Inefficient engines

[harrytuttle]

I can follow this thread, and I can pretty much see where everyone is coming from, but I consider the output of an engine using only three guidelines:

1. Area under the curve.
2. Area under the curve.
3. Area under the curve.


It's a simplistic way of looking at it, but unless we're talking about best fuel economy, the total area under the curve (power or torque) is the only real way to compare total output of any engine.


How can one directly compare VAG's 326HP 4.2L TDI V8 to their 420 4.2L FSI V8? One's torque curve is pretty much sub-4000rpm, the other is starting to really wake up at 4000rpm. One has peak torque of 480 lb-ft, the other only 317 lb-ft. How are these two engines with similar displacement, from the same manufacturer, and the same model year, so different? And which one is "more efficient"?

http://en.wikipedia.org/wiki/List_of_Volkswagen_engines#350-420_hp_4.2_V8_FSI


What is your definition of "efficient"? Is extreme turbo lag acceptable to acheive 800HP from a 2JZ-GTE? Or is the bottomless torque of a 1972 Chevrolet LS6 worth the breathless top end? What about Spoon's B16 topping out at 10,000 rpm? Which makes "best use" of the air & fuel mixture at each cycle?

I must stress that this only pertains to the engine itself. It ignores the entire remainder of the car: gearing, wheel size, vehicle speed, aerodynamics, weight...everything.

 

[Wolfe]

Did I say the title of the thread was slow cars? No. I said hp/l is a useless measurement, thrown around by fanboys who think that because an engine can make #hp/liter that it's the greatest engine known to man, even though there are more powerful engines in existance. There's your answer.

Power =!= Great engine

The idea of what a "great engine" should be will vary from person to person. It isn't always about pure power. For example, there are many, many production car engines I would take over the Veyron's W16.

I didn't say 80hp/liter would absolutely, one hundred percent mean an engine was going to hand grenade. Drop an extra 1,000hp into your M5 engine and see how long it lasts. Now do the same to a 400+ cubic inch V8. Get the picture?

No matter what, there are limits to what can be expected from an engine, and yes, 1000+hp is a bit much to ask of a sub-4.0L engine. However, that doesn't justify the idea that a 5.0L engine is better-suited for making 200hp than a 2.0L engine.

Also, for the record, I would trust BMW's 3.2L S54, Nissan's 2.6L RB26DETT, or Toyota's 3.0L 2JZ-GTE with the task of a turbocharged 1000 horsepower over Chevrolet's 7.0 LS7 or the Dodge Viper's 8.3L V10 any day of the week.
Hennessey's Venoms tend to break (not to mention the fact that Vipers don't exactly have a stellar reliability record when stock, either), and if 507hp is all GM could muster out of the LS7 for the ultimate, no-holds-barred 'Vette, I'd hate to see what turbochargers would do to that thing. On the other hand, I wouldn't trust the new M5's/M6's V10 with 1000 horsepower, either, and the same goes for the 1985 M5 (I assume) you were referring to. I tend to tailor examples to better suit my personal automotive tastes (and who doesn't?), but that doesn't mean I'll deny the truth.

The point is, there are more factors to a car's reliability than HP/L alone. Which brings me back to the point that HP/L is more useful when used in the context of the other specifications/characteristics of a car.

No, your argument is that since they make more hp/l, they're "better" engines, or that American auto manufacturers suck because they "can't" get more horsepower/liter. Which is more daft than you could ever dream of calling me.

My argument is that the Toyota/BMW/Nissan engines are better engineered, but not better in every way, shape, and form.

Obviously, if you want to win a race, the Mustang and Corvette are the painfully obvious winners compared to likes of the Yaris or Sentra. On the other hand, in that same race, if you were given the choice between the Mustang as it is normally, or a special Mustang that was just as well-engineered as the M5 and produced the same specific output, the "M5-like" Mustang would then be the obvious choice.

Furthermore, I don't think american manufacturers suck because they can't get more HP/L. If that were true, I'd hate Mercedes-Benz as well, because they almost need forced induction to get any respectable numbers out of their engines.

