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Has anyone ever considered converting a TPI style setup to use the 94/95 LT1 PCM? If you use the small cap distributor and external coil, modify the harness from the LT1 change to LT1 sensors???
this car is a drag/street racer, it has a 406ci engine and built 700r, it was a TPI car but is now a modified tunnel ram style intake, and many other mods. I'm also looking at turbocharging soon.
I just think it would be a lot easier to tune using the flash type ecm.
Rather than converting your TPI to an LT1 controller, consider converting to an LSx controller - especially considering the possible future forced induction setup (turbo).
To use the semi-famous 0411 LSx controller, you would need to run a distributor from an L31 Vortec (5.7L) - which should be a drop in conversion. Then a 4x CKP (crankshaft position sensor) would need to be added - a little more work, but not a huge deal in the grander scheme of things.
^^ X2 ^^
The LT1 has no provision or upgrade to boost. It was also never used with a distributor of conventional means, just the OptiSpark which is complicated. Although we have talked about the LT1 PCM being used in projects, re-writing code for use without the OptiSpark distributor just put's the project on the shelf.
I would not recommend using the LT1 PCM. I decided on the 0411 PCM with a fabricated harmonic balancer mounted trigger wheel. I was all out lazy, I did not want to disassemble the front of the engine to install a crank trigger, so the bolt on crank trigger system is what I came up with.
dave w
http://i239.photobucket.com/albums/f..._0411SBC-1.jpg
http://i239.photobucket.com/albums/f...nkPosition.jpg
I have everything I need to program OBD1, My understanding is it is expensive to program OBD2 stuff. EagleMark, I checked the distributor plugs and they are identical on the LT1. I have even used the LT1 coil with a small cap distributor before and that engine is still running today, also I have seen an LT1 with a distributor before. the guy said he got tired of having so much trouble with the opti so he drilled his intake and installed a distributor. Now I do not know what other mods were done as this was before I started using efi but I remember that the wiring looked stock.
the variable angle slots used for the optispark's 4X signal are able to allow the PCM to determine engine speed and provide a cam sensor function at the same time in that it will allow for the firing cylinder to be determined from a single signal. kind of neat, but a pain to look at the code for if you're not aware of it.
boost could be accounted for via patching, though the MAF doesn't care about pressure, only mass flowrate. that portion of the calibration/code is fine, it is the speed-density portion that would need some patching to emulate the 1BAR sensor for all but boost related functions. how the 4L60E trans code reacts.... not sure.
i...... wouldn't go the route, but it is possible to do.
I see your point on the OBDII prices.:mad1:
I think this link has a write up of what your wanting to do.
http://www.popularhotrodding.com/tec...onversion_ls1/
I'm thinking getting the intake modified with a distributor hole will be a challenge ... I can't find a link for a shop / business doing the LT1 intake distributor hole drilling.
dave w
Here is a link that might help?
http://www.eecis.udel.edu/~davis/z28...n/swapping.htm
dave w
Ummm, he doesn't want to use the LT1 engine or the LT1 intake.
You'd have to swap the Opti onto the front of your engine. You don't have to use it for the spark/ignition part but you need the two reference pulse signals from it. The actual spark could probably be passed through any distributor with locked out vacuum and mechanical advance or you could get the coil per plug conversion kit (can't recall the name but it costs as much as OBDII tuning software so why bother?).
I believe you are right that the coil and ignition module is the same, but that has nothing to do with the PCM receiving the pulses to know when to fire the injectors and plugs. The signals required for the PCM to time everything don't come from the ignition module like most of the GM OBDI TBI and TPI systems.
Drilling an LT1 for a distributor is done to convert it to a different PCM (TPI most likely) instead of the LT1 PCM.
Even if he did get it to work? Was it correct? Just because the plug fits means nothing to the PCM code that is looking for signals to run and they aren't there... so it runs in backup or LHM...Quote:
Originally Posted by 63LT1Vette
If you want to avoid OBDII software costs and still run boost correctly I'd say use this!
http://www.gearhead-efi.com/Fuel-Inj...information-58
Still no flash but it will run and tune correctly.
Maybe a Large Cap HEI distributor could be modified to hold the LT1 optical disk and module? Then the LT1 computer would be happy!:jfj:
dave w
Mark, if the LT1 had a normal distributor instead of the opti then it wasn't running a LT1 PCM.
Can't you convert the '7749 to use a flash chip? Maybe not as convenient as you need access to the PCM but it could probably be programmed just as quickly.
I may still have a Opti apart that I was looking into that project with but lost intrest. To much $$ fornot enough return on PCM. But if someone was itrested and it's still on shelf they can have it.Quote:
Originally Posted by dave w
Moates has a NVSRAM for the 7730... don't know if it could be done. There is also code/patch work involved but it was Open Source project and available.Quote:
Originally Posted by lionelhutz
But if you went with the 1227749 and Mask $58-$59 you could use a permanent mount Ostrich and be done?
Didn't I read somewhere that someone offered a Opti-spark eliminator. I remember something on this back when LT1s were the hot engine for GM (early 90s). LOL so in the early evolution of this project one of the first modifications I made was to adapt a LT1 intake to the L98 TPI. I built a jig that held the intake in position and milled the distributor opening. I then had to build a pad for the distributor to set on and also the hold down point. I drilled the head bolt pattern and had to run a external thermostat housing. It worked well and was a major improvement over the TPIs small runners. that was quite some time ago. I am just looking at all options before I go and buy a F.A.S.T. or Accel or something like that. I need to be able to make a change at the track from one run to the next. so I need to be able to flash a tune in between rounds as well as be able to data log each run.
