ALFAGTV6.COM

[Murray]

I have a 1986 GTV6 2.5L "S" cams no AFM converted to Megasquirt II.My CR is stock.

I have been researching the subject of ignition timing as I will soon be turning this function over to the MSII ECU.On this site there is a wide range of recommended settings for static ignition advance - I've seen as high as +28 deg.btdc ?

I'm wondering if you guys could toss me your opinions on this subject.It would also be interesting to know at what point you find that you have to start using higher octane fuel.

Currently I'm running 8 deg static through the Bosch EZ-L system per Greg Gordon's suggestions.My distributor currently has a vacuum advance setup.

[Mats]

Once you move out of the dark ages and have a custom setup those static numbers are totally out the window since they are really a compromise. By twisting the dizzy you move the entire advance curve on a stock engine when you really only maybe want more advance between 4 and 6k at full chat and really want LESS advance at idle or up to 2500rpm.
28* advance at tickover sounds absolutely mad to me but if you need it to make good power somewhere else in the map so be it.

[ar4me]

Murray,
Since your GTV6 has the vacuum advance I suppose you get the stock advance. Anyway, with my GoTech I plugged the vacuum advance on the distributor and control everything with GoTech (you basically want to "lock" the distributor). You want to have the advance a function of both RPM and load as Mats say. The ignition has been discussed in some places, but I'm not sure it answers your question specifically. I think idle is set at 7 (3.0 liter) and 2 (2.5 liter) stock. Nothing to gain by deviating from that I suppose. In other posts people seem to have anywhere from mid-20s to low-30s at WOT at higher RPM.

BTW, I think that corresponds to the 28 you refer to - which is not a static advance across all ranges!

Don't some of the MS guys have an ignition map ready to go that you can use as a decent starting point?
Jes

[Murray]

Thanks Mats and Jes.Now I get it I guess if your tuning for track only and you don't have the flexibility of changing the curve then radical increase of the static to get the desired dynamic values at high rpms is a necessary evil.
When I switch on the MSII control (that makes it sound easy eh ) Then yes I'll have control of this curve.I'll start with Steve Rosser's and that should keep me out of serious trouble.

[SamW]

Remember that the 7 degrees and 2 degrees is with the vacuum advance unplugged, once you plug it back in, the advance is greater at idle, at least it is supposed to be. So true timing at idle is greater than the 2 or the 7.

[enzo]

here is the vacuum advance table of the disributor of the GTV6