C5, PowerArc, and the mystery of Timing

[AApple]

dan filipi » Thu Sep 12, 2013 9:38 am[/url]":a3d3ptdu]
I gotta ask..

Is there any advantage or "reason" for the advance to drop off under acceleration in the way the stock advance is designed?

The design is to keep the ignition from be over-advanced on acceleration, which could cause ping, or pre-ignition. Keep in mind tho, that once the engine gets up to speed(not under a heavy load), the vacuum advance is creeping back up as the engine vacuum builds....this helps with acceleration. Between the vac, and mechanical advance, the ignition timing SHOULD be perfect for all rpm and load situations....but it rarely is....it's more of a "closest thing we could get" kinda deal...

Also, having full advance at idle helps with emissions...not that we care about that, but the manufactures did, since the gov has requirements.

 

[mcgovern61]

To add one more side story about engine vacuum. I agree that the vacuum is lowest when the engine is accelerating and at very high RPM. Many, many moons ago, I had a '69 LTD wagon with a 390 engine. The power brakes were vacuum controlled. Somehow, (not sure how :whistling: ) I found myself in a street race. That big old wagon had quite the get up and go!! Speedo might have been pushing slightly higher than 120 MPH before the end of the race and the street came to a dead end.

Well......I applied the brakes with the car moving along at high engine RPM and maybe a little faster than I should have and guess what..........no brakes at that speed! :shock: Just a rock hard pedal!!

(I shudda read the manual first! :whip: :rtfm: )

I finally stopped the car by downshifting, parking brake and keeping my foot on the main brake pedal. :roll:

At normal speed, the brakes worked great! (Just making the point about vacuum being higher at idle :hihihi: )

Lesson learned........ :smilie_happy:

 

[AApple]

As long as the throttle blades are OPEN, there will be no, or very little vacuum in an engine. Take a sneezle engine, fer instance....they don't create ANY vacuum, because they don't(normally) have a throttle blade, or any control over air intake. That's why they need a vacuum pump.
There has to be some sort of restriction in the intake tract to "create" vacuum....that restriction is the throttle blade(s). A carbed engine needs some sort of vacuum to "pull/suck" the fuel out of the fuel bowl. Fuel injected gas engines use a vacuum signal to determine engine load, among other things.
Vac 101...class dismissed.... :smilie_happy:

Now back to your regularly scheduled timing thread....
Looking at the charts posted, I see very little difference in the 4 plotted curves, and mostly the difference is above 3500 rpm...right about where the vac and mechanical advance would start pulling the timing back up(advancing). At least one of the charts shows a larger difference in the low rpms, but not much in the higher rpms.
So....I'm starting to unnerstand(it's a MIRACLE!) the programing on the Power Arc/C5.... I may be slow, but...I'll get there! :hihihi:

 

[ekvh]

The issue with the 1000 model anyways, which is hard to determine is: do the 30+ year old springs operate as new or have they weakened thereby advancing faster and earlier than they should and retarding slower than new??

 

[AApple]

I think that is a given. Between that, and the posts that the weights swing on wearing, as well as the pivot holes in the weights themselves, the timing has to be floppin all over the place after 30 years...

 

[dan filipi]

Well I can tell ya the weights flop loosely on all 3 of the mechanical assemblies I have.
The springs seem much weaker than those on cars I've worked on. Even no spring tension at rest on at least one of these 1100 assemblies.

 

[PowerArc]

I'm also wondering how the advance curve is figured, since you no longer have a mechanical/vacuum advance mechanism, nor are there any other sensors involved, such as baro/map, knock, or throttle input(tps)

1st people must understand how all aspects of the engine work to understand why the timing is placed where it is optimal for performance without damaging the engine.
Let's start here with the question of the mechanical/vacuum advance mechanism so we will discuss vacuum intake manifold vacuum.

When the engine is at an idle or under light load conditions the throttle minimally depressed the intake manifold vacuum will be high. As the throttle is opened the velocity of the incoming air increases, the engine rpm increases, mass airflow increases and manifold vacuum decreases. Simply when you open the butterfly or slide on the carburetor you are opening a large hole allowing more air in and intake vacuum decreases. (air pressure increases filling the vacuum)

The GL1100 has a idle timing of 10° or 13° year dependent and fully advances to 38.5°. Since the 1100 still has flyweights the advance timing of the flyweights is added when the engine rpm exceeds 950 rpm. (in a perfect world)
When you start the engine prior to actually running you have no vacuum, once the engine reaches starter override and the engine is running vacuum goes high and vacuum advance solenoid pulls the rod of the solenoid advancing the engine timing. At idle you will have full advance timing of the vacuum advance so it must be less than the 10° or 13° and I can't find out the amount advanced by the VA so we will assume 10° just to show how it works.

