6th Gen ('00-'05): LS-SS conversion?
#1
10-01-2015 | 12:16 PM
Thread Starter
Joined: Jan 2015
Posts: 43
LS-SS conversion?
I have an 01 LS 3.4. It has around 200K, but the body is super clean. My question is, in order to convert it to an SS (3.8) would I need to get the pcm and wire harness out of another car? I have the 3.8, but not The original car. I would be getting the parts from a junk yard, so the price wouldn't be too much. Would I need anything else, such as the ignition switch?
#2
10-01-2015 | 12:44 PM
you would need the pcm, wiring harness. not sure if the trans, engine mounts, intake, exhaust and bcm are the same or not so you will have to look into that as well
#3
10-01-2015 | 12:45 PM
Food for thought, i see you have an engine already but why not go for the supercharged version or do a top swap on the one you have. If you're going through the trouble of an engine swap you might as well go all the way. And as far as the computer, i'm not 100% sure on that but i know you will need some tuning done. I believe you do need just the pcm from the donor car and then it has to be programmed with your vin to match up to your car correctly.
#5
10-01-2015 | 12:53 PM
no, im almost certain the wiring harness is different, and as stated above even once you get the pcm from the donor car it will still need programmed/ tuned for your car
#6
10-01-2015 | 12:56 PM
Thread Starter
Joined: Jan 2015
Posts: 43
even if I took the ignition switch from the donor car? Oh and I've been looking around craigslist and found a supercharger from a 3.8, but it's from the 90s… would that work properly? The ad said it was on a Grand Prix.
Last edited by John1980; 10-01-2015 at 12:59 PM.
#9
10-01-2015 | 08:12 PM
Joined: Apr 2010
Posts: 12,273
From: Mentor, Ohio
BCM's are 1 time programming and have nothing to do with the engine. I would not worry about the BCM.
I have not done this swap, but from what I know of these cars, if I was to swa from a 3.4 to a 3.8 or 3.8SC, I'd want:
- Engine and trans (as the gearing on the trans bolted to your 3400 is probably different)
- The engine and trans wiring harnesses (knowing GM, where those harnesses plug in at, such as the PCM, probably all the same connectors on the car side of the wiring). 3400 wiring is completely different from 3800.
- Exhaust manifolds (should come with the engine) and the down pipe (the down pipe for a 3400 is different then a 3800, but rest of the exhaust no matter single or dual muffler is compatible, but dual muffler is nicer).
- PCM from the donor car (this will need a new VIN programmed into it). More then likely the security relearn process will be needed once the VIN is updated.
- If you get a SC engine with a 4t65e HD trans, I believe one, if not both half shafts are different from your current 4t65E non-HD trans, so grab those.
- The air box I believe is the same between a 3400 and 3800, but it's the duct from the box to the throttle body that is different.
Engine wise, any 3.8 or 3.8 SC that is a Series II should work. The thing I don't know, if you get the donor drivetrain from a different model car (like a Grand Prix or Bonneville), did GM keep the wiring the same between years and models.
It should be easy to confirm if the lower engine mount is the same (and I think it is), look up the mount for a 3400 and 3800 powered Monte at the parts store web sites.
That is my food for thought.
Like any task this large, expect no matter how much planning you do, there is always going to be a bump in the road.
Also, before slamming a different engine in, having it out of the car, great time to change head gaskets on up, new plugs and wires, clean everything during this process and the top end is fresh and solid!
BTW - If I were to go through this effort, I would given heavy thought to a 3800 SC.
I have not done this swap, but from what I know of these cars, if I was to swa from a 3.4 to a 3.8 or 3.8SC, I'd want:
- Engine and trans (as the gearing on the trans bolted to your 3400 is probably different)
- The engine and trans wiring harnesses (knowing GM, where those harnesses plug in at, such as the PCM, probably all the same connectors on the car side of the wiring). 3400 wiring is completely different from 3800.
- Exhaust manifolds (should come with the engine) and the down pipe (the down pipe for a 3400 is different then a 3800, but rest of the exhaust no matter single or dual muffler is compatible, but dual muffler is nicer).
- PCM from the donor car (this will need a new VIN programmed into it). More then likely the security relearn process will be needed once the VIN is updated.
- If you get a SC engine with a 4t65e HD trans, I believe one, if not both half shafts are different from your current 4t65E non-HD trans, so grab those.
- The air box I believe is the same between a 3400 and 3800, but it's the duct from the box to the throttle body that is different.
Engine wise, any 3.8 or 3.8 SC that is a Series II should work. The thing I don't know, if you get the donor drivetrain from a different model car (like a Grand Prix or Bonneville), did GM keep the wiring the same between years and models.
It should be easy to confirm if the lower engine mount is the same (and I think it is), look up the mount for a 3400 and 3800 powered Monte at the parts store web sites.
That is my food for thought.
Like any task this large, expect no matter how much planning you do, there is always going to be a bump in the road.
Also, before slamming a different engine in, having it out of the car, great time to change head gaskets on up, new plugs and wires, clean everything during this process and the top end is fresh and solid!
BTW - If I were to go through this effort, I would given heavy thought to a 3800 SC.
#10
10-01-2015 | 11:04 PM
There is minor differences in the connectors that are used on the trans depending on year. The new PCM can be matched to your existing bcm so no need for a new bcm, if you get a HD trans you will need the passenger side axle only (driver side axle is the same between the two)