I am disappointed that the american manufacturers can't get more power out of their engines, but I think they suck because I think they make vehicles that are just sub-par, overall.

It doesn't matter if an engine is 3l or 13l, horsepower is horsepower and the only difference is the bigger the engine, the less strain you need to put on it to make that power, and the more reliable it is.

A fair enough argument on its own, but when an engine with a higher specific output turns out to be just as reliable anyway, you gotta wonder whether holding back on the HP/L is really worth it.

And don't ask me for examples of engines that are just as reliable or moreso -- the reputation that Toyota and Honda have earned, despite building several engines that eclipse Detroit's best in the HP/L category, is more than enough proof all by itself.



The bottom line is this: We aren't going to change each other's minds, but I hope that you can understand where I'm coming from with this post, just like how I can understand that you value pure, unadulterated horsepower/torque, and couldn't care less about what it comes from, as long as there's a very short amount of time between the moment you stomp your foot down and the moment the car launches forward (ie. no turbo lag or "V-TEC" allowed). I'm not trying to mock you with that description, it is simply what I have observed from your posts, and what I assume your opinion is.

 

[daggoth]

Like, you know, most of Europe? Italy has one, France has one, Spain has one, and I beleive Britian has one. Japan also has one.

And Portugal

torque is the most important factor to a cars ablity

Formula 1 cars don't have much torque but they are the fastest cars in the world around a track! How do you explain this? I'm really just asking out of curiosity.

and the vag 1.9tdi can be an extremely powerful engine,ive seen one out do a toyota supra,got a video of it somewhere

You cannot really compare stock to modified cars. We all know how much a tuned Supra can do in a straight line.

 

[///M-Spec]

So far we have 3 people that say the LS7 is the better choice.

Would anyone care to argue on BMW's behalf?

Can it be that hard? Surely someone can explain to us the BMW is a far more efficient engine. In terms of weight, size, fuel efficiency, price... it's got the Chevy covered, right?

I mean, it's the do-it-all wundermaschine versus some smog belching American dinosaur 30 years overdue for replacement (evident sarcasm).

I think the biggest question would be where you could even pick up that 5.0L V10 from BMW, much less run it without their guidance every step of the way?

In the real world, no. But that's not really important at all. This is a hypothetical excercise designed to isolate the engine from the car.

Just pretend the YSFC organisers convinced BMW and Chevy to provide a batch of crate engines identical to production units, with all the wiring and ECUs needed to run them.


M

 

[Scaff]

So far we have 3 people that say the LS7 is the better choice.

Would anyone care to argue on BMW's behalf?

Can it be that hard? Surely someone can explain to us the BMW is a far more efficient engine. In terms of weight, size, fuel efficiency, price... it's got the Chevy covered, right?

I mean, it's the do-it-all wundermaschine versus some smog belching American dinosaur 30 years overdue for replacement (evident sarcasm).




In the real world, no. But that's not really important at all. This is a hypothetical excercise designed to isolate the engine from the car.

Just pretend the YSFC organisers convinced BMW and Chevy to provide a batch of crate engines identical to production units, with all the wiring and ECUs needed to run them.


M

I would have to go for the LS7, sarcasm accepted its far from a dinosaur of an engine and as much of a technical wonder the S85 is (and it certainly is), its also a road car engine. Yes its a damn good road car engine and its been specifically designed to be a seriously sporting road car engine, however a quick look at the spec of the LS7 and its instantly a different picture.

The LS7’s specifications include:

* Unique cylinder block casting with large, 104.8-mm bores and pressed-in cylinder liners
* Forged steel main bearing caps
* Forged steel crankshaft
* Titanium connecting rods with 101.6-mm stroke
* Cast aluminum flat-top pistons
* 11.0:1 compression
* Dry-sump oiling system
* Camshaft with .591-inch lift
* Racing-derived CNC-ported aluminum cylinder heads with titanium intake valves and sodium-filled exhaust valves
* Titanium pushrods and valve springs
* Low-restriction air intake system
* Hydroformed exhaust headers with unique “quad flow” collector flanges.