When the engine is above idle and you are at full advance 38.5° with a minimal load as you increase speed (open the throttle) you increase low and the vacuum seen at the VA falls and the rod attached to the timing pickups moves to a retarded timing position. So using 10° as the VA timing shift a total loss of vacuum at the VA would decrease the timing from 38.5° to 28.5° timing. Many of the other forums have posts recommending plugging the VA hose and forgetting it, I don't recommend this as you would reduce engine timing and could effect performance.

To further answer the question quoted above will take many more posts which will be done as quickly as possible to cover as many aspects of matching engine requirements to conditions.
What is the differences in the GL1000 and the GL1100? (100 cc) The GL1000 didn't have a vacuum advance, strictly points and flyweights as most engines manufactured to its time.
In many cases it probably ran very well and with the cam in it ran as well as the 1100.

Things to be noted:
Engine vacuum falls as the throttle is opened and is used to sense load.
Engine timing is reduced (retarded) under load.
Increasing useful torque ranges lowers the requirement for timing changes.

 

[slabghost]

While a great deal of this accurate I must point out a few things. Increased vacuum on the advance unit increases advance. While it's true manifold vacuum is highest at idle it really has very little to do with the vacuum advance. It will affect brakes and way back when the vacuum operated windshield wipers as those used manifold vacuum. Vacuum advance get's it vacuum from air flow through the carb. The faster the flow the higher the vacuum. In the case of goldwings the only true manifold sections are the sections between the carbs and heads. The "horns". They are not united in any real way as they are in cars.

 

[C5Performance]

dan filipi » Thu Sep 12, 2013 9:38 am[/url]":vepwx1jc]
I gotta ask..

Is there any advantage or "reason" for the advance to drop off under acceleration in the way the stock advance is designed?

I'll add some food for thought here. When you are attempting to accelerate, you are increasing the load on your engine. That increases "working" compression and increases the rate of fuel burn (remember my post about these changes).

All things being equal, if your fuel starts to burn faster, you must retard your timing. Using vacuum to measure how much load is on your engine is a simple and effective method. Although for me, being a visual guy, it can be difficult to understand pressure or vacuum since you can't see it, the basic idea is this:

When load goes up (acceleration or trying to climb a hill) the fuel burn rate increases. To offset this you decrease timing advance.
When load goes down (deceleration or coasting down hill) the fuel burn rate decreases. To offset this you can increase timing advance.

I have really simplified it to make a point but I want to make sure the people reading this don't get lost. These discussions are VERY important if you want to understand how to improve how your bike starts and runs. We will discuss multiple sparking very soon.

 

[C5Performance]

dan filipi » Wed Sep 11, 2013 8:22 am[/url]":2y7o6q17]

C5Performance » Tue Sep 10, 2013 10:27 pm[/url]":2y7o6q17]
So why would they use a different curve? "well the CBR has more power and goes faster"
Remember, the engineers have designed the transmissions so gearing matches the horsepower of the engine.

This should be elaborated on more because it's a key reason why PowerArc will not program in more advance than stock.

As I understand it, in the case of the CBR the power to weight is much different. Lot's of power on a light bike.
Because of this, engine load is lower so it can be advanced more to squeeze out more power.
Also the gearing is designed different to make use of the power better.

Like Joe's Hooch.
He has it geared down, that's why it will walk up his driveway at idle.
Since he has the lower gears he could possibly run a tad more advance, maybe not.
I think we tried it and Joe found no gain from it.

Dan,
Good point. Let's discuss Hooch because everyone can watch that video. For those of us who were there, Joe's driveway is MUCH steeper than it appears on film.
Hooch walked up that hill at just above idle more than once. There was no chatter or rattles. It was like watching a tractor pull a fully loaded hay wagon.
The other bikes at the meet & greet sounded horrible in comparison.

WHY?

