Why is a 1g ignition base map more aggressive?

[GeoKez]

I'm just going through my ECU maps trying to tidy some **** up and was looking to tinker with my ignition map. I started safe with ignition and realize now that at about 20psi at 6000rpm i'm only running around 6* advance for 98 octane (it should be 8* but haltec is ripping 2* out because of engine temp). After doing some research, it seems that the 1g motors run more advance than the 2g's and also the later backwards motors. I found it's not a little bit either, some 1g motors are pushing 15-18* at 20psi!! The later model base ignition maps tend to be much less, like 8's.

Do we know why this is? I wouldn't think the combustion cambers are different enough to warrant those sort of differences?

Anyone care to share their ignition numbers at full boost, particularly guy's running 1g heads? Or you guy's that do this **** for a living have a different general starting point for 1g's compared to the later engines?

I'm not about to screw 10* into it, but figure if it's capable of running 12's or something, it's going to make my dyno graph look a **** load better than what it does now.

 

[BMGTZ]

compression is usually lower stock on the 1G....what is yours

 

[DOUGMO]

yep, lower comp

 

[GeoKez]

sweet. mine I have worked out via cc'ing during the build, was about 8.1 - 1, maybe 8.4 - 1 due to not using the thicker head gasket as planned.

I have permanently install a mic for my diy det-cans, so I might start winding it up.

 

[Cranked]

Pretty sure my last tune was 10 degrees on 1g

 

[DOUGMO]

mine is similar comp to yours George, there might be a touch more in it on 98

 

[4piknup]

Spend your time on the coreflute ducting first. More timing is just going to put more heat into engine. Get your engine temps under control.

What timing do you have at peak torque as you should be adding timing back in from there up.

 

[BMGTZ]

got one of these yet george?

http://www.ebay.com.au/itm/Tomei-Oil-Thermostat-Killer-Mitsubishi-4G63-EVO-4-9-4B11-EVO-10-CP9A-CT9A-/121050446586?pt=AU_Car_Parts_Accessories&hash=item1c2f2b3afa


have you put a heat gun on the oil cooler after a hard run?.....these make a difference

 

[GeoKez]

Ducting is done Jack. I used the sheets of leftover MR2 undertray, and expanding foam to fill all the gaps. It wasn't easy to duct my car, I have the hot side intercooler piping running between the IC and the radiator, hence the silly foam, I had lots of little gaps everywhere that I needed to fill. I cut and shaped the foam after it dried and it doesn't look too bad, just sprayed it all black. 95% of all air going in the top grill and IC hole is getting jamed throu the rad now. I also flushed the coolant from the cooling system and replaced with distilled and water wetter as per George's suggestion.

And spent this arvo calibrating all my sensors, my coolant sensor appears to be way off, as do my other two water temp sensors. I went to jaycar and bought a proper temp probe, chucked it in a boiling kettle and it read 99*. Went out to the car put the same probe in the top rad pipe, it read 74 and the ECU was seeing 90........ WTF!!!! The closest sensor to the probe was the dodgy supa spastics auto one, but when I look at that one compared to the ECU after a proper hard run, it reads over 120* and ECU says 110*!?!?!? Anyways, long story short, I'm rewriting the tables for my intake air and coolant sensors. Real, verified data saves engines.

 

[GeoKez]

got one of these yet george?

http://www.ebay.com.au/itm/Tomei-Oil-Thermostat-Killer-Mitsubishi-4G63-EVO-4-9-4B11-EVO-10-CP9A-CT9A-/121050446586?pt=AU_Car_Parts_Accessories&hash=item1c2f2b3afa


have you put a heat gun on the oil cooler after a hard run?.....these make a difference

Yeah I have mate, when I bought my new oil pump from the states, they already stick one in for you.

 

[4piknup]

Good one geo. You are as thorough as I hope to be.
What is peak torque timing?

Would be interesting to run it at the drags and get a terminal velocity. Probably one of your electronic gadgets will do that for you?

 

[blackvr]

Jack, more spark advance actually lowers the exhaust gas temperatures... retarded spark skyrockets the temps.. So having an engine mapped with an optimum amount of spark advance and a bit less boost, rather than heaps of boost and significant spark retard , can actually result in a stronger cooler running engine. Food for thought ?

 

[4piknup]

Jack, more spark advance actually lowers the exhaust gas temperatures... retarded spark skyrockets the temps.. So having an engine mapped with an optimum amount of spark advance and a bit less boost, rather than heaps of boost and significant spark retard , can actually result in a stronger cooler running engine. Food for thought ?

Oh poo. My bad