“In many ways, the LS7 is a racing engine in a street car,” said Dave Muscaro, assistant chief engineer of small-block V-8 for passenger cars. “We’ve taken much of what we’ve learned over the years from the 7.0-liter C5-R racing program and instilled it here. There really has been nothing else like it offered in a GM production vehicle.”

Link - http://www.corvettemuseum.com/specs/2006/index.shtml

Now the above may be from GM themselves, but the spec of the engine speaks for itself, and I'm actually not talking about power, torque or specific output here.

Rather the design and build of the engine itself, which is far better suited to the application M-Spec has proposed, small items such as the dry-sump lub system will have a major impact in a racing application (I believe the S85 does have lub surge control but is still essentially wet sumped - checked its semi-dry able up to 1.4g).

Its an opinion, but for me I would go with the (far from a smog belching American dinosaur 30 years overdue for replacement) LS7.

Regards

Scaff

BTW - The S85 sounds like a diesel at idle as well, not strictly valid in the discussion but would you want your race car to sound like that?

 

[Danny]

Just one thread without an arguement about the Corvette or LS7.

Is that too much to ask?

 

[Poverty]

Someone explain to me how the LS7 is as much as a technical wonder as the S85? What are the criterias that put it in the same category?

 

[skip0110]

And don't ask me for examples of engines that are just as reliable or moreso -- the reputation that Toyota and Honda have earned, despite building several engines that eclipse Detroit's best in the HP/L category, is more than enough proof all by itself.

Keep in mind that Honda/Toyota earned that reputation making pathetic, 2-bbl carbureted 1.5 L engines with 8:1 compression ratios and under 70 hp (that lasted forever, mind you). They had specific output just as poor as anything Detroit was making, just smaller displacement. Only recently (say, the last 20 years) have they been pushing the technological frontier and really making what you would call "efficient" engines.

 

[Duke]

Someone explain to me how the LS7 is as much as a technical wonder as the S85? What are the criterias that put it in the same category?

The LS7 is lighter, cheaper, smaller in form factor, and has more torque.

Who cares if it's a "technical wonder"? What exactly is being a "technical wonder" doing for the S85? Oh, that's right, I forgot: having pushrods totally invalidates the LS7's existence.

For the record, my BMW 325i has a specific output of 69.5 hp/l - beaten by the Dodge Stratus R/T, among others.

 

[daan]

Someone explain to me how the LS7 is as much as a technical wonder as the S85? What are the criterias that put it in the same category?

But does it really matter? You're never going to agree anyway.

 

[Poverty]

The LS7 is lighter, cheaper, smaller in form factor, and has more torque.

Who cares if it's a "technical wonder"? What exactly is being a "technical wonder" doing for the S85? Oh, that's right, I forgot: having pushrods totally invalidates the LS7's existence.

For the record, my BMW 325i has a specific output of 69.5 hp/l - beaten by the Dodge Stratus R/T, among others.

but what makes the LS7 more specially than other LS engines other than it being in the Z06?

All im saying is that because it is such a simple engine any manufacturer could come up with one with similiar performance, whilst many for example the M3 motor hav tried to copy mimick or whatever, but failed.

What makes the S85 special is the fact that its the most powerful engine in the world, processor wise (unless something as come along since me reading that). What other engine can be asked to lower the power by 100ps or with a remap gain a extra 100ps over its 500 odd PS other than turbo units?

 

[Scaff]

but what makes the LS7 more specially than other LS engines other than it being in the Z06?

All im saying is that because it is such a simple engine any manufacturer could come up with one with similiar performance, whilst many for example the M3 motor hav tried to copy mimick or whatever, but failed.

What makes the S85 special is the fact that its the most powerful engine in the world, processor wise (unless something as come along since me reading that). What other engine can be asked to lower the power by 100ps or with a remap gain a extra 100ps over its 500 odd PS other than turbo units?

Did you miss my post from above, the older LS series engines may very well be of a simple design originally, but to dismiss the LS7 as a simple engine is, in my opinion, to be ignorant of the level of detail that has been put into it. The valves alone are superb pieces of engineering.

