Going from 1.4 to 1.6 on the same megajolt map

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

Moderators: JeffC, rdoherty, stieg, brentp

Post Reply
damunk
Posts: 65
Joined: Mon Aug 05, 2013 8:44 pm

Going from 1.4 to 1.6 on the same megajolt map

Post by damunk »

I hope you guys can guide me < noob

I am converting my 1.4 engine to a 1.6 by changing the crankshaft and conrod.

I need to get the car from my house to the rolling road guys who tune megajolt about 80 miles away.

They configured the first map for me.

Is it okay to use the original map to run the new 1.6 engine in?

Nothing else has changed apart from the increased capacity.


Other notes
The bike carbs have always run slightly running rich (150 jets).

Alex B
Posts: 163
Joined: Sat Aug 09, 2008 10:32 am
Location: Hegra, Norway

Post by Alex B »

Should be fine to start with. I have a 1.7 running on the same map as a 1.5 and that goes well. If I remember well it should be possible to retard ignition a bit when the stroke gets longer, so you could always put a retarded map in the second place.

Alex

damunk
Posts: 65
Joined: Mon Aug 05, 2013 8:44 pm

Post by damunk »

When you say retard you mean relax the timing?
If I post my map on here , could you guys advise me which section to retard.
I know it's my responsibility. I'd just like to have a back up.

damunk
Posts: 65
Joined: Mon Aug 05, 2013 8:44 pm

Post by damunk »

Attachments
megajoltmap.jpg
megajoltmap.jpg (20.94 KiB) Viewed 10571 times

Alex B
Posts: 163
Joined: Sat Aug 09, 2008 10:32 am
Location: Hegra, Norway

Post by Alex B »

Retarding is meant as less advance, so if for example your ignition is now 31 degrees at 10% load at 3000rpm you make it 30 or 29.

You have interesting bins at 8000rpm. I don't know if you rev that high, but is the retard as compared to the 7200rpm column meant as a soft rev limiter?

How does the engine pick up at low revs, no hesitation when you open the throttle? I guess not as you have quite a bit of advance, but should you experience it you may solve it by advancing at higher load, especially in the 500rpm column. As you open the throttle you may experience a short lean out of the mixture before the extra squirt of the acceleration pump arrives in the cylindres. A bit more advance may prevent this, as I have experienced myself. There are some inconsistencies in the 2200- and 3000 rpm columns at higher load. Was this done with a meaning or was it just forgotten to retard ignition there?

Alex

damunk
Posts: 65
Joined: Mon Aug 05, 2013 8:44 pm

Post by damunk »

I should have mentioned that bogg brothers timed it up to 6500rpm. There is rev limit at 6500rpm.

They just put it on thier rollers and timed it up with the bike carbs.

Their only one of few in the country that specialist in setting up bike carb n tuning megajolt.

I will be installing Phormula knock detection unit (cost around £400). I wonder if I can adjust it at home.

Post Reply