Windtunnel results for 240z

[Russ]

I imagine getting my hands on a ZG, seeing a genuine one in real life, or finding detailed pics on the net is going to take me many many hours or lots of £ travelling.

I do want to know why the ZG in the clip appears so rubbish, but not to the point where it'll take me any of the above to find out. I'd sooner spend that time/money on working on this site, aboutz, or my 240

 

[Albrecht]

I imagine getting my hands on a ZG, seeing a genuine one in real life, or finding detailed pics on the net is going to take me many many hours or lots of £ travelling.

I do want to know why the ZG in the clip appears so rubbish, but not to the point where it'll take me any of the above to find out. I'd sooner spend that time/money on working on this site, aboutz, or my 240

OK - I'll save you some of the effort, and all of the £s.

If you look closely at the "G-nose" used in the HybridZ wind tunnel tests, you will see that internally it is quite different to the Factory item in a number of ways. Most importantly, it does not extend all the way up to the radiator support panel and front crossmember or its sides. Air flowing into the 'mouth' of the car - which should mainly be ducted through the radiator - is able to flow out to the sides and also underneath the rad support panel. This completely disrupts the whole point of the G-nose's outer shape.

The tested parts also did not extend underneath the car in the same way that the Factory parts do. Presumably to make it easier to mould, the shape of the underside on the repro part was truncated - creating more places for air to penetrate around the rad support panel and also hit air that was coming down to meet it due to the bad shape of the 'mouth'. In short, the tested 'repro' piece was unlikely to offer anything like the same results as the Factory item because half the shape of the Factory item was missing......... Therefore the results of that particular inaccurate repro can only be used as reference on that particular part, and not on anything else. Useful data for people who might be considering the purchase of a similar repro part, but nothing to do with the proper Factory parts.

Having said that, the Factory G-nose is not a perfect solution by any means. But the people who designed it did understand what was happening around the front of the car and they addressed it. But they addressed it almost purely with respect to racing the car, and the Works race teams themselves were able to take the solution several stages further - with improved ducting and the separation of engine inlet ducting from cooling ducting, and sealing off most of the areas where 'unwanted' air was finding a way to penetrate.

For the road cars, Nissan started to properly address the subject of aero efficiency in the next generation; the S130-series Z. The treatment of the front end and radiator ducting on the S130-series grew from the lessons learned with the 240ZG. Nissan themselves acknowledge this.

Clearer now, I hope?

 

[twoforty]

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.

you were the one that said it was "clouding" my judgement about aerodynamic effectiveness...it was in no way clouding my judgement.

Pedal backwards? what are you talking about...maybe if you came out of your castle in the daytime you would see how bad your ZG looks

My point was if the G-nose didn't help the car then why ruin its looks...I have never suggested anything else or tried to back pedal. You are the one who got on his high horse about the looks of the car because you didn't like "my" opinion.


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.

Nissan have never had a recall on one of thier cars? If we all had millions of pounds to develop ideas at a faster more professional pace then things would be different, experts weren't always experts and you knocking anyone that is not an expert is plain silly, thousands of inventions have been made by common people through trial and error.

Oh and it was 135mph not 145mph as you are one for detail I thought I had better correct that..and it would indeed be a very very small part of my driving....even more reason not to mess up a good looking car for the sake of aerodynamics.


MarkP has it bang on....hilarious

 

[twoforty]

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.

I think you are getting a little carried away with this I never said I didn't believe Nissan, I said looking at the data it looks like it causes more lift on the front and on the rear...I didn't say this is a fact set in stone and everyone must agree with me.

So nissan only messed up the looks in order to produce a race car at a later date.....fine I can accept that. End of discussion

 

[Albrecht]

Noted. But what has that got to do with the parts that were being tested in the HybridZ article that you linked to?

It's quite simple. You didn't understand what was being tested, and you didn't understand the results either. Without my clarification, you'd be leading everybody else down the same road that you are already lost on........

Fail.

