Quote:
Originally Posted by PrematureApex
A JB4 has no timing control, and relies on the DME's adaptive advance.
For a big turbo, nitrous, etc. you can look into adding the CPS module (if you can find one...it it even F series compatible), or...a better idea, just get a back-end flash.
But the JB4...no timing control.
Terry, back in the day...
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I will deff look into the CPS. Hoping bc the i/c chiller,meth in, catless dp to 3"+ open exhaust which yes lowers iat & egt by as much as 50% and 115 octane, the DME may run an acceptable timing advance,,, I worry bc the meth and NOS are introduced post MAF and the 115 octane will result in zero pre knock activity the timing will be agressively advanced, even morso than now...
In regards to JB4 and ignition timing, I'm not an expert hence my OP, but common sense tells me it absolutely has to have an indirect effect...I believe F series relies primarily on IAT for timing, but it also relies on a myriad of other sensors, the same that determine boost levels...Just look at your JB4 logs in diff MAPs and conditions, you can see a loose correlation...However the algorithm used exactly I'm sure is extremely complex.
I just found a 200 page .pdf on the S55 and 1st paragraph it highlights the fact that MOST of the fueling, fuel, ignition, systems are identical in theory and mechanism of action...I have a month to study this before executing my plan of attack.......
This manual is clearly worded and a must read for ANY tuner of weekend warrior modding his car...It spells things out in black and white, what sensors influence what parameters...shared parts between n55, s55...Read earlier both the N55 (M2 specific) and S55 use Bosch HDEV5.2 Solenoid valve Inectors (n20, n54, and some other N55s do not, and they actually spray 10% per valve more fuel toward intake side under heavy load/ WOT ,therefor 20% less total fuel the opposite side of the combustion chamber... (They spray in a 4 way atomized mist pattern...) An even mist is sprayed under normal conditions and at idle....
However, I found this interesting....unlike the N55 the S55 atually has a second High Pressure pump that turns on at 3000RPM...also these two pumps have what looks and works like a camshaft on top. spinning and depressing a spring loaded button every 60* basically building up more overall fuel pressure then releasing it in time with the DME controlled injector pulse..
Way off topic but found this very interesting from an engineering stand point...
I'll get into the Ignition system next and be able to say with certinty what sensors determine timing and the order in which they are used in regards to importance...