Rod

What's the reason for this new trend?

For example, does Mitsubishi still make turboed Eclipses? I think they just have V6s now, right? And the RX8 and new Z car are also coming out naturally aspirated with no sign of twin-turbo versions.

This sucks, I'd really like a twin turbo version of the new Z or maybe a next-generation twin-turbo Supra, but that doesn't seem to be panning out either. Rumors are for a n/a Toyota V8 or even larger engine. The twin turbos would be so much easier (read: cheaper) to mod, just chip them.

mrdeeno

emissions is one reason.

another would be extra parts that are more prone to break. even though variable cam timing and whatever vtec and all those other variations do can break, i think it's less likely to than a turbo or supercharger.

and then there's liability. if turbos are easier to mod 'cuz you just chip them, then if something breaks, you can take out the chip and try to get it fixed under warranty (ie they're fixing something that SHOULDN'T be free which costs them $$)

moomaster_99

First and foremost, emissions is the problem.....that's why a lot of manufacturers are moving towards variable timing to achieve the new hp numbers.

Second, turbos have more than their share of problems....and after about 100K...you'll need a new turbo...in addition, turbos are very finicky....

mrdeeno

you know, if i was a bearing flying at 20,000rpm, i'd be a little finnicky too.

Rod

DAMN ENVIRONMENTALISTS!!!

Don't computers keep track of what went wrong and allow the dealer/manufacturer to determine wether or not the mishap should be covered under warranty? Isn't this what happened with all the blown engines on RSXs, it was determined that they were over-revved from the ECU data, or some other computer thing that tracked activity?

moomaster_99

True...just saying....reliability is a concern with turbos. RX-7s never really got it right......

gavriil

20,000 rpm?

Turbos idle at 140,000-160,000 and fully spooled reach 200,000 rpm depending on the unit, etc.

20,000 rpm is more of a supercharger range.

gavriil

Actually, that is not true. There are more force fed applications now than ever before coming out as stock from manufacturers. The best mass production example is VW and Mercedes.

VW's 1.8 liter 4cyl engine worn by a TON of VW Goup's autos is the best example. It starts at 150hp and will now reach 265HP in the new TT coming out soon. In that group of companies I include Audi, Seat, Skoda and Bugatti.

Mercedes chose the supercharging route. We saw it with the 2.3 liter Kompressor engine worn by several vehicles here in the US and its variation, the 2.0 liter Kompressor used in Europe A LOT more extensively than the 2.3 Komp. seen here.

The most convincing example that forced feeding is not dead is actually Mercedes's AMG division now switching to supercharging instead of enlarging displacement and general engine tuning treatments. The 3.2 liter Kompressor engine worn by the C32 is a kick ass engine in all respects. Even emissions and gas consumption. Even super cars by Mercedes will be wearing supercharged engines like the 5.5 liter Kompressor engine which will be worn by several cars to come by Merc.

As an ex 1996 Talon TSi AWD owner I can tell you that the reason Mitsu switched to a V6 engine with the new Eclipse was cost and not emissions. The V6 is cheaper to produce and it the car sells better with it. People dont know about forced feeding. They know: "does it have a 6 in it? No, a 4, but it is a turbo" Right away the customer is thinking of 2 things when he hears that: "turbos are unreliable" as someone already wrote in this thread and "turbos suffer from lag and power spikes". Both issues have been addressed in the past 5 years and are nearly NON-EXISTANT any more, but the public does not know of that yet. Which makes a V6 Eclipse sell easier than a turboed 4.

Another great example of force feeding is Volvo and Saab. Both companies at this point use turbocharging almost exclusively. One is owed by FOrd, the other by GM.

Another example is Jaguar with supercharging and Subaru with the WRX and a lot more to come with that engine in different variations.

Finally, there will be a turbo 350 Z. A twin turbo application of that engine is expected to appear in that car a year and a half after its introduction. The same engine will be used for the Skyline GTR which is expected in the US some time in the next yearh and a half as well.

Zapata

My next car will be a skyline

mrdeeno

i guess finnicky would be an understatement then.

i think the reason the biggest reason for varaible timing instead of turbos is just technological ground. who can say they got 240hp out of a n/a 2.0l engine? or 333 out of a n/a 3.2l engine? AS WELL as being emissions friendly, AS WELL as eliminating turbo lag and other reasons usually associated with turbos?

sure you can just add a turbo for power. but then again, where's the technological bragging rights that get people interested?

