Big Block vs Small Block

[Terry Oxandale]

To expand on Alan's detail, you need to fully grasp the conceptual and mathematical differences between torque and HP. Personally, I don’t like the term HP because all it is, is a means of quantifying torque and its relationship to RPM, plain and simple. Both are impacted by gearing of the transaxle, and having the torque curve shaped and located in a ideal location for your particular driving style is very important. Once you look at the numerous internet offerings and discussion regarding this relationship, you’ll be able to make an informed choice. I would search in the drag racing forums or interests to study this relationship. They’ve got it down pretty good (the relationship between torque, gearing, and its relationship to horsepower). Then you can go back to a “road” forum and put some handling to all that power.

An F1 engine comparison to the old Ford Galaxy 500 428 motor is a good comparison when talking about torque, RPM, and power. Finding out why you want one to turn 20K, and why you want the other to have a lot of "grunt" down low, will help you.

 

[Keith]

You said it far more efficiently and eloquently than I did Tim

I have a deep routed objection to sitting in front of or behind an engine that weighs 1 ton. The GT40 was never designed for such an approach but in order to save development time and 'face' the hot rod theory certainly worked but historically the BB MKII's were really only competitive for 2 years and the more highly developed MKI's went on to win many more races than the MKII's ever did.

To be quite fair, if the cylinder head solution had have been found 2 years earlier there would have been no need of the Big Block theory. Ford were warned time & time again that the gaskets would not stay in the 289's and their repeated failure stifled the MKI until the Weslake head was developed.

The MKI teams used Cooper rings in the engines with some success, and the 'lightweight' solution with the highly developed small block eventually proved to be the right direction.

I guess I have not made myself too popular with those statements, but the facts pretty much speak for themselves.

 

[Seymour Snerd]

What's with the grumpy crap?
People ask for advice or to be taught by people they think can help and they get condescending answers that border on abuse... Great... Ffs, this used to be such a great forum....

It's not a question of being grumpy. It's a question of wanting to protect an otherwise well-organized repository of knowledge about GT40s from turning into a room-temperature soup of general automotive text. Almost nothing in this thread is specific to GT40s. (so far)

There are lots of places he can go to get the information he wants: elsewhere on the internet and bookstores and libraries; he's just not willing to put in the time and effort to do so, and is taking advantage of your good nature by asking you to spoon-feed him. If this were a "cars in general" forum (and there are many) I'd be more than happy to help. And, if you look back in this and other threads I've put in a fair amount time trying to answer his questions.; But his reaction to each effort has been something of the order of "that's too hard, please dumb it down and don't make me do my own research."

Just like his "Superformance" thread, it has ended up having nothing to do with its title, "big-block vs small-block". It never had a chance too, because he wants a quick answer based on false premises; he doesn't want to be taught, he just wants quick answers to complex subjects.

I would have no problem with this and the other threads if they were simply moved to the Paddock, or if we had an "automotive, but not GT40" subforum for it.

But again, I'm not being grumpy; I just don't want to see this valuable information resource diluted.

 

[Seymour Snerd]

....the hot rod theory certainly worked but historically the BB MKII's were really only competitive for 2 years and the more highly developed MKI's went on to win many more races than the MKII's ever did.

....I guess I have not made myself too popular with those statements, but the facts pretty much speak for themselves.

Well, it would help your popularity if you wouldn't leave out the fact that the Mk I was so successful relative to the Mk II only because of a rule change and because the Mk II was superceded by another car from it's own manufacturer, the Mk IV, which, BTW, also had a "hot rod" architecture. Wow, no innovation there.....
The facts only speak for themselves if you allow all of them to speak. :idea:

 

[Seymour Snerd]

Chapman was a f.....g genius, Shelby just a hot rodder. .

That's a completely unfair comparison. I'm no fan of Shelby's, but he was just the team manager, not the designer of the car. He was handed a completely under-baked pot of design concepts and turned it into a successful race car. Shelby never claimed to be an engineer nor a designer.

Chapman had an opportunity for a role in the GT40 program but threw it away out of greed and arrogance. He would have stuck a V-8 into a Europa; what's that if not a "hot rod"?

Chapman was a genius at building successful one-offs that sometimes won, sometimes didn't and sometimes killed people. Rest in peace, Jochen Rindt.

