crankit

Just curious on what peoplep run for a timing spread between the trailing and lead plugs. Also any mods that required a change from stock.

damon

check out paul yaw's site at http://personal.riverusers.com/~yawpower/
and look up his pages on timing very informative (he knows a lot about our cars )

Peace

crankit

Seen Yaws pages on timing just want to know what people run and if different form stocK why?

damon

it al depends on your mods , driving , altitude , grade of fuel .

most people that Ive heard from use trial and error (between 10 and 26 degrees both leading and trailing ) our cars all started out the same but have differnt amount of wear on all the members makes them all different , things that do good on one car could be devastating to anothers performance

peace

peejay

Best power: Zero split (bad for emissions)

Best emissions: Factory (emissions is Mazda's primary concern with tuning)

Note that it's generally a Bad Thing for the trailing to fire ahead of the leading at heavy throttle, so you'd be good to put a little split in to be safe. I run 10 degrees of split, for a safety factor because I have an MSD on the leading side. (Just in case the first couple sparks from the MSD don't light it off...)

82streetracer

iTrader: (1)

you can have them fire at the same time?

that sounds like it would make good power.
also it would let you run direct fire on the trailing

I want to run direct on the trailing so that I can rid myself of the dizzy and run 4 coil (wouldn't it look tight to run 2 MSDs and 4 coils, then just have a cover for the dizzy)

4ohfour

how do you run zero split timing? Would that be both plugs firing at the same time?

cheers'

REVHED

I don't think having a 0* split will make any difference... you still won't be able to run direct fire on the trailing as the wasted spark will still be firing into the incoming mixture. This is due to the position of the plug in the rotor housing.

82streetracer

iTrader: (1)

Yeh I was looking at it yesterday.

I had a idea though. so you could run direct and msd on the trailing.

YOu would need 2 msds, 4 coil packs and a crank trigger setup. you could run two crank triggers.

one for the front rotor and one for the rear.
then just run a msd of each trigger and 2 coils of of the msd and those coils to each rotor.

with this you have zero split, Direct fire with multiple spark on both the leading and trailing and you can get rid of the distributor completely. the only other thing you would have to do is wire the tach off of one of the msd boxes.

What do you think.

82streetracer

iTrader: (1)

with multiple sparks on both the leading and trailing the emmissions difference would be negligable.

DriveFast7

iTrader: (1)

the shop that built my 12a sp, and many ppl i've talked to, say 8 degrees split leading-> trailing.

BradP

82streetracer

iTrader: (1)

so what would be the best timing. 0 degree tdc on leading and 7-8 atdc for trailing.

crankit

4 degree btdc lead and 4 degree atdc trail that should put your totals at 24 btdc lead@4000 and 16 btdc trail@4000

peejay

Always measure your timing at maximum advance (over 4000rpm). Some distributors have less advance than others. The RPM range below 4000 is unimportant so why should you care where the timing is down there?

I had problems running at 24/16, that's why I was running 20/10. I don't know where that was at idle, I never bothered to see where idle timing would up

I'm working on modifying a distributor so that each pickup has its own rotor. It'll be tricky to get it to fit right but it's doable. Then, each ignitor will drive a two-post coil which will fire L&T at the same time. (This means no waste spark on leading... oh well) No wires to the distributor cap at all.

crankit

I just said 4000 cause it sounded right . Really its the max advance wasn't looking at the rpm.