Horsepower ratings mysterys

[rjsmith]

Is it true that there is less parasitic loss in a 6 speed as compared to an auto?

The automatic tranmission uses bands and clutches and fluid to transmit force. It also uses a torque converter, mounted behind the flywheel. It is in two parts. The front half (engine-side) has vanes which swirl the fluid inside the torque converter. This swirling fluid strikes the vanes on the transmission-side half of the torque converter. This cause force to be transitted to the planetary gears. There is a considerable amount of parasitic drag produced by this process which robs some of the available force used to drive the output shaft which is connected eventually to the rear wheels. That is why early hot rodders refered to an automatic as a slush box.

The 6-speed manual has some parasitic loss due to the friction of meshed gears. The finer the gear cuts, the less loss. Rougher cuts produce more frictional loss. But overall, the manual transmits more force to the differential giving better acceleration and better fuel economy.

Generally speaking, a stock auto transmission will transmit less force to the rear wheels than will a manual transmision, because an automatic loses more internally.

But more importantly, God intended that sports cars have a manual transmission. As a matter of fact, God drives a Z06.

 

[sleepyhead]

As a matter of fact, God drives a Z06.

:L

:L

:L

 

[vettepilot]

... and here in the good ole USA... in God we trust, so that settles the question of who has the fastest factory stock car among the major manufacturers. :L :L :L :L

 

[Stan A]

News!

Talked to a business associate who is on the GM payroll. He close to the Corvette development division. He mentioned that the C6 will have not only a new look but a new engine setup. In some ways it is like the current LS series but will utilize a "multi-value" setup. This will push the power to the upper rpms side to help with the new CAFE requirements that will go into effect in 2004. With most states running an emission system like the IM 240, upper levels of power will help these cars get thru the test cleaner now and in the future.

The other thing he mentioned was that the cars will be lighter in the range of 2700-2800lbs and that the horsepower will be reduced back between 330hp to 350hp. If this be the case than we would see about the same performance or better than we are currently experiencing in both models of the Z06.This would also satisfy those buyers who want the Z06 performance but in a regular coupe and or convertible. He said something about a possible manual transmission changes. I have heard that GM is working with tremec on a 6 speed that will reduce transfer loss by as much 25% over the current setup. Nice way to get more power without raising the output of the motor.

We all have to remember that this motor he was speaking about will be used throughout the GM car and truck line like the LS, LT, L98 series before it. Wagonmaster has pointed out what I am saying again here. I do believe that the days of high HP are behind us when it comes to the major automotive manufacturers. Even Viper will reach a stopping point at a future date. It becames more and more difficult to clean up the exhaust fumes with high horsepower (mainly a cost item).

We all know that many rumors have been surfacing over the last year or so about the C6. Whether what he has passed on to me will actually happen only time will tell. But it all makes sence based on what we know will take place in the next few years. It appears that we are heading for "more high end tech car and less horsepower".

Everyone have a nice day,

Stan

 

[Edmond]

Stan,

Since we're on the subject of high horsepower and emissions: do you know anything about the European emission standards? I mean, they produce cars with gobs of HP just like us.

I think that when you get to the point of 500 HP, it's just too much for practical passenger car use. It's much easier to engineer the car to the engine than the engine to the car right?

 

[Stan A]

Emission standards Overseas

This is an area that I have little knowledge about. Emissions standards are in effect in some of the european countries. I don't know which ones off hand. I also understand that some countries emissions standards are very strict. Interesting thing to research.

The european building like Lamborghini and Ferrari and a few more seem to take the approach of building the car around the engine. But I cannot say for sure. However, note that there have been a very small number of exotics passenger cars build with more than 550hp. Also worth noting the number of exotic sports cars built with more than 600 ponies. I can only think of one at this time. The McClaren F1 is considered a Canadian registry I believe. I could be wrong here.

Stan

 

[rjsmith]

Re: News!

Talked to a business associate who is on the GM payroll. He close to the Corvette development division. He mentioned that the C6 will have not only a new look but a new engine setup. In some ways it is like the current LS series but will utilize a "multi-value" setup. This will push the power to the upper rpms side to help with the new CAFE requirements that will go into effect in 2004. With most states running an emission system like the IM 240, upper levels of power will help these cars get thru the test cleaner now and in the future.

The other thing he mentioned was that the cars will be lighter in the range of 2700-2800lbs and that the horsepower will be reduced back between 330hp to 350hp. If this be the case than we would see about the same performance or better than we are currently experiencing in both models of the Z06.This would also satisfy those buyers who want the Z06 performance but in a regular coupe and or convertible. He said something about a possible manual transmission changes. I have heard that GM is working with tremec on a 6 speed that will reduce transfer loss by as much 25% over the current setup. Nice way to get more power without raising the output of the motor.

