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catera and grand national
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9 Posts
Discussion Starter #1
hi, newby here. good site. i have a lead on a catera with a blown engine, bent valves due to timing belt. i also have a buick grand national with a spare engine and was wondering if anyone has done this swap before. thanks for the advise.....
 

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1997 Catera
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172 Posts
You'll have a hard time cramming that 90 degree V6 in the engine bay. Its a bit wider than the Cat engine.
Electronics are another issue. Adapting them to the 80's vintage engine would be a huge hassle; gutting them kinda turns the Cat into...well not a Cat.
Unless you got the turbo SEFI GN I wouldn't consider it even if it did work OK. Carb (turbo or not) will have a hard time beating the Cat at highway speeds - the Buick V6 is a low-torque and the Cat 3.0 is a spinner (r.e. hi-RPM performer). Compare the HP - the Cat engine does really well as a 3.0 and has numbers above the stock form 3.8 or 4.1 N/A. Even the turbo is not much higher than the Cat.
That smooth running car will be a low-torque growler but it won't be a luxury Cat. And it won't run like a GN either with the extra weight of the Cat.

Now...I do have a 4.1 Buick GN (1984 N/A) sitting in my garage inside a 1980 TR7. It will break tires loose in all four gears even at 80mph. It's a screamer from a standing start. Still wouldn't want it in my Cat. My Cat's a smooth hi-speed cruiser. I don't break the tires loose on it. But I don't lollygag behind obnoxious traffic either.
 

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catera and grand national
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9 Posts
Discussion Starter #3
i think i saw you over at turbobuicks.com someone thare has a TR7 with a GN set up. your right about the low end power my GN has ALL the low end power anyone would want and it kind of flattens out around 85 MPH. from what ive been reading the easiest engine swap would be from a CTS with the 3.2L can the 3.0 be built with relibality....thanks. p.s. the GN is a 87 with intercooler and methanol injection 25LBS boost
 

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92' Eldorado, 97 Catera
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289 Posts
I really did not research it very much but since you have an interest I will say it. Isuzu has a 3.5L v6 that has the same tranny as the Catera that might work. I have heard and seen pictures of an Isuzu with a 4.0L oldsmobile aurora engine in it. This is a V8 who's sister is the Northstar. You have to remember this was built for FWD applications so even more customization would have to be done to make it fit. That would be the most powerful engine you could mount to this transmission without worring about blowing it up with to much torque. Of course you could switch off the intake covers (at least I think) and have it look like a Northstar.
 

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Platinum 2001 Cadillac Catera Sport
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1,840 Posts
Adding an expensive turbocharger and increasing the intake air pressure might not be a smart thing to do. GM's L81 3.0 Liter V6 hasn't proven to be the best engine they've ever made. Among other things, its timing belt system is prone to failure and has been the subject of a major recall. The internal oil cooler/heat exchanger can leak causing oil and coolant to mix, cross-polluting both systems, and causing major damage if gone unnoticed. Plus, the transmission and differential might not be up to the added HP strain. That said, the L81 2.5 Liter was used in the SAAB 9-5 Turbo. According to Wikipedia it produces less HP than the 3.0 Liter, but more torque. To me it's not worth the time, energy, or expense to warrant a swap. The L81 in the SAAB is configured for a front driver so it's positioned transversely. You'll need parts off the 3.0 to make it fit in a Catera.

There is an alternate supercharger kit I found while googling but it sounds a little like snake-oil to me. At best I think it would perform like a Ram-Air system but I guess it's better than nothing. A Google search for: Electric Supercharger turns up quite a few products.
http://www.mimousa.com/info/blowerinfo.asp
http://www.electricsupercharger.com/eram2.php
http://www.turbomagazine.com/tech/0406tur_knight_turbo_electric_supercharger/

None of these should put a strain on the engine other than on the battery charging system, and there is no mechanical drag as with a conventional supercharger. Off boost they freewheel like a turbocharger. I'm not in any way recommending these products. I just thought those looking for gains via K&N intakes, or removing exhaust resonators, might be interested. Those are passive devices that only allow the engine to inhale and exhale easier. A fan in the intake path is an active device that pushes more air than the engine will normally draw. If you honestly believe that an air filter will give you 20 HP extra then one of these blowers should be good for 50 or more. (Sorry for the sarcasm. Couldn't resist.)

GM revised the L81 3.0 Liter engine for use in the Cadillac CTS where its displacement was increased to 3.2 Liters (LA3). They don't appear to suffer from the same problems as the L81. It will fit in the Catera seeing as the engines are the same externally. The swap has been performed successfully a few times I know of by owners who suffered catastrophic cambelt failures. The LA3 will give you 220 HP with the CTS ECM versus the L81's 200. If you have a ruined L81 this might be worth a trip to the recycler.

The way to go if you want really serious power and reliability, and if you have deep pockets, would be to swap the L81 for an LS1 5.7 Liter V8. It is rumored to fit though I haven't read about one here. The late great Pontiac GTO (Holden Monaro) might be a source for parts like the LS1 V8 itself, transmission, ECM, wiring harness, driveshaft, and differential. Some GTO measurements taken at a friendly auto-recycler will answer a lot of fitment questions. Holden in Australia has been putting LS1s in their Commodores for years so the other necessary bits are available. Just find yourself a helpful Aussie parts counterman.
 
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