Page 1 of 4 1234 LastLast
Results 1 to 10 of 37

Thread: LT1 coil conversion

  1. #1
    Club Member mustangmike6996's Avatar
    Join Date
    Aug 2007
    Location
    Harrison Twp
    Posts
    7,206

    Default LT1 coil conversion

    I'm 99% sure the Optispark in my 93 vette took a crap again. What coil on plug options are there? The only thing that keeps popping up is the LTCC LS coil swap which is $300 for the module, plus wires and coils. Are there any cheaper or better options?

  2. #2
    Club Member CamaroKid91Z's Avatar
    Join Date
    Sep 2004
    Location
    Canton
    Posts
    1,333

    Default

    As far as the LTCC conversion, it still uses the opti for the cam position, so if the optical portion of your optispark went bad you will be in the same boat of having to buy a new optispark ontop of the module, wires and coils.

    The EFI Connection 24x conversion has pretty much made the LTCC conversion obsolete. It is a bit more pricey at about $1600 or so, but for the price and peace of mind of never having an opti again it seems like a better option. You will need to run an LS1 PCM, but if you message EFI connections they will hook you up with all the necessary tech and hardware you will need.

    93 has the non vented opti which seemed to be more problematic than the 95+ vented ones. You can convert to vented but by the time you get all the right pieces you will have pretty much the same amount of money into it as you would if you just did a 24x conversion, so that swap is kind of pointless. MSD opti's have a 50/50 reputation, I never ran one so I have no first hand experience, ive always replaced with an OEM opti but my LT1 never made huge amount of power.
    Last edited by CamaroKid91Z; 09-09-2022 at 01:49 PM.

  3. #3
    Club Member 1BADAIR's Avatar
    Join Date
    Nov 2003
    Location
    cardboard box
    Posts
    28,339

    Default

    Ask Britney Friesen on youtube.
    forgoet what she has
    A gun is like a parachute. If you need one, and don't have one, you'll probably never need one again.

  4. #4
    Forum Member raroz28's Avatar
    Join Date
    May 2008
    Location
    Dearborn, MI
    Posts
    2,588

    Default

    I bought a 411 PCM at the junker in case i ever want to do that swap. Essentially, you install a distributor, cap and rotor and it eliminates the opti 100%. It is pretty well documented and a pinout diagram is online. I think there are some drawbacks, but as opti's become harder and harder to come by (I cannot find an OEM new opti), this may be the direction I go in the future.

    I also believe that this PCM is more familiar for tuners. For the LT1, the only guy I know thats super solid is Moe Bailey and he may not do it forever.

  5. #5
    Club Member mustangmike6996's Avatar
    Join Date
    Aug 2007
    Location
    Harrison Twp
    Posts
    7,206

    Default

    I have been chipping away at the Vette. Following the factory service manual, it led me to the ICM (ignition control module). I decided to replace the ICM and coil at the same time, the AC Delco ICM was about $150, coil was around $40. Installed the parts, car fired right up, ran for a few minutes then suddenly died. I was in the driver seat and watched the tach immediately drop to 0 RPM before the car actually stalled. That lead me to focus on the Opti. During the diag, the service manual led me to the opti or the PCM. I spent a while looking for a OE replacement Opti, they are pretty much non-existent. I found OE reman units but they dont always have the good Mitsubishi optical sensor and they cost about $375. All of the other replacement units are junk and expensive (MSD being about $700). Hell, just the MSD cap and rotor are $220.

    I ended up removing the opti to inspect for water leaks/moisture etc, I pulled the cap/rotor and the housing looked great. I posted on a LT1 forum, someone pointed me at an AIP brand sensor. I ordered the sensor for $60, figured it was worth a shot at this point.