MarkP has it bang on....hilarious

MarkP.com is a member of the famed Peanut Gallery and not to be taken seriously, but it is interesting that you agree with him. I can't help thinking that you would have preferred to have been right rather than merely funny though.

 

[Albrecht]

I think you are getting a little carried away with this I never said I didn't believe Nissan, I said looking at the data it looks like it causes more lift on the front and on the rear...I didn't say this is a fact set in stone and everyone must agree with me.

New development: Back-pedalling with afterburners switched on.

So nissan only messed up the looks in order to produce a race car at a later date.....fine I can accept that. End of discussion

See, I knew that's really where you were coming from on this one. I'll file you in the appropriate section from now on.

 

[twoforty]

Yeah ok count you do that. Afterburners on..back pedal..you're a funny guy.

 

[Russ]

See that's the response I was fishing for to start off with, thanks very much for that

Did we really need all the faffing about in between?

 

[ZHead]

I have to say Guys that this could have turned into an interesting thread, vitriolic maybe, fiercely contended and debated maybe but interesting and informative. I for one would like to understand the subtle, almost tiny changes that could be made to help my S30 when it finally rolls out into the sunlight.

Instead, what do we get again ?, uninformed crap that does little to either enhance the club, the cars or the attraction to newcomers.

There are some seriously cute steering mods coming down track that I want to invest in and improving the aerodynamics would also have been a fascinating and cool thing to do. The factory designs would obviously be a great place to start.

I have often heard "Devious clever those Japanese", said in a derogatory sense but if they are so stupid how come they managed to totally f**k our automotive industry over with superior products at more competitive prices ? How come the reliability of most Japanese cars FAR exceeds that of Mercedes or BMW ? Silly rhetorical question, they are obviously stupid and just got lucky.

As Alan points out, these cars are what they are, cheap, mass produced GT cars from a bygone era. They are not true classics, not supercars, just fun, affordable sports cars that were ahead of their time. The expression goes "you cannot polish a turd" but that is exactly what we are all trying to do, take a budget car and make it behave like a much more expensive one. Understanding and improving the aerodynamics would at least allow these cars to be polished to a satin sheen.

 

[Russ]

I not sure who you're arguing with, but I agree mostly.

Don't undersell the S30 as a turd though, look at the racing heritage and what the current flock of drivers are still doing with the car

They are definitely classics though! Shame on you for letting that slip into one of your sentences

Now a Miura, I'd give everything to posses one, but the bloody thing had really crap aerodynamics

 

[boomer]

Is a 911 a Turd by your book? How do you rate it against the 240Z turdwise?

 

[boomer]

Myth busting...

On the infamous HybridZ is stated somewhere that one big downfall of the 240Z is the air entering by this whale of a mouth and hitting the firewall without room to escape... Myth or reality?

When I look at one of the first track car... it could be true!

Time for a 240Z Myth-busting tread

 

[Russ]

Nice pic!

Surely if it's gone through the 'mouth', through/around the radiator, and past the engine, there's plenty of room for it to escape underneath the engine (whether this is good or not is another question). I don't imagine (guess) that the engine bay will pressurise?

Like the idea of this thread though!

 

[Ian Patmore]

Russ,
If you read a bit more about the threads around this subject on Hybridz site, there is a big discussion about how the air behaves once in the engine bay. From my limited assesment, its not a good idea to have a load of air going into the engine bay and thus under the bulkhead, as this air then goes under the car and "lifts" it up, 'cos the air hits the bulkhead and finds the only way to escape is under the car. A car wants the opposite to happen, down force. It seems a good idea to have a small "mouth" with most of the air getting pushed aside by the frontal air dam (hence why its called a dam) and not entering the engine bay. As been talked about, this is why I presume that the inner "floor" of a genuine G nose has air boards that angle the air towards the side and encourage the air to escape before entering into the engine bay, rather than a repro G nose. And it seems that some pressure is made in the engine bay, bonnets have been known to bulge and there is talk on Hybridz about how to combat this by say, opening the windscreen edge of the bonnet or lourves in certain places to release the pressure.

