Ignition Impulse @ Balancer/Dampner

[A26B]

I found another unusual LT5 goodie in my stash. New balancer/dampner machined for interference fit with the impulse wheel. Once it's properly timed with the crank, would probably be best to drill & tap for small screws to keep it in place.

Anyone care to step forward with some information & suggestions?

http://i190.photobucket.com/albums/z224/A26B/P2180009.jpg

[LGAFF]

I am guessing this was the crank trigger that was to be used when they did the 2 Bentley LT-5 engines...the engine in Michigan that was for sale some time ago had a trigger setup and was a Bentley engine

....you can see the motor in the Thunder at Stillwater video...they actually are talking about it(what the motor is) but the music drounds out the audio

[Tyler Townsley]

Do you have any of the phase 2 motors? If so what are the s/ns. Geoff gave Britt a document that lists what engine is what car.

Tyler

[LGAFF]

24 hole reluctor with the other 8 holes to tell the engine firing order????

http://lukeskaff.com/?page_id=380

[XfireZ51]

We might be able to interface that w LS PCM to run CnP
although still issue of secondaries.

[A26B]

We might be able to interface that w LS PCM to run CnP
although still issue of secondaries.
I just love it when you talk like that. WTH does it mean?

[LGAFF]

I am guessing doug Rippie might know how these work

[tomtom72]

I just love it when you talk like that. WTH does it mean?

Yea, it sounds so official! So this would or could be made to work if bolted to the balancer and we use a ECM from an LSx motor to just run the ignition system? We could delete our ignition box and coils and how would we tell our LT5 ECM it's alright nothing is wrong?

[XfireZ51]

I just love it when you talk like that. WTH does it mean?

Jerry,

I love getting you excited ;). A 24 tooth reluctor is what is used to trigger the LSx Coil near Plug ignition. A crank sensor on that wheel can feed the signal to an LSx PCM which in turn would send the firing signal to each of the coils. Our Zs have a 9 tooth reluctor so that crank signal is incompatible with the LSx programming unless somehow?? it could be converted. However, once we get passed that hurdle, we still have the issue of 2 sets of VE and SA tables. Some of us have yanked the secondaries, but the calibrations still use both sets of tables since the
Port Closed tables are used when throttle is closed for idle conditions. Probably no way to get injector pulse width small enough with 2 injectors operating. If that wheel was to go into a Bentley or even for marine use, I imagine there was a different ECM for that or at least different programming which would make sense given the different environment the motor would be operating in.

[Paul Workman]

Jerry,

I love getting you excited ;). A 24 tooth reluctor is what is used to trigger the LSx Coil near Plug ignition. A crank sensor on that wheel can feed the signal to an LSx PCM which in turn would send the firing signal to each of the coils. Our Zs have a 9 tooth reluctor so that crank signal is incompatible with the LSx programming unless somehow?? it could be converted. However, once we get passed that hurdle, we still have the issue of 2 sets of VE and SA tables. Some of us have yanked the secondaries, but the calibrations still use both sets of tables since the
Port Closed tables are used when throttle is closed for idle conditions. Probably no way to get injector pulse width small enough with 2 injectors operating. If that wheel was to go into a Bentley or even for marine use, I imagine there was a different ECM for that or at least different programming which would make sense given the different environment the motor would be operating in.

Aside from an alternate ignition system, tell me again what problem you;re trying to solve with the CNP?
:icon_scra:icon_scra

P.

[VetteVet]

Paul,

The 411 PCM swap is a good one if we could get it to work on the LT5. The third gen F-body guys are doing this swap and reporting improved driveability, power and fuel economy. The tuning is much easier and there are third party code mods available for forced induction, nitrous, launch control and wide band O2 support. Going to COP or CNP would get rid of the Ignition Control Module that is getting harder and harder to find. Hell we could even implement Electronic Throttle Control with the torque management that would make possible. Also 4L60E and 4L80E transmissions would be on the table.

I've been looking at this for the last couple of weeks and it looks really promising. If we could only get past the 16 injector issue, this would be a no-brainer for me.

Jep

[XfireZ51]

Aside from an alternate ignition system, tell me again what problem you;re trying to solve with the CNP?
:icon_scra:icon_scra

P.