    In the mean time, I hooked up a 12vdc power supply and attached my oscilloscope to the low and hi res wires then spun the opti with my cordless drill to look for a good square wave from each side of the sensor. I see a somewhat distinct (but noisy) high res waveform. The low res waveform seems like its inconsistent but it is tough to tell. I plan to retest, with my o-scope tuned a little better and focus on the low res side.

    The low or high res signal loss should have set a DTC. No DTCs are present (except #12 which is an OBD1 BIT check for the ECM in diag mode). It is possible that the opti failed fast enough that it wouldnt set a fault but most of the people who are seeing my symptoms are also finding a crusty opti unit from water/oil intrusion.

    One random thought I had, which I am not sure about yet... Adding an old school coil to fire the opti distributor to get the car running temporarily. Im sure it would set faults, the PCM wouldnt be able to advance spark etc but in theory, is there a reason adding a standalone coil work???

    So here are the options I see going forward

    1- Replace the opti, car runs and everything is great. Replace opti sensors as-needed (no clue on longevity)

    2- Use aftermarket components listed above, which are also recommended in some C4 forums/FB pages

    3- Do an opti delete, pull the LT1 intake, maybe convert to a carb style intake/cam and use aftermarket fuel injection (I don't like this option)

    4- LS swap. Very costly to fix the problem at hand but not too much more than some of the LS ignition swap kits. I would most likely try to swap in a manual transmission at the time, because, why not.
    Last edited by mustangmike6996; 02-02-2023 at 06:14 PM.

  6. #6
    Club Member 1BADAIR's Avatar
    Join Date
    Nov 2003
    Location
    cardboard box
    Posts
    28,339

    Default

    That Britney girl now works for Brian tooley racing. Could buy her ignition/conversion cause she is putting an a new LT in the car
    A gun is like a parachute. If you need one, and don't have one, you'll probably never need one again.

  7. #7
    Forum Member CruisnCobra's Avatar
    Join Date
    Oct 2013
    Location
    Farmington Hills
    Posts
    502

    Default

    Have you looked into doing a 24X Crankshaft Reluctor wheel conversion and run the LS computer & ignition? Don't know if that is still or ever was a legit common thing. Had a buddy do it home brew style almost 10 years ago.

  8. #8
    Club Member mustangmike6996's Avatar
    Join Date
    Aug 2007
    Location
    Harrison Twp
    Posts
    7,206

    Default

    Quote Originally Posted by 1BADAIR View Post
    That Britney girl now works for Brian tooley racing. Could buy her ignition/conversion cause she is putting an a new LT in the car
    I looked her up and dont really see any info on what shes running (I have not tried to reach out to her for more info, yet).

    Quote Originally Posted by CruisnCobra View Post
    Have you looked into doing a 24X Crankshaft Reluctor wheel conversion and run the LS computer & ignition? Don't know if that is still or ever was a legit common thing. Had a buddy do it home brew style almost 10 years ago.
    I looked at an aftermarket company's 24x setup (Torqhead) which is either $1500 or $2100 depending on which kit. There isnt a ton of info available (or I cant find it) because pics are missing from older forums or looking up the 24x conversion pretty much only brings up the torqhead kit.

  9. #9
    Club Member mustangmike6996's Avatar
    Join Date
    Aug 2007
    Location
    Harrison Twp
    Posts
    7,206

    Default

    https://www.eficonnection.com/home/p...cal-water-pump

    There is also this 24x kit but it doesnt say anything about upgrading a PCM/wiring etc, which I assume is required.

  10. #10
    Club Member dave89iroc's Avatar
    Join Date
    Nov 2005
    Location
    Taylor, Mi
    Posts
    16,272

    Default

    Quote Originally Posted by mustangmike6996 View Post
    https://www.eficonnection.com/home/p...cal-water-pump

    There is also this 24x kit but it doesnt say anything about upgrading a PCM/wiring etc, which I assume is required.
    correct, will need a LS1 PCM/calibration... convers it to all LS1 inputs so will give you coil near plug
    ASE Master Certified Technician

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •