18 replies to this topic

[MAXR]

I've finally decided to do a few modifications to my VX & get it looking tidy again & I'm after simple, inexpensive changes to make it a little bit different, but that will also give some benefits on track.

 

Firstly, no more additional power!

 

Ideas so far:

 

1. New front Jonnyboy lightweight clam (mine's damaged, although it's repairable)

2. Slats cut directly into the front wings to reduce air pressure.

3. Fitting canards

4. No front lights, just covers with simple indicators where the fog light openings are. 

5. Ditching the front bonnet completely or heavily modifying it with a Lotus style curved servo cover to expel hot air with a gurney strip to the leading opening edge.

6. Fitting a CF front splitter to the Crashbox with stays

7. Fitting a single skin bonded roof but possibly with an air scoop to the rear.

8. New single skin rear clam modified possibly as per photoshop'd image of Mike's car. Side buttresses to have Polycarbonate windows with engine vents.

 

[MAXR]

...OOps...blimming iPad!

 

9. Rear lights ditched & mesh fitted in the shape of the light clusters with lights fitted behind to vent hot air from engine

 

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[FLD]

It might be helpful if you elaborate on the outcome you want from this. No 2 is clear but some of the others I'm not sure what you're after. I have some stuff from Mira I can email to you if you're interested.

[Jason]

Cut out the whole rear end like this fill in the side of the clam were lights were. Cut off lower section and make a deep wedge diffuser.



Or this



Front headlight pulled out, then mould into funnels for brake cooling.

Edited by Jason, 18 August 2015 - 09:21 PM.

[smiley]

Please define "inexpensive" before this topic goed beserk.

 

[MAXR]

Firstly, my VX now needs a proper make over now. I have had her for many years & the car now needs tidying & making reliable as it is not fit to sell as is, even as a track car. So, I'll hang on to it as well.

 

 

Oily bits:

 

Matt B is currently fitting new Quantums, Arb, bump steer Kit, Geo & returning back to 17/16 wheel setup, new Clutch & checking all the usual consumable items brakes, bearings, toelinks etc.

 

Interior:

 

My interior is fully stripped out at the moment. I have ordered some lightweight Regelin-Performance.de CF door trims with openers. I will be re-fitting a alcantara covered dash top (to reduce sun glare) & with real working air vents & some welcome air in the cabin! I may even replace my MOG CF driver’s seat with a more comfortable one. I need new polycarbonate side windows with vent sliders as mine are Sh1t. It’s easier to buy the polycarbonate sheet in and make some up. My rollcage needs padding by the head area!

 

 

Bodywork:

 

Currently my front clam’s lower half has been ripped away from the top part & the plywood front splitter is due a change as it’s delaminating. It’s more cost effective to replace the front clam rather than repair it as I will also be able to reduce the weight with a replacement jonnyboy one.

 

The front bonnet is just not required as I have a gurney strip along the leading edge ensures the air deflects over the aperture & allows air from the radiator an easier exit. All I require is a cover over the servo/brake/bulkhead area. Cut some simple slots above the wheels with mesh under. I don’t use any wheel arch liners.

 

The rear Clam I have outlined already, It’s one option. I have purchased Mark’s rear clam sections & will either purchase Jonathan’s Coupe back & roof or have one made up (I’ve always loved the Exige S1 Perspex rear hatch) but, why waste a lot of effort into just aesthetics?

Fitting vented polycarbonate rear windows where the buttresses are should allow more air into the engine area allowing even more time on track! The petrol filler will need to be moved to the rear of the poly window on a bracket or fitted lower down in the bodywork, but that’s all.

 

The rear light openings will remain as is. I will have black mesh formed over a fibreglass buck of the standard VX light cluster & bonded to the opening. A single exige light will be fitted behind on a bracket behind the mesh. There should be enough mesh area to vent hot air from the engine without cutting out ugly openings in the clam? Although I may have to cut out the rear central lower sill to allow heat from the exhaust a chance to escape.

 

I’m still not sure if a rear diffuser does anything sat up so high when the car is 100mm off the floor? Am I just carrying additional flippin weight around? Ideally I want a quick release rear clam (hinged is too complicated!). How I could attach the coupe rear to allow this? I’m not worried about rigidity of the bodywork, I have a 6pt Rollcage fitted, so can brace/bracket off that for fixings.

 

I need to fit proper pylons for the rear wing to the subframe. Has anyone fitted short pylons from the subframe to the underside of the rear clam with additional pylons from the rear wing bolted to the lower ones for easy removal?

As for budget to do the work? £12k ish?