I guess you could ask why GM would bother if it wasn't worth it. CnP is credited with providing some of the power increase for the LSx motors.
We have 4 coils that fire in "waste spark" mode. So even tho we have 4 times as many coils as an LT-1/L98 motor, the coils fire only half as many times as a single coil, not 1/4. One coil per plug means one coil's full power per cylinder, therefore longer dwell times for charging the coil, ie more power. More power equals better burn on less fuel. Now instead of our coils which fire twice per revolution, imagine a coil only needing to fire once. The coil has twice the amount of time to fire and at 7000rpm, time is something that is very valuable. CnP also minimzes the resistive losses due to the length of the conductor. Higher voltage, hotter spark and more accurate timing. Less advance needed. My blue car only ran for about 30-45 sec with CnP but the idle was noticeably smoother and quieter.
Basically what GM did with CnP was eliminate the need for an ignition module. The tasks the module performed were distributed between the
coils and the PCM. The PCM determines the firing order, the coils manage the actual firing (which in the LT-5 is done by the IM). The 24 tooth reluctor provides nearly 3x better timing resolution than our reluctor.
Obviously with what Jerry has, someone was thinking it could be a better alternative.

[VetteVet]

Well said, Dominic!!

[Tyler Townsley]

Paul,
.

I've been looking at this for the last couple of weeks and it looks really promising. If we could only get past the 16 injector issue, this would be a no-brainer for me.

Jep

This a non issue, pull the secondaries and fire them togeather. Thats what I do with a stock ecm and no secondaries.

Tyler

[-=Jeff=-]

Well doesn't the Stock Ecm have all the injectors on 8 ports anyway? the injector modules allow to run 16 injectors but I believe the Ecm has only 8 outputs

Also keep in mind if you solve the issue of running a LT5 with a LSx PCM. you also need to make the CCM happy

[VetteVet]

Tyler,

I have done the secondary delete. Are you running all 16 injectors at idle? I was under the impression that pulse widths got too short at idle to fire all 16 injectors reliably enough for smooth idle.

Also, I'm not sure that the 411 injector drivers could handle the current required to drive two injectors per driver, which could mean an add-on driver circuit to handle the exra current.

I think that the mods could be made to the 411 code, the hard part is getting the code hacked. I've started disassembling it, but it's a lot more complex than the P4 code.

One interesting note: the Motorola 68332 processor has table lookup instructions as part of the instruction set. Instead of having to execute a routine for lookups, it just takes a couple of instructions to load the registers and then execute the lookup instruction.

The 411 PCM code has adaptive octane control with high and low octane spark maps with interpolation between the two. The PCM basically maintains an effective octane rating variable that is used for the interpolation between the two tables. It also has shift light control that can be set independently for each gear. All of the tables extend up to 8000 RPM. It also uses an adaptive idle strategy, although I'm still trying to figure out exactly what that is.

The really cool thing is that the code is divided into segments. My understanding so far is that segments can be mixed and matched and features can be turned on and off. If you want air pump functionality, click the mouse and you have it. If you don't, click the mouse and that code is not executed. If you're using electronic throttle, click and it's turned on in the code. Cable throttle? Click and those routines are made active and the electronic throttle routines are disabled. The alternator excitation can be controlled by the PCM if you enable it. The alternator is de-excited at WOT to make the extra power available.

I've just started digging into the 411 PCM, but so far I'm pretty impressed.

[XfireZ51]

Well doesn't the Stock Ecm have all the injectors on 8 ports anyway? the injector modules allow to run 16 injectors but I believe the Ecm has only 8 outputs

Also keep in mind if you solve the issue of running a LT5 with a LSx PCM. you also need to make the CCM happy

There are only 8 injector drivers. Remember the LT5 code is a derivative of the L98. GM didn't move on to the 2nd Gen LT-5 because of the need to develop and certify a new ECM and code.
The firing for the secondaries is piggybacked from the primaries with the power for the secondaries provided thru the secondary relays. The secondaries shut off at 0 throttle and use the VE Port Closed tables at that point. You can see that in a data log with the ECM switching from Port Open to Port Closed.
By the way that goes for the SA tables as well. And then there is the question of the CCM.

