Top speed SHoot out!!!

[zedhead260]

My car will be "limited" to 150mph anyhow.

 

[SeanDezart]

You techy snob you !

I'd have thought that a 3.9 limits the speed anyway - where's Skiddy with a snazzy mathmatical formula to tell us how fast we should all be able to go ?

 

[zedhead260]

I'd have thought that a 3.9 limits the speed anyway

LOL, that's what I mean

 

[SeanDezart]

Don't matter, like Zhead, I have a 3.5, 3.6 and a 3.7 at my disposal

 

[SKiddell]

Using a 3.9 diff with the right box (late 280 with the longer 5th) on 225x50x16 inch rubber and a redline of 7500 will still get you a theoretical 190+ (yeah right)

http://www.geocities.com/z_design_studio/

However, in the real word its the law of diminishing returns as aerodynamic drag logarithmically destroys the horsepower applied.

I have seen 140+ GPS verified MPH but it scared the heck out of me -- I would have thought that a geniune 150 - 155 was possible but not much more, as Zhead said previously - despite its looks the S30's coefficient of drag is somewhat closer to a brick than a bullet. Still not bad for a 30 year old classic.

 

[SeanDezart]

Well, my old 240Z gearbox on 15" wheels and 55 rubber and a 6500 redline might pull me 140 mph verified ??? (how do you work that one out without the bhp figure ?) but I would so enjoy the challenge !

Maybe I'd be better off with our 280ZX 2 seater...........

 

[Zed2k]

I'd hope to hit 150mph as it's always been my target speed which is supposed to be the bench mark super car speed ( in the old days ). I will be trying very hard to achieve it. I too have seen around 140mph and the car was very stable but a bit scary. so it should be good for 150 EEK!!

 

[Albrecht]

Top speed competitions have been quite popular in Japan for many years now, and were often organised by magazines.

Here's a couple of L-series engined S30-series cars that went quite well:

 

[Tony 260Z]

I've wound my 260 up to 120-130 but it wasn't very happy. It would have gone faster, but I could feel the steering getting very light indeed so I bottled it. Maybe if she was lowered and had harder springs it would have been better. I did it when I had a "what will it do?" moment some time ago. I won't be doing it again!

 

[JEZ 280ZX]

Hi,
From the photos, it looks like you will need to remove things like wiper arms and mirrors and fit some headlight covers and smooth hub caps to achieve a good top speed!....Oh! and make sure there's plenty of horses available too!

 

[johnymd]

Some cars seem to love high speeds and some just don't. I remember in the 80's doing 130ish(on the speedo!) in my 240 and it felt very stable, even on a sweeping bend, until the front cross member came away from the chassis. I also remember 90 in a marina with 3 passengers feeling VERY scary on an undulating road.

The key must be down to the correct suspension setup and the improve stability provided by a well designed front spoiler.

 

[johnymd]

I guess also as you start to climb higher up the speed ladder, then ground effects start to play a more important role. When I crawl underneath my R34 and look at the extents the engineers have gone to with the underbody tray and carbon fibre rear diffuser, I start to realise why it handles so well at speed. Not sure I have the R&D budget to take my 240 to this level, but any areas addressed(providing you know what’s going on and the principles of how to improve it) should show some improvement. Then again you could end up with a car that fly’s rather than sticks to the ground.

 

[Russ]

I was planning an under body tray and maybe a rear diffuser, Darius is doing this with his 240z at the moment. OK neither of us would have the budget to calculate the rear diffuser, but if it looks similar to one I don't think it can be that far out.

I remember watching a video of the Skyline with and without its front diffuser and under engine tray, was worth quite a bit on a lap!

 

[zedhead260]

The top speed event that is held at Woodbridge MOD site in Ipswich has a 2.6 mile stretch of runway available for use. The speed trap is at 2.1 miles giving half a mile to slow down.

I had a couple of days there with the Ferrari Owners Club in the past; sitting as a passenger I recorded 140mph in a 308GTB4 (indicated 150), 150mph in a 512BB (indicated 170) and 170mph in a 360 Modena (indicated 170).

Even if my 260Z does reach 150mph, it'd be interesting to see if it could do it in 2.1 miles.

 

[SeanDezart]

Even if my 260Z does reach 150mph, it'd be interesting to see if it could do it in 2.1 miles.

hee, hee, hee - at least we know now she'll stop !

 

[ZHead]

Top speed competitions have been quite popular in Japan for many years now, and were often organised by magazines.

Here's a couple of L-series engined S30-series cars that went quite well:[/quote]


Alan, the magazine picture you posted shows 290KMH, I am assuming that is for the S30 on the cover and not another car inside (sorry, cannot read Japanese ). If that figure is correct then the car concerned would have just topped 180MPH - mighty impressive. The Americans also claim to have S30s going that fast....... do you know how the S30 on the magazine cover was prepared ? What was done to it in order to help the stability ? I am assuming again that the car was stable as you would have to be insane to pilot an unstable car at those speeds.

 

[SeanDezart]

Top speed competitions have been quite popular in Japan for many years now, and were often organised by magazines.

Here's a couple of L-series engined S30-series cars that went quite well:

Vive les series L moteurs ! Booo les yankees !

 

[Albrecht]

Alan, the magazine picture you posted shows 290KMH, I am assuming that is for the S30 on the cover and not another car inside (sorry, cannot read Japanese ).

Yes - the Fujima-prepared car was clocked at 290.45km/h at an 'AutoWorks' magazine top speed test day at Yatabe test course on 5th November 1995.

If that figure is correct then the car concerned would have just topped 180MPH - mighty impressive. The Americans also claim to have S30s going that fast....... do you know how the S30 on the magazine cover was prepared ?

I should imagine any American top speed attempts were at Bonneville, and run under SCTA rules ( presumably? ) with strict class eligibilty regulations being enforced. The Japanese magazine tests are much less strict with regards to mods - but the Fujima-prepared car we are talking about was running in the Normal Aspiration class.

It was using an old Japanese tried-and-tested combination of Honda XL500 pistons, L14 con rods and LD28 crank in an N42 block ( 3100cc ). Carbs were 50PHH Mikunis. It used a 3.1:1 ratio diff, and ( crucially it seems ) a transmission with a 1:1 top gear ( ie - no overdrive ). Wheels were 16 inch, with 225-50-16 rear tyres. Report says that they were topping out at 8200rpm in top gear.

What was done to it in order to help the stability ? I am assuming again that the car was stable as you would have to be insane to pilot an unstable car at those speeds.

Car was fitted with a modified replica G-nose and a modded version of the Works-type 'B' front spoiler. Rear sported a fabbed aluminium rear spoiler with end plates similar to those used by the later Works Groups 4 & 5 race cars. Not much else it seems.

See pics below:

 

[SeanDezart]

I love you Count !

 

[SeanDezart]

Interesting that it's still water cooled, I'd have thought they could have saved some useful weight if planning to run at those speeds.

Too complicated I guess, to cool the block otherwise ?