Has that helped Russ?

Cheers
Ian

 

[Albrecht]

When I look at one of the first track car... it could be true!
Time for a 240Z Myth-busting tread

boomer,
One of the first 'myths' to dispel is that the car in your picture is "...one of the first track car..."

That's actually a replica of an SCCN Works team 240ZR. I know it very well, and some very good friends of mine were part of its creation.

Here are some real ones:

 

[boomer]

Granted! Still, if it's a repro I assume there is a real one... and it's ain't a year's bird?

So what's the story about this mouth? Less drag? Cold winter start shield (guess not)

Because if it's 180° away from your all time Beef-Eater's favourite Big Sam, which is nothing but a hole, and did quite good on the track

Could Big Sam have been even better?
Is the SCCN Works a turd
Is it none of the above

Please enlighten me

 

[boomer]

Granted! Still, if it's a repro I assume there is a real one... and it's ain't a year's bird?

So what's the story about this mouth? Less drag? Cold winter start shield (guess not)

Because if it's 180° away from your all time Beef-Eater's favourite Big Sam, which is nothing but a hole, and did quite good on the track

Could Big Sam have been even better?
Is the SCCN Works a turd
Is it none of the above

Please enlighten me

 

[datsun dave]

Russ,
As been talked about, this is why I presume that the inner "floor" of a genuine G nose has air boards that angle the air towards the side and encourage the air to escape before entering into the engine bay, rather than a repro G nose.

Photo my help

 

[twoforty]

A smaller entrance openning into a large space gives more pressure to force air through the rad.

 

[Russ]

Ian,

I'm an idiot, I pretty much knew that thinking about it, I have a book on chassis engineering that goes over some simplified aerodynamics I'm surprised though that bonnets have bulged, that's quite mad! Never really thought about why it's called an air dam either, thanks for that

To quote my book

And, when the low pressure behind a spoiler can act on a horizontal surface on the bottom of the body, it will also increase the downforce

I.e. you have positive air pressure in front of your air dam, negative behind, which would then act on the "inner floor" you mentioned.

Here is the discussion on this very topic Boomer has started

Radiator Air Inlet & Exhaust: About 20% of the airflow affecting a race car goes through the radiator and oil cooler, so how this air is managed is important to both the drag factor and the downforce factor. From a drag standpoint, you want to let the minimum amount of airflow through the grille opening and to the coolers. This means that it is important to be sure that any air that does go through the grille opening also goes through the radiator or the oil cooler. The best way to accomplish this is by building an airtight duct to guide the air between the grille opening and the coolers. Since the grille opening is smaller than the radiator, it is better to mount the radiator at an angle so the air doesn't have to bend up to hit the top of the radiator.

Where the radiator inlet is poisition can have a big effect on the front-end lift or downforce. If the radiator for air inlet is above the front spoiler, it will see positive pressure and there will be nothing to disturb the low-pressure area behind the front spoiler. If however, the radiator air inlet is behind the front spoiler, two problems exist. One is that the radiator inlet is in a low-pressure area, and the second is that the radiator air inlet disturbs the air behind the front spoiler. Cars that have this arrangement usually require a second spoiler behind the radiator to cause a high-pressure area to feed the radiator. Since this spoiler is also behind the front of the car, it cause a high-pressure area under the car which can reduce the downforce or even cause lift.

Even the radiator air outlet or exhaust is important, because dumping this air into the low-pressure area under the car can reduce the downforce. It is better to exhaust the radiator air out the side of the car through the wheelwells. This is because it does not upset any low pressure area that might be acting on the bottom of the car. Keeping the radiator air exhaust away from the engine can help reduce the air temperature at the carburettor inlet.

Next time your inner arches rust through just use the holes to duct your radiator air away!

Interesting stuff, I/people really need to think more about what they're doing and why. I didn't notice at first the small rad opening on the red zed so missed some of the point.