An article on my race car build

[turbotoaster]

let me know what you guys think, its only about 70% done on it at the moment but its making progress.

If you can see where I can make improvements im all ears

http://www.carthrottle.com/this-big-winged-monster...

[FussyFez]

Love it!


I especially like the minimalist interior, and the fact you use it on the road.

I think I'd st myself if I saw that in my mirrors.

[TobyLaRohne]

FussyFez said:

I think I'd st myself if I saw that in my mirrors.

I think I'd piss myself if I saw that in my mirrors.
All you'd see is the monster rear wing, the rest would be too low to see.

[turbotoaster]

everyone in normal cars look like 4x4s when i drive it, most of the time i can only see there doors and not them im that low, will be lowering the car anoth 15mm on track, cant go any lopwer on the road as i cant get off my driveway else

[turbotoaster]

I did put this in the general discussion but then I suppose since im building this for racing in Time Attack its probably best to go in here.

Let me know what you think, im hoping to have it on track next month with the first competitive showing in august at cadwell park.

http://www.carthrottle.com/this-big-winged-monster...

Lee

[Graham]

Interesting, my first thought are that its just going to create loads of drag and not much else, ride height looks too hight for underfloor to work, and I'd be a bit concerned about front to rear balance. but heck what do i know I drive a tuscan with no aero ( not even the rear lip spoiler or rear under tray as they erm fell off with the help of a barrier) and im usually see going sideways.


As you say you'll have no idea what it will be like until you get it on the track, it might work, or it might just give you extra confidence as you expect it to work so you still end up going faster...

But best of luck it certainly looks mad let us know how it goes, im genuinely interested



G

[turbotoaster]

your right in terms of ride height, currently the chassis is set at 98mm front and 115mm rear, i cant go any lower as i wouldnt be able to get off my drive.

On track ill lowering the car by an additional 15mm to try and bring the front splitter and underbody more into play so that I can make more use of the rear wing.

Ideally I would like to lower the entire car another 25mm but im not sure if I will be able to keep the rear stable enough that running the rear roll centre underground will have more of a detrimental effect on lap time than the increase in downforce it will produce.

I am pretty much limiting myself to a 20mm rake in the chassis and unless im willing to spend about £1500 then my rear of the car is limited to 100mm rear height(115mm if I dont spend £500 on a used race upright kit)

[chevronb37]

I assume the EP Tuning Exige is the other car mentioned in the article? I interviewed Jamie Willson last year for Race Tech:

Part 1 - http://www.racetechmag.com/features-1/item/535-max...
Part 2 - http://www.racetechmag.com/features-1/clubmans/hil...

Oh, and had a quick passenger ride around Oulton Park for good measure:

http://www.seloc.org/articles/motorsport/a-ride-in...

I wish you good luck with the build and will follow your progress in Time Attack with interest.

[turbotoaster]

yes it is jamies, since his had been in the wind tunnel I used alot of his data to work as a basis of known facts to work on, since work saved me alot of trial and error that i wouldnt have either known or been able to test, btu when i say this is a budget build, his gearbox cost less than my entire car and mods

[Startline Al]

It would probably be worth getting in touch with the scrutineers to check everything is ok.
[e-mail]

[turbotoaster]

Already did months ago. They have said the car is fine to compete. The only thing up in air at the moment is which of the 3 tyre manufacturers I decide to choose as thats very important when looking for the fastest lap

[Ahonen]

My concern would be that it will create too much drag for the power and might be painfully slow in a straight line. Aero is a difficult thing to understand and working with such extreme splitter and diffuser lengths can make life very tricky as the car becomes very pitch sensitive. If it was me I'd be more inclined to get the chassis working properly first, then add the aero bits one at a time to evaluate them. Lowering the car and messing up the geometry just to find some underfloor downforce won't do any favours. Does time attack run on road legal tyres? If so then the downforce won't find you as much grip as it would on slicks.

Sorry to sound negative, but I've done a reasonable amount of dicking with reasonably powerful cars with reasonable downforce and I know how hard it can be - 5mm of splitter height difference can make a huge difference to the balance, for instance.

[Startline Al]

turbotoaster said:

Already did months ago. They have said the car is fine to compete. The only thing up in air at the moment is which of the 3 tyre manufacturers I decide to choose as thats very important when looking for the fastest lap

What did you discuss, classes etc?
I'm not being funny here but perhaps arrange to get it to the next round (Snetterton 5th July) so they can have a look at it. Far better to sort any problems out now rather than having stress at your first event.

