Setting up an initial ignition timing table

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superelbert
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Hmmm..

Post by superelbert »

CHB wrote:do you all think this map will work on my 3TC?

To me, that MAP looks a bit up-side down.. least advance at low manifold pressure in thstead of the other way around???

High vacuum = high advance :!:
Ferret
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Post by Ferret »

Some time ago somone (ones?) posted excel files that generate initial ignition maps.
My HD crashed and I lost these files. I can't locate that thread (deleted?).
Can somone please post these files?
Thanks,
Avner.
Jon k
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Post by Jon k »

Yeah uh, where'd all the files go?
Jon k
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Post by Jon k »

Anyone?
juls
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Post by juls »

I had to log in before i saw the excel files in the first couple of pages.

I used one just then to generate my ign map.
Jon k
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Post by Jon k »

juls wrote:I had to log in before i saw the excel files in the first couple of pages.

I used one just then to generate my ign map.
The file posting is back up :)
Neno
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factory ignition tables

Post by Neno »

factory ignition tables

lancia delta integrale 2.0 16V turbo

pictures are from http://www.rplab.co.yu/
Last edited by Neno on Wed Aug 16, 2006 4:00 am, edited 1 time in total.
Neno
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Post by Neno »

ford sierra cosworth
PSIG
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Re: factory ignition tables

Post by PSIG »

Neno wrote:factory ignition tables
lancia delta integrale 2.0 16V turbo
pictures are from http://www.rplab.co.yu/
Could they be thrown together just for screen shots of the tuning program? Those do not look like typical factory maps to me. :? They look a little screwed-up even. Timing is pulled way before boost onset and there is no 'cruise' timing built in to the low load areas from what I can see - although I'm not used to reading maps in that configuration. I'd be careful if you use them as the basis of a new map until you can verify applicability.
Image
David
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Re: factory ignition tables

Post by Neno »

PSIG wrote:
Neno wrote:factory ignition tables
lancia delta integrale 2.0 16V turbo
pictures are from http://www.rplab.co.yu/
Could they be thrown together just for screen shots of the tuning program? Those do not look like typical factory maps to me. :? They look a little screwed-up even. Timing is pulled way before boost onset and there is no 'cruise' timing built in to the low load areas from what I can see - although I'm not used to reading maps in that configuration. I'd be careful if you use them as the basis of a new map until you can verify applicability.
Image
David
I think that they are definitly original ones because they were extracted from the original CPU.
This is only the basic timing map. There are many modifiers. You can download the pictures from that web site. There you will find screenshots of the entire program. Also there is an e-mail so you can contact the autor of the program for more detailed information. Unfortunatly the program is not open-source :(.
Neno
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Post by Neno »

Also I've found the maps extracted form digiplex and microplex ignition systems used by fiat and lancia before they went using standalone engine managemet.
thechuckster
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Post by thechuckster »

thanks Neno! is helpful to to see what these cars started out with.
RA40 + 18R + Turbo
MZ10 + 7MGE = track barge!
MonzaRacer
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timing issues

Post by MonzaRacer »

It seems to me that a lot of you folks understand the soft ware and the electronics but have yet to grasp the actual relationship of ignition advance on a gasoline engine.
Basicly up to and around 3000rpms give or take timing is advanced as we have to start the fire sooner and sooner in the crankshaft rotationor as stated in the term before top dead center (BTDC). BUT as we speed the engine up it requires less and less timing and can actually use some retard at high rpms.
This is evident by looking at high speed retard built into some MSD/other boxes.
As I have been tuning engines for years I do know one thing that may help some,,, if you advance the engine it "sees" its self as running richer AF mixtures and if you retard it it "sees" its self as being leaned out.
I have a method I use in tuning most V8 engines but the newer v8s may need some tweaking as the newer heads nad aluminums may not neeed or may need more timing.
SBC standard: i usually set it at around 14 to 18 degrees initial then i dist engines I use heavy weights and light springs and then vacuum advance hooked to manifold vacuum.
Now if you think of it this way at high rpm the engine doesnt need a lot of advance and wont have it at WOT(ie no vacuum) another reason is at high engine speed you need to actually start fire as close to TDC as possible because if not you are trying to push piston backwards rather than forward.
So as for the engine tuners rule giver your self a solid base timing and as much as the engine can handle without spark knock/ping upto or just below your cruise rpm, then as the map levels off at cruise the computer should use timing and advance up to spark knock then back up a little ,wait then do it again. You can run timing advance up to as much as 60 degrees BTDC on some engines.
I run anywhere around 50 to 60 degrees total advance in my 355 and with a heavy truck (78 C10) loads in bed and cab and can squeak out around 14/15 mpg from a truck with no overdrive, I hope to get a 700R4 soon and set up with lock up converter and overdrive and should get some close to high 20s on a carbed engine (it will soon have a MegaSquirt?TBI soon but I am just going to use it as a closed loop fuel control and leave in my signature "Blackwidow" custom HEI distributor.
Now my next car project will have a MSnspark with all the bells and whistles but I intend to use the Delphi/AC Delco 4 coil DIS from Aurora/Caddy Northstar V8's and if I can get it bought I intend to modify an older Hilborn *port FI set from dragracing to work on my 283 unless my twin turbo setup comes through.
Anyway hope this helps some people to understand that timing is "fluid" and should flow up till about cruise/3000 est and then gets less and less as the time to burn the fuel at high speed is less so you have to bring the curve back closer to TDC and if you have a boosted setup then rule of thumb is to remove at least 2 or3 deg of timing from total for every 10 psi or 50 hp of boost. The relationship varies but this can get you started and then finesse it to your application.
Good luck to all
Lee
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Post by coyoteboy »

so youre saying I should advance to 3500ish then begin to retard towards 7500? Even/especially on boosted engines? Every "tuned" map ive seen continues advancing towards redline by 3 or 4 degrees in total. however i always found my setup doesnt respond well to any extra advance after its spooled above 3500rpm - flat line or rising makes no odds going by the ass-dyno.
Avinitlarge
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Post by Avinitlarge »

