9-7 Engine Nay-sayers

[fabric]

For those who are poo-pooing the GM engines:

The inline 6 in general is one of the most inherently smooth engines. There's a reason BMW uses that arrangement. And every review I've read says that the GM I6 is a great engine.

As for a pushrod V8 - pick up the newest edition of Car and Driver and read Aaron Robinson's column on GM's pushrod V8.
While a DOHC V8 is technically better, it's probably only a 10% improvement over pushrods. You're not making a quantum leap. The biggest place you get an advantage is marketing, and keeping up with the other guy. GM decided to stick with the pushrod in it's small block V8 because it's a lighter, more compact package, and it saves money in production, while really offering very few drawbacks.

[CosmicSaab]

GM's pushrods also tend to be very fuel efficient.

I don't know how you can argue with a totally modern DOHC I6.

[fabric]

Originally Posted by E715

I don't know how you can argue with a totally modern DOHC I6.

Packaging is it's main drawback. Not a good fit for transverse mounting. I think it's a good match for the 9-7, although I agree with you that a supercharged I6 would be better than the V8. Oh well.

[Mattlach]

Originally Posted by fabric

Packaging is it's main drawback. Not a good fit for transverse mounting. I think it's a good match for the 9-7, although I agree with you that a supercharged I6 would be better than the V8. Oh well.

Hmm I know Volvo put a transversely mounted twin turbo I^ between the front wheels of the S80, but its a much smaller engine.. (2.9L I believe)

[CosmicSaab]

Originally Posted by Mattlach

Hmm I know Volvo put a transversely mounted twin turbo I^ between the front wheels of the S80, but its a much smaller engine.. (2.9L I believe)

Yeah, the 4.2 is HUGE. I feel that an Inline 6 fits in well with the European character of a Saab though. OHV V8 does not.

[fabric]

Originally Posted by Mattlach

Hmm I know Volvo put a transversely mounted twin turbo I^ between the front wheels of the S80, but its a much smaller engine.. (2.9L I believe)

It is indeed an I6. Kia did it in their "top" model as well.

Not that it can't be done, just not the best application.

[CosmicSaab]

Originally Posted by fabric

It is indeed an I6. Kia did it in their "top" model as well.

Not that it can't be done, just not the best application.

Kia doesn't have an I6 (or at least not in thr U.S.) Suzuki does (in the Verona) but the Kia/Hyundai 3.5L V6 is what is used in the Amanti (and the Sorento, and the Sedona, and the XG350, and the ...)

[Lodro]

FWIW, I've heard rumours that BMW may be moving away from signiatur inline engine, mainly for packaging reasons (obviously an I6 is going to be longer than V6).

I have also heard good things about GM's new inline engine btw. One article went so far as to say that GM powertrain was the hidden gem at GM.

[TwoSwedes]

Originally Posted by Lodro

I have also heard good things about GM's new inline engine btw. One article went so far as to say that GM powertrain was the hidden gem at GM.

Yes, I've read it compares favorably with BMW's "jewellike" I-6.

[fabric]

Kia doesn't have an I6 (or at least not in thr U.S.) Suzuki does (in the Verona) but the Kia/Hyundai 3.5L V6 is what is used in the Amanti (and the Sorento, and the Sedona, and the XG350, and the ...)[/quote]

You're right, I mis-remembered which make it was. Thanks for the correction.

[valbowski1980]

The pushrod has proved itself when it comes to big power. To me big power is no longer really that attractive since there are too many other cars on the road as well as police. The automakers who make cars which are fuel efficient and don't polute much are the ones that get my attention.

[Lodro]

Originally Posted by valbowski1980

The pushrod has proved itself when it comes to big power. To me big power is no longer really that attractive since there are too many other cars on the road as well as police. The automakers who make cars which are fuel efficient and don't polute much are the ones that get my attention.

To each his own. :-) I agree w/ ther pollution part, and I like efficency, but for me big power is key, especially big torque. Our route home from the city is through mountainous interstate and passing power uphill at altitude is especially key. But I also like a car that can easily light off from a stoplight. And for that, our Viggen will always be a benchmark, getting 25 mpg at 80 mph in the process. OTOH, we have been quite dissapointed w/ the performance of our WRX.

There was a very interesting article in this month's Automobile magazine on just the subject of pushrod v. OHC engines. An engineer for GM made a very interesting point -- we ware used to comparing specific output v. displacement (kind of like how people use Mhz to compare processor performance), when perhpas a better measure would be output v. weight and size of the engine. (Or efficency, fo that matter.) Using this as a guide, pushrod engines perform very well, as they are a much more space-effecient design, cc fo cc. It is only when you compare say a 3.2 liter DOHC engine to a 3.2L pushrod that the pushrod suffers by comparison.

[elitotaco]

Originally Posted by fabric

...although I agree with you that a supercharged I6 would be better than the V8. Oh well.

How about a TT I6? http://motortrend.com/future/concepts/112_0203_blazer

[Garuda]

Displacement is an extremely lousy measure of an engine's "size". I don't understand why it's so commonly used.

It's like saying GWB is bigger than Arnold Schwarzeneggar because he has a longer arm span. Well, it is true that arm span is a measure of man's size, but it's not the only measure, and it's actually a pretty lousy one given alternatives like weight, height, etc.

Pushrod engines are extremely compact. GM's 3500 takes up less space than their Ecotec 2.2. And GM's LS6 engine is smaller than Nissan's sucks-fuel-like-a-pig VQ.

