Windtunnel results for 240z

[twoforty]

http://forums.hybridz.org/showthread.php?p=814017#post814017

More info here

http://www.nissansportmag.com/

 

[twoforty]

Looking at the data....Looks like not only does the G-nose ruin the looks of a Z it causes more lift on the front and more lift on the rear than on the standard car. Both standard and G-nose cars have the same Cd.

 

[Albrecht]

Looking at the data....Looks like not only does the G-nose ruin the looks of a Z it causes more lift on the front and more lift on the rear than on the standard car. Both standard and G-nose cars have the same Cd.

Looks like you didn't understand what you read. They didn't test a car with a Factory G-nose, did they?

You also don't seem to understand the purpose behind the design of the Factory parts ( and the parts that they were supposed to be paired with ), and the reason for making a special model that the general public could buy. Nissan were not mugs who were just thinking about looks.

Any discussion about whether or not the G-nose "ruins the looks of a Z" is going to be a matter or opinion. You are quite welcome to your opinion, but you might like to remember that the 240ZG was a 'Z' too, and it was designed by the very same people, and for a specific purpose.

 

[Russ]

Yeah seems to me that it caused more lift. Were Datsun aiming on something that flys, it looks a bit like an amphibious vehicle so maybe that was in their thinking?

What was the point of it then as according to THESE results it's gone backwards in developments?

 

[Albrecht]

Yeah seems to me that it caused more lift. Were Datsun aiming on something that flys, it looks a bit like an amphibious vehicle so maybe that was in their thinking?

"Datsun"?

If you really set store by the HybridZ team's results, then anything I write here will not be likely to convince you otherwise. But do you really think that the Works aerodynamic parts performed worse than the standard body? You think Nissan didn't have access to their own wind tunnel? You think the Works circuit race cars had the parts fitted just for looks? You think the drivers and engineers would have ignored any evidence of negative effects? Get real.

What was the point of it then as according to THESE results it's gone backwards in developments?

I'm afraid THESE "results" are - in my opinion - less than conclusive to say the least. We have already established that the "G-nose" they used was nothing like a Factory piece, and they never used it in the way that the Factory piece was used anyway.

Bringing the discussion over to this forum is going to water it down. I suggest you discuss it at source.

 

[twoforty]

Reading the data it clearly states the amount of lift on the standard g nose car...negative numbers being downwards force. It's not as simple as that, you would want huge negative numbers on the rear and high lift on the front, a good balance would give good stability.

I wasn't looking at it from a factory design point I was looking at it in comparison to a standard Z body.

Factory staff can and have made mistakes, just because the "factory" made a decision doesn't mean it's the right one.

Factory ZG? no, same shape? yes.

As far as looks, it looks like a bad kit car conversion(to me).....the front just doesn't match the rear...similar to one of those Quantum things for the 80's.....yep that's my opinion which I am certainly entitled to.

 

[twoforty]

I was a little surprised that there would be so little difference, it looks more aerodynamic for sure.....that didn't stop the Miura from taking off though.

 

[Albrecht]

Reading the data it clearly states the amount of lift on the standard g nose car...

"....standard g nose car...."

WHAT car are you talking about????!! They never tested a standard G-nosed car ( a 240ZG ) did they? Did you read the article AND all the other threads that discussed these points? Seems to me that you have not even started to read and understand it yet.

Factory staff can and have made mistakes, just because the "factory" made a decision doesn't mean it's the right one.

So you trust these HybridZ figures - extrapolated from something that wasn't even the same shape externally ( let alone internally - and that's the BIG point ) as the Factory design - over those of the original manufacturer and the factioy race teams who used them to good effect over the course of several years?

Factory ZG? no, same shape? yes.

Again, you miss the point. It was nothing like the Factory item - externally OR internally. Go read ALL the threads in that discussion again.

As far as looks, it looks like a bad kit car conversion(to me).....the front just doesn't match the rear...similar to one of those Quantum things for the 80's.....yep that's my opinion which I am certainly entitled to.

The above is a big clue to your opinion on aesthetics ( Russ would appear to be in the same boat ) clouding your judgement about aerodynamic effectiveness. Says it all really. Not much point in arguing the toss with someone who already knows what they want to believe.

