Building my own ignition....

[Buggy]

I've gotten kind of sick of the serious mess that DLIDFIS has created under the hood of my Rx-4 so I'm playing around with the idea of building my own ignition system using LS series coils and possibly a CAS to trigger the whole thing. I know people have done similar setups before using haltech, motec, etc ecus to controll it all, but I'm just building a simple ignition system. No need for an expensive ECU on a carbed engine. Does anyone have any insight on this? I can't see why you couldn't use the stock CAS to trigger the coils themselves. Each individual coil has its own ignition module built in so it should be as simple as just wiring it all up. I'm no electronics expert though so I thought I'd ask before I start breaking things.

[t_g_farrell]

I think you need a computer to interpret the CAS signal and trigger the coils.

Remove the trailing and it will help clean up a lot of the mess.

[Buggy]

That's what I was thinking. I know the CAS creates an analog signal and I'm almost positive the LS coils require a digital signal and the voltages of both will probably be different as well. I'll have to do some more research. I was hoping someone else would have possibly tackled this already.

[2gslse]

if you were able to make the system work that easy you would also lose your vac. and mech advance that your distributor has built in already

[RETed]

+1

How do you dial in your ignition advance or any custom ignition timing curve?
This is why aftermarket computers are used in between everything.


-Ted

[Buggy]

That thought never crossed my mind either. Right now I don't run vacuum advance, but mechanical advance is being used. It would be like using a completely locked distributor. Seeing as it is going on a bridgeport the ignition could be left way advanced all the time. Some adjustment through the rpm range would be much more ideal though.

I could modify a distributor and just use it strictly for a trigger device. I have to go look at some parts and come up with ideas. This will work one way or another........

[Buggy]

Also another reason I want to get rid of the current ignition system is the fact that I do run into some ignition breakup at high rpms ( like about 8k). I may have to go full electronic with some sort of ECU.

[t_g_farrell]

What are you using for ignitors in your current DLIDFIS?

What dizzy are you running?

[Buggy]

I'm running a distributor from a GSL-SE and igniters as well. Good old J109's.

[t_g_farrell]

I'm no expert but I think an MSD might fix your >8k ignition issue.

No ECU needed either.

[FC Zach]

Thats a big 10-4 on the MSDs, but you will either need to modify or bypass the igniters for that set up.

[Buggy]

If I'm going to spend cash, I'm not going to waste it on an MSD box. I'll go all out and get an ECU that I can tune an ignition map in to suit my needs and I can run the coils I want. I can always add fuel injection then later if I choose to do so. You can pick up some pretty good and cheap used stand alones these days. I had a megasquirt I sold for next to nothing. Should have kept it...... Oh well, hindsight is 20/20 as they say.

[Buggy]

My whole idea here was to build something on the cheap as my recent TII purchase has left me slightly broke. I already have the LS coils (got them dirt cheap) and i have tons of CAS gears and distributors and crap. Keep throwing thoughts and ideas at me though. This thread is helping me think about this and I like hearing everyone else's thoughts.

[NoDOHC]

I would install the aftermarket ECU, your engine will thank you. The fuel is much easier to tune using an aftermarket ECU than a carb.

Your engine has a lot more than 156 WHp in it, given the mod list.

I made 155 WHp with a stock 6 port and Haltech e6x.

[Buggy]

This is all very true. To be honest though the car is making more power than that. We stopped the dyno pulls at 7000rpm because the dyno was overloading the car and it was getting hot. They hp curve was still increasing at 7000rpm and this was on a mustang load dyno. I'm sure its closer to 170whp, but I do agree it has way more and FI with a standalone would tap into that. I like the weber carb though. It keeps with the old school feel. It's a tough decision.

[NoDOHC]

You should be above 200 WHp by 7,000 rpm. The old engine in my car did that with a cleaned-up stock port, factory manifold, factory ignition, and 8.2:1 polished turbo rotors. I also use a mustang dyno - you can't improve on steady-state loading...

I think that the carbs are running very rich. I always had trouble getting a carb to run at all with vacuum if I leaned it up enough to make power at WOT.

I really like fuel injection.

Still, there is something to be said for old school.

[Buggy]

It is running perfectly fine as far as AFR's go. We had it hooked to a wideband on the dyno as well. If I remember right it was in around the 12's or 13's. The big problem is the carb and intake. A 48IDF is too small for the engine its on and the intake isn't the best flowing intake ever made. Also my exhaust isn't ideal for power. I traded maximum flow for my hearing.:lol: The first exhaust I built for it made far more torque down low but I just could stand it and neither could anyone else (like the cops).