 

[Keith]

Whooops! That told me din' it.

It's like being back at school, I love it. :drunk:

Hardy! See me after class!!!! :laugh:

I think that's fairly grumpy too actually, taking three posts to tell me where to stick myself and my fancy theories :lipsrsealed:.

Poor old George, what must he think.... :shifty:

 

[Cliff Beer]

Franky, Chapman and Shelby were both geniuses in their own way. Chapman had the advantage of a frequently clean design slate, and stuck to his basic principles of lightness and finess with suspension work. Lots of his stuff broke (with tragic results sometimes) or was under powered, but generally his cars were always near the front of the grid. Shelby was a master of taking a bunch of half-baked and marginal existing ideas, and making something successful out of it with a big load of grit determination. Need to go faster? Stick a bigger engine in it. Need to turn the corners better? Stick a bigger engine in it and go faster down the straight instead.

In the old days both approaches worked well. Not so much these days.

 

[Seymour Snerd]

Hardy! See me after class!!!! :laugh:

The only people I feel grumpy toward are Colin Chapman, from my owning too many Lotuses, and Carroll Shelby, from his filing too many lawsuits. But Chapman's dead and now Shelby's getting sued himself, so it all kinda comes out even.

Cliff's right, they're both geniuses.

 

[George]

Keith

How do I feel? Fine. :thumbsup:

I see Alan Watkins would probbably have the answer Im after but wont produce it. He knows I dont really understand all the technica terms/stuff but expects me to go get a degree in engine understanding to simply make a choice once off in my life for what engine I would want in the car. Also to say its not to do with GT40s, considering its an engine for a GT40, I would beg to differ. Whole thing is to me, as me being the customer in a sense (guy buying either big block or small block) the proffessional who DOES have the degree in engine building etc is the guy that should advise the customer why BB or why SB and help the customer (who wouldnt have a clue) understand at least in a very basic sense what the overall difference would mean. He isnt there to feed the customer a whole list of technical stuff, to show off his university degree in engine understanding and years of experience, as all that would go over the top of the head of the customer. He is there to try and help the customer make an informed decision by saying basic things, such as "Well more torque means, when you press the accelerator on ur car, it would feel like such an such and accelerate faster/slower than the equivalent SB/BB, on the other hand if you had more power, it means such and such" etc. This way at least the customer can have some informed decision in real world terms, not a theoretical theses on how it all works together. I Searched google as much as I knew what to even search for, I read the differences between torque and HP, and something to do with RPM = multiplication (which I dont understand). I can read that 1000000 times I still wont understand what that actualy means without somebody EXPLAINING it, why do you think there are teachers in school if you could just read and thats it? Its to explain i lay men terms those concepts for the student to grasp so that it can make sense.

Going by Alans philosophy, whoever buys a car should first be an engineer in car design before buying so that he understands how aerodynamics works in all ths aspects and so forth RATHER than just asking the person that did the degree considering its his JOB to know.

He has info he can give but wont, arrogance perhaps? I wont judge, but much could be assumed. I just shrug and say, o well, he has his reasons, probbably not trying to offend, everyone is a certain way, n this is the way he is. Cool.

 

[Seymour Snerd]

....as me being the customer in a sense (guy buying either big block or small block) the proffessional who DOES have the degree in engine building etc is the guy that should advise the customer why BB or why SB and help the customer .........

why do you think there are teachers in school if you could just read and thats it?
.....
Going by Alans philosophy, whoever buys a car should first be an engineer in car design before buying .....RATHER than just asking the person that did the degree considering its his JOB to know.

.

George -- You're onto the right approach: you have to buy an engine from somebody, why aren't you asking him all these questions? You are not my customer and I am not your Mommy.

As for teachers, I am entirely self-taught and an amateur with respect to everything I know abaout automobiles and mechanical engineering. I don't have a degree in anything we're talking about. I went to high school, listened an little bit, and then I READ BOOKS. Why won't you give it a try?

I have demonstrated here and elsewhere on this forum that I'm happy to try to help anyone with a question relevant to the forum. This is not a basic automotive forum and you are not at the stage yet to ask GT40-specific questions.

All I'm asking you to do is take your basic questions to the right forum. I'll meet you there and give you all the help you can stand.