The heads feature 70-cc combustion chambers that are fed by huge, 56-mm-diameter titanium intake valves. The lightweight titanium valves each weigh 21 grams less than the stainless steel valves used in the LS2, despite the valve head having 22 percent more area. They are complemented by 41-mm sodium-filled exhaust valves (vs. 39.4-mm valves in the LS2). To accommodate the large valve face diameters, the heads' valve seats are siamesed; and, taken from experience with the engines of C5R racecars, the LS7's valve angles are held at 12 degrees - vs. 15 degrees for the LS2 - to enhance airflow through the ports.

You need to know how it differs from other LS engines, follow the link I posted above and have a good read.

Regards

Scaff

 

[Poverty]

Dont other cars use similiar valve technology though...

 

[Scaff]

Dont other cars use similiar valve technology though...

Very few road cars use titanium and sodium filled values, its far more common in race engines, but remember you said...

but what makes the LS7 more specially than other LS engines other than it being in the Z06

and

All im saying is that because it is such a simple engine any manufacturer could come up with one with similiar performance

...valves are just a small (but very obvious) part of why this comment simple is not true as far as the LS7 is concerned, the full piece I linked to details the exact nature of the differences and exactly how the LS7 relates to the race engine fitted to the LeMan 'vette.

To dismiss the LS7 as simple just because it is at heart a pushrod design is simplistic and inaccurate, its a superbly designed engine just as the S85 is, and for the application M-spec has outlined the better option for me.

Regards

Scaff

 

[Poverty]

But arguably someone would have a hell of alot easier time making a replica LS7 than a replica S85.

A serious question here thats been bugging me lately. Why do some manufacturers make such advanced engines when a simple one can do the job just as well or better? Anyone got any ideas ont his?

 

[Scaff]

But arguably someone would have a hell of alot easier time making a replica LS7 than a replica S85.

Well in theory if you buy the component parts right of the shelf and have the tech manuals one is no more difficult than the other, but in the case of the LS7, I would not agree. Older versions of the LS yes may well be easier, but the LS7 has some serious engineering know how tied up in it.

A serious question here thats been bugging me lately. Why do some manufacturers make such advanced engines when a simple one can do the job just as well or better? Anyone got any ideas ont his?

It depends on the application and environment it needs to run in, a lot of the 'tech' in modern road car engines is designed around meeting current and future emissions regulations, maximising fuel mileage while generating the power wed as drivers often demand.

After all the piston engine is actually a very inefficient design in itself, it experiences massive internal power losses due to friction and the sheer number of moving parts. A lot of work goes into minimising these losses.

Regards

Scaff

 

[skip0110]

What makes the S85 special is the fact that its the most powerful engine in the world, processor wise (unless something as come along since me reading that). What other engine can be asked to lower the power by 100ps or with a remap gain a extra 100ps over its 500 odd PS other than turbo units?

I'm not so sure, as far as I know Ford/GM are the only automakers to have a diagnostic port on the ECU (seperate from the OBDII port, which is not on the ECU anyways) which allows the engine to run off a fuel map on a seperate chip, without altering the ECU or opening it up, even. This was designed into the ECU so as to be simple to use and add in external fuel maps.

So if you wanted, you could get a 3.0 Ford Duratec to lower it's horsepower by 100 at the press of a button without too much trouble.

 

[Gil]

Well, I hate to disagree bud, but the Vtec kickin point for my Civic is at 2700 rpms, and my redline is 7200 rpms. The point at which my car loses it's powerband and starts to decrease gains per rpm, is around 6700 rpms.

Now, as far as what Pickup I would choose to use for towing 5tons, it'd probably be a Toyota Tundra or Nissan Titan (the Honda model needs to come a VERY long way for me to use it as a towing vehicle). I've towed 11,000 - 12,000 lb trailers with F-350's, 1ton Suburban's, and even a Dodge Cummins (my favorite of the Domestic Diesels). Also, comparing turbo diesels to naturally aspirated cars, isn't a truly fair comparison. If I were towing upwards of 15k lbs or more, it'd definitely be a turbo diesel pulling the trailer. But, I HIGHLY doubt that this thread was designed to discuss the relativity of the efficiency. I think it was to discuss how inefficient engines can be made.

