This was also from Stealth and was a 1803cc with headwork, panel filter, exhaust and WUR mod for comparison
That first plot is a good comparison for the stock good working KR. So if yours was tested with the same care and corrections, then that is what the acceleration would look like on the road. The second is not compatible, as that was when that Sun 12 dyno was run on old software, compared to the sport devices software. Your engine could benefit from mapped ignition changes, to make full use of the 1.9 16v and allow it to be mapped to optimise cylinder fill beyond 7000 rpm as well as spark adjustment to MBT everywhere. I suspect, there is more torque to have in that midrange, where there is a hole in that plot. The KR ignition ECU will run the engine, but these days, there are more accurate controls.
Just to update that last few comments, back on the RR recently after the below changes -Stock ECU Crystal back in -Adjusted Cams -More Ignition advance -Air Box mod with jetex filter (was Piper) -Single tip NGK plugs (gapped 0.8mm) -Ran on 99 fuel
Good information in here as always! I'm just catching up and trying to understand the stock ignition map. I assume the table above shows total advance including the distributor set at 6deg BTDC, since that is the value shown for idle. So the added advance at WOT and 6827rpm would be 20deg on top of the 6deg. Do you know if the PL knock box (811 907 397 E) map is the same as the KR? I think I saw an old post on the vortex that it was +20deg advance above 4,500rpm, which is not that different from the KR map. I currently have a 4.58752Mhz crystal swapping in the PL knock box for a 7,875rpm rev limit. If I understand correctly, swapping the crystal would effectively stretch out the map, so that my engine would not hit 26deg on that map until 7,467rpm. What I don't fully have a grasp on is if changing the clock frequency also changes the amount of advance? Seems like it might if the controller is calculating how much earlier (in micro-seconds) to send the spark. If so, it seems the additional advance should be proportional to the crystal ratio, so about 9% or 2deg extra. I did a back to back run on the dyno last year with the stock and modded knock boxes and there was not a significant difference between the torque curves (until you got to redline obviously). I'll see if I can dig out a plot.
With a theoretical idle setting of 14° BTDC (8° more than stock) the table below should be what timing we are getting at WOT (i have only changed the numbers in red) This would bring it into a ideal window for a performance engine with idle advance over 10° but not more than 20° and a 30-32° maximum advance which should be a ideal number for the vw pent roof combustion designed. Obviously this is all theoretical as every engine is different. Again this is really only improving the max end of the scale and as with k-jetronic fuel you can only shift the point up or down the rev range
I think from previous info and findings the crystal only effects the actual limit so say 6800 stock rpm on stock 6deg base advance so 26 deg max advance at 6827rpm (from stock map) It would remain at 26 deg untill the new limit of 7910 (4.608 crystal) it reached
Just done some tests on my 16v Stock crystal Base idle 12.7 deg 4k rpm 31 deg 4.608 crystal Base idle 12.7 deg 4k rpm 31 deg So from that it seems pretty conclusive that the crystal only dictates the rev limit and has no effect on the rest of the ign map