We all have to remember that this motor he was speaking about will be used throughout the GM car and truck line like the LS, LT, L98 series before it. Wagonmaster has pointed out what I am saying again here. I do believe that the days of high HP are behind us when it comes to the major automotive manufacturers. Even Viper will reach a stopping point at a future date. It becames more and more difficult to clean up the exhaust fumes with high horsepower (mainly a cost item).

We all know that many rumors have been surfacing over the last year or so about the C6. Whether what he has passed on to me will actually happen only time will tell. But it all makes since based on what we know will take place in the next few years. It appears that we are heading for "more high end tech car and less horsepower".

Everyone have a nice day,

Stan

Please define "multi-value". I'm assuming you don't mean multi-valve.

Also, do you really believe that it is possible to get the weight down to "2,700-2,800lbs" and still "...satisfy those buyers who want the Z06 performance but in a regular coupe and or convertible"? To get the weight down that much you would have to dump 400lbs worth of options, the lack of which those same people cite as the reason they won't buy a Z06. I mean really, do you NEED a power passenger seat in a sports car? Do you NEED foglights? (I've had them on my last three Vettes and can't remember them doing anything and we get fog here regularly). Do you NEED a 6-disc CD changer?

Chevrolet has a long history of limiting the options you could get on a higher-performance Corvette in order to deter the posuer from purchasing one. Looking at the list of what IS available on what they call "a race car for the street" is actually rather amazing. I can readily imagine using the "auto-down" feature of my power window-equipped Z06 while screaming through Thunder Valley at Road America enroute to the checkered flag in an SCCA event. Heck, forget cool-suits and drink-bottles, I'll just adjust the climate control to maintain a steady-state 68 degrees while I listen to some Smokey Robinson CDs. If I need to communicate with my pit, I'll press the OnStar button. No doubt they'll respond with "Hello Ray, I see that you are just exiting the Corkscrew at Laguna Seca, and oh, by the way, you missed the apex by about a foot and you were late on the throttle at the exit. Did you need directions to your pit? How about directions to some fine restaurants in Monterey for your post-race partying? Turn nine is coming up so you'll want to downshift to third and trail-brake through to a late-apex...did you need help with that?"


Ray

 

[Stan A]

Spelling errors

Sorry about that. Typing is not what I do as a living. You are right...Multi-Valves.

I am not an engineer but I believe that anything is possible. Lowering the weight 300lbs or so can be done if enough time and research (and dollars) is put forth to develop the right materials to build with. No one knows for sure what has been taking place with this idea and how long development has been in the works. This is the first time that reducing weight on this scale has been talked about.

No one is talking about discarding any options. Weight and its reduction can come from what I have mentioned in the previous paragraph. Keep in mind that the Z06 has offered the least options where the ZR1 had about everything that was offered on a Corvette during its production. You can have power, performance, and comfort but it may well cost.

Most performance cars today come with many power control and creature comforts. We want both! Is it necessary. NO! A lot of weight could be saved by not offering these items. But from a production and sales stand point of view, these items help to sell the car and help to justify the price too.

Z06 performance package in the other two models is not a new idea. People were asking for this last year. Sometimes manufacturers are forced to changed guidelines because of government regulations.

No one knows for sure what will happen. Every now and then a piece of information about a development leaks out that does get incorporated into a later model. That is what makes this whole communication thing so interesting.

Stan

 

[rjsmith]

Re: News!

Talked to a business associate who is on the GM payroll. He close to the Corvette development division. He mentioned that the C6 will have not only a new look but a new engine setup. In some ways it is like the current LS series but will utilize a "multi-value" setup. This will push the power to the upper rpms side to help with the new CAFE requirements that will go into effect in 2004. With most states running an emission system like the IM 240, upper levels of power will help these cars get thru the test cleaner now and in the future.

Stan

Since the LS6 has two valves per cylinder, and is therefore multi-valve already, it is assumed that your business associate on the GM payroll close to the Corvette developement division means more than two valves per cylinder. If that's the case, it's gotta be an overhead cam engine, since I would hate to see an engine with a single in-block cam (e.g., the LS series) and all those extra pushrods. It would be a neat trick to see someone make that puppy rev "to the upper rpms side" (imagine the increase in reciprocating mass). However, that certainly would qualify as "...a new engine setup".

On the other hand, an overhead cam engine would not be a new engine setup. The LT5 was developed in 1989.

Is it possible that your source works in the mail room at Bowling Green?

He certainly needs to take Design of Internal Combustion Engines 101.

As for "...anything is possible", that may be true, but had you gone to engineering school you would have learned that something may indeed be possible, but have an extremely low probability. It is *possible* I could play center for the Lakers. The probability of that occuring is so extremely small as to be safely ignored.

