c20xe map advice please.

cobweb · Post by **cobweb** » Sun Jul 05, 2009 6:48 pm

Hi all, im new to the forum and was wondering if anyone can help me please?
I have just purchased a megajolt lite jr tps version for my c20xe engine.
The engine is standard apart from twin 45 weber carbs and bigger exhaust manifold.
I was after some advice on maps for the engine, is there a base map available for the c20xe engine using tps? or can i use the map that it comes with? Sorry to sound stupid.

If anyone can help i would really appriciate it.

NITROPIXIE · Post by **NITROPIXIE** » Mon Jul 06, 2009 12:26 pm

There is a standard map built into the megajolt which shoould be safe for most engines and then its just a case of getting in your car with a friend and a laptop or take it to a rolling road to get the best out of the system as they will be able to check fuelling aswell.

Probably best to get fuelling done first as a lean mixture can cause damage to the engine.

cobweb · Post by **cobweb** » Tue Jul 07, 2009 9:05 pm

Thanks for replying, i see there is a map for an c20xe on weber 45 carbs in the map library section but its for a map sensor version, will this still work ok? if not is there way of converting it into tps?

NITROPIXIE · Post by **NITROPIXIE** » Wed Jul 08, 2009 12:37 pm

I believe you can. First off you have to calibrate the tps as follows http://www.autosportlabs.net/MJLJ_V4_Op ... alibration

Then the you will need to change the load axis of the map to suit your TPS settings. I don't think there is an exact way of doing it to be honest. Try changing the MAP load axis to an equivalent voltage from your TPS. So if the load changes by 10% on one bin then change your TPS value by 10%. On most Maps there will be little change at the high end (full throttle) load bin, so ignition advance changes more at the part throttle positions. This therefore makes for much smoother running engine and better low end torque. This should hopefully give you a pretty close map to begin with. Just make sure you don't have too much advance which could result in pinking especially at the high end.

It would be best to get the timing done when you get fuelling done in my opinion. Don't run the engine unless your fully sure that the jets and setup you have for the carbs has been proven on another engine from guys with quite a bit experience or you have taken it to get rolling roaded from a garage with plenty of experience.

cobweb · Post by **cobweb** » Mon Jul 13, 2009 10:23 pm

thanks again, that sounds a bit complicated