Hey guys, kind of new to the forum, have been lurking for a while but just recently joined. any ways I have a few questions, I have a 1988 iroc with an ls6 from a 04 z06. locally I found a ls9 for a great price and I am contemplating swapping from ls6 to ls9.
my current set up is NA with just a cam, injectors and some head work and studs. makes decent power but I want a little bit more. any info on exactly what I would have to do to change it over. would I have to change harness over? would there be extra plugs that my current set up doesn't have? What about the ecm, can the current ecm be programmed to work on this engine? if I have to change the ecm I believe there are different connectors so I would also have to change the wiring harness? looking for some info guys thank you for any help you may be able to provide.

 

This thread talks about fitment issues.
https://www.thirdgen.org/forums/ltx-...-not-left.html

Gen III vs. Gen IV engines, you will not be able to re-use your old ECM.

 

Is there a specific part of the thread you're referring to, I took a quick look but could find anything in particular to answer my questions, it also looks like Lingenfelter makes a conversion box to go from 24x to 58x and does the cam as well. why couldn't the ecm be used? just couldn't be tuned for the ls9?

thank you though for the response!

 

I provided the link because I think Pocket talks through where clearances get tight and how to resolve those issues.

Besides 58x timing system, Gen IV knock sensors are different too. You can drill and tap the block to install your LS1 knock sensors but your knock strategy isn't built around sensors in that location. It's not a big deal with a naturally aspirated engine, but knock sensors become more important with a supercharged engine.

I've never played with an LS9 but I think it uses a different ECM than other LS engines with additional functions and sensors. The throttle body and DBW pedal are maybe different too. And different fuel system layout too. I suppose you could use your ECM and just run it like you would an aftermarket supercharger. But it seems a shame to give up the superior ECM, controls, and tune that are already loaded in the LS9 ECM.

You might already know this but LS9 is a dry sump engine. Are you going to install a dry sump tank in your car? They're huge. You can do a wet sump conversion but it ain't cheap and you might lose mounting provisions for the oil cooler. And LS9 has more oil demand than normal so you'll need to choose the correct oil pump for sure. None of this is standard LS swap parts. I did a wet sump conversion on an LS7 and it cost me around $1200.

 

If you just want to keep it simple and kick things up a few notches then my 427 will drop in. It will run better than you think. It never had a good set up in my car. The cam was advanced 5 degrees, I didn't have enough fuel pump, and it didn't have the correct intake runners. And yet it still kicked *** on the street! It's a badass engine that never had a chance to strut it's stuff.

 

Thanks for the reply qwktrip,

Is your engine a 24x? do you have an ecm for that engine? would it work with my harness??

 

Yes, it was built as a 24x and can be run by your ECM. Some of the sensors are in different locations so you'll need to extend a few wires. (Cam sensor, knock sensors, and MAP sensor) I had Holley HP EFI so my tune isn't usable to you.

The engine needs a lot more air, fuel, and exhaust than your old setup. I don't know what you have for hardware in that department.

I learned a lot with my new engine, and those lessons taught me that this 427 was being held back. No more guessing, I know what this engine wants now.