I don't particularly mind if you disagree.
However, I also have a Civic, and I've checked the figures on msn, and intellichoice. For the 2000 model year (the year I happen to own) the lowliest civic makes its 106 HP at (to me) a high Rpm of 6200.
The Si turns a whopping 160 HP at 7600. That's 400 RPM's over your claimed redline of 7200.

If your car is kicking over into V-TEC at 2700, I have to ask if it has been "chipped"/engine management "re-mapped"?

Max torque (and what precious little there is) happens at 4600 in the lowly DX, and at 7000 in the Si.
I still say that your power is above where you normally run the engine.
I don't drive our Civic much, but I did spend 9 hours in the driver's seat bringing it home from CO. As, I recall, at highway speed in top gear my civic is running at about 3000 rpm.

Granted, it is an automatic, and the trans is mapped to shift at about 5,000 at WOT. Even so, the car never hits the meat of the power band, except for the 400 RPM between 4600-5000 when it's in the meat of the Torque band, for about 4 seconds before upshifting.

My Camry also very rarely gets to the meat of the power band (133 hp at 5200), and it will roll 75 mph all day at 2600 RPM in top gear. But it feels strong from down low in the RPM band. BTW 133HP out of a 2.2 comes out to 60.45 HP/Liter. Lower than any car you mentioned. And it's the same engine that was "farmed out" into the MR-2.

The Vette with it's "antiquated" pushrod V-8 makes it's highest power at 6000 rpm, yet it's pulling down 0-60 times in the low single digits.
That indicates that it's still putting down some major power, from just off idle.
HP numbers are basically meaningless. Torque has a bit more bearing on what's really going to happen when the hammer is put down. And overall, the stopwatch, not the dyno, is the great purveyor of "truth".

As for the Tundra and the Titan, both are excellent trucks. If Toyota and Nissan keep improving they will be a much bigger force in the light truck market, possibly kicking the big three to the curb in the next 5-10 years.
However, the max towing for a Titan is 9500lb. For a Tundra its 7100lb.
The max towing on an Chevy 2500 HD is over 16,000lb.
The Ford F250's max is near 15,000.
The Dodge, the "weakling" of the bunch is just under 14,000 lb max towing. (all the big three-diesel numbers given)
Gas vs gas, the numbers are pretty much even, but with the big three you also get a larger cab, for "crew comfort".

I continue to use the diesel for an example because the big-three (Power Stroke, Duramax, and Cummins) come in around 6.0 liters. Yet, all three are rated under 350 hp. That's pretty weak in the Hp/liter wars. (Somewhere in the neighborhoood of 55 HP/liter.) Interestingly enough, the HP/liter figures on the Nissan gas truck and the Ford diesel truck are very, very close. The 5.4L Ford gas motor actually makes 1 more HP/liter than the Nissan. But the Nissan is marginally torquier. 67.54 lb/ft per liter vs. 67.67 lb/ft. per liter.
Yet it's the torque the diesels put down (well over 500lbs/ft in all three) that makes them better for towing/hauling than any gas-powered truck. The Ford 6.0 Powerstroke makes over 93 lb/ft per liter.
The diesels also turn "acceptable" fuel economy. I'm getting over 18 mpg with mine.
That's similar to a Titan, and I can carry 8 people and their gear.

 

[Wolfe]

So far we have 3 people that say the LS7 is the better choice.

Would anyone care to argue on BMW's behalf?

Can it be that hard? Surely someone can explain to us the BMW is a far more efficient engine. In terms of weight, size, fuel efficiency, price... it's got the Chevy covered, right?

I mean, it's the do-it-all wundermaschine versus some smog belching American dinosaur 30 years overdue for replacement (evident sarcasm).

