Big Stuff 3 & LT1 owners step in....
07-29-2016, 12:19 PM
#1
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Big Stuff 3 & LT1 owners step in.... I have a question regarding the cam sync on an opti and changing distributors is not an option. I have the MSD 83811 opti with an MSD crank trigger. I need 1 pulse per rev out of this thing to tie down my phasing for sequential.
Does anyone make a custom reluctor that can get this done? If so, who?
Anyone have a set up like this?
Does anyone make a custom reluctor that can get this done? If so, who?
Anyone have a set up like this?
07-29-2016, 12:45 PM
#2
You should not need a crank sensor for sequential for the optispark. The opti spark has a high res and a low res signal. The high res is the cam sensor (1 pulse per degree of camshaft rotation with 1 degree ref angle) and the low res is your crank. That should be everything needed to get sequential in aftermarket EFI.
http://bigstuff3.com/pdf/OPtiSpark%2...I%20Wiring.pdf
The MSD crank trigger is a 4 pulse per revolution setup and is for crank speed only. You would want more than 1 pulse per rev on the crank which is why it is setup as a 4 pulse system. You would then need a 1 pulse per rev of the camshaft for sequential. You should not need anything other than the opti to get sequential on the BS3. However, if the BS3 is not compatible with the optispark OEM sensors you would need to modify the optical wheel the block off the 359 slots and leave 1 open for a 1 revolution of the camshaft type sensor.
http://bigstuff3.com/pdf/OPtiSpark%2...I%20Wiring.pdf
The MSD crank trigger is a 4 pulse per revolution setup and is for crank speed only. You would want more than 1 pulse per rev on the crank which is why it is setup as a 4 pulse system. You would then need a 1 pulse per rev of the camshaft for sequential. You should not need anything other than the opti to get sequential on the BS3. However, if the BS3 is not compatible with the optispark OEM sensors you would need to modify the optical wheel the block off the 359 slots and leave 1 open for a 1 revolution of the camshaft type sensor.
Last edited by Nostang; 07-29-2016 at 12:55 PM.
08-02-2016, 08:06 AM
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Thanks for the reply, I really appreciate it. I have spoke with the BS3 guys and they have said 2 things about the MSD opti. If I were going to use the high and low res signals, I would be leaving about 10-15hp on the table. In a stocker motor, that's a lot! The way I understand it, the low res is 8 pulses per rev and the high res is 60 pulses per rev. I assume I could use the low res feedback and block off 7 slots instead of 359. I'm just thinking out loud a little here.
08-02-2016, 09:46 AM
#4
No problem. Check out this link for opti functions. It goes into pretty good detail
http://www.underhoodservice.com/diag...t1-v8-engines/
This is also another good link where you can see the 360 slots for the cam sensor. Technically, it would be 180 pulses per 1 revolution of the crank due to the cam spinning half the crankshaft speed but it is 360 pulses per camshaft rev. http://www.superchevy.com/how-to/031...ing-modifying/
Why did they say you would lose hp with the optispark? Were they talking about sequential vs batch fire?
Another option for you would be to use a crank trigger and a rear mount distributor where you grind off 7 teeth and leave 1 for the cam sync. I have this set up on mine and completely removed my opti while staying sequential injection. This setup is also good as the oil pump drives are known to fail on the lt1s and then you engine is toast.
Good luck and post up results.
http://www.underhoodservice.com/diag...t1-v8-engines/
This is also another good link where you can see the 360 slots for the cam sensor. Technically, it would be 180 pulses per 1 revolution of the crank due to the cam spinning half the crankshaft speed but it is 360 pulses per camshaft rev. http://www.superchevy.com/how-to/031...ing-modifying/
Why did they say you would lose hp with the optispark? Were they talking about sequential vs batch fire?
Another option for you would be to use a crank trigger and a rear mount distributor where you grind off 7 teeth and leave 1 for the cam sync. I have this set up on mine and completely removed my opti while staying sequential injection. This setup is also good as the oil pump drives are known to fail on the lt1s and then you engine is toast.
Good luck and post up results.