: Rebuilding the Catera V6 For More Power

01-06-08, 04:46 AM
I know we all want a Corvette V8 under our hoods but likely that ain't gonna happen. These links lead to a normally aspirated 3.0 V6 project. This British builder is mixing the best parts from the L4 and V6 engines available in the Omega as well as a few Saab parts. He doesn't mention HP and Tq numbers but it sounds like substantial gains can be expected. From his article I see that the parts are mainly all factory pieces with the exception of a homemade high-rise induction system. I'd stick with the standard intake plenum myself but with bigger Throttle Bodies to take advantage of intake port work he performs. Or maybe an induction system like the one from Jenvey Dynamics.


I sent him an email requesting an update and explained our lack of performance options over here. Maybe he'll take pity on us and throw us a bone.


01-07-08, 04:07 PM
Yeah he was building that motor for his Opel Manta B.... then he gave up on the V6 went apeshit with a complete tube frame chassis and an LS2 V8 motor.

01-12-08, 08:36 AM
You could always do what I am in the process of doing. I am gather up the parts to put a Supercharged 3800 in the car. This engine came in the Catera Australian relative, the Holden Commodore VT series. I have gather most of the factory Holden parts and have started the fab work on the Engine mounts. If you are interested, I can go into more detail if you would like.

Po Pimp
01-12-08, 11:28 AM
How are you going to make that compatible with the EBTCM?

01-12-08, 10:45 PM
I have the shop manual for the VT Commodore and the EBTCM is very similar. The Holden had and option for traction control with the abs, so it will adapt to the Catera. The Holden also has the sport / economy mode for the transmission. The Holden uses a ECM that is similar to the pre - OBD II GM and I already have the ECM and wiring. I still have a few minor parts to get before I start.

01-12-08, 11:34 PM
Can you post pictures of this, I would be very interested.

The Australian version of the V-platform was VERY different from the original European V-platform. One difference being that the front strut towers are approximately 2-inches further apart. I presume this in addition to the steering box location will make issues when fitting the 3800.

Also though both Bosch EBTCM's are similar, they differ in a very important aspect. The Catera uses the CAN protocol for communication between the TCM, ECM and EBTCM. In the Holdens, they use a traditional serial bus and not CAN for communication between the modules. Are you planning to use the 4L60E with the engine?

You could still retain traction control, but you would have to use the Holden EBTCM.

The ABS is a redundant system (ie, not dependant on any other control modules) so you could just cut all of the lines (2 or 3 if I recall correctly) between it and the PCM or TCM and ECM (I'm not familiar with the systems of the older Holdens, but the auto GTO uses a PCM) and you will still have 100% functionality of the
ABS system while only losing Traction Control.

01-13-08, 07:07 PM
Your right, The Australian versoin is wide and the steering and engine mounts are different. In order to retain the stock Cadillac mounts, you would have to use the rear engine mounts.

The stock US version 3800 oil pan will not work without cutting it up. I'm using a VT Holden pan. I got mine off eBay for about $85.00 with shipping.

Rough dimisions of the 3.0 engine are 22 inces from corner of valve covers, 19 inches high from center line of crankshaft and 9 1/2 inches wide and the bottom of the block. The 3800 SC is 20 incehes wide, 17 inches high and 9 inches wide.

I still have to fabricate a 90 degree elbow to turn the throttlebody facing forward.

I will be using a 4LE60E from a Camaro/Firebird that has a 3800.

None of the original ECM and TCM will be retained so using all Holden ECU part should make all TC/ABS system work.

01-14-08, 01:17 AM
sounds like an awsome project.
can you please document what you do?, I'm sure there is a lot of people who would love to do this. when it turns out, and you have some sort of instructions, I will deffinatly look into doing the same.. I'm just to chicken to blaze the trail.

just curious, how much was your engine? how much are you expecting to spend?

01-14-08, 04:14 AM
I know nothing about the electronic requirements to making this swap work but it sounds great if you can pull it off. That 3800 has been around in some form or another since the early '60s. It's very reliable and there are tons of performance accessories for it. The Series III Supercharged version is good for 260HP. I'd miss the high rev sound of the 3.0L but the reliability improvement alone would be worth it. Good Luck.


01-14-08, 07:41 AM
I purchased the engine, a 1998 SC 3800 from a 1998 Buick Regal GS for $500 off eBay. It was complete all the way down to the Alternator, starter and A/C compressor. The engine is rated at 240 HP but by the time I am done it should be around 280 -300.
Other things I have noted is the battery will have to be moved to where the air box is now so air inlet will be on the driver's side, the thermostat side of the intake will have to have a pipe fabricated or find the Holden version to plumb the coolant from the top of the engine to the radiator.
The whole idea of this swap is to remove the shrt comming of the Catera and build it as it should have been. I have already obtained the emission control and belt routing stickers from GM as well as the Supercharged emblem for a Regal.
I would have liked to put a Northstar in it but the engine is app. 30 inches wide and that is being conservative, will not physically fit. The oil pan mods and water pump issues just add to it.An LS1 is just to expensive at this time for consideration.
I will start posting pictures and keep up with the steps required to do this swap so others may follow.

01-14-08, 12:47 PM
Sounds Sweeeeeet!!!

01-15-08, 06:03 PM
Thanks, I will start a thread detailing the swap. It probably be titled 3800 Supercharged engine swap.

02-23-13, 06:56 AM
Guys, I know it's kinda old thread, but did you finish the swapping??? I'm still Catera lover, actually I have two, 2000 and 2001. Want to keep one for projects, to make really cool and fast catera. any gaining in 30+ hp will be worth to mess around. So sounds like 3800 engine is the easiest and cheapest way to dramatically change catera's character?! With all optional mods to this engine? What's estimated price? Thanks for any input!

02-23-13, 02:52 PM
Easier to make the car about 1000 pounds lighter.