When it comes to power density, fuel efficiency, maintainence and construction costs, OHV is hard to beat, at least for 6 and 8 cyllinder engines.

[Stefano]

Originally Posted by Garuda

Displacement is an extremely lousy measure of an engine's "size". I don't understand why it's so commonly used.

Engine 101. An engine is very simple concept. Air in, exhaust out. Pour some fuel to match with the air, and the engine goes. The less losses you have, the better it is.

Since ideally air in is displacement times engine speed, and this is proportional to power, you can see how displacement is important to guess an engine's power.


What else would you suggest to measure engines?

[Garuda]

Originally Posted by Stefano

Engine 101. An engine is very simple concept. Air in, exhaust out. Pour some fuel to match with the air, and the engine goes. The less losses you have, the better it is.

Since ideally air in is displacement times engine speed, and this is proportional to power, you can see how displacement is important to guess an engine's power.


What else would you suggest to measure engines?

Yeah, no kidding.

We were talking about *size*. Specifically, how many car enthusiasts mistakenly think displacement is an absolutely proportionate measure of how "big" an engine is, when in reality it is a poor measure, because the combustion chamber is only one part of an engine, accounting for only a small portion of its overall size.

[Garuda]

Originally Posted by valbowski1980

The pushrod has proved itself when it comes to big power. To me big power is no longer really that attractive since there are too many other cars on the road as well as police. The automakers who make cars which are fuel efficient and don't polute much are the ones that get my attention.

GM's OHV engines beat the competition not only in horsepower/torque, but also in fuel economy in many segments.

The Malibu V6 gets about the same fuel economy as Honda and Toyota's 4 cyllinder variants (Accord and Camry), while besting them in power.

And this gap is one that will grow, because GM is adding displacement on demand to most of its OHVs over the next few years.

[valbowski1980]

Maybe so but it's still really no faster than the Accord with 4 the cyl motor which is still more efficient. A honda 3.0 makes 240hp while a chevy 3.5 makes only 200hp, a honda's 4 = 160 hp and the Chevy's 4 = 145. Lastly the Honda can be had with an stick or a 5-speed auto, the Malibu comes with a 4-speed only.

My family was in the market for a mid-sized sedan and I drove all the usual suspects. After the Malibu it became clear to me why Honda sells cars for a set price while Chevy has to bribe buyers with discounts.

[Garuda]

Originally Posted by valbowski1980

Maybe so but it's still really no faster than the Accord with 4 the cyl motor which is still more efficient. A honda 3.0 makes 240hp while a chevy 3.5 makes only 200hp, a honda's 4 = 160 hp and the Chevy's 4 = 145. Lastly the Honda can be had with an stick or a 5-speed auto, the Malibu comes with a 4-speed only.

My family was in the market for a mid-sized sedan and I drove all the usual suspects. After the Malibu it became clear to me why Honda sells cars for a set price while Chevy has to bribe buyers with discounts.

Yeah, it's too bad your family has to settle for any of that bland appliance mobile stuff. Next time, save up a bit and buy a real, luxury car.

By that token, I guess Saabs must be absolute crap, given the $4,000+ discounts just about everyone here seems to get on them.

Good job completely missing the point though. I was comparing the power output of the Malibu V6, which gets the same fuel economy as Toyota Camry's 4 and about the same as Honda Accord's 4. The V6's of the latter two get much worse fuel economy, so the comparision is not apples to apples.

Numbers taken from FuelEconomy.gov, comparing automatic transmission models.

GM will soon be debuting a 3900 engine in the Pontiac G6, which will have 240 HP. That's when things will get interesting. This thing will own the V6 Camcords in low end torque and high end passing power, while besting them in fuel economy (especially when DOD is added on the following year).

OHV's have plenty of fight left in them.

[valbowski1980]

Originally Posted by Garuda

Yeah, it's too bad your family has to settle for any of that bland appliance mobile stuff. Next time, save up a bit and buy a real, luxury car.

Thanks for the advice jackass. Some of us need daily drivers and not luxo toys which spend weeks at the dealer to sort out. The Honda and Toyota make these daily drivers better than anyone else. The Camry (IMHO wrong choice since Accord was better) will easily out live the GMs.

Originally Posted by Garuda

By that token, I guess Saabs must be absolute cr*p, given the $4,000+ discounts just about everyone here seems to get on them.

I have no interest in the new Saabs, they bore me. Also, they aren't crap but they don't come near what the competition makes. Why do you think they are disscounted 4000+? If they price them with the BMW, Audi and Lexus what do you think would happened? From what I see Saab is now the Saturn of the luxo car marketplace.

Originally Posted by Garuda

Good job completely missing the point though. I was comparing the power output of the Malibu V6, which gets the same fuel economy as Toyota Camry's 4 and about the same as Honda Accord's 4. The V6's of the latter two get much worse fuel economy, so the comparision is not apples to apples.

What is your point exactly again? The Accord with a 4 and an autobox is more fuel efficient and only a fraction of a second slower than a Malibu with a 6. Who cares about a 6 if the 4 can do the job just as well.

Originally Posted by Garuda

GM will soon be debuting a 3900 engine in the Pontiac G6, which will have 240 HP.

By the time it comes around I'm sure there will be something to top it from Honda or Toyota.

Originally Posted by Garuda

OHV's have plenty of fight left in them.

Maybe you're right, the LS2 is an awesome motor.