This feature has raised questions by many including my self as to its real intended function however when comparing this advanced table setting among other Honda EMS systems, to me, it looks like an RPM based dwell correction if I'm not mistaken.

Crome (Advanced tables>Ignition Base)


Here's an older thread where the table was pointed out

https://honda-tech.com/forums/forced-induction-16/timing-table-help-pic-inside-crome-stock-jdm-h22a-9-psi-spring-2089932/

Some suggested to zero out the figures because these values are added into the main low cam and high cam tables to the overall ignition values ontop of mechanical timing, however since dwell timing tables exist in other EMS's (including stock) could it be that this table just wasn't properly named as a dwell correction?

Vegas Invasion, in your informative guide to Crome tuning with versions 1.6 or higher, you quoted -

"Base Ignition Table–
a useful option for global timing changes for a broad RPM range. This
can save time while tuning engines that are expected to require a lot of ignition changes,
rather than changing individual cells. This should really only be used if the engine has a
drastically different timing curve, such as an H22 imported to a P30."

So should anyone tuning with Crome zero these values out to prevent too much overall timing advance, or is this feature something else besides a dwell feature that has never really been given much explanation to its true use?

Dwell examples of others Honda EMS systems

eCtune Dwell


Neptune Dwell

 

It performs the same function as others. A name is just a name as the brief description in CROME is the dead giveaway on what it does. As far as zeroing it out - I am on the fence myself. Many different opinions on this one...

 

Yeah it raises many questions, so I take it the overall timing advance is always higher so if zero'd I presume ill experience a loss in TQ which then will need to be brought back up by upping the main table values but I really wish I knew its purpose.....even info on PGMFI is vague

 

It is for the coil collapse delay that plagues the OEM distributor. In the end I have seen tunes from some higher profile tuners that leave it in tact and tune out the ignition tables accordingly. The issue with this sometimes is not all EMS's will display the total timing value with all modifiers added . Some EMS's say you don't need to know this which I personally find to be complete BS. This is somewhat why it is just in your best bet to tune ignition only on a dyno. With that being said, I have never had a car on a dyno before, LMFAO!!!

 

Yeah I plan to have it re-dyno'd for a baseline before I swap in my GSR cams and other mods, however I'll be fine making more substantial timing changes once I get a knock system installed either by doling out the money on a demon with Neptune and wiring in the knock as an input for graphing or at the very least just listening to this with a set of headphones and gaining practice with training my ears.

 

Yeah, the distributor is the spark equivalent of a carburetor.
I digress, base ignition advance is technically more of a correct label, but yes, all those tables are doing the same thing.

Let's simplify dwell:

The distributor rotor only has a small time frame that it's passing or "dwelling" over the cap node where it can transfer power.
If it pulses outside of that angle it will arc or not transfer at all, causing stuttering.
The base ignition multiplier values anticipate how long the coil needs to charge and when the rotor will be dwelling, so all your ignition tables will always land within that window.

Only on a FEW applications with a large igniton range or when using a garbage external CD, the combination of a slow coil and short dwell angle may not be enough, so it can help to tune the base ignition.
Typically when dwell angle becomes an issue, people just convert to COP.

Zeroing it out with any engine just takes longer to tune, so there really is no point.
Don't mess with it unless you absolutely have to.

Fun fact, you can usually solve dwell stutter by reclocking the distributor instead of blindly changing the base values.

 

Thank you sir!

 

Interesting situation here.

I noticed that the Crome GOLD ROM does not have the availability of adjusting these values.

Are these values effectively "0" all across for the Gold ROM?

 

no, they're stuck at P30 values. that's important to remember when tuning H22 or F22, as you may already have higher ignition advance even with stock imported tables. otherwise I very very rarely come across a car that needs the distributor reclocked for dwell. as I said before, you should really never have to modify this table.

 

FWIW, I just did some datalogging in Crome with Crome Gold ROM

The Gold ROM has 0 ignition correction by RPM.

At all rpm and vacuum levels and conditions (normally operating with 0% correction for any special conditions, that is), the numbers in the ignition tables EXACTLY MATCHED the ignition advance in the datalogging.