[-=Jeff=-]

There are only 8 injector drivers. Remember the LT5 code is a derivative of the L98. GM didn't move on to the 2nd Gen LT-5 because of the need to develop and certify a new ECM and code.
The firing for the secondaries is piggybacked from the primaries with the power for the secondaries provided thru the secondary relays. The secondaries shut off at 0 throttle and use the VE Port Closed tables at that point. You can see that in a data log with the ECM switching from Port Open to Port Closed.
By the way that goes for the SA tables as well. And then there is the question of the CCM.

Okay..

my point was is that couldn't those 2ndary driver modules be used with the LSx PCM?

[A26B]

If 16 injectors are a problem, why not just ditch 8 of them and simplify?
Here's a solution, work-in-progress......

http://i190.photobucket.com/albums/z224/A26B/INJHSNGS8injmodB.jpg

http://i190.photobucket.com/albums/z224/A26B/INJHSNGS8injmodA.jpg

[XfireZ51]

Okay..

my point was is that couldn't those 2ndary driver modules be used with the LSx PCM?

Yes but you still need to have 2 sets of VE and SA tables to do that. One way of having both injectors operate constantly, including idle, and still have a controllable pulsewidth would be to vary the fuel pressure. That would eliminate the need for the Port Closed tables but then you would need a regulator that varies pressure and some code to deal with the changing the variable base pulsewidth constant similar to what EBL (www.dynamicefi.com (http://www.dynamicefi.com)) does now and what I believe the C6 ZR-1 also does. The 2nd Gen LT-5 was going to use single injectors and I wonder if Lotus was thinking along those same lines?

[Tyler Townsley]

Tyler,

I have done the secondary delete. Are you running all 16 injectors at idle? I was under the impression that pulse widths got too short at idle to fire all 16 injectors reliably enough for smooth idle.

I've just started digging into the 411 PCM, but so far I'm pretty impressed.

My idle is messy but I am also running stage 2 cams and pretty serious porting so not sure if it because of the pulse width or low velocity at low rpms. It comes on so strong about 6k that it pulls through the clutch.

GM learned a lot from the development work done by Lotus and followup stuff with the racing effort. If you are going to compete at that level you need the best.

Fastlane went to single injectors and a Motec in 93-94 and he probably knew more about what works than we realized at the time. Every time I talked to him I learned something. He told John L what he wanted/was doing and John woluld try it and find he was ahead of everyone. To bad he left the hobby. You want turbo code for the LT 5 just borrow the ecm/code from the Cerve III. Geoff said they tested that for a lot of hours on the dynos at Lotus before releasing it for that car. (He did have that code, not sure he still has it though.)

Tyler

[VetteMed]

If 16 injectors are a problem, why not just ditch 8 of them and simplify?
Here's a solution, work-in-progress......



Jerry, I was wondering if someone was going to bring up that option! Looks like a lot of work into those pieces, any "story" to go along with them?

[RHanselman]

What are you going to do with it? I could give it a try on the turbo car...

[A26B]

Rat,
Well, you know it's like a Mona Lisa, there's only one.....except i think i have 2 of these, so they are worth only 1/2 a zillion apiece. Kidding aside, I'm not sure yet, probably offer them on the website. I have billet rods & titanium spring retainers now, so may as well offer the advanced balancer!

No one has yet offered up an opinion on the inner circlle of windows. Looks just like the crank reluctor to me, with the 9th small cutout. If it serves the same purpose, it could eliminate the need for the reluctor on aftermarket stroker cranks by picking up the crank position here, with it properly indexed to the crank. Cam timing could be handled with a degree wheel, something a stroker build would do anyway.

[Merlot566jka]

I found another unusual LT5 goodie in my stash. New balancer/dampner machined for interference fit with the impulse wheel. Once it's properly timed with the crank, would probably be best to drill & tap for small screws to keep it in place.

Anyone care to step forward with some information & suggestions?

http://i190.photobucket.com/albums/z224/A26B/P2180009.jpg


Interesting. I do not think this will work on the 411 pcm. the pulses on the 411's reluctor are 12* and 3* (total 15*) and I believe its the trailing edge of the tooth that initiates the trigger. As you can see on this wheel, the tooth and gap count are even.

I am in your area Jerry, Is there a way I could come by and throw this on a coppy machine and leave with a print of it?