NOVAwhiteTypeS

Im most dissappointed at the fact the new s4 will be a v8 instead of a twin turbo.

gavriil

Is that right? I have heard so many rumors about what engine this car will wear, I cant count them anymore. The last I heard was a W8 which will be a derivative of the one used in the W8 Passat. In the case of the S4 it will make about 320Hp. Is that what you have heard?

Still it does not sound like they can go against the M3 this time either.

gavriil

You might be able to come out with 240Hp from 2 liters but there is no way you will be able to make 214 pounds of torque from 2 liters like the 4G63 engine in the Eclipses and Talons of the past generation. Or 217 lb-ft in the case of the WRX which is also a 2 liter engine. And it can get higher from there in other cases.

In other words, we go back to what I always used to say, that "one can make more power with a given displacement by making that engine spin at higher rpm efficiently, BUT one can make only so much torque".

And that is what most folks fail to understand when it comes to undestanding engine performance. Look at the numbers:

The S2000 which mentioned earlier, yes, it can make 240HP but it can only make 153 lb-ft of torque (at what rpm this torque appears is irrelevant in this case). Usually, engines that make that much torque make about 150HP on the average.

In the case of the M3. 333HP yes but 262 lb-ft of torque. Usually engines that make that much torque make about 260HP-270HP.

A good rule of thumb is that when the number of lb-ft of torque is higher than the HP number, the engine is tuned for turque instead of HP. When the HP is higher than the lb-ft number, the engine is being tuned for HP. When they are about the same, then the case is nuetral or average or normal, whatever you wonna call it.

Our engine is tuned towards HP for example because the 260HP is clearly larger than the torque number of 232. But it is not dramatically larger like in the cases of the S2000 and the M3 engines.

Finally, about the bragging rights. I disagree. I would feel the same pride if I had a car with an engine that made 240HP from a 2 liter NA engine or from a force fed 2 liter engine. I would actually prefer the latter as long as lag was not much of a problem because I would then know that there would be no lack of torque in the cast. I mean can you imagine the new Audi TTS making 265HP from a 1.8 liter 4cyl. ? Stock Not bad at all.

mrdeeno

i'm not talking about YOUR bragging rights, i'm talking about corporate bragging rights.

gavriil

Not to bore all with math but here are a couple of interesting questions that came to my mind thinking about the above issue of torque and HP and their relationship.

I am going to take the case of the M3's and our engine because they are both of similar displacement and they are both NA engines.

I was looking at the M3's specs:

262 lb-ft of toruqe at 4900 rpm

But what does that mean really? Well in order for one to simplify the meaning of torque, he would have to covert it to HP. Why? Well look at the formula:

HP = (torque X rpm) / 5252

Since 5252 is a fixed number, one can say that:

"some HP" is "some torque" at "some RPM". In other words, in order to understand torque it should ALWAYS be expressed at what rpm does that rorque appear at when the case is not such in the case of HP.

OK, OK what about the bottom line in our example though?

Well, that M3: 262 lb-ft of toruqe at 4900 rpm

So what does that mean? Well let us convert the above to HP.

(262X4900)/5252 = 244 HP.

So that M3's engine makes 244 HP when the tach shows 4900 which is where its peak toruqe appears.

In our case, according to Acura, our torque is peaked and stays flat at 3500 till 5500 rpm at 232 lb-ft. Although that is not realistic and we have seen it on dyno graphs, let us assume it is real.

So in the case of the CLS's engine:

(232X4900)/5252 = 216 HP.

SO KEEPING THE RPM POINT CONSTANT AT 4900RPM, WHEN THE M3 MAKES 244HP, OUR CLS MAKES 216HP.

The fact that the M3 redlines at 8000rpm and ours at 7000rpm is irrelevant in this case. Just for the sake of leveling everything.

Dont forget, these are simmilar engines in displacement and are both NA engines. So the comparison is pretty valid.

Now, let us look at the peak HP figures for both engines:

The M3 makes 333HP at 7900 rpm. To understand the efficiency of the engine there, we have to convert that to toruqe. So the question is, "how much torque does that engine make at 7900rpm?"

Back to the math:

(X times 7900) / 5252 = 333 OR

1748916=X times 7900 OR

X = 1748916 / 7900 OR

X = 221

So, the M3 makes 221lb-ft of torque at 7900 rpm!!!. Now that is a lot more impressive here.

What about our engine?

260HP at 6100 rpm

What is the torque there?

