Many manufacturers will use basically the same engine in multiple different vehicles and even different types (meaning cars, trucks, SUVs, vans, etc.). They will be adjusted slightly differently for different uses.

Maybe one vehicle would be best served by something that has a little more low-end torque, and another would require something set up for cruising at freeway speed. If the manufacturer has something that can be slightly adjusted to meet both needs, they save money on R&D / manufacturing. The differences might be as simple as a tune, or it might be cams, pistons (compression), exhaust and more.

It's not just engines. For the same reason, you'll find vehicles of the same model that have slightly different suspensions or gearing depending on what use they were intended for.

I know this isn't a really technical explanation, but I was just responding off the cuff.

 

I really don't pay attention to newer fwd stuff so I don't even know what else the engine comes in. That said what is the octane rating on the other vehicles? The Impala being big for fleet use they might have given it more forgiving spark tables. Or maybe underhood space dictates a tight restrictive turn in the intake tract.
Maybe given the fleet use they made the intake and or exhaust a little quieter.

 

Even the new 3.6 is rated as 323 hp in some Cadillac applications
while its only 300 in the Impala.

 

And 281 and 275 in the Lambdas.

 

If I was going to buy a Cadillac I would hope it had more power than a Chevy that cost so much less. The corvettes have always had more power than the Camaros, otherwise it would be hard to justify the cost of a more expensive car. TPI, LT1, LS1, ext.... Better flowing heads, more aggressive cams, better intake design, better exhaust design, all topped off with a computer tune to make it all work together.

 

There is a lot more to a car than the amount of power. A Cadillac and a Chevy are very different even if they did have the exact same amount of horsepower... Most Cadillac owners probably don't even know (or care) exactly how much horsepower they have... You don't buy a Cadillac over a Chevy just because of the horsepower...

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The LT1s in the Vette were the same as the Camaro, the difference there was more advertising than actual, bet the same goes for the LS1.

GM actually underated the f-bodies and gave the Vette a couple more main bolts in the same block casting just to make the Vette buyers feel special.

 

Actually I bought my 07 Escalade over a Tahoe LTZ because I couldn't get the 6.2 403 HP engine in the Tahoe and it was standard in the Cadillac. I am probably not the typical Caddy (former) owner though. If I could have got the LTZ with the 6.2, that would have been my choice.

 

Yeah, I guess I'm thinking of "old school" Cadillacs, when they were mostly owned by old men that purposely drove them very slowly!

Nowadays, Cadillac is gearing their vehicles toward much younger owners (pretty successfully, I might add!).

 

Of course there is more to a car than power but if engineers at Cadillac dont do research and development to give you more power, what else are they not researching? Are you getting more for your money or are you just getting a fancy grill that your neighbor or buddy at work can't afford?

 

What you are getting is a vastly superior product with higher quality parts, fit and finish... There is a huge difference between the way a Chevy is put together and the way a Cadillac is put together.

There is even a pretty big difference between a Chevy and a Buick. Just some examples off of the top of my head:

My Buick LaCrosse has laminated side windows (helps reduce cabin noise) that my Chevy Impala doesn't
My Buick LaCrosse has additional weatherstripping around the back doors that my Chevy Impala doesn't
The a-pillar covers in my LaCrosse are extremely "solid" feeling where the a-pillar covers in my 2012 Impala have "give" to them.
The dash in my LaCrosse is built better than my Impala.

However, my Impala has a smaller engine that produces much more power (3.6L/300HP vs 3.8L/200HP). Like I said, the horsepower of a car is a pretty small factor when it comes to low-end/high-end cars. My examples were just between a Chevy and Buick.

Generally, everything in my Buick uses higher quality parts and is just put together better - the difference between a Chevy and a Cadillac would be even more pronounced.

The amount of power plays a part, but there is far more to the higher-end cars than just the amount of power they have. There is a pretty big quality difference.

 

I completely agree. Every aspect has to be better in a more expensive car. I would expect buick to switch to the higher power engine and the stronger/ better gas mileage trans at the same time if not before Chevy.

 

I agree about better materials used up the product line for Caddy and Buick 100%. I will tell ya though, they are often built on the same line. Workers see a Chevy, next a Buick, next a GMC, etc etc. I have been on quite a few line tours from 1992 though 2013. They literally all mixed together, so I can't necessarily agree that there is a difference in how they are put together.

 

Understood - when I say "put together better", I guess that I really mean "engineered to be assembled better" - things just fit together better are are designed in a way to be sturdier, etc...

 

Gotcha ^. Don't disagree with that. Learned on a tour that the Enclave gets 20 pounds more of sound deadening and insulation than the Traverse/non Denali Acadias. Yeah, you read that right, 20 pounds! And they are built all together on the same line in Lansing.

 

to answer your question its gm playing game, done it for ever, they simply post the hp made at X rpm..

Chevy, then buick then caddie, i think is the order, sorta like Chevy truck, GMC truck and the caddie,

But if you look way way back, 427's came in different hp, I dont rememeber off th top of my head but a the low horse, was like 390, then 420, if you did side pipe 435, then "special heads" got you another 10 HP,, But if you where baller and bought the aluminum race motor, It got you 5 more hp for like total of 450, But in real dyno's they are close to 650-700 depending on the rpm.

