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Megajolt map
scutter - 23/3/07 at 05:10 PM

Finally got the Megajoplt running in 2D mode, once i've uploaded the V3.1.3 firmware I'll go 3D.

The question is does anyone have a 3D map for a 1700 crossflow running TPS?

ATB Dan.

MikeRJ - 23/3/07 at 05:45 PM

There is a map for a 130bhp xflow with a Kent 234 cam in the Megajolt forum. Doesn't say capacity but probably 1700 and should be a reasonable starting point if yours is in a simmilar state of tune.

http://www.autosportlabs.org/viewtopic.php?t=1085

scutter - 23/3/07 at 06:33 PM

I'd seen that one, but thanks.
It's got a massive hole/dip in the advance around 1500/2000 and runs to over 44 deg at high map/part throttle openings.

from what ive gathered i only need between 14 deg and 34 deg in total which make me not trust that map.

Many thanks Dan.

MikeRJ - 23/3/07 at 08:03 PM

quote:
Originally posted by scutter
from what ive gathered i only need between 14 deg and 34 deg in total which make me not trust that map.


That really depends on the spec of your engine, there are no absolute limits on how much advance you should need.

The "hole" in the curve is almost certainly to help stabilise the idle speed as it's in about the right load area. The way the map is configured, as the engine sits in the 600-1500RPM band, the slower it runs the more advance is applied which really helps to sort out the dodgy idle that hot cams can produce.

TangoMan - 24/3/07 at 09:12 AM

quote:
Originally posted by scutter
I'd seen that one, but thanks.
It's got a massive hole/dip in the advance around 1500/2000 and runs to over 44 deg at high map/part throttle openings.

from what ive gathered i only need between 14 deg and 34 deg in total which make me not trust that map.

Many thanks Dan.


Engines with poor squish do needs lots of advance. I thought the crossflow need around 36-38 degrees but most engines need lots of advance at low throttle/high rev combinations as the poor cylinder filling needs plenty of time to burn.
As said, the hole (although I haven't seen the map) could be to control idle. This is used frequently with sparks and injection to give a stable idle. Bear in mind that the most common part of your map will be a diagonal line up from low throttle/revs to WOT?max revs, with other areas being used at different times where economy running or acceleration will be required.