Is it possible to spend millions to develope new composite materials that would be incorporated into the Corvette chassis to reduce weight? Yes. What is the probability that Chevrolet will do that to satisfy a few buyers who desperately need a power passenger seat? Extremely small.

 

[Edmond]

I actually like my chances of playing center for the Lakers, LOL!

But Stan is right, you have to have really up to date technology in the car to justify it's high sale price. Imagine a $50,000 C5 that didn't have a CD player, air conditioning, power windows, etc... Now, if they actually lowered the price for less gadgets, that's a different story but I don't think any of us are naive enough to ever believe that GM will ever lower the price of the Corvette. Especially since the C5 has gained such popularity.

And by the way, I'm no engineer and don't claim to be one so I'll leave the engineering part for you guys to discuss.:confused

 

[vettepilot]

Remember the first time we were told that Chevrolet was going to produce a bare essentials Corvette, no frills, just a potent engine in a light chassis. Enter the fixed roof coupe....
None of the FRCs produced were bare essentials, and they had the same LS1 engine as their Coupe and Vert brothers.
So I, with my cracked and crazed crystal ball don't foresee an ultra light exotic material Corvette in the next generation. Maybe the C7, but not in the C6. For what my .02 is worth.
I would rather see an affordable Corvette with lots of aftermarket performance parts available for those who want to continue what Chevrolet started. Otherwise, I afraid that the car could price itself out of the intended market.

 

[Stan A]

Multi Valve

The question is will it be three or four valves per cylinder. There was no mention of an overhead cam system. Frankly, there is not the room. Too tall of a motor. I think they learned from the ZR1 about big motors.

The gentlemen from GM that passed on this info did not or choose to disclose every deal about what we spoke on. He assumed that all smart enthusiasts would know what he meant by multi-values. He also happens to be an engineer and has been with them for 20 years.

Get reasonable....

By the way, you did not mention what type of contract the Lakers gave to ride the bench??!

Stan

 

[Rob]

Re: Re: News!

Since the LS6 has two valves per cylinder, and is therefore multi-valve already, it is assumed that your business associate on the GM payroll close to the Corvette developement division means more than two valves per cylinder. If that's the case, it's gotta be an overhead cam engine, since I would hate to see an engine with a single in-block cam (e.g., the LS series) and all those extra pushrods. It would be a neat trick to see someone make that puppy rev "to the upper rpms side" (imagine the increase in reciprocating mass). However, that certainly would qualify as "...a new engine setup".

On the other hand, an overhead cam engine would not be a new engine setup. The LT5 was developed in 1989.

Is it possible that your source works in the mail room at Bowling Green?

He certainly needs to take Design of Internal Combustion Engines 101.

As for "...anything is possible", that may be true, but had you gone to engineering school you would have learned that something may indeed be possible, but have an extremely low probability. It is *possible* I could play center for the Lakers. The probability of that occuring is so extremely small as to be safely ignored.

Is it possible to spend millions to develope new composite materials that would be incorporated into the Corvette chassis to reduce weight? Yes. What is the probability that Chevrolet will do that to satisfy a few buyers who desperately need a power passenger seat? Extremely small.

First....let's put the daggers down and keep the sarcasm in check. "Multi-valve" has a couple different connotations and as far as predicting what it means in terms of the C6, that's how rumors spread which I prefer do not begin from this site.

Second, multi-valve does not necessarily mean an overhead cam configuration and I don't think it's safe to assume so.

Third, the LT5 engine was not developed in 1989. It was actually in the planning stages and began development in 1985 with a Phase 1 Prototype engine brought to life in early 1986.

Last, I disagree with the last assumption: Is it possible to spend millions to develope new composite materials that would be incorporated into the Corvette chassis to reduce weight? Yes. What is the probability that Chevrolet will do that to satisfy a few buyers who desperately need a power passenger seat? Extremely small. Given past history of Corvette Development, if the technology can be utilized across multiple platforms, starting out on the Corvette and eventually spreading to other car lines, then, yes, it is most definitely possible. A perfect case in point is the LT5 engine. The development costs of that engine was enormous....however, the Northstar engine was born from the LT5 engine and would not be here today if it was not for the LT5 engine. The technology utilized on the LT5 engine trickled over to another platform - Cadillac, and as a result, has proven to be profitable for GM over the long run.

If there is a technology that's costly, that can allow Development engineers to shave 400 lbs off the chassis, all while allowing them to keep luxury items such as power seats, AND that technology can be incorporated into other platforms, GM WILL do this and they've done it before.

