I was 100% sure I was going to build an MK Indy with a Fireblade engine (now purchased) purely for trackday use, not road registered.

All the feedback on the Indy and MK is very positive, but somebody just pointed out that the whole "7" shape isn't very aerodynamic and that a similar engined Fury will easily beat an Indy round a track due to the better shape.

I'd never really thought about the actual speed element and aerodynamics, just thinking that a BEC Indy will be blinking fast, but there is little point building something for speed and it being 9/10 when I could build a 10/10 Fury.

Pricing appears very similar between the same "comprehensive"/"deluxe" kits, apart from the Fury needing the bodywork as well (another £1400 with doors).

In reality how do completion costs compare between a Fury and an Indy? Looking at the kits and prices, it should just be the donor parts and bodywork where the differences lie, but is there something hiding?

Then I need to weigh up the actual speed advantage of a Fury over an Indy, in reality how much difference is there over a lap, does anybody have comparative times?

If the problem with the "7" shape is mostly the front end, does anybody do an all-in-one nosecone and front wheelarch setup which is more aerodynamically shaped?

Thoughts/feedback/etc welcomed please.

ta
Chris

Hi Chris

I've built a car engined stylus, which is very similar to the fury, its cost about 6K so far, just got to paint it

For more info on a BEC ask on

http://www.smartgroups.com/groups/sylva-chat

As for speed, when Jeremy Philips ( designer of Fury ) designed an enclosed body for the Sryker he said it gave him an extra 15mph on the main straight of his local track

Also their is a good build diary in Practical Performanc mag

Adrian

Thanks for that Adrian.

15mph is quite a bit and I guess would also affect the diff ratio chosen.

I've got the last few issues of PPC, only found it recently as I'd given up on all the car mags since Fast Car, Max Power etc totally destroyed the car mag scene.

Still got boxes full of CCC mags from years ago, PPC is almost as good and definately on the right track.

I'll re-read the Fury build stuff!

ta
Chris

re drag

i was concerned about this when we started developing ours to race ( we will be racing in the rgb when i get chance to finish either of my racecars !!!!!!!!!!!!!! )

we went to a trackday at donnington with our class c car as luck would have it a couple of class c cars there, one was the kitcar workshops top man in his fury.

we struggled down the long straight to keep in touch with the standard scuttle and a perspex makeshift aeroscreen

so we swopped the scuttle panel for our built in scuttle / aeroscreen assembly that we had taken with us and wow what a difference !!!!, we where able to easily slipstream the fury on the same straight and within four laps had pulled out 2 1/2 second gap !!!!!!!!!!!

we have recently made some new wrap around front arches to try and reduce frontal drag and have now mounted front coil overs in board and have now seen a 3 /10 second improvement again !!!!!

we are now working on yet another version of the nosecone to further help things along.

basically all the rambling above equates to the fact i believe that the 7 can be just as quick in a straight line if you follow the same route as we have.

best regards

marc

also dont forget the 7 has less frontal surface area altough it is squarer

best regards

marc

Thanks Marc, positive news for a "7" type
I didn't want to do a Fury but I don't want to do something which is infurior for the purpose I want it.

If it was my money I would build a fury, they look great (much better than an Indy in my opinion) , the suspension and handling is fantastic and they are very aerodynamic compared to a seven - that's why they win so many races and are so popular in the RGB class. It's also very proven as a track machine when it comes to reliability - with all the extra stresses that comes from driving on a track.

But hey - the difference on the track will be more down to you as a driver than the cars, so build the one you like most.

I think this is exactly as you would expect. With two cars of similar weight, power and handling, the one with the better aerodynamics will win on a track. As standard, the Fury has better aerodynamics, so its going to be quicker. Modify the MK to match (or better) the Fury, and the situation will change. However, I agree with Jasper ... for most of us, with less than perfect track-driving skills, the car is not going to be the limiting factor.

Sounds to me like either of your choices would be competitive, so build what you fancy the most and enjoy it

Cheers
Richard

Hi,

I'm currently building a ST Loco to race in next years RGB(hopefully), I looked into this question before i started and from what i saw(at a couple of RGB Meetings) was that for a while whatever car i built would exceed my driving skill anyway, and if you take a look at the tracks in the UK, and the length of the straights,i decided to go for the seven style(and in my opinion looks better anyway).

Ray

I agree the Fury is beautiful, but the Menace looks better as a strict trackday car.

As far as aerodynamics goes I think the Seven could be improved, if not to be as slippery as a Fury but close.

I'm no expert, but I have my own pet theory, which I'll try out on you lot before I wreck my own bodywork.

If the square, but open nose of a Seven scoops loads of air into the under bonnet area it's got to go somewhere. I think it was David Jenkins who mentioned his bonnet lifting at speed as all this air built high pressure under the bonnet. Most goes out down the open floor (producing lift?) and the rest down the tunnel to the diff or back axle, which is nearly completely filled in an Indy, into the boot space.

I was thinking about putting some large Range Rover style vents in the sides, at the back of the engine bay, just in front of the firewall. This would allow me to duct the hot air out the sides, and fit a flat underside, aiding aerodynamics.

Do you think that'd help top speed?

Mike

[Edited on 6/8/05 by Guinness]

I put metro bonnet vents in the position you mentioned (mostly to keep everything cool under bonnet) and ive managed to get 130mph before i bottled out (private road of course!!!)

its a good idea too vent the air out anyway.........

the air goes through the radiator, heats up too whatever degree's C, then you blast it all over the engine your trying too keep cool, most race 7's and my rear engined one for that matter don't allow the air from the rad anywhere near the engine, i have a thin ally shield that deflects all the "used" colling air out the back of the car and away from the engine, excess heat on the intake side of things kills power too, vent it out.

I've got Mk3 RS2000 style bonnet vents in mine, and no problems with the bonnet lifting, irrespective of speed. Admittedly, my over-centre catches are pretty tight, and I've not tried panelling the bottom of the engine-bay either, but even so ...
Cheers
Richard

try the phoneix or stylus rt and also the riot they all seem more race oriantated

i was on the phone yesterday to the guys doing the phoneix, stuart taylor motorsport, there new race chassis is laser cut round tube and is giving them good results over last years car slightly more expensive than the square tube chassis but smiles better