Swapping 4.6l into the 3.8l car or older 4.0l Aurora - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Bonneville GXP/ Northstar Powered Cars Discuss your Bonneville GXP and/or any other Northstar powered Olds or Cadillac... Including the 3.5L Twin Cam V6 (Short Star ) 4.0L and 4.6L Northstar V8's. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 01-11-2004, 09:07 PM   #1
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Default Swapping 4.6l into the 3.8l car or older 4.0l Aurora

Domestic performance has received alot of interest in this subject and I wanted to share the idea formally so others could chime in.

Now I understand the itchy finger of 3.8l owners and enthusiasts who might want to compare the two engines but this post is exclusively meant to be about the option of and interest around the swap of the Northstar 4.6l into the 3.8l cars and older 4.0l cars.

To start i prefer the 4.0l over the 4.6l but for smog reasons (i unfortunately live in califoornya ) and the end power potential of the 4.6l. I have extensively researched swapping the 4.6 into the H body.

So what’* your thought?

Personally i would mod a 4.0l and add a Turbo.

The 4.6l is a great engine and can take on internal options capable of up to 100hp gain. This will put you in the 400hp range. Not crazy hp but respectable and you can still smog the car. Add Nitrous and you’re in the 600hp range.


Ty
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Old 01-11-2004, 10:01 PM   #2
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Quote:
Personally i would mod a 4.0l and add a Turbo.
Ahhh to be rich and impatient

Good luck Ty!
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Old 01-11-2004, 11:37 PM   #3
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Well if it wasn’t for the smog rules I would do a 4.0 with turbo but for now the best rout for me personally is to pursue the 4.6l with a serious shot of NX.

Street legal and very powerful.


Ty
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Old 01-12-2004, 04:02 AM   #4
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leaving me in suspense! lol

4.0 -> 4.6, can you guys do it? what kinda $$? i relieze you probably need a 4.0 car in the shop, but im sure you could do some number crushing. the 4.0 and 4.6 have the same external dimensions, i believe i heard if they where directly swapped the 4.6 would sit a little high in the engine bay because of the mounts, so a little modifying is necessary.

don't crush the dream!
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Old 01-12-2004, 04:02 AM   #5
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id even take a l67!
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Old 01-12-2004, 10:50 AM   #6
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The swap with a 4.0-4.6l physically is a simple replacement. The engine block is the same no major work required. The rest is wiring and or computer mods.

Look up the cost of any shop offering a engine swap and add about $1000.00 and that is a good ballpark. Your 4.0 is the same external engine block and the transaxle is the same so the only issue left is the interface between the cabin computer, engine computer and maybe some wiring harness issues.

Now comes the cool part.
The 1995 Aurora and caddy are very similar and we already can do the computer for both. So use the same sensors that came with the Aurora and same computer but modify it to work with the 4.6l. It "should" work just fine. Yes we would need the car to be 100% sure but if we have a connection with whoever was doing the swap then it would be fairly easy.

The L67 swap in a 4.0l Aurora is alot more work... and silly consider you would be stepping down for that car.

When all is said and done you could just rebuild the 4.0l and get the computer mod to match the build. You can easily get 400hp out of a 4.0l. I suggest looking up the Shelby Series 1 cars. Look at what he has said about the 4.0l.

If you go to the bottom of the linked page and click the play button you can get a great sound clip.

http://www.musclecarcalendar.com/Car...RoadKings1.htm



Ty
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Old 01-12-2004, 08:21 PM   #7
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i thought the shelby was at 320hp, and they sacrificed alot of torque for that, which is needed in this boat.

it makes sense, 95 being the easiest. maybe when i get the $$, i look for a mint black on black 95 w/ low miles, then look you up

also, i was told by someone who parked there aurora side by side with a STS and popped the hoods, that it appeared that if the swap was done, the 4.6 would sit to high in the engine bay, never seen it personally
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Old 01-12-2004, 09:26 PM   #8
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Yes this is why I add the NX into the formula. I would personally add a turbo for a car in a reasonable state but i am stuck in cali so its NX. I could use a centrifugal SC that i could bolt on after i smog the car but the pain is not really worth it and at that point i might as well have a second engine for smog. lol.


From what I have been told the block externally is the same. I will however confirm that this is 100% true for all the Northstar years and get back with the details.

Ty
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Old 01-22-2004, 01:31 AM   #9
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honestly..if you've got a few grand lying around .. putting a different engine in ur car is probably the worst way to spend it IMO. buy some rims .. or some major engine mods..or a paint job.. who knows.. lol. ill quit bitchin.. go on....
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Old 01-22-2004, 02:52 PM   #10
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ive got some 18" chromes..

i just wanted to know if it was possible, my current car isn't worth that kind of money
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