hard WOT pass and killed the engine, tow it back to the shop and pull the heads with the injectors in place?

You'll be surprised at what you can learn.
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post #9 of 87 (permalink) Old 08-27-2009, 05:10 PM
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Re: Piston Star Patterns - continued - Discuss

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Originally Posted by Pocket View Post
With these two statements, one might ponder something: There might be nothing wrong with having a star pattern on the top of the piston. Heck, if it's evident on a bone stock motor, maybe Ford did it intentionally? Maybe it's for emissions, advance the timing to burn more complete and reduce NOX emissions. Maybe it's for EGT control, if you advance the timing a bit, EGT's will drop. After all, they tried to make the engine dummy proof so people wouldn't melt pistons driving around towing loads that exceed the rated capacities, driving blindly without pyros, etc. I dunno, just throwing that out there. Ford engineers do strange things at times

Then we come along and jack up the fueling....
That makes plenty sense... BUT... Why, then, are the rods failing? What gets the blame next? I'm just wondering...
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post #10 of 87 (permalink) Old 08-27-2009, 05:10 PM
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Re: Piston Star Patterns - continued - Discuss

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Originally Posted by bbbxcursion View Post
On the ground from the whole in the block???
If you would stop posting smart a$$ remarks you might get some answers.
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