Ive got my timing quite retarded on boost at 18psi, I get no det and am working on advancing it slowly, 9 deg at 18psi

Its far from finished but works quite well

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coyoteboy
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Post by coyoteboy »

I currently have my timing as per the msq in my sig, seems to work well on v-power but pinks like a pinky thing on 95 ron, must get table switching sorted today!
Anyone know if you should retard across the board for poor fuel or just in load areas, as a rule of thumb of course?
boost junkie
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Re: timing issues

Post by boost junkie »

MonzaRacer wrote: Now if you think of it this way at high rpm the engine doesnt need a lot of advance and wont have it at WOT(ie no vacuum) another reason is at high engine speed you need to actually start fire as close to TDC as possible because if not you are trying to push piston backwards rather than forward.
This is backwards. As engine speed increases there is less time for per cycle so you need to advance the timing to get a complete burn.
coyoteboy
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Post by coyoteboy »

Thats how i always saw it too. Apparently alcohol based engines burn faster with faster piston movement so it might apply there (read it in a few places) but id never heard that on petrol engines.
MonzaRacer
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timing

Post by MonzaRacer »

OK , in school we haad to learn timing and it just seems to be that a engine does need more timing but remember timing is fluid and is a result of combustion chamber design.
So as a drag engine builder I see several different engines in a single tuning session.
Well several years ago one of the engine builders had his engine set up with a reversrotation cam and left his distributor loose after resetting timing and at the top end his car made better trap speed and went slightly faster.
Well this guy found the loose dist never put 2 and 2 together till some time later when he figured out the collar had cracked on the dist and at high rpm it started slipping back all the time.
Anyway they found on the dyno how he made better runs when dist was loose, the engine wanted retard on the top end. Now dont get this wrong not all engines want retard on the top end BUT under boost most engines want some type of retard.
AGAIN let me reitterate, this is dependant on chamber design and air/fuel distribution as some engines will just want to keep advancing.
BUT also remember we have people out there using locked distributors and a flat amount of timing with no advance.
BUT for me i have found pretty much any engine needs some type of non static advance that is RPM sensitive but it needs to be able to go both ways.
It was either Arnie "TheFarmer" Beswick or or one of the old super stockers of the time that used a simple throttle cable through the firewall and a loose ditributor and would retard his dist by as much as 20 degrees on the top end ,and all while shifting a 4 speed too!
As for timing and octane rating of fuel , we should keep the forum posted numbers in R+M/2 rather than RON or MON as one will be high than the other but can switch between brands. The best fuel I have here in Indiana other than E85(105 R+M/2) is Sunoco Ultra which is 94 (R+M/2) Also its getting better as now we have been mandated to use Ethanol over MTBE federally and I like it much better as the alcohol makes it easier to read plugs as MTBE can cause wierd plug colors and isnt as safe or renewablew as alcohol. And alcohol makes a better oxegente and adds octane rather than just adding an oxegenate.
We just took a 355 with AFR aluminum heads to the dyno and I used a 10 degree retard and it was still picking up power after 5 different pulls. Now we ran out of time and had to shipp the engine so I gave the owner some instructions on the ignition setup(Holley Pro Strip Anihillator) and to keep pulling timing out on the top end.
Amazingly the plugs kept getting cleaner on every pull.
The engine made best timing with 20 initial and a advance total of 61 and we kept trying to vary the low end peak and the engine kept wanting a faster and faster curve up to the owner stated cruise rpm of 2650 (I try to get all my timing in by cruise speed. At a steady pull we let it advance to the total of 61 BTDC. Now figure this was then retarded on the NOS pull (250 shot) by 10 degrees and then at top end had the other 10 pulled so it was yanked back to 40-41.
The owner of thedyno had never seen anyone use retard to get better peak torque readings, as most people try to hit better average HP/LB FT over a dyno pull.
I learned that a flatter, higher torque curve always gets me a harder pulling engine.
Its all in learning to give the engine what it wants rather than completely copy other tuners work which may be a great place to start but you gotta set your engine up as it is unique.
I built 7 "spec SBC" engines and none of them dynoed exactly the same and trust me we had every cylinder down to .0001 +or- ,cranks same, bearing clearances , valve spring seat preasures, Literally as identicle as I could get them and they all varried from 7 to 10 lb ft of torque from each other AND none had exactly the same timing curve(all used same dist/box setup and carb and none had same carb jetting) kind of makes a fella wonder so I labeled his engines from lowest to highest and he never had a problem as even as he hurt an engine he was putting in a faster engine (and he had all the tuning specs to start from on each so he could take it from where I started)
Just remember timing is fluid and every engine is a simple fluid pump and it takes time to tune an engine even with a set fuel/ignition setup let alone open sourse/prototyped like Megasquirt.
Good luck
Lee
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Post by MegaScott »

Lee,

The history lesson aside, Megasquirt can and will do what you want with the spark timing, no cables or vacuum advance mechanical kludges. I realize some of the racing orgs still require antique carbs and mechanical dizzy's but we are not limited to this stuff here. The reason for Megasquirt and Spark, full control of whatever you want, you want 61 degrees of advance, more power to you, literally, that's the great thing about it, experimentation is the rule around here!!

My spark curve -
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