Mega jolt

Fuel Supply & Ignition Systems

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advinnie
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Location: Oxfordshire

Mega jolt

Post by advinnie » Wed Oct 26, 2016 7:23 am

Afternoon every one. Right I have a 2276cc engine in my bug running a megajolt trigger ignition system and have got the engine running pretty good but I do have one question.
Now I know that at WOT (3000rpm) I want the timing advance to be 32 BTDC witch I have and my cruising Kpa at this rpm is 72Kpa put should I add the other 10 degrees of vacuum advance at cruise Kpa or at the lowest Kpa reading I get on over run witch is 39Kpa?
Cheers

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Jadewombat
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Location: Houston, TX

Re: Mega jolt

Post by Jadewombat » Wed Oct 26, 2016 12:07 pm

Not really sure what you mean. The 3D map should account for both conditions and the advance you program for each one. Are you running wasted-spark (coilpacks)?

Can you share a screen shot of your ignition map?

advinnie
Posts: 284
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Mega jolt

Post by advinnie » Wed Oct 26, 2016 5:43 pm

Here's to maps I'm playing with
Tried to up load them but they are to big sorry so here's a link to them
http://i1303.photobucket.com/albums/ag1 ... fsphnb.jpg
http://i1303.photobucket.com/albums/ag1 ... ex9kic.jpg

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Jadewombat
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Re: Mega jolt

Post by Jadewombat » Wed Oct 26, 2016 8:08 pm

Looks OK to me. Are you running:

-Single ignition coil (stock distributor and pointless ignition)?
-Dual coil pack (like Ford EDIS in wasted-spark configuration)?
-Or 4 individual coils (Coil-on-plug in wasted-spark configuration)?

If you have a 2276 motor, I assume it's not a stock camshaft or stock valve springs? If so, you don't need to be so tame with the RPM range. You have the most advance at 3500 then tapering off up to 6800 which is a little counter-intuitive.

The most a stock motor can spin is about 4500 RPMs. I would suggest just setting the max. RPMs of the Megajolt (MJ) to 6000 and still keep advancing spark gradually up from 3500-6000.

The stock distributor curve and advance settings are a good place to start from, but you'll find you can run much more advance with crank-trigger.

advinnie
Posts: 284
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Mega jolt

Post by advinnie » Thu Oct 27, 2016 1:30 am

I'm running a Dual coil pack (like Ford EDIS in wasted-spark configuration)
The cam is a webcam 86b and I have set the rpm limiter to 7000rpm witch I keep hitting.
My main question was , should I have the highest ignition advance at cruise manifold pressure or at max over run pressure?

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Jadewombat
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Location: Houston, TX

Re: Mega jolt

Post by Jadewombat » Thu Oct 27, 2016 9:10 am

Short answer--at cruise.

Since you're running wasted-spark, you'll find that you can run MUCH more advance that a distributor system. What I did with my ignition table was start with the VW/009 type settings, then gradually increase the advance across the board a few degrees, drive it, change some again until I found what the engine was happy with. Crank-trigger systems are far more efficient and the engine will be able to handle a lot more spark. Some example MAPs of similar engines to yours:

http://www.shoptalkforums.com/viewtopic.php?t=98618
http://www.shoptalkforums.com/viewtopic.php?t=110006

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Piledriver
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Re: Mega jolt

Post by Piledriver » Thu Oct 27, 2016 10:23 am

Most engines usually need far more timing at lower MAP, and like a lot more initial, esp with a big cam.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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