There's a thread active today on this forum ( it started yesterday ) about a car racing in Holland during 1974. Take a look at the car in the photo. Do you notice anything? Do you understand the body parts that you are looking at? Are you ready to open your mind to the fact that the Factory G-nose was designed to be used with other parts as part of a package? Think about it.

 

[ZHead]

Aerodynamics and stability at high speed are as integral a piece of the holy grail jigsaw we are all trying to put together as anything else.

Alan, I have heard tell that in Japan some of the top S30s are capable of in excess of 185MPH on the track and are stable and safe at those kind of speeds. My interest is not in the engine side, because any idiot (read me), can throw in a big powerful lump, my interest is in the modifications done to the chassis, suspension and body to create such stability.

Firstly, do you know if the mythical, tenth hand stories about those kinds of speeds are true and if so, can you shed any light on what has been done to the cars to make them stable ?

The challenge with high BHP cars is not making them fast, it is making them behave when they are going fast .......

 

[twoforty]

The car in the racing thread is another story, huge arches blended into a smooth front end.....looks nothing like the production ZG's pics I have seen.
I'm sure that race car would have a much better Cd than a standard Z body.


Like Zhead said, its a balance and I know how unstable a standard body Z feels at 135mph.

 

[twoforty]

"....standard g nose car...."


The above is a big clue to your opinion on aesthetics ( Russ would appear to be in the same boat ) clouding your judgement about aerodynamic effectiveness. Says it all really. Not much point in arguing the toss with someone who already knows what they want to believe.

Well lets talk about the look....I don't like the way it looks, there is nothing wrong with the G-nose and nothing wrong with the Z but put the two together and it looks wrong. I'm not asking for you to agree with me, I'm judging it on my own taste, my own idea of what looks right or worng. Some will agree and some will disagree to the end of time. There is no point in trying to convince me that you think it looks good becuse I am not you. So lets not get into a silly battle over the front end of a car.


Now if it was to gain speed in a race then "looks" don't come into it, if it goes faster and handles better then it is better, period.

I'm open to proof that the G-nose will out perform a standard body Z of the same power and weight.

 

[Albrecht]

Alan, I have heard tell that in Japan some of the top S30s are capable of in excess of 185MPH on the track and are stable and safe at those kind of speeds. My interest is not in the engine side, because any idiot (read me), can throw in a big powerful lump, my interest is in the modifications done to the chassis, suspension and body to create such stability.

ZHead ( how are you anyway??? ),
In Japan, those kinds of speeds would only be possible on the 'Wangan' ( Bayshore Route highway - ie highly dangerous and illegal ) or big purpose-built test tracks such as Yatabe proving ground, or the private test tracks owned by the major Japanese manufacturers. I'm not including drag racing in my discussion, as trap speeds in that discipline can be very high indeed - but somewhat different circumstances apply.

If you look at speeds attained in small competitions such as those started by 'Car Boy' magazine back in the early 1980s, all of the S30-series Z cars taking part used body kits that were derived from the full ( late ) Works 240ZR Group 4/5 aerodynamic package, because that was the best solution - outperforming any 'private' body treatments by a long way. Apparently, these also offered good stability at such high speeds - but you'd have to admit that drag must have been quite high too. But what are you going to do about that? Apart from making your car look like 'Thrust 2' I don't see where you can go with it? Once they had got to a certain level in aero efficiency ( or inefficiency ) the other deciding factors were engine power, gearing and tyres. Tyres 'grow' centrifugally at high speeds to such an extent that bodywork could get touched - and this caused a number of memorable tyre failures.

The Works circuit race cars didn't have any 'special' chassis / mechanical mods to cater for just high top speeds as far as I am aware. They spent such a short time in this part of the 'envelope' that it would have been only a minor part of their setup anyway. That's one of the things that I find so frustrating about this kind of conversation; You hear people going on endlessly about cd figures and performance at mph speeds over three figures when they are relating their findings to their own ROAD cars! Such cars are compromises already, so it is hard to take the subject seriously when their chosen tyres would probably fall apart at speeds over 140mph anyway. I don't know why we see such emphasis on this kind of discussion when the bottom line for most people is more biased to what their car actually LOOKS like over any other factor.