Thanks to all of you for the discussion.
There were kits to use a coil per plug to get the spark out of the opti but I don't recall ever seeing a kit to get rid of the opti itself.
Maybe an EBL Flash would work for you - http://www.dynamicefi.com/EBL_P4_Flash.php
I had the same idea a couple of years ago. I knew a guy who had wrecked out a bunch of camaro s with lt1s and gathered up a bunch of old optisparks and reverse engineered the wheel and module into a small cap distributor. I hooked it all up on a test engine fired it up and it worked just fine. Then I had some other projects to do so I boxed it up and put it away.
It required turning down the dist base and machining a piece to mount the optispark wheel on but it used the stock dist cap and required a very tight end play tolerance . I still plan to use it on something since I have the software and several lt1 ecm's around.
Willing to post some pictures?Quote:
Originally Posted by Big don
dave w
I would love to but it will take a few days . This is the first time I have ever posted and just figuring out how will be a learning experience for me. The hard part of building one is figuring out tdc on the lt1 and inside the optispark. I looked at several and they vary. They do not seem to have been built with much accuracy. Any way once the relationship between the module, wheel, and rotor is established the rest is just work. I used the wheel from a early opti and module from a late opti to get in a small cap dist. Some aluminum welding is also needed and exact size reamer for the piece to mount the wheel on.
Probably does not matter as to the timing as the small cap EFI distributopr can be moved as well as wires moved and rotated around the cap, then timed to whatever need be. This is what I found when I built these.
http://www.gearhead-efi.com/Fuel-Inj...BI-Conversions!
For pictures once you have them on your PC, post like you just did but at bottom of box look for, Go Advanced, then when that window pops up look below bottom of box for Attachment Manager and open it to look through your computer and pick the pictures you want to upload.
Here we go trying to up load photosAttachment 6436This is plug side of dist.Attachment 6437Here with cap off showing rotor and shieldAttachment 6438With shield removedAttachment 6439View from topAttachment 6440Modified capAttachment 6441Side view
End play must be held between .009 to.012 set close on module cold. This dist runs and is complete except sealing and venting
Not sure how you attached, but maybe the screen shots below will help?
Click Reply
Click Go Advanced
Click Manage Attachement
Click on Browse to find the file(s) you want to Attach
Click Upload
dave w
All of the photos were on the reply when I posted but disappeared on the site. When I went to edit all of the photos was there and I do not know how to change it . The reply took more space than was allowed
That EBL Flash is exactly what I am wanting to accomplish, Has anyone used one of them? If I went with the 0411 PCM route I'm wondering if the cost would be wash, EBL Flash @ $470 Vs 0411 PCM @ $????
I've used EBL, it's good product.:thumbsup::thumbsup:Quote:
Originally Posted by 63LT1Vette
EBL Flash is going to be the lower cost option.:thumbsup: EBL will support turbo.:thumbsup: EBL will do VE Learns (fuel table corrections) with or without a Wide Band O2!
OBDII has the same features as EBL, expect it's more expensive if adapting an OBDII '0411 PCM to an OBDI system.
I purchased my EFI Live System (used) on Ebay a few years ago for about $600. EFI Live will support Turbo applications, with it's special operating systems feature.
To update a SBC 406 TPI engine to an '0411 PCM is an estimated $250 in parts (maybe less). Wiring harness modifications will be required, so add in more labor and expense.
The '0411 is better than EBL, and might win more races?
Winning races might be expensive?
dave w
LOL, That's correct Dave, Winning races is always expensive. You said the 0411 is better that EBL, What could one expect to better about it?
The 24X '0411 system is a per coil ignition, allowing spark advance of more than 45 degrees BTDC. The V8 distributor has a physical limit of 45 degrees. More tuners are using EFI Live vs. EBL. The '0411 is in nearly every salvage yard and very affordable, the EBL is special order. Could an EBL failure ruin a race day?Quote:
Originally Posted by 63LT1Vette
On the front end EBL is less expensive. On the back end the '0411 could be the consistent winner?
dave w
OK It looks like IF I already have the small FI Distributor I have all I need for hooking up a LT1 PCM??
Rich
I have a 1993 Custom G20 Van it is TBI and I want to swap in a TPI with a LT1 PCM as I NEED better MPG as 15 with a tail wind is not cutting it...and have a tune-able PCM seems the way to get ever MPG out of this rig.
Any one heard of the Lean Burn Cruse setting in the earlier PCMs for TPI??
85 Camaros can get 30/35 MPG with it.
Rich
you need an optispark distributor to use the LT1 ecm. no other distributor or cam sensor will work unless you fabricate somethingQuote:
Originally Posted by Racprops
I read all that was said earlier and it seemed these FI small distributors do the job...if not please point me to what and how we can make this work.Quote:
Originally Posted by steveo
Thanks.
Rich
Maybe there is some confusion on TPI vs. LT1 intakes?? See Pics below. LT1 intakes do not have a distributor hole. TPI intakes have a distributor hole. The LT1 distributor is mounted in the front of the engine, near the water pump.Quote:
Originally Posted by Racprops
dave w