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Discussion Starter · #1 ·
I've been looking at a lot of SERT maps, and have noticed that alot of them have no timing changes at all.

I'm going to be playing with the sert stuff to see what it's capable of doing before getting the engine bored and stroked, and will be playing with the TwinscanII+ in order to read afr real time.

I ain't no rocket scientist, so I want to be sure I know EXACTLY what I'm doing before going ahead and doing it.

I have the SERT, and the TS2+. I'm opening and looking at maps for my current configuration.

V-Mods, SE Air Filter, Topless, Stock ECM.

The question I have, is how do you know how much to advance timing, and where to advance timing. It looks like most timing is advanced at Higher MAP and Higher throttle position.

Can anyone offer a rule of thumb for advancing spark timing?

Thanks all.

RJ
 

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RJ, it has been a while since I read the SERT manual but I believe there was a section on timing in the manual in the Advanced Tuning section.

The basic theory of it is if in a data log and you experience spark knock activity you should reduce the timing in those cells. If you do not have any spark knock activity in the data log you can advance the timing further.

I would advance a couple degrees and do a log and go from there.
 

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Discussion Starter · #3 ·
o2man98 said:
RJ, it has been a while since I read the SERT manual but I believe there was a section on timing in the manual in the Advanced Tuning section.

The basic theory of it is if in a data log and you experience spark knock activity you should reduce the timing in those cells. If you do not have any spark knock activity in the data log you can advance the timing further.

I would advance a couple degrees and do a log and go from there.
Yeah, I read that. I was wondering if anyone has any "shortcuts" to make the process a bit faster than that, while still being safe.

You know how lazy I am. ;)
 

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lurch on two wheels
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I noticed too that it seems that very few tunes do much spark mapping, I was looking mostly at the PCIII tunes, but this seems to be pretty common on these motors. I'm guessing nobody has really sat down and worked it out much, or the factory spark curve is just really good.

As far as where to start, I think its going to depend where you are tuning, if you are tuning for power, obviously you need a dyno and there you add timing until A) you stop making power then for safety back up a bit to just before that or B) you experience spark knock, then obviously you back it up.

When you are going for the cruise section of your map, you'll need to keep an eye on knock of course, but you probably won't be quite so high. Keep an eye on the WB and get a feel for the rideability of the different maps. Doing a little refresher reading on how the GM ECM guys tune their part throttle maps would be a good idea here. Tons of info out there on that, and the same methods should apply.

-jt
 

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SNAFU
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I think the H-D spark maps are pretty good from the start but there's always room for improvement. The only way you are really going to get a handle on it is trial and error but it seems that this motor likes around 30 degrees under load and can go as high as 36 at lighter loads like cruising and maxes out the 50 under hard deceleration.

I don't think you are leaving too much on the table if you don't adjust anything and it takes so many samples to get a true reading of your knock potential that it's actually harder to tune the timing than the fuel IMHO.

If you are feeling like playing around I would focus on WOT and the meat of the cruise RPM's. WOT will get you the best peak HP and timing can get you as much as 10% better fuel economy in the cruise section.

Personally, I like ramped up timing curves without too many spikes so smoothing out what you have along with a few bumps would be my goal.
 

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mjw930 said:
I think the H-D spark maps are pretty good from the start but there's always room for improvement. The only way you are really going to get a handle on it is trial and error but it seems that this motor likes around 30 degrees under load and can go as high as 36 at lighter loads like cruising and maxes out the 50 under hard deceleration.

I don't think you are leaving too much on the table if you don't adjust anything and it takes so many samples to get a true reading of your knock potential that it's actually harder to tune the timing than the fuel IMHO.

If you are feeling like playing around I would focus on WOT and the meat of the cruise RPM's. WOT will get you the best peak HP and timing can get you as much as 10% better fuel economy in the cruise section.

Personally, I like ramped up timing curves without too many spikes so smoothing out what you have along with a few bumps would be my goal.
We have 93 octane everywhere in Western PA. This is what I run.

Is there a way to do a global(across the board) advance with the SERT? I'd like to try just a couple degrees.
 

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Discussion Starter · #8 ·
drhooligan said:
We have 93 octane everywhere in Western PA. This is what I run.

Is there a way to do a global(across the board) advance with the SERT? I'd like to try just a couple degrees.
Yes. Change the spark timing in the basic mode. It'll advance the spark timing in both cylinders.
 

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WHATEVER
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rjrivero said:
Yes. Change the spark timing in the basic mode. It'll advance the spark timing in both cylinders.
Or you can highlight all cells in advanced mode and then increment or decrement as needed for each cylinder.
 

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Discussion Starter · #10 ·
DTHDOC said:
Or you can highlight all cells and then increment of decrement as needed for each cylinder.
Sure, in the advance mode. Right?

If you want to bump a few degrees over the whole thing, wouldn't it be easier to do it in the Basic Mode?
 

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Discussion Starter · #12 ·
drhooligan said:
Should I advance 1 or 2 degrees to start with?
I can't answer that. I haven't played with it yet. I do know that you should make sure your ion knock sensor is turned on!
 

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rjrivero said:
I can't answer that. I haven't played with it yet. I do know that you should make sure your ion knock sensor is turned on!
Yeah, I'm looking at the tune that I have here from the board for a Rinehart 2:1(Streetrods) converted for an 04 ECM. The color, 3D graph shows some significant increases in timing advance through the middle, 3,500-5,550 and 40-60% throtle. The grid is showing 10-11.5 increase in these areas, is that degrees of advance over the base?
 

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Discussion Starter · #14 ·
drhooligan,

a little background. I've not used the SERT. I have bought the latest software, and have read the instructions cover to cover twice. I have played with the tables, and the graphs. I am working up the courage to put it on my bike with the Daytona twintec Twinscan2+ wideband 02 sensors. I will have three days off, starting tomorrow to play with it and I hope to have good news then.

with that caveat, the manual says that this table is in degrees of advance.
 

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rjrivero said:
Sure, in the advance mode. Right?

If you want to bump a few degrees over the whole thing, wouldn't it be easier to do it in the Basic Mode?
Yea but I like to tune the front and rear independently
 

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Discussion Starter · #16 ·
DTHDOC said:
Yea but I like to tune the front and rear independently
I completely agree, but his question was how to do it globally. :cheers:
 

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Discussion Starter · #18 ·
After reading the SERT instructions again, I get a chuckle out of the claim "There is no other device available that lets you tune your EFI HD as thoroughly."

Except the VRFID.

I also think they need a new section on how to tune the motorcycle using a dragstrip and Twinscan II +. It's pretty myopic of the moco and pretty condescending to the guys developing other hardware and software.

:2cents:
 

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I'm wondering now after looking at the spark advance table and 3D graph of the tune I'm running if the areas that have 10 or 11 degrees added are not too much advance. Some of the tunes have all 0's in the cells which is no additional advance. Don't know, but the tune shure runs good.
 

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The best spark tables I have found are the factory ones in the 159 (07 folder) series MAPS
 
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