Aerodynamics is a black art that amateurs can try to dabble in if they want ( good luck to them ) but I think it is clear to all of us that very subtle changes and modifications can make a HUGE difference to results, and not even the 'experts' always understand what is going on ( look at the current Honda F1 car for example ). Sealing off the radiator area on an S30-series Z make a major difference, and at high speeds I think it is acknowledged that the standard S30-series Z front end hits something of a brick wall. If anybody thinks that a properly implemented factory-style G-nose with its associated parts actually makes this worse then I'm happy to let them believe it. It sorts the wheat out from the chaff to some extent........

 

[twoforty]

Good job I have ZR rated tyres...wouldn't "look" good with them falling apart now would it

Aerodynamics is a science that amateurs can dable in and have huge impact on the world.....wright brothers for one, maybe they shouldn't have bothered dabbling

 

[Russ]

"Datsun"?

Sorry, my bad. Keep associating a looky likey with the original.

If you really set store by the HybridZ team's results, then anything I write here will not be likely to convince you otherwise. But do you really think that the Works aerodynamic parts performed worse than the standard body? You think Nissan didn't have access to their own wind tunnel? You think the Works circuit race cars had the parts fitted just for looks? You think the drivers and engineers would have ignored any evidence of negative effects? Get real.

No of course I don't, or at least as much as I think they designed the ZG as an amphibious vehicle... stop being so defensive all the time.

I could go either way on the wind tunnel and possibly it's effectiveness as I'm not too hot on what technology was to hand back then. You only have to look at the bricks America was making at the time and other silly ideas around the same period. Did the S30 screen really need to be so vertical?

I'm afraid THESE "results" are - in my opinion - less than conclusive to say the least. We have already established that the "G-nose" they used was nothing like a Factory piece, and they never used it in the way that the Factory piece was used anyway.

When you say nothing like, I think us and you have different ideas on what "nothing like" is

Bringing the discussion over to this forum is going to water it down. I suggest you discuss it at source.

I'm not really interested as I'm not too fussed about what they have/haven't concluded from it. The test looks too Heath Robinson for me to worry about.

What interests me is that a bumper that to my eyes appears to be similar to that of a ZG from outward appearances is apparently working against the car. Why is this? Is it because the copy is too poor and missing fundamentals to its design? Is it the entire stance of the car is making it work against it? Is it other aero parts that are required in conjunction with it to make it work (e.g. under engine tray or something)?

 

[twoforty]

What looks good and what works are two different things for sure, I know that a certain ICBM has a small flat disc that sticks out at the front which gives it an extra 1000 mile or so range....you would think it would slow down!

 

[Albrecht]

The car in the racing thread is another story, huge arches blended into a smooth front end.....looks nothing like the production ZG's pics I have seen.
I'm sure that race car would have a much better Cd than a standard Z body.

You still don't get the point. That car would not have been able to use those parts in Group 4 or 5 if the 'HS30-H' model had not enabled Nissan to homologate the base package. The Works / Sports Option parts were a package intended to be used with the homologated items, made legal by production and sales of the road version. Testing and critique of just the standard 240ZG parts in comparison to anything else is missing the point of why they existed in the first place.

Well lets talk about the look....I don't like the way it looks, there is nothing wrong with the G-nose and nothing wrong with the Z but put the two together and it looks wrong. I'm not asking for you to agree with me, I'm judging it on my own taste, my own idea of what looks right or worng. Some will agree and some will disagree to the end of time. There is no point in trying to convince me that you think it looks good becuse I am not you. So lets not get into a silly battle over the front end of a car.

You were the one that brought up the looks in the first place. Look at your second post on this thread you created. Now you don't want to go there. Fine. Seems you can pedal backwards just as fast as you can forwards.

I'm open to proof that the G-nose will out perform a standard body Z of the same power and weight.

"Out perform" it according to what criteria though? Seems to me that your bias - evident from the second post in this thread - is overshadowing all else. I suggest you go over to the HybridZ forum and discuss it there, as the people providing the data that you have accepted as proof otherwise are right there and probably willing to debate it with you. One of the people involved in the debate about the G-nose is part of a team that runs an S30-series Z at Bonneville. If you want any 'evidence' then I suggest he would be a good person to ask. 'TonyD' is his forum name there. He knows what he is talking about in theory as well as practice.

