Aerodynamics and Relationship to Speed

I'm sure a tonneau cover of sorts wouldn't do the cabby any harm if Ben takes the roof off.  Cars of the 50's and 60's had them - could be a whole heap of retro cool  

so paul do you reckon run without a bonnet?? or get the filter hanging out of it :dontknow:

as for the hood i may leave it but try with it up and down to see what difference it makes

In my old Westfield owning days the pursuit of losing weight was almost an art form and some of the more fanatical types reckoned that in the car world at least a weight loss of 50kg is worth 10ish bhp so with lighter seats and no spare wheel/carpets etc its a cheap way to get better power.

Ergo if you have poor aerodynamics (as do Westfields and Seven type cars) you need more power or increased power related to weight.

paul_c said

power is probably the least important aspect of going fast - its mostly down to weight (or lack of it!)

I would say power is the most important myself.
A lighter car will do the same top speed but just take a shorter time to get there.

This was told to me by a good friend who was an engineer and currently owns the worlds fastest Sierra Cosworth at an official 209mph

Regards the removal of the bonnet, a friend of mine with a 3dr sierra cosworth was at santa pod running 13.1's all day, took the bonnet off and was down to 12.7 for 3 consecutive runs, refitted the bonnet and was back to 13.1-13.2 so on that car it deffinatly made a difference.

And yes i know its all fords but i own one aswell as the Mk1,lol

i think the bonnet things is all down to getting air into the bay .im running the filter through a hole in the bonnet so should see the same results

but i will be removing the following
bumpers
wipers
mirrors
interior
door card

my cars not high on power, but I am low on wieght which has helped loads   I plan on stripping more off before the year is out.

aero on starts to make a big diff above speeds of 70 or so, bellow that its power to wieght and traction that has the biggest effect.

but you need to consider what you want, going fast in a straight line requred different thinsg to going fast round a track, ie run skinny rears pumped up for straight line, but for track you will need beefier rears for the grip.

bens_cab said

so paul do you reckon run without a bonnet?? or get the filter hanging out of it :dontknow:

as for the hood i may leave it but try with it up and down to see what difference it makes

I've chanced upon a little bit of a tip which could give you a temporary 'boost' in performance if you are desparate for a little more power: Bung some cellulose thinners into the fuel tank. Thinners are made up of xylene (octane rating of 136) and toluene (octane rating of 124), so this will definitely improve your octane number and allow you to turn up the boost even more. Petrol already contains 5-10% of these chemicals anyway, so its fine to do. 5l can of thinners for around a tenner, into say 10l of existing fuel in the tank, will give you 109 octane fuel!

Worth a go?

http://www.stfrancis.e…ponents of Various Brands

well ive been told to stick some aviation fuel in with the petrol :mrgreen:

or i may even just program the wideband for methenol

bens_cab said

well ive been told to stick some aviation fuel in with the petrol :mrgreen:

or i may even just program the wideband for methenol

Yep, Avgas would be fine, or methanol - both of these will improve the octane, although for the methanol you'd need to make a big adjustment to the fuelling amount (lower the AFR right down to about 6). Don't use Jat A-1 though, its different and will burn worse in a piston engine.

Methanol can't be used long term because it corrodes rubber seals and fuel pipes, though.

But I think a good dose of toluene is what you really need. Basically, its the stuff that goes into 118 octane race fuel, etc.

bens_cab said

so paul do you reckon run without a bonnet?? or get the filter hanging out of it :dontknow:

as for the hood i may leave it but try with it up and down to see what difference it makes

A air filter sat in the airstream ie up out of the bonnet in the air flowing over the car causes turbulance within the air inlet system causing losses in power, plus it destroys the airflow over the car causing drag.

you reckon i think it will keep my intake air temps cool lets face it the air is being sucked in by the turbo so shouldnt effect the running other than keeping it cool :wink: