LT5 Ignition Systems Question???

[Blue Flame Restorations]

Hey guys, let's get Ron Wozniak involved here.

Here's the ???

How can we update the ignition system for a coil to plug (LS) type system?

It would be nice to update the technology with modern day parts that are accessible and may help to aid in HP gains.

Here you go, Ron!!!
Thanks!
Brett

[Tyler Townsley]

Can a Northstar dis module be used in place of the LT 5 dis module? Can the LT 5 dis module be rebuilt? If so how do you get it apart. I understand you have a lt 5 module with the cover off? Can you post a picture of it?

Tyler

[LGAFF]

What was the DIS system used on the two motors that were built to solicit potential business from Bentley/Rolls Royce? My undestanding was that it utilized a crank trigger system.

[LGAFF]

Well since the engine is gone, I will let the cat out of the bag. If you recall a motor being sold in MI recently....well a few weeks after it went up for sale, I bought the Thunder at Stillwater video. Amazing there was the gloss black engine shown during the plant tour, grey plug wires and all. I contacted a workers at Mercury and it was a test engine for a possible outsourcing of the LT-5 to Rolls, there was one other built with a crank trigger, and that was it.

Engine has apparently sold

[XfireZ51]

Originally Posted by todesengel

I found a more recent posting explaining the cop conversion on the 4g63. Just a little food for thought.

http://www.dsmtuners.com/forums/arti...tall-pics.html

Were it only that simple.

[tomtom72]

I know I really don't belong posting in this thread because I don't understand this ignition stuff. I would like to ask a couple of questions. I'm sorry to clutter up this thread.

Why do we need to consider reconfiguring our OEM ignition system? Strictly because our parts are NLA, and no one is able to repair our OE DIS boxes?

Does a COP system allow tuning latitude specifically for ignition events? Our system does not allow any type of ignition tuning, right?

See how much I don't know! Sorry guys.

TIA

Tom

[tomtom72]

Thank you Rob.


I am a bit less in the dark now. I wonder if in the LT5 application that our system was easier and less expensive to do than a COP system. I'm wondering if combustion chamber design, our vs the LSx motors', indicated that an LT5 could get away with using a waste spark system and not suffer?

Okay, I ask too many questions because I don't really get electronics at all. Sorry all.

Thank you for helping me to gain some knowledge!

[Hog]

There are some SAAB CNP(Coil On Plug) setups that look like the setup above which do not use high tension plug wires.
The GEN III (LS1/6) use a CNP(Coil near Plug) ignition which use short high tension wires.

The only shortcoming I see with the LT5 system(if there is 1) is the length of the high tension plug wires.

The Northstar uses a wasted spark setup as well.(plug fies both on the power stroke and the exhaust stroke).
Getting away from the distributer was the big step in GM ignitions which was used in the 2002 L31 Vortec SBC350 in the trucks. Timing advance was PCM controlled, but as coil voltage goes up, cap/rotor wear increases. The L31 uses a 4x reluctor wheel on the crank.(4 pulses per crank rev. and a 1x camshaft sensor in teh ditributer body-1 pulse per camshaft rev)
There was a Vortec 454 BBC that uses the same distributer as the L31 Vortec 350 SBC and the same coil(which is the same coil the LT4 engine uses) as well it uses the same 4x crank and 1x camshaft position sensors.
In 1998 GM took the L29 Vortec 454, installed a CNP ignition along with a 24x crank reluctor/1x cam sensor and used an ETC(electronically controlled throttle) and called this the Vortec L21 454. This was the 1st GM truck engine to use CNP ignition. The camshaft position sensor(CMP sensor) is the same sensor as was in the older distributer body which was driven by the camshaft gear, except instead of the typical ditributer cap, a plastic cover is used. The only purpose of this cam gear driven unit is to drive the oil pump, and to give the PCM a 1x signal.
This engien was used in HD truck applications like the Kodiac meduim truck, P30 vans and motorhomes. The conventional Vortec L29 454was used in3/4 ton and 1 ton trucks.

In 2000 GM went from the L21 454 and the L29 454 to the Vortec 8.1(496) which used a full CNP ignition with a 24x reluctor crank reluctor and a 1x camshaft position sensor. For the new engine, the cam driven ditributer was needed as the PCM got its cam sensor info right off of the cam sprocket reluctor from a sensor mounted in the front timing chain cover.

Sorry for the book, but thats illustrates the ignition evolution for GM trucks. This has made it possible for more modern PCM's like the 411 PCM along with a SBC version of the L21 24x crank reluctor to convert conventional SBC's to run LS1/L21 style CNP ignition. It has also made it possible to run LS1/L21 styke CNP ignition on LT1/4's, eliminating the Optispark system.
The 411 PCM is GM p/n 12200411, it uses dual 80 pin connectors, and is a 512 kb OBD2 PCM.
If you can feed the 411 PCM a 24x signal, you could use is to fire an LS1 GEN 3 SBC CNP 8 coil ignition. Also feed it the TPS and MAP data, you coudl also control its fueling. No morew chips, say hello to flash memory and OBD2 tuning products. But it can only control 8 high impedance injectors, and wouldnt control the secondary throttles. I assume if someone really wanted to, they could eliminate the secondary throttles, and even the secondary injectors.

I dont see much if any gain (powerwise) from using a Northstar coil pack, as the LT5 uses pretty much the same setup IIRC. There would be soem advantages so far as parts availability goes.

Sorry for the book.

peace
Hog

[XfireZ51]

Rob,

I was commenting on the article for comverting the Toyota motor you posted.
The issue that I and several others found is that the LT-5 ignition module acts more like a. co-ECM. It has it's own processor. Remember that the LT-5 ECM code is really a modified L98 code. Do with 8 injector drivers, they adapted it to run 16 by powering the secondaries thru the secondary injector relay. The primary injector provides the firing signal and so they fire in tandem. The L98 code assumes a distributor. That's why the crank signal feeds the ignition module and not the ECM. So we believe that parameters like coil dwell time are managed by the ignition module. The LSx coils have the PCM providing that control. These are the things that have me excited about LT5Ignition coming on board.

[tomtom72]

Thank you Hog. On the length of the secondary wires, couldn't you just go up a few mm to compensate for voltage drop?

A little more light for the mushroom!
I'm going to ask one more dumb Q in a "what if" vane....the Ford GT motor has two injectors per cylinder and COP ignition ( I think it don't have a distributor? ) and a blower. I wonder how they drive two injectors and could their ECM and ignition control box ( if it even has an ignition control box? ) be adapted to an LT5?

The way I see it if you want only one injector per cylinder in an LT5 you need the whole top end of the second design motor. It only had one injector per cylinder. Hummmm, I wonder what they used for an ignition system?

Thank you both, Rob and Hog, for putting up with my ignorance.