Aerodynamics is a science that amateurs can dable in and have huge impact on the world.....wright brothers for one, maybe they shouldn't have bothered dabbling

I don't have a problem with that. What I object to is people being all too willing to disbelieve the practical experience of a manufacturer and their racing activities over thirty years ago, and at the same time make comments on the aesthetics of said parts. You want to have your cake and eat it, all in the same thread. I don't believe you are coming to the discussion with knowledge of what the Factory were really up to.

 

[Markp.com]

This thread is hilarious!

"Mines bigger than yours!"

 

[Albrecht]

When you say nothing like, I think us and you have different ideas on what "nothing like" is

Russ,
Not to put too fine a point on this - but when was the last time you had a really good look at a Factory-made lower G-nose panel ( both inside and out )? And have you had a good look at the Factory race car parts both inside and out? What might seem subtle to you actually makes a BIG difference in the science of aerodynamics.

I'm not really interested as I'm not too fussed about what they have/haven't concluded from it. The test looks too Heath Robinson for me to worry about.

Huge volte-face there. Seems to me that at the beginning of this thread you were all too ready to accept the results of the HybridZ test in relation to their "G-nose". Now the test is "Heath Robinson". Case closed I'd say.

These Z enthusiast forum discussions always talk in such ideal terms about the design and details of the car. Obsessed with figures and fine tuning that really have almost no measureable effect within the parameters that their cars are usually asked to work in. Just where and how often does 'twoforty' find himself travelling at 145mph in his Z? Surely it is such a small part of his overall driving experience that it is almost not worth concentrating on, and focusing on making his car 'better' at those speeds will quite possibly hamper it at all other times. Is he going to be putting a diffuser and side skirts on his car now?

Russ, you ask about the windscreen rake - but to what end? Face it - these cars we spend so much time talking about were never no-expense-spared supercars. They were budget sports/GT cars designed around saloon car running gear! Bloody good little cars for the money, and brilliantly designed and engineered considering the concessions they were built to - but they are what they are. So much of the 'performance' talk about these cars is just bench racing. Yes you can make them go well, but disproportionate improvement in one area will often lead to a negative effect in another. Taking discussions of aerodynamics to a minute degree on standard road cars that were designed over 35 years ago is ultimately somewhat futile. It is even more so when some of the people in the discussion don't have a good idea of what the Factory - and some privateer racers - were doing in period whilst at the same time poking fun at them.

 

[Russ]

Russ,
Not to put too fine a point on this - but when was the last time you had a really good look at a Factory-made lower G-nose panel ( both inside and out )? And have you had a good look at the Factory race car parts both inside and out? What might seem subtle to you actually makes a BIG difference in the science of aerodynamics.

I haven't, nor am I likely to, nor am I interested enough to do so. However I am interested in why this repro front end is misbehaving so badly.

Huge volte-face there. Seems to me that at the beginning of this thread you were all too ready to accept the results of the HybridZ test in relation to their "G-nose". Now the test is "Heath Robinson". Case closed I'd say.

I think you got the wrong end of the stick, I'll throw in a few more smilies next time as my point was lost, and I won't bother posting when I'm in the mood for stirring things up

I'm stepping out of this discussion now as I've lost interest and don't see it's going to go anywhere, apart from the usual knocking Datsun, then defending, then losing the thread entirely and no one learning anything apart from getting a virtual clip round the ear.

 

[Albrecht]

Russ,
Don't you see where I'm coming from on this? If left unchallenged or not commented on, a thread such as this one becomes the seed of the very kind of weeds ( read: garbage ) that we spend half our time struggling to get to the truth through. It's the interweb at its worst; unsubstantiated data and unscientific opinion being laid down as though it is "truth" for us to trip over in future.

I haven't, nor am I likely to, nor am I interested enough to do so. However I am interested in why this repro front end is misbehaving so badly.

That's a classic. Not interested to know about The Real Thing ( or the story and related parts attached to it ) but interested in the recorded data surrounding an inaccurate reproduction! Aren't human beings wonderfully complex and strange things?