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Ignition timing SV1000

6K views 14 replies 11 participants last post by  oldbaldsob 
#1 ·
Hi guys,

I am currently modifying a SV1000 engine and need some information about ignition timing.

The service manual told me it should be 5° bTDC at 1,200rpm. But I cannot find the maximum amount (not maximum power but maximum advance) anywhere. It should lay around 55-60° bTDC.

Anybody has some info about this?

Thanks,
Oliver
 
#2 ·
Its not in the manual but at an educated guess I'd say around 40 to maybe 50 but not 60. I assume you have a power commander or some form of modifying it. I would expect it to rattle it's head off at 60. If you poke around at downloadable maps to suit a power commander for an sv they normally list what the settings are and would give you a rough idea of where to start. If it pings it's tits off at high revs back it off :)
 
#3 ·
Man...you got around with the question!:) It's been answered elsewhere, but a comment on aSparky's statement worth mentioning. That is: you'll NEVER hear it 'ping' so using that as a tuning tool is not the way to go. Even with a knock sensor it's questionable whether it would be able to sort through all the noise and detect detonation. This is one of the reasons the SVT Focus engine doesn't have a knock sensor...the rest of the engine noise made one unreliable.

There ARE ways to detect combustion anomalies such as monitoring the spark current flow that would work well here, but that's well beyond the stock ECU's capabilities. The best you can do in this case is to map for best power and call it good. The combustion chamber is turbulent enough to prevent serious detonation and if you should manage to create it...you're so far past best power it isn't even funny.

Some of the Porsche engines are very similar in that they make best power with maybe 30 degrees of lead...but won't make any audible signs of detonation even with over 40 thrown at it...and the power has been dropping for a long time as the lead was added so you'd have to be pretty thick to not realize what's up and back the timing off.:)
 
#4 ·
Yep, you're both right :)

I got around as I really needed an answer urgent. I do have a map which was extracted from the ECU but shows values I cannot decode. Now I can, but the diagram Rob posted over on svrider helps even more! :)

Thanks guys!
 
#6 ·
Theree is no easy answer on that. Its like building the fuel map. You need a dyno and an experienced mechanic who knows his stuff so that he builds an optimum ignition map. This doesn't necessarily mean a timing adnance always. When i bought my pc3 i got it from a guy running a dragster sv. He was able to hack the ecu so he didn't need the pc anymore. so i got both the pc and ignition module. I use an ignition advance up to 4 degrees in the middle rpm range from 4k up to 8k and for throttle openings up to 60%. Above 8k its untouched. sure its not optimal but it helps the motor run smoother down low.
For the ignition module, the cell numbers are degrees, not sure about pcv but i guess its the same.
 
#7 ·
It's all about the flame speed! Years ago, Honda built a test engine to see if the rpm could outrun the flame speed increases they were seeing with their racing engines. Once the intake is flowing positively and it's 'up on the cams'...then as the rpms went up the flame speed quickened accordingly which meant no more timing advance was needed or desired. In many cases the timing curve must go back down in advance when a tuned intake gets with the program.:)

Anyhow...Honda found that the flame speed increased up to the limits of their test engine which was over 24,000 rpm! And interestingly at that speed the engine made maximum power only needing 50 octane fuel! In the aircraft world the various books say that flame speed on a good running engine will be about 250 fps but that's at a fixed rpm and situation of 2800 revs in a large displacement dual-plug cylinder and bears no direct correlation to a high rpm bike or car engine.

If you increase the breathing it should quicken the burn speed from better filling, as well as increasing the compression or decreasing the squish clearances which do the same to the burn speed and will require less lead to make best power. I know that a 4 degree increase doesn't help the SV motor with 12.5:1 CR and advanced intake cam timing and in fact hurts it on the top end, but the stock engine did seem to really like the extra advance at low-mid rpm and it wasn't so clear what it did to the top end but I suspected it didn't help and might have hurt a bit. The stock SV timing seems very compatible with more compression and tweaked cam timing using 93 octane fuel...and I've been afraid to try anything lower seeing as hearing the detonation is not going to be likely and the only way to tell if it's been mildly pinging would be tell-tale damage to the sparkplug electrodes....but I like the motor too much to willingly do ANY damage to it.:)

What would be VERY cool would be to build the motor then hook it to a REAL dyno where a steady-state condition of throttle and rpm could be reached and then move the timing up and down while watching the exhaust gases to achieve best conditions for every rpm. This is a FAR cry from the Dynojet 'dyno' where the engine is run from 2500 to redline in a single 4-6 second pull as it doesn't duplicate the internal temperatures that will be present while running the engine in the 'real world' and could likely lead you to believe it's safe...when it's not. The Factory Pro guys say the combustion temperatures can be 300-400F higher easily on a steady-state condition than are reached on a Dynojet....so be careful if that is what you're using to tune with!:)
 
#9 ·
I've lost the original maps to a computer malfunction, but can link you to them over at SVR. Timing map - Suzuki SV650 Forum: SV650, SV1000, Gladius Forums For the stock motor the timing 'should' be pretty close to good on the top end where it's far beyond any emission considerations though the bottom and midrange do seem to enjoy a little more lead. If you increase compression either by static or effective means the timing becomes pretty decent and might actually be a little optimistic unless very good fuel is run. Mine seems close enough that trying to retard it 4 degrees didn't seem worth the effort...but it might be interesting to give that a try during the winter doldrums when looking to stave off cabin fever.
 
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