Edited by Startline Al on Thursday 12th June 11:55

[turbotoaster]

Ahonen said:

My concern would be that it will create too much drag for the power and might be painfully slow in a straight line. Aero is a difficult thing to understand and working with such extreme splitter and diffuser lengths can make life very tricky as the car becomes very pitch sensitive. If it was me I'd be more inclined to get the chassis working properly first, then add the aero bits one at a time to evaluate them. Lowering the car and messing up the geometry just to find some underfloor downforce won't do any favours. Does time attack run on road legal tyres? If so then the downforce won't find you as much grip as it would on slicks.

Sorry to sound negative, but I've done a reasonable amount of dicking with reasonably powerful cars with reasonable downforce and I know how hard it can be - 5mm of splitter height difference can make a huge difference to the balance, for instance.

Well thats what testing is all about, you can make educated guesses on what the car will do but until you hit the tarmac you never know.

I understand about pitch sensitivity and the risk of 'porpoising' hence im running fairly hard springs to keep the aero platform fairly stable, the diffuser is also incline adjustable from 5-14 degrees so I will be tuff testing it to see what angle the air becomes detacted/stalls.

Also the height of the splitter I understand the closer you get it to the ground the more downforce it produces so what you dont want is a car that in high speed corners oversteers due to too much front and understeers in the medium speed, so im starting with 900/1150 spring rates which hopefully should keep the downforce in check.

The chassis itself isnt a black art really they have been raced by so many people over the years that setup info is common knowledge, yes the ultimate setup comes from testing, but with a pirometer and some known values you should have it setup pretty fast.......if I decided to do that though it would mean that I would then have to re do everything again when I change spring rates, rake angle etc.

I understand if im messing up the roll centres by running the car to low will cause issues, hence the effort to try and get the lower wishbone horizontal(the front ive made and fitted roll centre adjusters already) The back is what im working on next.

Time attack run road legal tyres for my class, but with downforce its possible to pull a fair bit of lateral G, for example in OZ there is a Honda CRX that with the help of an ex mclaren aero guy now peaks at 2.72g in a high speed corner on semi-slicks so its possible to have alot of grip, because the tyres ill run wont be as sticky since we cant use them(yoko ao50) im aiming for 1.8g lateral.

Startline Al said:

What did you discuss, classes etc?
I'm not being funny here but perhaps arrange to get it to the next round (Snetterton 5th July) so they can have a look at it. Far better to sort any problems out now rather than having stress at your first event.

Edited by Startline Al on Thursday 12th June 11:55

It was a while back, but I did email pics, which I think they forwarded onto Andy Barnes and noone said anything that needed changing, ive read the rules carefully and I understand that as long as I build it to those rules then ill be fine, for example minimum underbody clearance of 40mm, fire extinguisher, safety clothing and helmet, tyre choices ill be club rwd.

[Ahonen]

Well you clearly have it all planned, so good luck. You may need to find another 300bhp to make use of the downforce, though.

[Startline Al]

I still stand by what I've said, get it along to Snetterton, either drive it or trailer it and the Scrutineers will be more than happy to go over it, you have done a lot to that car and this gives you a great chance to make certain everything is ok, lots of people have done this before.
PS, remember Andy isn't a scrutineer.

[turbotoaster]

If it was closer like Donnington or oulton park I would but its basically a 9hr round trip plus cost just for people look at my car. For me I will build it to the rule book and see how I get on

[teamHOLDENracing]

Ahonen said:

Well you clearly have it all planned, so good luck. You may need to find another 300bhp to make use of the downforce, though.

Don't know what you've been making a fuss about all these years Steve

[Ahonen]

teamHOLDENracing said:

Ahonen said:

Well you clearly have it all planned, so good luck. You may need to find another 300bhp to make use of the downforce, though.

Don't know what you've been making a fuss about all these years Steve

I know. It's clearly more straightforward than I thought.

I'll reply to your email later today, Andy, after a stein and a wurst.

[emicen]

teamHOLDENracing said:

Ahonen said:

Well you clearly have it all planned, so good luck. You may need to find another 300bhp to make use of the downforce, though.

Don't know what you've been making a fuss about all these years Steve

Yeah but he's seen stuff on the internet and copied it, that's half way to be a professor or aerodynamics surely.

Not much can be said that's not been said before:
http://forums.overclockers.co.uk/showthread.php?t=...