Gordo takes over the Peter Mac Build.

[luvemfast]

Aero goes over my head! 

[hmd]

No I don't Have any data. Its all old school.

What you can't measure you can't improve on.

 

will PM on data logger.

[dat2kman]

Interestingly, the top Group S Historic cars, are doung 235-240 kh just prior to turn 1.

That is the Z's, with very lttle aero.

We are doing a fair bit more rpm, due to smaller diam tyres.

What detracts, is the lesser rubber, and less ability to put power down on exit of corners.

[d3c0y]

Aero goes over my head!  :

 

Is that a high pressure joke?

[luvemfast]

Is that a high pressure joke?

Nope. No pressure here. Basically a vaccum.......

 

But I'm enjoying Gordo's journey

[Gordo]

Got any idea at what speed the current wing starts working Gordo? Some start from as low as 80kph. From Richard.

How would anyone know. All I now is it works. The Lukey Hights spin was my fault, to fast on entry. The speed there is pretty fast.

About 6200rpm in 4th, maybe 175kph on entry, so the wing would be working.

[hmd]

Interestingly, the top Group S Historic cars, are doung 235-240 kh just prior to turn 1.

 

That's very fast, my data logger said 208.3kph when I was down there with Gordo.

 

Gordo, data logged one run with and one without the wing preferably on same day same condition.

[dat2kman]

Iusing GearCalc, ( no data lgging in Group S cars!) it indcated rpm, in fitfh with the running gear and diam of tyres, 235 kh

I was able to ull in and Ppass Peter Hall across start line.

He'd get me around Siberia.

At Bathurst, same year, rpm a bit higher, 240kmhcar was understandably twitchy

 

Chaps I know in the Group N Mazda RX2's are doing 250.

[hmd]

Data logging in non racing practice only!

[260DET]

Some relevant comments about the aero effectiveness of several cars including the Z and a Mazda RX3 in this video 10+ minutes in http://www.scca.com/videos/1972570. As they say, the RX3 has awful aero and is very draggy so if a Group Sc RX2 did a genuine 250 at Bathurst, well, 'interesting', my V8 should do 300 

 

The Z has a relatively good slippery shape and small frontal area although Gordo's with the body kit would suffer a little bit there. Power to weight, a Z with just enough aero to negate lift should enable a very good straight line speed.

[dat2kman]

Rcho, i reckon that'd be a Group Nc Mazda!

Yes when they worked it out on that Peter Ogden "Gear Calc" software, they just wouldn't pull over a certain kph figure, even though the engines will spin higher.

Brick wall!

[DatZed]

Do you know what the airfoil is that you are using? Perhaps you have a little too much aoa and that's what is costing you the top speed? You reduce the aoa by 1 degree every session until you find the balance point between drag and downforce. This is obviously predicated on the assumption that the airfoil is reasonable efficient and not stalling and becoming a sail on the straight.

[260DET]

There is a thread on HybridZ about a S30 doing standing start mile speed runs, engine is a virtually stock LS2 which would not be delivering any more power than a a good worked L series. With no aero but running a lot of rake it reached 269kph during the first attempt. He then fitted a front spoiler and splitter and found that the front was being pushed down three inches so the splitter was hitting the track at over 270kph, 

 

Just shows the power of aero and how fast the S30 body can be pushed without big power.

[Gordo]

I've put the rear spoiler on. Will try the car with the wing on, and then take it of to see what the speed difference is on the straight.

[luvemfast]

Have you thought about a G nose?

I've heard that it will cut your revs 500rpm down the front straight at PI

Edited March 10, 2016 by luvemfast

[TomC18]

Hey, maybe you should flatten the wing right out before removing it, if you have enough runs.  I found my old data and was doing 238kph at the end of the straight when I did the 1.46.5 - that was with half a G Nose and minimal front downforce, ie just the spoiler, no splitter on front, and  rear spoiler all as currently.  

[Gordo]

Was at the Island on the weekend trying a few things out.

First run no front splitter. 6100 rpm on the straight. 10kph head wind.

Second run, no front splitter and took the rear wing off. 6450rpm on the straight. 20 kph head wind. And the car handled like crap.

Almost lost it twice, and very unstable in all the fast corners.

Third run, put the splitter and wing back on. Car felt fantastic and was 2 -- 3 seconds faster at 6100rpm on the straight.

Testing complete. Leave the areo stuff on.

[Sirpent]

Testing complete. Leave the areo stuff on.

 

Love your work, thanks for putting our half witted theories to the test 

[TomC18]

Looked like times were very slow. 2-3 secs. Track a bit Cold and windy. Sounds like I will need that front spoiler/splitter!

[Gordo]

Hi Guys, Tom (TomC18) and I were down at the PI track on the weekend and lucky for us we were in the same run group.

On the last sprint we rolled out together and the GoPro shows us having some fun. Was a great day and Tom took the Trophie home.

Not much in it. We both have different driving styles. Some differentses . I have the std 260z gear ratios, Tom has the option 1 box 1 to 1. Tom is about 90kg lighter. I run more Areo. Same horsepower and a few other minner things, but over all very evan track performance . Hear is our run together.

 

https://youtu.be/7X-IGQU7e7E.

[gav240z]

That was awesome, who built the engine in Tom's car?

[TomC18]

Steve Newing did the last rebuild - originally built by Stan Holmes with Neil Cartledge machining special bits...  I am down a bit on power as it was detuned to run on 98, but still goes ok and revs cleanly to 8300.  i will try to work out how to load a video link too, as it sounds great

[260DET]

Oh man, what a great video   Noticed that Tom was doing some later apexes, nice driving both of you.

[PeterAllen]

It is the 100th running of the Indianapolis 500 next month and I'm following an interesting thread about some of its history. Here is the text from a few of posts which are relevant to this discussion:

 

- "Peter Revson qualified for the pole in 1971 at record speeds. His time would not have been quick enough to qualify for the 1972 race."

 

- "Were the rule changes or was just the development that fast in that time?"

 

- "USAC allowed wings for the first time, so the wedge shaped cars of 1971 were now replaced with cars that had massive rear wings. I believe they were much slower in terms of top speed along the straights, but obviously gained enormously in the turns."

[luvemfast]

Its basically a father son race here.

When Peter was building the 260Z, it was based on Neil's 240Z.

So this is literally the best!