You do bring up an excellent point with your "game." The S85's only real advantage in the hypothetical racing series is its higher redline.

Yet again, it all comes back to what you're looking for from an engine, and using HP/L in conjuction with other aspects of an engine.

Also, again, I must pose the question -- which would be better for your racing series...a 507hp LS7, or a 710hp LS7, even with the bit of a weight and fuel economy penalty that a so-tuned LS7 would take?

 

[Firebird]

I am disappointed that the american manufacturers can't get more power out of their engines, but I think they suck because I think they make vehicles that are just sub-par, overall.

So then, what you're really trying to do here is find any excuse to put down 'American' manufacturers their products?

A serious question here thats been bugging me lately. Why do some manufacturers make such "advanced" engines when a "simple" one can do the job just as well or better? Anyone got any ideas on this?

To impress the easily-impressed.

 

[YSSMAN]

A serious question here thats been bugging me lately. Why do some manufacturers make such advanced engines when a simple one can do the job just as well or better? Anyone got any ideas ont his?

A few years ago, an story was covered in several major American automobile magazines in which General Motors proclaimed that they would remain "comitted" to OHV systems on almost all of their engines for atleast the next 10 years (I belive the story hit the streets in 2004). GM's arguement was that in order to pack in the "value" in which many of their customers demand, OHVs are still relevant enough to make the power, run efficently and reliably, and match the performance of the competition well into the forseen future.

...Of course, GM has only quasi-honored that story. They have been adding DOHCs and VVT setups to many of their designs outside of the V8 line (probably will remain OHV for as long as possible), and that too is a good thing.

Money is the biggest issue here, particularly with American automakers. As long as the engines are powerful and fuel efficent enough to meet the needs of consumers, they will build them that way. When trends push them to bump up the power, they will do it as well. The 3.9L V6 and 3.6L V6 were both answers to demands of the public, the 3.9L replacing the old Buick-designed 3.8L, and the 3.6L becoming the "elite" V6 in GM's lineup.

 

[harrytuttle]

What makes the S85 special is the fact that its the most powerful engine in the world, processor wise (unless something as come along since me reading that). What other engine can be asked to lower the power by 100ps or with a remap gain a extra 100ps over its 500 odd PS other than turbo units?

Don't just about all modern engines have a "limp home" mode? For when something catastrophic happens, but the engine still barely runs. This seems to be the same thing, only it's manually controlled.

Someone explain to me how the LS7 is as much as a technical wonder as the S85? What are the criterias that put it in the same category?

GM took what is essentially 50-year-old technology, on a 50-year-old engine block, and re-engineered it without changing a single part in concept, but re-inventing every single component from the ground up.

The S85 uses all new concepts, all new technology, and uses them well. That's great. But it's like using FiOS to download a 10MB file in 30 seconds. The challenge is getting the same transfer rate over dial-up, which is pretty much what GM did.

A serious question here thats been bugging me lately. Why do some manufacturers make such advanced engines when a simple one can do the job just as well or better? Anyone got any ideas ont his?

Simple: "What is the target market?"

BMW buyers want high-tech, Corvette buyers want a L88 (or something like it). Substitute in your brand of choice.

 

[toyomatt84]

If your car is kicking over into V-TEC at 2700, I have to ask if it has been "chipped"/engine management "re-mapped"?

I wish I could say yes to that, but unfortunately no. The D17A2 is the red-headed stepchild of the D-series, and probably the plaque of Honda's Vtec lineup. There's really no aftermarket for the engine, especially when comparing to it's siblings. It's amazing it lasted 5years (production wise). The D16Z6 was a much better engine, and even though it's dated, has a much higher potential.

 

[neanderthal]

theres another thing to consider here engine wise

when M division makes an engine, they really make it to complement the whole car. you rarely get people saying this car needs more engine, especially those who race in anything that doesnt resemble a straight line or a big circle. thats pretty much the only circles where people only care about more power.
high rpms, mild torque and good cornering can result in better exit speed. whereas same corner, add big displacement and big torque and you're possibly spinning out when you mash on the throttle. you have to feather it in that situation.

company philosophy goes a long way to why BMW and GM make very different 500hp engines. remember that BMWs racing tool is the M3, not the M5. GMs is the vette. but i dare say most people who buy a vette are more likely to exercise the straightline speed than the cornering speed.

gil. good points but comparing the half ton titan and tundra to 3/4 ton fords and chevys?????? really!!!! not quite apples to apples is it.