This is different than normal Crome ROMs, where the advance is added (and listed in the datalogging) to what is written in the table.

So unless the datalogging is way wrong (and my test Integra is handling 50+ degrees advance at the top of the RPM range), the Gold ROM does not have the built-in table.

I made a spreadsheet of what the Gold ROM would look like if you corrected for the curve. I will share it when I get to my other laptop.

 

Good to know....I've never been able to get the Gold ROM, the program seems to have it locked but at the same token I don't have the Pro Version so I always presumed it was just a feature that could only be used when unlocked.

Also for what its worth, I was chatting with VI (our mod) and he said that the Crome ignition problem stigma that everyone always complains of is merely just a matter of correction factors that are of course added to the main tables so by the time you add up the IAT, ECT, and other corrections its no question that the actual ignition values wont match the main tables which you would figure most who are familiar with ROM editors should know

 

The thing that intrigues me is how different the slope of these different ignition corrections are.

There seems to be ambiguity over what a stock Honda ignition correction curve even is.

For example, the slope on the P30 (and others) base maps in Crome are steeper (more correction per RPM) by far than Neptune.

This would lead to a tuner adding more timing to the tables in Neptune for the same motor than they would have to in Crome.

This is why tuning is done car-by-car and instance-by-instance. Even with two different pieces of software, a tune that runs the car nearly the same can look completely different!

 

That pretty much sums up this entire discussion.

 

one doubt.

stock/original honda ecu has Ignition Dwell ? for exemple p30

 

The way I understand this is the Ignition advancement (regardless of ECT/IAT corrections) is needed with increased engine speed for general operation to accelerate all-in-all....

Example...go to a playground, spin a merry-go-round, in order to spin it faster your hand has to catch it in motion that much sooner as it spins to get it to spin faster and faster so in this sense the base timing table increase's the ignition in a linear fashion as rpm's increase.

 

Lately I've been encountering an issue that I believe has to do with the Base timing......I say that because only when I reduce base timing do I notice a difference.

I'm using the new TunerView App in combination with Crome regular (not Pro) and for ignition tuning I have an isolated circuit tapped into my Siemens knock sensor so I can actually hear when it starts pinging long before it becomes audible from the cab of the car (if you could even hear it over my exhaust).

Posted below is my highcam Ign table and I start to get pinging at 7250-7500 @ 7-8psi.

With TunerView's App (a revised Linszter DL) it records everything into a nicely organized CSV file in which I can graph in Excel as also shown below....

My issue is not necessarily the det that occurs because I'm sure with enough timing taken out it will stop BUT please take note of the timing in the 7 & 8 PSI columns from 6500 -8000 rpm and note that it does not increase in either column as RPM's increase, the only thing that would add to this is base timing with increased RPM's. Also, the IAT's and ECT's when recorded were not a factor as the air temp was in a cool 60's range when tested so no timing is being pulled by my IAT or ECT corrections.

In the graphing below the Purple=Ign, Red =AFR, Blue = Boost, Green = TPS %

Graph showing Ign @ 6970 @ 18.25 deg


Graph showing Ign @ 7022 @ 19.25 deg


HIGH CAM


Whats odd is how at only 52 RPM's faster the Ignition will advance 1 full deg when theirs no advance on either MAP column (7-8 psi) from 6500-8000.

I've tried removing timing to curve this but graph after graph I see this sudden rise in Ign advance from 6900-7100 RPM so I'm wondering if the basetiming is causing this even though the basetiming should be gradual and not so sudden between such a short RPM span.

I have however notice a delay in the onset of pinging when reducing the base timing at its highest engine speed by .5 to 1 full deg however in the graph shown the base timing was reduced at 8976 RPM by .5 deg (14.25 from 14.75) and this increase still occured

 

Sorry to self bump this but has anyone here who's worked with Crome ever encountered this sort of problem and would this fall in the category of Ignition related discrepancies associated with Crome?