(X times 6100) / 5252 = 260 OR

1365520=X times 6100 OR

X = 1365520 / 6100 OR

X = 223.85 lb-ft

So at their PEAK HP rpm point, our engine makes MORE torque than that of the M3.

Or one could say that at their PEAK HP rpm point our engine "pulls" harder than that of the M3.

Of course the M3 folks would say that the comparison is not fair because we have to compare the above with what torque does the M3 make at 6100 rpm which I cannot know from the above numbers.

The bottom line of all of the above is that torque should stop be given the way it is given from manufacturers. Actually it should not be given at all.

The most comprehensive way of understanding how an engine performs in my opinion would be the following:

Show my how much HP does a given engine make for every 500 or 1000 rpm. In that way, we would be able to make VERY fair and accurate comparisons between engines and get a better feel of how the car would feel to drive factoring in weight, what wheels does power affect, tranny type, etc.

So, how much HP does the CLS make at 1000 rpm? How much at 2000 rpm? How about 3000 rpm?, etc, etc, till REDLINE. Not till peak RPM. Till redline or even better, till fuel cutoff.

Peak HP and/or torque numbers are less than half the truth.

bioyuki

What you talking about? The 4G63 engine in the Evolution VII makes 280hp (really about 300) and 282 lb feet of torque. The WRX STi makes same horsepower and slightly lower torque (somewhere in the 270s I believe). It is possible to get both torque and horsepower out of little 2 liter engines.

A lot of manufactueres still turbocharge: Saab, Volvo, Mitsubishi (cause MHI is one of the biggest turbo manfactuers in the world), Subaru and Nissan.

bioyuki

Oh yeah, the Evo VII's peak torque is made somewhere around 3500rpm. It has a redline of 7000 rpm. Its got a pretty flat torque curve for a 2 liter engine...

If you want the dyno its in .pdf form so PM me if you want it...

gavriil

True but corporations will brag about something only if it is acceptable to brag about by their buyers. Which is me and you.

If me and you see 120HP per liter from an NA engine, as something more extraordinary than 147HP per liter from a turboed engine (Audi TTS, 265HP from 1.8 liters), then manufacturers will brag about it that way.

In other words, manufacturers will brag about anything that their market would find acceptable to brag about.

gavriil

I do not think you understood what I meant there. Let me rephrase it:

"You might be able to come out with 240Hp from 2 NA liters but there is no way you will be able to make 214 pounds of torque from 2 NA liters like you would in the case of the 4G63 engine in the Eclipses and Talons of the past generation. Or 217 lb-ft in the case of the WRX which is also a 2 liter engine. And it can get higher from there in other cases."

Is that clearer now? NA stands for Normally Aspirated.

gavriil

Please post the link for the PDF, it would be interesting to see its dyno graph.

bioyuki

Sorry don't have the link on me...PM me or email me @ bioyuki@socal.rr.com and I'll email it to you....

gavriil

gavriil1@yahoo.com

Thanks.

bioyuki

Opps didn't see you were making a comparison between the S2K and other turbocharged cars....

bioyuki

File sent...its 1.61 megs.

mrdeeno

i disagree...they only brag about something if it sounds better and doesn't have to do with being acceptable or not. do you think most people actually care that their car is n/a or turbocharged, as long as it has 240hp? most people, probably not.

but what "sounds" better? "my car is turbocharged", which has been around for so long that no one really cares what it actually means (and they think it's that thing that michael does to kitt on knight rider), or "my car has a variable intake system and vtec" or "my car has a continuously variable tranny"?

and what do magazines write about? most may go over what a super or turbocharger does, but they usually focus on newer technology. then this technology is associated with the brand, and then they can use it to market the brand. does volvo focus on the fact that it turbocharges it's cars? no, volvo doesn't have any specific technology, but they use all the ones associated with safety.

does audi focus on using turbos? no, they use "quattro" as their marketing technology.

i don't know what saab uses, but i guess that's why saabs are quirky.

probably only porsche uses the turbo effectively as it's marketing technology.

honda has vtec and ivtec.
toyota has vvti
mb keeps coming out with new ones like it's electronic brake system
bmw keeps coming out with new ones like it's 6spd auto and infinitely variable intake

so, bottom line, porsche already owns the "turbo" bragging rights, and every other car that has it, they just "have it".

bioyuki

Saab will probably be using variable compression in a couple of years and that technology will hopefully revitalize the use of turbos...

acura_service

TURBO LAG SUCKS
.........and i'll take more torque anyday