 

[Wolfe]

So then, what you're really trying to do here is find any excuse to put down 'American' manufacturers their products?

If I just wanted an excuse to put down american manufacturers and their products, I'd go for something that more people can agree on, like crappy interiors, terrible reliability, or frighteningly bad handling (even though Detroit has improved substantially in these three areas within the last 5-10 years).

Believe me, if we lived in a fantasy world where Toyota came up with a $70,000 descendant of the Supra that made 507hp from a 7.0L V10, which was designed to go head-to-head with BMW's latest offering, an M1 successor that cost $100,000 and made 510hp from a 8.3L V12, I'd be just as disappointed. In fact, I already mentioned (in the post that you quoted a part of) that I am disappointed in Mercedes-Benz's utter inability to extract power from a given engine size without resorting to forced-induction, especially when it comes to their sportier "normal" models and AMG models.

 

[Scaff]

theres another thing to consider here engine wise

when M division makes an engine, they really make it to complement the whole car. you rarely get people saying this car needs more engine, especially those who race in anything that doesnt resemble a straight line or a big circle. thats pretty much the only circles where people only care about more power.
high rpms, mild torque and good cornering can result in better exit speed. whereas same corner, add big displacement and big torque and you're possibly spinning out when you mash on the throttle. you have to feather it in that situation.

company philosophy goes a long way to why BMW and GM make very different 500hp engines. remember that BMWs racing tool is the M3, not the M5. GMs is the vette. but i dare say most people who buy a vette are more likely to exercise the straightline speed than the cornering speed.

gil. good points but comparing the half ton titan and tundra to 3/4 ton fords and chevys?????? really!!!! not quite apples to apples is it.

How does that add up when you look at the success that the 'vette has had at Le Mans, hardly a circuit that could be described as favouring straight line speed over cornering speed.


Going back to M-Spec's challenge even small things about the LS7 design favour it, given that the application was for a racing series and I suspect that the cars would be running racing slicks or at least shaved 'stock' tyres I would suspect that we are going to be encountering some quite substantial cornering forces. Not a problem for the LS7 with its dry sump, but the S85 is going to start running into problems if we get over 1.4g on even a semi-regular basis. I know I would not fancy having to pay out to replace one.

Regards

Scaff

 

[Tornado]

GM took what is essentially 50-year-old technology, on a 50-year-old engine block, and re-engineered it without changing a single part in concept, but re-inventing every single component from the ground up.

The current small block is only a ten year old design. All of the other versions of the small-block built before 1996 are irrelavent to the conversation. Just putting it out there before that blows up into a full scale argument.

 

[YSSMAN]

The current small block is only a ten year old design. All of the other versions of the small-block built before 1996 are irrelavent to the conversation. Just putting it out there before that blows up into a full scale argument.

Correct, for the most part, but the design is "essentially" the same one that first appeared 51 years ago... Of course modern technology has changed it quite a bit, particularly in LT and LS generations, but the baisics are still there.

 

[Tornado]

Not quite. The LS-series small blocks shares nothing (not even bore sizes) with the LT series (or any versions, for that matter) the precluded it. I don't think any of the parts are even interchangeble, and the engine block is completely aluminum now. It was a ground-up engine that just happened to share the same basic shape and roughly the same size. It is, essentially, related only by names, looks and rough size.

 

[skip0110]

The only dimension that is the same between gen 1, 2, and 3 small-blocks is the bore spacing at 4.400", but you can't even put a get 1 crank in a gen 3 block due to the lack of a place for the ignition trigger.

Gen 1 included the TPI's up to the LT series. LT was a clean sheet design and then the LS was another clean sheet design. LT/LS parts don't interchange.