Also, to clarify, I've asked Peter Linszter if the logged ignition values of TunerView's android app are a reflection of the cell represented ignition or that of total ignition....He wasn't sure when asked and stated he would get back to me once he looks into this so that in it self could answer alot with regards to this

 

Well, when you use Crome Pro or Dealer, and use the Gold ROM, there is no default ignition correction curve. In Neptune, I think they call it 'Dwell', and most people leave it in. Crome, Neptune, EcTune all have a SLIGHTLY DIFFERENT curve built in, and it appears to be this way due to where they pin the highest-available RPM row on the table to be (it adds ~14.75 degrees at 8979 on most Honda ROMs by default, but some it adds that around 11,000, etc etc, so the slope is different).

For Crome's default ignition correction, I plotted the ignition correction by RPM for myself in a table. The reason for me was that I wanted to translate my normal Crome ROM to Gold ROM, and keep the ignition timing in place. So there wasn't any other option other than a full re-tune. Here are the values in RPM, and corresponding ignition advance that happens at those RPM (high cam/low cam, doesn't matter, it's always there):

0 - 0
500 - 0
703 - 0
797 - 0.155068
1000 - 0.517309
1250 - 0.963419
1500 - 1.409529
1750 - 1.855639
2000 - 2.301749
2248 - 2.74429
2500 - 3.193969
3000 - 4.086188
3188 - 4.421663
3500 - 4.978408
3521 - 5.015882
4000 - 5.870628
4014 - 5.89561
4507 - 6.775339
5000 - 7.655068
5775 - 9.038009
6000 - 9.439508
6514 - 10.35671
7000 - 11.22395
7500 - 12.11617
7936 - 12.89418
8521 - 13.93808
8979 - 14.75535


Now, obviously, the system is going to round those numbers. So those are raw based on the slope of the line. The formula (which, if the answer is <0, means 0 ignition correction) is Deg-Advanced = (RPM x 0.00178443968593862) - 1.2671306

So in cases where RPM is say, 700 or below, the formula turns out a number less than 0. For 703, it's -0.01267, but there's 0 advance (rather than .01 degrees retard).

Anyway, that's how much advance is, by default, in every single 'normal' Crome map, at the RPMs listed. Perhaps your motor just wants less timing up at that RPM. Typically, in Neptune (or other programs), when guys street tune their own cars, they don't mess with this default ignition curve. They leave it alone, and they'll describe "anything over 6000, it just lives at 15 degrees, and doesn't go up any higher with RPM, at 15psi", or some such description. In reality, they ARE adding more advance as 6000 gets to 8000, by the virtue of the software, but the numbers in the tables (such as yours with 14.75 that you highlighted) may be the same.

So I'd take out another degree or two, EVERYWHERE over 6000rpm, if you're having any hunch that there are knocking issues, and then start turning it up .25 degree at a time, at most. Some motors just need to have your tables reflect less timing and less timing straight through 7500. You have some timing taken out between 5700 and 6000... I would take timing out at EVERYWHERE 6k and above there, and at 6500 and above, even a couple of degrees.

Another thing to note: if you use E10 gas (most 93 octane around the US these days), if the car sits for a month or two, the fuel technically loses effective points of octane. After 3 or 4 months, you could have 89 octane in there, easily. For this reason, I always back off a few degrees when I get to knock, and leave it there. Sometimes you get a crappy tank of gas, and nothing good happens when you do.

I hope my information was helpful here.

 

Excellent breakdown, Thank you! I'll take more timing out and if not I'll test reshaping the basetiming curve to see where this gets me.

And yes I'm aware never to leave gas sitting or else the octane widdles away but admittedly I am prob too close in areas where det doesn't occur so I need to back off a bit to build a buffer margin in for random fuel occurrences however I generally always try to fill up on shell 93 rather than any other brand and it never sits for more than a day.

 

Today I tested quit a bit of timing reduction and unfortunately still encountered this same problem of sudden ignition advance. I left the basetiming alone and reduced timing from 7000 - 8976 rpm's. The factors of what I reduced it by were based on total timing @ 6500 before the onset of det which equaled roughly 27.5 deg to 26.75 deg as rpm's increased with the base timing left alone.

Blue = Boost, Red = AFR, Black = TPS, Yellow = Ign

6944@18 deg @ 8.7psi


7048@19 deg @ 8.5psi


High Cam



Looks like I might have to try reducing basetiming to see if this helps instead....