And finally, I'm not withholding anything and I resent the implication that I am; go look at some of my other posts.

I cannot answer the question you asked because your question makes no sense. And that is because you don't understand the basics well enough to ask a sensible question. I told you what you need to do to get there.

You don't need a degree to figure this out; you just need to spend a few hours with a few books. Is that really asking too much?

 

[roaldin]

George, it's like the computer "Deep Thought" in "The Hitchhiker's Guide to the Galaxy" -To understand the answer you really need to understand the question. 42 doesn't mean much without understanding what was asked. If you haven't read it then you have some extra homework.
Getting the concept of torque and power does not require you to be an engineer but it is absolutely necessary if you want to make an informed decision on the question you are asking. Without that understanding all you are asking for is someone else's "recipe" and opinion and those will be many and varied.

As simple as I can make it - force acts on a piston, it is converted to twisting force (torque) by the bottom end of the engine, this twisting force can do work but how much depends on how fast it is spinning. More revs with the same torque means more work. That work is called power.
More torque with the same revs also means more work.
Two shafts, one with x torque and 2y revs and the other with 2x torque and y
revs:
If you lift a weight with the power from those setups without gearing then one will lift a lighter weight faster than the other, but geared correctly both setups will lift the same weight the same distance at the same "speed". Ie they have both done the same amount of work - same power. Hope that makes things
clearer.
There are some other things to consider, eg friction, but you must grasp the basic concept first.

Once that is understood then the importance of things like the shape of the
torque curve will become clearer. An engine has to suit the car and purpose for which it is built. Understanding another persons desires is far more difficult than understanding basic physics.

Chapman and Shelby, yeah I guess it is an unfair comparison... Best not to
explain further methinks. Sleeping dogs and all that.

Davinci's aircraft designs looked a bit dangerous but he was still a genius. I don't remember the other guys name or what he did unfortunately...
Or maybe this old historic story I just made up might illustrate it. Two guys stand by a river trying to get a message to the other side, they both roll it up and throw it. Later on the river gets a bit wider and they have to get a message across again, this time throwing doesn't quite get the message across. One guy folds the message into a paper plane and it flies across the river, the other guy rolls it up and gets a bigger guy to throw it harder. Eventually they get to a wider part of the river again and the plane flies across easily but no matter how strong the other guy is, he just can't throw the message across the river. BTW the second guy, Rod, was pretty keen on his image and looked pretty good so he was called 'Hot Rod'.
These days in that country you are free to make a paper airplane but if you want to get a bigger guy to throw a paper ball for you then you might strike a few legal issues.
I wonder if this story got the message across... ;p

Hardy, you and I can sit up the back with the other cool kids.


Tim.

 

[Seymour Snerd]

I wonder if this story got the message across... ;p

I don't know if it did, what was the message?

:thinking2:

Two shafts, one with x torque and 2y revs and the other with 2x torque and y revs:

Oh, and let's have a wager: I bet that you lost George right around the time you introduced algebra.

 

[George]

Thanks

I found some detailed things to do with RPM, Torque, Horsepower and so forth.

To what I have understood reading it all (Correct me where I have missed something or understood it wrong)

Whether a small block or big block, whether low or high CI displacement,

Horsepower = how fast a car can go
Torque = how fast it can get to that speed

Also, it seems to my understanding from whats been read is that, Horsepower dertermines the top speed of a vehicle (whether 200kmh, 300kmh, 400kmh etc), not the RPM range it functions in.

So whether big block, High CI discplacement at 6000-7000rpm or small block with Lower CI displacement at 8000-9000rpm, both will have the same top speed given they both have the same HP, given the Big Block was geared correctly, as both will be geared differently as they make power differently.

On the other hand, the more CI displacement an engine has, the larger the power band would be, thus the 'average' power it makes would be more overall. So though the BB and SB peak at 600hp, the BB would actualy be better in accelerating (other than the fact its 100 ft/lbs of torque more) due to having that power for a longer period of time.

How does this all translate to circuit racing though?

Given what I have understood, the more times u have to slow down (due to corners, S bends etc on the road/circuit) the broader the power band is the better as whether u slow down or speed up, ur still in ur peak performance... again this says more CI discplacement is better as you are not narrowing the powerband down.

