LT5 swap into 89MY L98?

[widebodyzr-1]

thank you Jeff, starting to make sense now.

eddie

[mike100]

Since you have an earlier car without the CCM or stability control, it might be a lot easier to do an LSx conversion. Bill B (aka the ZF doc) did an LS1 on his 89 and he got the Atari dash working in tandem with the new engine ECM. I suspect the car still uses the orig ecm to piggy-back the speed signal and tach line to the gauges, but either way, having a pre-92 car makes for an easier installation.

I would do the LS3 over an LT5 in a lightweight coupe chassis for many reasons.

[widebodyzr-1]

i considered it, but something special about a 4 cam/32 valve V-8. besides, already picked up a 90MY engine. i'm committed now, just need to figure out how i'm going to get dash to work.

option 1) graft LT5 ECM into existing harness/dash (need Leon's help here)
option 2) use 89MY 8K dash (CCM on prototypes? require prototype dash harness?)
option 3) use CCM w/90MY dash (not certain what other parts would be required)

btw - my 89 has FX3, i ordered it w/every option sans tpms.

[-=Jeff=-]

Originally Posted by widebodyzr-1

i considered it, but something special about a 4 cam/32 valve V-8. besides, already picked up a 90MY engine. i'm committed now, just need to figure out how i'm going to get dash to work.

option 1) graft LT5 ECM into existing harness/dash (need Leon's help here)
option 2) use 89MY 8K dash (CCM on prototypes? require prototype dash harness?)
option 3) use CCM w/90MY dash (not certain what other parts would be required)

btw - my 89 has FX3, i ordered it w/every option sans tpms.

you DON'T need the CCM AT ALL

I see you are still a bit confused..

the CCM is ONLY for the 90-newer style dash, it is not needed in your 89 at all, whether you have a L98 or LT5 or LSx

you need to compare the engine harness connectors at the firewall. get them to mate..

[widebodyzr-1]

i wasn't certain if the 89 prototype dash switched to CCM.

i'm now feeling option 3 might be best option, depending how much i can source a clean and complete dash for.

[-=Jeff=-]

If seems to me you are hung up on having a CCM.. Why?

I think Option 1 is the best solution.. I did the 90-91 dash in an 89 it is not as simple as it may seem

[Corvettes White]

The ’89 Z’s used the same computer as the ‘90’s mounted in the engine compartment. I believe that the electronics in the Atari dash were replaced by the CCM in ‘90. None of the references I have show a second computer in an ‘89 Z.

If you are dead serious on doing this, give me a call, I have thought most of the project through. Make sure you do not mix and match parts too much. And expect to spend some coin depending on how far you are going to take this.

George

[widebodyzr-1]

Originally Posted by -=Jeff=-

If seems to me you are hung up on having a CCM.. Why?

I think Option 1 is the best solution.. I did the 90-91 dash in an 89 it is not as simple as it may seem

ultimately, looking for least painful (time and $$$) route to getting dash/electronics working. i just need to slow down and think this one through.

[widebodyzr-1]

Originally Posted by Corvettes White

The ’89 Z’s used the same computer as the ‘90’s mounted in the engine compartment. I believe that the electronics in the Atari dash were replaced by the CCM in ‘90. None of the references I have show a second computer in an ‘89 Z.

If you are dead serious on doing this, give me a call, I have thought most of the project through. Make sure you do not mix and match parts too much. And expect to spend some coin depending on how far you are going to take this.

George

thanks George, i will be calling you this week.

and yes, dead serious on swapping LT5 into my 89. i realize the easy route is to pick up a real Z... but there's a certain sentiment to 22 year old low-mileage vette ordered from the factory.

[VetteVet]

Just some thoughts based on what I know (and some of what I think I know). I'm not putting this out as gospel, just the way that I understand things to work.

As far as I know, the only dash info affected would be the fuel economy information and possibly the tach. The oil pressure, coolant temp, oil temp, fuel level, etc. should be OK since they have dedicated senders feeding the dash directly.

The tach could be a problem because the 89 gets it's tach signal from the ignition primary circuit via a tach filter. The ZR-1 tach signal is a 5 volt TTL level signal generated by the Ignition Control Module. If the 89 dash will trigger from the TTL signal, you should be OK.

The digital dash gets information for fuel economy, range, etc. calculations from the ALDL data that the ECM is broadcasting. There are different datastreams used, depending on year, model and ECM. This will lead to problems.

For example, if the dash is looking for byte 6 in the 89 datastream, the same byte in the 90 ZR-1 ECM datastream will more than likely not be the correct piece of information that the dash needs. Thus the info displayed by the dash will be erroneous.

With that being said, the code that the 90 ZR-1 is running can be modified to broadcast a compatible datastream. The downside to this is that the modified datastream will now cause problems with diagnostics when a scan tool is hooked up.

I don't think any of this is insurmountable, just pointing out some of the problems that you could possibly run into.

Jep