Hi folks I suspect my spark map on my megasquirt setup may be well CRAP. Or has become corrupted by saving and loading in speed density rather than alphaN.
So I'm looking for a comparisson between mines and anyone else who has a similar setup.
Set up is vauxhall 2ltr xe 16 valve with megasquirt V2.2 board with wasted spark and gsxr 1000 tbs. running alpha N
I've attached a document file of a screen dump showing my map.

Almost 100 views and 20 downloads and no comments?????
Surely someone else must thinks either the map is wrong or I am wrong

[Edited on 15/6/09 by omega 24 v6]

Well!! no expert, either on your engine or MS, but the advance figures seem very low to me, I would have expected the 1100rpm figure to have been some where around 10 to 12 degs, and max advance something like 36/38degs, (cruising light throttle opening). Would think that a session on a R/Road would be a good idea. Just my opinion, could be way out. Cheers Ray

Ray,

16v pent roof engines usually only run a maximum of 26 to 28deg advance at WOT (which is what I would expect to see along the top line of that table).

If you think about what a dizzy gives you, ie varying advance with rpm only you could in effect make a '2d' ignition table by setting your WOT line (at the top) to rnage from 10deg at idle to 28 deg at say 3500rpm, and upwards. Everything inbetween 1000rpm and 3500rpm should be roughly linear, rising with revs.

You could, if you wanted to have a rough starting map, then make all the columns the same you would then have the same sore of advance curve as a mechanical dizzy.

Anything else you want to add in, like more advance on overrun you can once you are happy with everything else.

Bear in mind changing the advance will change your AFR as well.

David

So are we sayong the table is pretty much OK then??

Looks ok to me, would expect the advance to be higher on the top line as i said above, but otherwise it doesnt look far out.

As long as you dont have any knock and the throttle response is good then i wouldnt worry too much.

I would expect to see some higher values around the cruising area too, which will help economy and throttle response.

[Edited on 16/6/09 by flak monkey]

OK cheers and thanks to Bentyreman as well.

I'd be bopping 6 or so degrees extra on all of the values from 4600rpm upwards, and then blending the lower half of the table into it.

There's a set of rules that got posted on the MS forums yonks ago that help you calculate a rough starting map, i've used them a few times and it's always given me something that runs well and only needs a little tweak here and there. I'll try and dig them up...

Here you go

I have seen that estimator before, but it gives some rediculous figures lower in the load range, like an idle advance of 35deg.

It looks like the only correct area of the table is the top line....even the cruising area seems ambitious with the advance....

I hadn't noticed the silly idle figures the spreadsheet gives, to be honest i've never used the sheet itself to generate a table, I do it by hand using the rules as a guide.

You can get away with some stupid amounts of advance at really light load, 45deg isn't unrealistic

Here is my spark table for comparison. It is, however, running MAP sensor, not alpha N but the figures ought to be similar. Notice my top line. The advance should be almost "all in" by 2800 and completely "all in" around 3200. My full throttle advance is 34 degrees. This is correct for my engine which is a Gen 3 2 litre 3SGE Toyota Celica 16v.
I suspect the total advance requirement for the XE is around 32-34 degrees as the 3SGE engine is not too dissimilar to yours.
This table is simply a tweaked Zetec one.
The car runs fine under all conditions and gave out 166bhp on the dyno at Newark yesterday, despite being strangled by undersize carbs. No pinking or hesitation.
You could adapt this table and back the whole thing off a few degrees to be safe.
Hope this helps.

[img][/img]

Well perhaps my map looks not too bad after all.
So Just to let you all know that the car now revs to the full rev range.
This was achieved at the weekend by placing various sizes of resistor in line withthe Vr sensor +ve cable ( as advised by Phil Ringwood ) ( thanks Phil). I made up some leads with a few differing sizes of resistor and finally came up with a solution to the problem.
What a difference and it looks like I'll now be able to get on with tuning the car in earnest.
So tuning question to follow shortly LOL

Excellent news