Hooch is geared really low.

First: We advanced timing to show how simple programming is for the C5.
Second: I wanted to see what would happen to the power delivery if we increased it
Third: Hooch is geared so low there is a greatly reduced engine load that allowed us to cheat death.

LOAD...
If we put that much timing into a standard Wing and had Joe climbing hills, Hooch would have big holes in the pistons already.
I don't want to get off track, but there are several types of detonation and not all types can be heard. With a strong ignition and multi-sparking, you must be careful not to exceed what the engine can handle, because the ignition is NOT going to fail. Your engine will most likely be the loser.

Honda took the power and weight of the Wing, and calculated gear ratios and sprocket sizes that carefully match power (timing) to engine load (gearing).
Most situations require LESS timing, not the other way around. Yes I know young punks buy timing advancer kits for their sport bikes all the time. I also know they don't have a clue what it actually does. All they know is their "buddy" said it makes the bike go faster. How do I know this? I worked at dealerships my entire life and sold a ton of them.

Simple question.
If your engine load doesn't decrease, would it be an advantage to increase timing?

Simple answer...MAYBE.

Hooch has a transmission from one bike, connected to a rear differential from another bike. Do the math and Joe says it is geared much lower than stock. This means Hooch now has a mechanical advantage that decreases the load his engine must endure. We could safely increase his timing.

He did say (its on film) that when we increased his timing, he LOST some of the low end "tractor" pulling he loved. I did leave his other curves stock, and suggested to Joe that he use a less aggressive curve if he intends on climbing big hills especially with a passenger. If you took a standard motorcycle and increased total advance without changing anything to reduce its load, i believe it would potentially suffer in performance (and certainly in reliability).

 

[joedrum]

ok ....hooch ok .....I have to get in here ...I think what been said has valid points .... but not the full story ....

hooch before c5 ...with dyna and 1100 carbs ... the first video of hooch was right after it first ran ... only the second time it was started I think.... sheesh it fired right up and strong In video ...then electrical problems and stator problens

once that was sorted out hooch test rides didn't go well ... hooch pulled like a tractor ..ran good down low ......but then would start missing ...I kept thinking iggy ....dynas wants it warm failure of module I kept thinking ...

im not always right ... in reality ... and in Hine sight im thinking it was carbs now ..but then I never had carbs racks fail like this .. I get them spot on and it run great ... run rev hard ...think everything was good and then just go several miles and it would start missing and running like crap

this was the first time I had moded an oldwing to where cv stock carbs would go right in the dumper right before your eyes .....not good enough for me im still iggy problems ....I must say there were times I could hooch to good before failure creep in ... it was obvious the bike had tons of power in places I was kinda worried about ....so much so that so far I havnt been able to keep the bars from slipping in triple tree ....1000-1100-1200 racks all did the same way ... only difference was who long they would go and that didn't vary much ....

enter c5 want the c5 was install at first it seemed fixed ... it went 10 mile test rides with 1000 rack and come home even longer rides .. but eventually it failed also in the mix was the rev limiter sheesh that really got me dizzy and I was just baffled

okay the c5 didnt bring tractor power to hooch it was already there ...c5 was so precise in timing it really increased time of running before carb racks would give out ..that's just plain facts now in hine sight ... the bike ran well during meet and greet ....and never showed signs of failure till just before v left .....it also showed signs of failure while jerry was here but we were working on his bike ...

enter 24-25 weber carb ... after awhile my dumb butt has figured it is carb racks were the problem they all did the same thing ..when the c5 would the life out they were toast ..this was all brand new to me .. to watch racks just go to garbage on hooch ....the weber stop it all ... idont even have the weber truly dialed in yet .. its way rich ... dosnt miss a lick ...is it right totally now no ...bur neither am I right now were both mending right now ....now with the weber and poorly adjusted ...hooch turned into a tazmainian devil down low in rpm ...coning up the driveway went from smooth and sweet ..to gravel spitting monster ... my first test ride I bearly made it to the pavement...twisted the throttle oh my it took off ...got to thee hiway let it rip a little sheesh instantly bars sliped again ... theres just to much leverage in the oldwing bars for the mounts clamping force to hold ... mod coming sheesh ....daughter arrives to see me ... we ride hooch several hundred miles ... we had fun ... hooch torched an Harley in its best envirment ...down low from stop ... from the first turn of the wheel its was over and increasing ...we were two up ...