Let's try to bring this thread back on track and in focus with what the original question was: is the C5's horsepower measured at the flywheel or the rear wheels.

 

[rjsmith]

Re: Re: Re: News!

...multi-valve does not necessarily mean an overhead cam configuration and I don't think it's safe to assume so.

Would you care to share your insights on how a three or four valve engine would be constructed with pushrod technology? If you can cite a current example of such an engine it would be enlightening.

BTW, is the C5's horsepower measured at the flywheel or the rear wheels?

Personally I think it is measured at the flywheel, if for no other reason than the marketing department would rather use the higher number.

FWIW, when I was at the plant I saw them roll the cars onto a chassis dynomometer at the last stage in final assembly and run them through the gears (rather enthusiastically I might add). There is a large digital display which the operator monitors as he does this. I can not swear to it, but I believe our guide mentioned that one of the things they were checking was whether rear-wheel horsepower was within acceptable manufacturing tolerences.

One last thought. If you don't want baseless rumors to originate on your web site you might direct your reply to the individual posting the baseless rumors. You might also want to ask yourself why an employee with 20 years service to Chevrolet would risk their job (and retirement benefits) by violating the Trade Secret Protection Act and divulge confidential and proprietary information that would put the employer at risk of losing a large investement in R&D.

I work in network security and I can assure you employers are taking these types of inappropriate conduct very seriously, to the point where they are prosecuting employees who violate the TSPA in Federal court.

Save the wave.

Ray

 

[Rob]

Re: Re: Re: Re: News!

Would you care to share your insights on how a three or four valve engine would be constructed with pushrod technology? If you can cite a current example of such an engine it would be enlightening.

At this time, no.

BTW, is the C5's horsepower measured at the flywheel or the rear wheels?

Personally I think it is measured at the flywheel, if for no other reason than the marketing department would rather use the higher number.

FWIW, when I was at the plant I saw them roll the cars onto a chassis dynomometer at the last stage in final assembly and run them through the gears (rather enthusiastically I might add). There is a large digital display which the operator monitors as he does this. I can not swear to it, but I believe our guide mentioned that one of the things they were checking was whether rear-wheel horsepower was within acceptable manufacturing tolerences.

One last thought. If you don't want baseless rumors to originate on your web site you might direct your reply to the individual posting the baseless rumors. You might also want to ask yourself why an employee with 20 years service to Chevrolet would risk their job (and retirement benefits) by violating the Trade Secret Protection Act and divulge confidential and proprietary information that would put the employer at risk of losing a large investement in R&D.

I work in network security and I can assure you employers are taking these types of inappropriate conduct very seriously, to the point where they are prosecuting employees who violate the TSPA in Federal court.

Save the wave.

Ray [/B]

Point taken. Back to the question about flywheel vs. rearwheel horsepower....

 

[Jack]

multivalve w/pushrods

For the life of me I cannot remember the examples ... I've seen more than one. It was configured with a forked rocker arm. I think someone is currently building-selling such a setup for Harley V-twins ... producing a head with 4 valves, 2 forked rocker arms.
JACK:gap

 

[Stan A]

Attention

Ray,

There is no violation of the Trade Secret Protection Act if the information has already reached the public thru the media.In addition, many times at national Corvette events factory reps talk about what is in the development stages. So far none of them have lost their jobs or have been taken to court.

Like Rob said, lets try and stay with the original subject in this thread.

Stan

 

[David-F]

Let me step in here for a minute and make a few points, first the next gen. Vette needs to be lighter! I realy feel the C5 was to be lighter but because of the tight buget for devolopment they opted for cheap and heaver metals partly because some of them needed to be such as the frame because of the method used to form the frame in had to be mild steel which is heavy. But look at all that was done to lighten the C5 and it's just a very little lighter than the C5, no spare, no clamshell hod real light doors, all over the car things wher made lighter but still the car was heavy. I realy feel they are going to make changes in the front and rear sub frames they are very heavy especialy compaired to the C4. But again the main reason for getting the car lighter is not performance but fuel mileage. I have hear from more than one sorce that if does apear that the C6 may wind up with a smaller displacement engine and less HP again for fuel mileage. I have also heard the next engine will be based on the GENIII engine and I have also heard there will be a increase in the number of valves per cylinder so maybe thay are looking at forked rocker arms. Think about it if the bore gets smaller the valves will have to also but the addition of another valve even if it's smaller can help to make up for this. Again this is all speculation and only time will tell. But one thing I bet we will see for sure is a lighter car and don't except to see less options but more the Corvette has always been the sports car that offered frills too, that's what makes it an Amercian Sports Car. As for the original question the HP figures they are at the flywheel with all assecories and exhaust, if they rated at rear wheels you would have to have different ratings for every trans.

David Fulcher