[FLD]

Enclosing the rear wheels like this is supposed to reduce drag quite a bit (but it looks sh*t!)

 

Venting the front arches gives only a small reduction in drag and only when combined with a blocked in wheel.  There is some benefit to blocking off the arch from the underside.  I can send you the details if you let me know your email address.

 

I have pylons from my boot floor to my rear wing.  I believe several people have done this.

 

If you're budgetting 12k why not make carbon clams?  I know you looked at this some time ago.  It's something that's on my 'to do' list at some point.  Perhaps you could persuade JB to look into a front clam.  You could extend this theme further to the rest of the bodywork.  Eg my carbon roof weighs less than my soft top but has all the rigidity of OEM and bolts on.  A carbon outer skin should be less than 2kg (my outer was 1,8 kg)

[haggi961]

Lotus Exige bodywork with flip up rear clam on a hinge system.

[chris_uk]

No.2 =

[chris_uk]

Although you could go even further and do what the lemans cars are doing but i think on ours its a bit ott.

[VXT Tim]

This is all very exciting Max. Keep us updated with progress/pics.

[MAXR]

Enclosing the rear wheels like this is supposed to reduce drag quite a bit (but it looks sh*t!)

 

Venting the front arches gives only a small reduction in drag and only when combined with a blocked in wheel.  There is some benefit to blocking off the arch from the underside.  I can send you the details if you let me know your email address.

 

I have pylons from my boot floor to my rear wing.  I believe several people have done this.

 

If you're budgetting 12k why not make carbon clams?  I know you looked at this some time ago.  It's something that's on my 'to do' list at some point.  Perhaps you could persuade JB to look into a front clam.  You could extend this theme further to the rest of the bodywork.  Eg my carbon roof weighs less than my soft top but has all the rigidity of OEM and bolts on.  A carbon outer skin should be less than 2kg (my outer was 1,8 kg)

 

I'm not really after making a radical looking car & yes that would look pants on a VX.

If I don't go for a roof scoop, then a CF one may be an option, although I have removed my inner shell & it's not heavy now. The Coupe back & roof would save weight by way of discarding the roll bar cover.

JB, has plans...

 

12k is including the oily bits & paint job! But, I have most of the main bits I need or know of companies that can make parts for me relatively cheaply. 

 

 

 

 

 

 

 

Lotus Exige bodywork with flip up rear clam on a hinge system.

 

Yes, that was my original plan, except that I would keep the lower clam fixed in place & have the top part hinged. But, the coupe back, rear wing, polycarbonate buttresses & roof make it a little more of a challenge. I may be better off, weight wise too, if I just have quick release system.

 

I do like that photo of the rear of the lotus with the large meshed area & hidden lights. I would like to produce a couple of fibreglass bucks for the front lights too & form black mesh covers to replicate the shape of the original lights, then take off air into the cabin & perhaps brakes. But, I presume it would drastically effect the air flow? However, it would allow for a simple halo light & indicators to be fitted behind

 

No.2 =

 

 

Exactly like that Chris!

[garyk220]

Bodywork mods might help with engine cooling but I don't think they will make the car much faster on track, over what you have already done.

 

If I was in your position with your car and a £12k budget I would use Mike's car as a template. The times he posted in his second year of Time Attack were a huge step forward from the first year. With that budget you could;

 

- sort the intake temperatures by commissioning a new inlet manifold and intercooler/chargecooler system that reduces intake temperatures and gives you peak engine performance for longer

- coupe rear to give you the space for the above mods

- fit GT hubs to allow lower ride height and maximise any down force from front splitter/rear diffuser

- better/lighter brakes to prevent brake performance reducing your time on track

- fit a better rear wing and place higher to maximise rear down force and designed to work with the coupe rear

 

Everything else will just be chipping away at small issues IMO. There is little point improving engine bay cooling if your intake temps rob you of power after a handful of laps.

 

Personally, I would prioritise no. 1 to get the maximum performance and maximum track time with your current engine set-up.

 

Nos. 2 to 5 will give you the biggest improvement in speed and lap times on track.

 

Say around £5k to £7k for nos. 2 to 5 and the same again to crack the intake temperature issue once and for all. Plus you'd potentially have a product that others would want to buy to keep the development costs down.

 

 

[chris_uk]

Think about side skirts like mine and lees also.

[MAXR]

Bodywork mods might help with engine cooling but I don't think they will make the car much faster on track, over what you have already done.

