Electromotive SDI: To use or not to use; that is the question.
11-24-2002, 12:44 AM
#1
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Join Date: Mar 2002
Location: Missouri
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Electromotive SDI: To use or not to use; that is the question.
First off, please do not reply if you don't know about this system. There are so many people that bad mouth this system yet can not even point it out if they see it.
I am at a point now where i either need to get a new opti or put my SDI on. What would you do??
About how long do you think it would take me to put it on?? I am pretty good with engine work.
Ryan
I am at a point now where i either need to get a new opti or put my SDI on. What would you do??
About how long do you think it would take me to put it on?? I am pretty good with engine work.
Ryan
11-24-2002, 12:08 PM
#3
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Join Date: Jan 1999
Location: I reached back like a pimp and smacked that LS1....
Posts: 886
I've heard of problems with the cam signal not synching correctly on every startup. (or something like that)
IMO the opti kicks ***. I don't know why everyone knocks it.
I'm at 634 rwhp with a stock ignition, except for plugs and wires. (No MSD etc)
IMO the opti kicks ***. I don't know why everyone knocks it.
I'm at 634 rwhp with a stock ignition, except for plugs and wires. (No MSD etc)
11-24-2002, 02:07 PM
#4
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Location: Hell was full so they sent me to NJ
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It's impossible for the synthesized low res pulse to always provide the correct "synch" signal..... there is no cam position info in the system. Only the info provided by the crank timing wheel. So 1/2 the starts, the injectors will be synched one crank revolution out of phase. Whether this becomes a factor at max fuel demand depends on the duty cycle of the injectors. In most cases, the injectors are firing 80% of the time, and the "synch" position has very little impact on HP.
The only down-side I noticed was a stumble off idle on cold start. The fuel was puddling against the intake valves and there wasn't enough heat to vaporize it until things started to warm up. After that it was not noticable, at least not SOTP (I never did any dyno testing with the E'motive).
I did switch back and forth with the Opti from time to time, just to compare, and the Opti felt sluggish.... but then I knew the Opti was failing anyway, so it wasn't a fair comparison.
Of course the one-crank-rotation synch error has no impact on ignition, since they are using lost spark.
The other negative I noticed was an extended crank to start the engine. I was always used to the typical LT1 start - instantaneous. But the E'motive would crank away for a few seconds at times.... I assume while it managed to synthesize the low res pulse and feed it to the PCM to activate the fuel system.
And, the system would not work at all with the OBD-II diagnostics.
It seemed very reliable. I used it for two years. The magnetic sensor for the crank trigger is supposed to be replaced every two years. You may also experience some electrical interference. I know Dave Wedland ("DaveW 396ci" - excellent website, byt the way) used the SDI along with an electric water pump and the Pete Jackson gear drive, and eventually gave up on the SDI, and the PJ gear drive. You might want to e-mail Dave for his experience.
DAVE W's Website
As far as the install, it is VERY easy. The plug wires are the hard part. I used the Taylor 10.4mm wires, using a universal length set, and you need standard terminals, rather than the Opti terminals.
SDI INSTALL PROCEDURE
I agree..... the Opti is much maligned, but when it is working correctly, it provides an extremely accurate ignition. If GM had looked closer at the 3.0L V6 Chrysler/Mitsubishi engine they copied the system off of, they would have realized Chrysler/Mitsu had the sense to put it in a conventional distributor housing on the top of the engine....
.
CRANK WHEEL/SENSOR
ENGINE OVER-VIEW
SDI CONTROLLER ON DRIVER'S VALVE COVER
The only down-side I noticed was a stumble off idle on cold start. The fuel was puddling against the intake valves and there wasn't enough heat to vaporize it until things started to warm up. After that it was not noticable, at least not SOTP (I never did any dyno testing with the E'motive).
I did switch back and forth with the Opti from time to time, just to compare, and the Opti felt sluggish.... but then I knew the Opti was failing anyway, so it wasn't a fair comparison.
Of course the one-crank-rotation synch error has no impact on ignition, since they are using lost spark.
The other negative I noticed was an extended crank to start the engine. I was always used to the typical LT1 start - instantaneous. But the E'motive would crank away for a few seconds at times.... I assume while it managed to synthesize the low res pulse and feed it to the PCM to activate the fuel system.
And, the system would not work at all with the OBD-II diagnostics.
It seemed very reliable. I used it for two years. The magnetic sensor for the crank trigger is supposed to be replaced every two years. You may also experience some electrical interference. I know Dave Wedland ("DaveW 396ci" - excellent website, byt the way) used the SDI along with an electric water pump and the Pete Jackson gear drive, and eventually gave up on the SDI, and the PJ gear drive. You might want to e-mail Dave for his experience.
DAVE W's Website
As far as the install, it is VERY easy. The plug wires are the hard part. I used the Taylor 10.4mm wires, using a universal length set, and you need standard terminals, rather than the Opti terminals.
SDI INSTALL PROCEDURE
I agree..... the Opti is much maligned, but when it is working correctly, it provides an extremely accurate ignition. If GM had looked closer at the 3.0L V6 Chrysler/Mitsubishi engine they copied the system off of, they would have realized Chrysler/Mitsu had the sense to put it in a conventional distributor housing on the top of the engine....
.CRANK WHEEL/SENSOR
ENGINE OVER-VIEW
SDI CONTROLLER ON DRIVER'S VALVE COVER
Last edited by Injuneer; 11-24-2002 at 02:11 PM.
11-24-2002, 05:59 PM
#5
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Join Date: Mar 2002
Location: Missouri
Posts: 595
Yes, Fred, I'm talking about the discontinued one. I just have had the SDI for quite some time so I figured since the opti was out I may as well just put this on. Wires won't be too bad for me as I mocked the system up on an LT1 in the garage and made my wires there; I also have headers so it will be a little better on the install.
As for the opti being good or bad, it's both. Good due to the ignition standpoint, but bad in location. I'd guess I will be more than happy to wash my engine down now but I will bet you won't want to whether you have 240 rwhp or 600+, right??
I think I am looking towards the SDI for ease of maintenance; crank trigger takes all of 5 MINUTES to change and the coil packs are just as easy. If it fails on the roadside, I can fix it right there without losing a drop of coolant.
Yes, I know there are drawbacks but then again, aren't there with anything??
Thanks for your info, Fred, I'm putting it on right now.
Ryan
As for the opti being good or bad, it's both. Good due to the ignition standpoint, but bad in location. I'd guess I will be more than happy to wash my engine down now but I will bet you won't want to whether you have 240 rwhp or 600+, right??
I think I am looking towards the SDI for ease of maintenance; crank trigger takes all of 5 MINUTES to change and the coil packs are just as easy. If it fails on the roadside, I can fix it right there without losing a drop of coolant.
Yes, I know there are drawbacks but then again, aren't there with anything??
Thanks for your info, Fred, I'm putting it on right now.
Ryan
11-24-2002, 07:44 PM
#6
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Join Date: Mar 2002
Location: Missouri
Posts: 595
Wow. If that little cranking is all I have to deal with, I am kicking myself in the butt for not putting this thing on a year ago!!!!
Opti may be nice but there's something about being able to WASH my engine now......
I am sure you have already gathered that it is on and running; only took about an hour and a half to install it. All that is left is to make some spark plug wire looms so everything is neat and safely away from my headers.
Ryan
Opti may be nice but there's something about being able to WASH my engine now......
I am sure you have already gathered that it is on and running; only took about an hour and a half to install it. All that is left is to make some spark plug wire looms so everything is neat and safely away from my headers.
Ryan
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