engine swap questions. 98 S/C 3800 into an 01 originally equipped with a 3100

[pbrmeasap2112]

First, some of these questions may be answered here or elsewhere on the interwebz. I know this, and i am currently searching for answers to alot of these things already. I am just trying to expedite the process (or be lazy, however you want to call it is fine with me, lol). If its already posted up in here on another thread, and your going to tell me to f*** off, please at least include a link to the place where the answer is already covered along with your comment telling me to f*** off. It would be much appreciated. I have been absent from this forum for a few years, and there is alot of data to sort through.

 

Now. On to brass tack's.

 

Had two great deals fall into my lap. Have an 01 Century with a blown up 3100, while searching for a suitable replacement engine i stumbled onto a rolled over 98 Regal GS with a properly modified Supercharged 3800. I'm planning on swapping the powertrain of the Regal into the Century.

 

Mechanically this is a no-brainer for me. however i am curious what i should expect as far as electronics go.

 

engine bay:

Will the wiring harness's/ECM's be plug and play?

 

Dash/Gauges:

The gauge cluster of the Regal was rebuilt (no dead displays! ) Will i have to reprogram anything when i put it in the Century? was there a different wiring harness used in the century that wouldnt allow certain gauges/displays of the Regal's guage to function...? Is the data depicting mileage stored within the gauge or is it stored in the BCM?

 

Transmission:

not swap or electronics related, but did these transmissions come from the factory with a limited slip diff? does anyone know the final drive ratio, as well as if there are any alternative ratios available..?

 

also, is there a good no B.S. site showing all the factory specs of these cars (track performance) engine's (depicting internal differences between the N/A 3800 vs S/C 3800, like whether or not the S/C 3800 has forged pistons/crank/rods, etc)

 

Better yet, is there a good site showing in detail the evolution of the Series 1 / Series 2 / Series 3.8L's?

 

Thanks in advance for any help & input.

[Nas Escobar]

1. The wiring is not plug and play, the easiest thing to do would be to re-pin or pull out all the wires out of the Regal. You also have to pull out the PCM out of the Regal, or re-tune the Century's PCM. It's easier to do the former than the latter.

 

2. The gauges of the Regal are different from the Century. IIRC, the Regal had a tach, the Century did not. The mileage on GM cars seem to be stored within the gauge cluster, you have to take out the odometer piece and I think that's how you can transfer mileage between clusters.

 

3. The transmissions between the Regal and Century (and any 3100/3400 and 3800 engine) are completely different. The 3800's gearing is different from the 3100 and the S/C 3800 was bolted to a 4T65HD. You can't use the 3100 trans without beefing it up and regearing it or frying it... whichever you prefer. As far as different ratios, look up the final drive of each 4T65HD. Some cars were geared mildly different i think.

 

4. Not that I know of.

[nitehawkjcb]

You're going to need the Regal's motor, transmission, and engine wiring harness. You will have to get a PCM from somewhere too, the Regal PCM MIGHT work, but I doubt it.

 

The wiring harness from the Regal should be plug and play for the most part, but you're likely going to have to rewire some connections at the C100 connector. I still need to rewire my rear defrost to this day lol.

 

The supercharged 3800 cars come from the factory with HD transmissions. Pretty sure I've had both my front tires smoking, so it's limited slip enough for me. The gear ratio of the 4t65e-hd is 2.93. Non supercharged 3800's have a standard 4t65e with 3.29 gears, but you can upgrade the differential to make it HD.

[l67ss]

3100 4t65s usually have 2.86 gears, some had 2.93s. Look at rpo stickef on trunk lid. If you code fq3 you have 2.86s

[ryan1989]

a century is a regal same car different body kit and steering shift and obliviously the 3100 i cant see why anything from a regal wont fit a century it is probaly a plug and play swap just drop the whole sub frame and lift ur car off and put the regals in with the motor still attached and the wiring gm is pritty good on interchanging parts i got a sum pontiac montana van parts on my regal lol

[Nas Escobar]

a century is a regal same car different body kit and steering shift and obliviously the 3100 i cant see why anything from a regal wont fit a century it is probaly a plug and play swap just drop the whole sub frame and lift ur car off and put the regals in with the motor still attached and the wiring gm is pritty good on interchanging parts i got a sum pontiac montana van parts on my regal lol

 

The reason it's not plug and play is because the engines have different pin outs in the wiring harness. Yes the easiest way to swap in the 3800 S/C is simply to drop the subframe but the trans is geared differently and the wiring harness has very small changes. Other than that, you're right. He just needs a new HD trans and to repin his C100.