 

If I was in your position with your car and a £12k budget I would use Mike's car as a template. The times he posted in his second year of Time Attack were a huge step forward from the first year. With that budget you could;

 

- sort the intake temperatures by commissioning a new inlet manifold and intercooler/chargecooler system that reduces intake temperatures and gives you peak engine performance for longer

- coupe rear to give you the space for the above mods

- fit GT hubs to allow lower ride height and maximise any down force from front splitter/rear diffuser

- better/lighter brakes to prevent brake performance reducing your time on track

- fit a better rear wing and place higher to maximise rear down force and designed to work with the coupe rear

 

Everything else will just be chipping away at small issues IMO. There is little point improving engine bay cooling if your intake temps rob you of power after a handful of laps.

 

Personally, I would prioritise no. 1 to get the maximum performance and maximum track time with your current engine set-up.

 

Nos. 2 to 5 will give you the biggest improvement in speed and lap times on track.

 

Say around £5k to £7k for nos. 2 to 5 and the same again to crack the intake temperature issue once and for all. Plus you'd potentially have a product that others would want to buy to keep the development costs down.

 

 

 

I'm aware that possibly the easiest route to improving lap times is to throw on a Harrop. But, I don't want to add any more power. However, I am considering GT hubs, they would be a worthwhile upgrade & I haven't ruled them out.

The main reason for the bodywork upgrades is because my front clam is shagged & so too is my rear clam. My gearbox tends to get hot easily, so an oil cooler/ naca duct could help that. Typically, I would spend 30 mins+ out on track at a time & probably 15 mins back in the pits for refuelling/cooling before going out again. I typically get through a full pro alloy long range tankful plus almost 80ltrs of fuel during a track day.

 

Inlet temps, I agree would maintain power, but I don't want to do the development donkeywork. I really don't have time to spend developing it & my car is not road legal, so testing will be tricky. It's a trailer queen.

 

Mike's aero & suspension setup has set his car apart from others. The Harrop power his car was producing was a big asset, but IMO did not give his car the biggest advantage. I could go to slicks, but would prefer to have other cars to play with on track. I have had plenty of opportunities to go down the Radical/R500 route, but neither float my boat, i'm probably just too old!

 

I would however be prepared to stump up some cash towards a redesigned inlet manifold. There are enough people on here that could also benefit from it, some who may also be prepared to join forces & contribute towards development costs?

 

I also believe that the sum of the changes will give me a tangible, worthwhile improvement especially with GT Hubs. I would rather pay for tuition (which I will be) to help improve lap times. What I really don't want to end up with, is a turbotoaster looking car, no matter how fast it goes around a track!

 

 

 

 

Think about side skirts like mine and lees also.

 

Chris, what have you used for the side skirts? How are they fixed on? can you send me any details? it looks quite simple (which I like). I presume your car is still a road car, so would it make any difference on a track as your ride height is set for road use? (100/110mm?)

[chris_uk]

Exactly max, it will do something but the lower it will be the better i guess. Its just a sheet of ali bent at a right angle using 2x 45 degrees. I installed some ricnuts into the underside of the sill and then just use bolts to attatch. Dead easy. I will drop you a pm with the dimensions.

Edited by chris_uk, 19 August 2015 - 01:38 PM.

[chris_uk]

I would also consider installing vents in the front clam like lee has done and then you could redesign your chargecooler and have 2 smaller rads mounted in the new holes, shouldnt really be too much work to change and you could sell your current cc rad on. Ive thought about doing this myself. It has got to be better because its not soaking heat up from the engine rad. And since its a small amount of water i dont think it will effect temps at all, expecially with them being in direct airflow.

[MAXR]

I would also consider installing vents in the front clam like lee has done and then you could redesign your chargecooler and have 2 smaller rads mounted in the new holes, shouldnt really be too much work to change and you could sell your current cc rad on. Ive thought about doing this myself. It has got to be better because its not soaking heat up from the engine rad. And since its a small amount of water i dont think it will effect temps at all, expecially with them being in direct airflow.

 

 

As I've got an electric water pump, I was contemplating removing the two front rad fans altogether, which would allow more air through the rads with no restrictions. Apparently, the Gurney strip would allow the radiator output air flow a better path into the airstream over the bonnet without too much turbulence.  I guess the only downside is heat soak after switching off after a long run? 

 

 

 

Neil (vocky),

 

As my clutch is out at the moment, are you aware of any lightweight balanced flywheels that would allow my engine to Rev a little more rapidly? I think I currently have a Courtenay Lightweight one fitted.

[MAXR]

 

It's been a while since I used Photoshop, anyway here's a mock up based on Cliffie's old car. The rear lights would actually be Exige ones as I have a set (somewhere?)