Just look at rpm when compairing hp.

 

Yes , I guess like when I bought my C5 ,the Camaro SS got 330 HP, & they listed the non Z06 C5 @ 350 HP.Just wonder if the Impala 3.5 is 211 HP at the rear wheels?Are they going BHP or net HP,these days?I know when I had a '72 Comet GT back in the day ,they rated the 1972 302 @ 142 HP.But that was net HP.The 1971 302, (both '71 & '72 were 2bbl.) were rated @ 210HP,BHP.In fact I had heard that there was really very little diffence in the HP of both those engines.Ford did it too,& from the info I got ,lately Ford has been exagerating HP ratings on some of their cars ,slightly upwards of where they actually are.That was unlike in the Muscle car era when the US manufacturers ,under rated their HP ,for insurance puposes in high HP engines.Like Chevy's 427 or 454 was much higher than stated.In HO engines, all across the GM,Ford,Mopar lines of High Performance engines,big block of small, were rated less than what they dynoed at the engine.So I have read?

 

Sounds like you are getting confused by the early 70s change from STD HP to SAE ratings which made the published number plummet for the same exact engine.

The "underrated" thing that happened in the musclecar era was an insurance game.

 

Sounds like you are getting confused by the early 70s change from STD HP to SAE ratings which made the published number plummet for the same exact engine.

The "underrated" thing that happened in the musclecar era was an insurance game.

No,I was aware of the change from a rating of HP numbers with all accessories atached to the motors of cars mostly after 1971,starting with the 1972 model year.Prior to '72 the HP was a more of a Brake HP or SAE HP, some refer to it as Gross HP,that is an engine HP measured at the FW no accessories, like a PS pump,WP, or an AC compressor, not even exhaust manifolds!Like stated very little diffence in the Ford 302CID engine from 1971 to 1972.People have dynoed both eng.Just a slight decrease in compression & a hotter thermostat put in that engine in '72, so it ran hotter & theoretically burned gas more thoroughly.Thus decreasing emissions?

Later on ,like 1973 air pumps or as Ford terminolgy calls them,thermactors, were put on to further decrease emissions.Then when catalitic converters were installed as ealy as 1974,as Ford called them,"air control valves" or the GM term "diverter valves" further complicated the emission sys., & of course an even greater reduction in compression ,decreasing HP further.EGR valves came into being then too,along with a host of other devices on cabureted cars, like transducers etc.,that made the engine bay look like a bowl of spaghetti,so many small vacuum hoses there!

The question at hand is ,how are our Impala engines rated, Net HP or SAE/BHP?

 

I'm pretty sure its measured at the fly and not the rear wheels..

 

So its the same as Net HP.That was actually how they measured HP from the early 1970s onward & why an engine of the pre 1972 year, like a 302 2bbl. was stated at say 210 BHP or SAE HP while after '71. it had 142 NHP.The Olds 350 was listed with a duece carb & 250 BHP in 71, after that around 180 NHP.

So 211NHP in our 3.5s are not bad for V6s.

 

yea, but as for why the same motor make different power across the GM brands, its just advertising. The wifes denali, is 400 hp but the caddie is 405 or something like that.

I have not looked in a long time at dealer brochures, but when you use to compare side by side the rpm was the difference, 400 @2800 rpm vs 405 @ 3100 etc...

Im sure there are little changes in the motors, but the denali is a 6.2L 403, hp the SS camaro is 4XX then the new SS car is 4XX all different.

 

You all seem to be ignoring details outside the engine like intake tract, exhaust, MECHANICAL FAN, what octane is recommended and tuned for, is there a subtle cam difference, does one model have flat top pistons. Yes sometimes a "cheaper" model will get say a dished piston and half a point less compression, so the manufacturer can sell the "higher power" engine that cost the exact same to make for a $1500 option and it can make people feel special to have to buy 91 octane vs. 87, because they bought the 'better" engine.

Reading a book from a couple decades ago doesn't give a complete understanding of thing.

 

Yes Dwayne J ,we aknowledge that & we're simply asking a question if anyone knew of these cam or tune improvements in other 3.5s on different GM lines.But I for one am satisfied with the conclusion here for these engines ,& this is pertaining to our 3.5s & probably even 3.9s as to why slightly higher ratings on the Buick & Pontiac versions.The difference is fairly miniscule,215 or up to 217 HP for the non Chevy ,ADVERTIZED HP 3.5L,& ours 211 Advertized HP ratings.I too may think its a game by GM in taking the readings at different rpms, or a slight change in tune for this small difference of 4 - 6 HP or so, in its same displacement & equipped engines.I guess GM is still doing that for its percieved more "premium" cars,as they did in the past?While Ford & CC, seemed to allways have the same HP numbers across the line on all engines they produced ,put large cars,small cars,luxury ,less expensive, cars.A Ford 351,302,400,460,now the modular engines, & CC engines seemed to be fairly consistant on HP readings across the model lines.Thats comparing apples to apples in carburation,etc.Were not talking about performace packages in engines in premium or muscle cars here.

 

Paragraphs!
After the 2nd word I just passed over that last post.