Found this great down load by a bloke called Peter Ogden (no relation to percy i hope).

Its called gearcalc and if you input your diff ratio, tyre sizes, and gearbox ratios it will tell you all sorts of info like top speed and which gear you will reach sixty in for that all important dash!
It even has all the ratios for common gearboxes (type 9 is there) under the tools pull down.

http://locost7.info/gearcalc.php

Mine will do 143mph!

Ps sierra 4x4 LSDs are 3.62 ratio.

155 not taking into account wind resistance and the like....

More than fast enough for any Locost type methinks.

Rich.

shit now i'm worried

Gear Mph per 1000 RPM Mph @6500 RPM Mph @7000 RPM
--------------------------------------------------------
1 6.30 41 44
2 10.41 68 73
3 15.38 100 108
4 20.60 134 144
5 30.30 197 212

Already done me own (much simpler and more basic) Excel-based version so I'll have to download this one and see if mine is close. If it is then I'll be able to pull 60mph in second gear, which should be enough for anybody!

Think with the rv8, lt77 and sierra lsd ours redlines at about 130mph, according to the quaife calculator.

assuming a standard rv8 redline (with solid lifters and other crazy potatoes you can get from 5500rpm redline to 8000 or something, I think.. nuts)

Like Blueshift, RV8/LT77 but with 3.82 diff:

117mph

Sad, but true!!

ATB

Simon

PS Ned - have you still got your 3.38?

so how can you do your 0-60 time,my sundial aint that acurate

Har har 60 in second thats first in our beastie, but gawd it HOWLLLLLLLLs
Shug.

According to Andre Jute,

BHP =
Cd x Frontal Area in Sq Feet x Speed Squared

Divided by

146,000 x 0.7

which means

speed =
BHP x 102620

divided by

Cd x frontal area

all cube rooted

For my pinto, (assuming the Cd is the same as a caterham, 0.65), a frontal area of 3'x5' x 0.7 (0.6 for the fact that the car is not completely 3'x5'

This gives a top speed of 109.45mph

Thats what I'm telling the SVA!

If I've got it right , using your calculations it would take

95.4 bhp to get 100mph,
149.06 bhp to get 125mph
173.8 bhp to get 135mph
200.58 bhp to get 145mph
309.09 bhp to get 180mph
381.6 bhp to get 200mph

I'd be interested to know what top speed 'Hicost' has seen in his car , as it is quoted at 400+bhp

Like most of these formulae, they work well within normal (normal!?) parameters, but at the extreems, they get a bit fuzzy. The top speeds look very believable and relatively normal BHP outputs - I don't think any locost would do 200mph without some pretty special aerodynamic aids which would put up the Cd by an appeciable amount (I think an F1 car has a Cd of 1.15)

357mph....

Well, you lot started it.....

here we go again!!!

I think it s food for thought when considering a trick motor just how much extra power you need for a modest improvement, I'd rather hit a speed bump at 100 mph than 200mph

I find that when you get to 100mph in a 'Locost' you start wondering just how good your welding is!!!

No worries on the welding, but the aerodynamics worry me a bit at anything above 90mph, had a look at the new carerham in EVO magazine, they have an F1 style front spoiler which looks good and may even make SVA easier on the front suspension lagging

Real figures from speed trap.

Toyota 4 age with matching 5 speed box. 3.89 diff, 15 inch wheels.

Windscreen fitted. (Air Dam !!)

5th gear 109mph.
4th gear 117mph.

I think when I did the calc last time I was truly excited as it quoted something like 135mph max. Yeah right!

The windscreen makes a huge difference.
You can see and definitely feel the pressure exerted upon it.

Haven't been able to try it with sidescreens fitted but they are supposed to help for about 3-4mph. Certainly more comfortable and I've since seen 125mph indicated with them on, not on empty motorway officer.

Just to qualify this, when I had 3.54 diff fitted I'm sure it would reach 130 on the right road but i never found one long enough! The acceleration was much slower with that diff so I changed to the 3.89.

0-60 is now 5.5 secs, which probably helps rob the top speed with 3.89 diff.

[Edited on 11/11/03 by Rob Lane]

Is it just me?

The top speed thing has virtually no interest to me......(hence the p***take earlier)....

To me it's all about acceleration and handling......

Anyone else feel the same?

quote:

---

Originally posted by Alan B
Is it just me?

The top speed thing has virtually no interest to me......(hence the p***take earlier)....

To me it's all about acceleration and handling......

Anyone else feel the same?

---

I think the shocks are of mminor importance when considering drag and aerodynamics of a locost, i agree with the windscreen rake / removal. the most burning issue is the hole in the nose that creates the wind sock effect!

The shocks create as much aerodynamic "damage" as the roll bar!

All IMHO of course.

I agree with Alan - top speed is rather unimportant - with the ZX9 and a 3.54 I only get 112mph, but I rarely go on a track with a long enough straight to reach it (excpet Donnington), it's all about acceleration and handling

I am not really into top speed, more back lane bashing.

but this spoiler caught my eye, it could make the SVA alot easier, bit like the Dax 'front bumper'
Rescued attachment CaterhamFrontSpoiler.jpg

Having passed the ton mark only last week (not on the road, of course??) the buffeting and eye watering effect detract from the fun element, and a s for Daves wise comments
I find that when you get to 100mph in a 'Locost' you start wondering just how good your welding is!!!

I always think of the front wishbones for some reason,


they do look quite flimsy

steve

I would trust mine more than production car wishbones - especially Vauxhall. In my trade you see all the weak points of tintop cars

I'd have to go with the vocal majority about top speed not being as important as the "Squirt Factor". The ability to squirt through traffic with ease. The 40-60MPH timing is important to me for passing on curvy 2 lane roads.

Of course, hitting your calculated top speed might induce a 'squirt factor' of a different nature. I made it to 130mph in my 250GTO replica (once) and remember wondering how many pieces they would find my body in if a tire blew out... Talk about anal constriction!

No, top speeds not my bag either. I just posted real world examples to show the huge discrepancy in the modeling software.

As you can tell from my post I have experimented in depth to achieve a fast accelerating, good handling car.

It's not perfect but whatever is!

On some tracks it's spot on but as a road going car it cannot match the cars with the availability to change gears and diff for each track.

Donington springs to mind as a good example, car matches it perfect. Croft, much too low geared, topped out third way down straight. Others just the same, a compromise.