before wreck ck hooches plug it was way rich turn in mix screw ....sheesh hooch was revving hard and running much smoother and not loping as much ... ididnt get far ... it was obvious hooches but not quickly enough that the power down low had jump up more ...the first situation igot into I could not keep under control .....

point being hooch never got right till there was a carb system to work on it ... the c5 is not going to instantly get rid of spit and pop or any other carb problem instantly or clean out a clylinder that is just not doing it part instantly hooch didn't have that to deal with but bikes that have weak running clylinders will and carbs will need get right ....what c5 dose is bring a solid iggy to the table so one can go other places to look for problems to solve that will huge power to the table not because the c5 in and of itself dose that ... it just takes the iggy to a supreme level this story ive posting of hooch is no different than that ... im in the process of getting things around the c5 up to par ...

im getting so close now with hooch ..... on stock bikes this will just getting the carbs right not a full fuel set up change ... it may take awhile to get dirty cylinders and carbs up to par on a stock bike ... its foolish to blame c5 or think theres a flaw in this system .... its the bikes ... the bikes have huge stock flaws

anyway that's what I think :mrgreen:

 

[Ansimp]

The thing that I think most indicates a great spark is that Hooch is running well even though it is over fuelling and the C5 ignition system keeps firing that rich mixture :good:

 

[skiri251]

My stator and clutch are done.
I am waiting for C5 to arrive so that I can put the engine back in.
As I understand it, C5 for GL1100 is still under development?
Is it possible to update advance curves in the field?
Is there USB connection or something so that I can upload the curves through PC?

Or should I wait until all these development issues settle?
Should I rebuild my mechanical advance and put the stock ignition back in and ride before switching to C5?

 

[joedrum]

hmmm ... ill let paul answer this ... but id be sitting on it in your position ...if I could ...till you know more that might be rather quick I think ...

 

[C5Performance]

The coil mounts are done. I revised the rear one based on feedback from Dan.
The ignitions will be here today (waiting impatiently).

I've got everything else sitting here in a box. We added an additional ground wire as well.
I will post photos tonight.

 

[skiri251]

Great!

 

[dan filipi]

C5Performance » Fri Sep 13, 2013 9:02 am[/url]":1qnnww5e]
The coil mounts are done. I revised the rear one based on feedback from Dan.
The ignitions will be here today (waiting impatiently).

I've got everything else sitting here in a box. We added an additional ground wire as well.
I will post photos tonight.

How is THAT for service!

Paul really is passionate about this ignition and is doing a fine job keeping on top of developments.
Good to see this in a world that lacks good service in so many ways.

 

[AApple]

skiri251 » Fri Sep 13, 2013 9:20 am[/url]":2lwkf09c]
Is it possible to update advance curves in the field?
Is there USB connection or something so that I can upload the curves through PC?

I kinda have the same question. I know that on Joe's deal, they were plugging it into a laptop to mess with the curves, which, as I understand it, will NOT be needed in most cases. The 4 installed programs should cover just about everyone. My question am, HOW do you change it from one pre-programed setting to another? Is there a switch internally, or what? If it is internal, that's gunna be a pita on the 1100 to get to. Is it like a rev limiter on an MSD that just takes a different resistor "chip" change to accomplish it?
If it requires plugging in a laptop, that's going to be an issue with folks that don't have laptops.
Inquiring minds wanna know! :read: opcorn:

 

[skiri251]

Didin't Paul mention the controller can take optional input which can be vaccuum sensor signal?
If that's the cace, I think you can hook up rotary switch of something to choose different curves.
And if you like, you can switch it manually while you are riding a la vintage motorcycle with manual advance.

 

[dan filipi]

skiri251 » Fri Sep 13, 2013 10:13 am[/url]":1y8pvlls]
Didin't Paul mention the controller can take optional input which can be vaccuum sensor signal?
If that's the cace, I think you can hook up rotary switch of something to choose different curves.
And if you like, you can switch it manually while you are riding a la vintage motorcycle with manual advance.

Yes.
There are 2 wires that get grounded and ungrounded to select one of the pre-programmed curves.

Paul will have to answer the question about changing the pre-programmed curves on an 1100.
From what I've experienced so far there's no need to.