So in the end

Both engines BB or SB, both 600HP, SB has 550 ft/lbs while the BB has 650ft/lbs

The BB will accelerate faster over a broader powerband, thus 'in peak power for longer'. It also means the BB would achieve the same speed as the SB in each given gear, given it is geared propperly.

I know people have said More RPM alows the engine to not have to shift as early thus the BB might take off faster but the more RPM motor would catch up... not if the BB is geared to utilize speed with its torque, its just that its got more power over more RPMS due to its broader power band keeping it infront.

So with race rules limiting CI etc to make a more equal playing field, people have to use what they can to increase more power... but where rules are non existent it seems to me the BB can do all the SB can and then 'some extra', making it the 'better' engine in terms of performance overall. Which means the BB in the identical car should be the 'faster car' around the track, while being less stressed and thus live longer ontop of being more street friendly and more economical as its a mild build.

On a side note...

Alan, stop being a little kid with all the Mommy comments and so forth. Its immature. Thanks.

 

[Seymour Snerd]

Alan, stop being a little kid with all the Mommy comments and so forth. Its immature. Thanks.

George --

U sound annoyed; I'm not trying to annoy u; I'm trying to help u to acheeve some prespective so ur not waisting so much of ur tim. Not trying to offend, everyone is a certain way, n this is the way I am. Cool.<!-- google_ad_section_end -->

Tim --

As Robert Heinlein once advised via one of his characters:

"Never try to teach a pig to sing; it wastes your time and it annoys the pig."

 

[Darrell]

George if what you are trying to acheive is quick lap times you will AWAYS get more seconds per dollar spent with good handling and brakes.
I have seen 450 cars of similar weight lap much faster than 600HP many many times.
My advice for what it is worth is lightweight (heavy engines make great Pendulums)engine of about 400 to 450HP with a well set up chassis and brakes would be a quick as any non professional driver would ever need.
If you are talking drag racing that is another story.

Darrell
DRB
LS1 G50

 

[roaldin]

I always feel like a stranger in a strange land but I grok Alan.

Front!

BTW I should have said "lighter weight faster AND FURTHER" in post #31 (even though the "further" is implied by its moving faster in the same time).

The message Alan - well there were multiple messages in there but the one I feel most strongly about is summarised in post #20 - my opinion of course.


Tim

 

[zollis]

Half of that I dont understand as its technical... ( quote from post # 12 by George )

George you don't say it is TOO technical but technical at all . Therefor I would like to suggest you buy some books and study a little bit . Then if you have some sort of technical back round knowledge you might start to understand what these discussions actually mean.

This comment also takes into account your responses to the other threads you have started .

Z.C.

 

[Keith]

I remember a few times when college kids came on here wanting to tell the GT40 story for their thesis. They were unconditionally met with politeness and assistance no matter how stupid their questions. Some of them said that they were amazed that a bunch of old farts could be that accomodating to kids.

Where has that all gone I wonder?

This is a 'car nut' forum where such stuff is discussed openly freely and unconditionally.

If your (you know who you are) answer to basic questions is "go read a book" then you have totally failed to live up to the expectations and reputation of this fine forum. Not only that, I am amazed no one has commented in the past concerning my own 'stupid' questions. If this is to be the flavour of the future, I for one will not be asking any more questions unless I have read up the answers beforehand.

You go read a book!

Titled "Common Courtesy"

 

[zollis]

Oh I am sorry . I missed post # 29 ( I can read that 1000000 times I still wont understand what that actualy means without somebody EXPLAINING it )

Z.C.

 

[Pat Buckley]

I remember a few times when college kids came on here wanting to tell the GT40 story for their thesis. They were unconditionally met with politeness and assistance no matter how stupid their questions. Some of them said that they were amazed that a bunch of old farts could be that accomodating to kids.

Where has that all gone I wonder?

This is a 'car nut' forum where such stuff is discussed openly freely and unconditionally.

If your (you know who you are) answer to basic questions is "go read a book" then you have totally failed to live up to the expectations and reputation of this fine forum. Not only that, I am amazed no one has commented in the past concerning my own 'stupid' questions. If this is to be the flavour of the future, I for one will not be asking any more questions unless I have read up the answers beforehand.

You go read a book!

Titled "Common Courtesy"

I think we are all kind to kids........