LQ1----->3400... Questions

[Addicted To Boost]

In order to swap a LQ1 car to a LA1 3400, what needs to be changed over? Can I use all the accessories mounted on the 3400?

Can I still use the 3400 wiring harness, or do I have to use the harness from the LQ1?

Can I re-use the LQ1 ECM with a tuned memcal to run the 3400, or will I need the 3400 ECM as well?

 

I'm curious as to what is all plug and play, what extra parts will be needed, and other things that will need attention.

 

Thanks in advance.

 

Edited May 1, 2011 by Addicted To Boost

[RobertISaar]

can use the 91-93 LQ1 PCM with a freshly blended tune.

[GOT2B GM]

Do that car some justice and keep a LQ1 in it.....

[Addicted To Boost]

In this case, mileage > all. It will be my new dd. I'm not going to be satisfied with 25 MPG from an LQ1. I can't find any LQ1s anywhere near here anyway.

[White93z34]

I don't know if the 3400 will net you much more mpg.

 

But anyhow, id use a 3.1 mpfi harness, dohc injectors, dohc chip, you might need 3.1 mounts, accessory mounts, maybe a early 3100 fuel rail, thrlotle cables, power steering hoses, downpipe, misc brackets, ac compressor?, ac lines, prolly fuel lines too, but if its a 91 you'll have to make something custom to go from the threaded fuel lines to the quick connect lines... probably an fittings and line could do that well.

 

To me it would be more of a pita then its worth, but those are what I can think you'll need off the top of my head.

[RobertISaar]

DOHC PROM has more or less adequate fueling, but WAY too much advance for a 3x00...

[White93z34]

I was just going off information I read forever ago about how lots of early 3400 swappers were getting away with using 3.4 DOHC chips with little issue. I've never done the swap in question and am just going off observations I've seen. So for all I know I could be talking out my ass.

[RobertISaar]

just a warning from me....

 

Jason's 3400 likes around ~25* of advance at 1800RPM and 50kPa before knock, the factory LQ1 tunes run 30* of advance in the same cell.

 

granted, the WOT spark stuff is very similar, and even a little bit conservative on the LQ1 tune for a 3x00, it runs a few degrees less at times.

[xennith]

There were a few brand new crate 3.4 DOHC on car-part.com in California for around $1000. My friend got his in about a week. Talked them down to $900. ended up being $1200 with shipping and a 2 yr warranty. My mechanic seemed to think it looked like the real deal. just a thought

[Jonpro03]

Here's a good read for ya. This guy swapped a 3.4dohc for a 3500. Basically the same thing you're doing.

 

http://60degreev6.com/forum/showthread.php/47806-3500-Swap-Finally-Underway-a-few-questions