I am getting reading to build a motor. It will be a 600hp 383 LT1 or 400 TPI with a stealth ram. My question is which motor should I build based on ECU options? I have heard that the TPI ECUs are hard to tune if you dont know what your doing. One of the big reasons I like the LT1 is bcuz there are so many tuners out there for it. Any options would be appreciated.

Thanks
Jeremy

 

It's not that the older PCMs are difficult to tune, it's that they are inconvient when it comes to doing the programming for the EPROM chips. The great part about the LT1 is that the 94 and up PCMs have the EEPROM or FLASH chips, so you can program them via the ALDL port. You never have to pop the hood or pull out the PCM. With the older EPROM PCMs (93 LT1 and earlier TPI), you have to pop the hood, pull the PCM, pull out the EPROM chips, erase them with a UV eraser, and then program them. Annoying, to say the least, if you are trying to get a perfect tune, which will probably require you to reprogram quite a few times (I just finished tuning someones LT1 383 for cam surge and a few other things, we ended up reprogramming the PCM 9 times). It took long enough without having to pull the PCM, I can't image how long it would have taken if it were EPROM rather than FLASH. However, one good new thing that might solve that problem for the old EPROM PCMs is the ROMulator program, which allows you to make changes on the fly via computer with the engine running. Once you get it perfected, save the state, and then pull the PCM and reprogram the chips. Or so I believe, but I have no idea, since I haven't had a chance to use the program yet.

 

I guess the real question is which ECU would you rather have runner your motor if it could be adapted?

 

Ultimately, that's up to you. Either one will work fine. But it would be cheaper to go the OBD1 LT1 FLASH PCM, simply because all you need to reprogram it is the cable. With the old EPROM PCMs, you will need to have a UV eraser (or purchase the compatible EEPROM for that year PCM so you can just use a programmer to erase and program the chip) and an EPROM programmer. You can get a cable for less than $100, the minimum you would need for the EPROM programmer would be $150 and then another $50 for th eraser or about $10 for some EEPROM chips. If you plan on doing a lot of your own programming, I'd definitely say FLASH LT1 PCM. If you plan on having someone else tune it, then I'd let whoever is doing the tuning decide.