The new (old!) approach to going faster. How much weight does a carbon roof save over a standard one?
I like you already 
5 maybe 6KG Sector111, Lotus can’t be much more.
Jonny, after a marvellous 2 days at Spa keeping up with with faster stuff in my NA, I want to adopt the less is more approach. So a saving of 5 - 6 kgs at the highest point of the car; can this help by increasing ability to carry speed through corners?
I dare to say yes, BUT you would have to take out A LOT more than 5 kg to feel the difference, or do you already notice when your car has burnt 5 kg of fuel during a track session?
Heres a list, not all relevant to S2 but some good ideas.
/nicked from SELOC
Weight reduction
Original Weight (kg) Aftermarket product and weight (kg)
[edit]
Brakes
S1 MMC 2.9 kg/each EBC 6 kg
S2 Drilled 5.9 kg/each Ali bells 5.0 kg
[edit]
Exhaust
S1 Standard 20 kg S1 Eliseparts Sport Exhaust 8 kg
K series standard manifold 3.3kg flexi pipe 3.4kg k series full stainless steel 4-1 manifold 8kg
[edit]
Door
S2 w/o ali beam complete: 15.1kg
S2 window mech.: 1.375kg
S2 window winder: 120g
S2 mirror fixing triangle: 355g
S2 mirror: 405g
S2 seal window: 302g
S2 inner trim (plastic+leather): 705g
[edit]
Elise Weight Reduction
S1 Alarm Fob 20 grams
Carbon clams are hideous money compared to the weight saved, and don’t save much at all unless they are autoclaved or vacuum formed. Benetec CF Front Clam 4.95 kg Vs std at 15 kg but cost �58k 
Benetec CF Rear Clam 7,2kg
Be very wary of polycarbonate side screens. They are very flexible and, with the roof fitted, flare out dramatically at speeds above 60MPH.
Early rear arch liners are 2.8 kg. Later liners are lighter.
Removing the GRP where the reversing light and fog lights are, along with the grilles and the reversing light saves about 1 kg.
The rubber seals around all four wheel arch liners (assuming you haven’t ditched the arch liners) are about 200g each, and most of the boot lid seal can be removed with just token parts left in to prevent rattle giving about 1 kg of saving.
Exhaust Exige/111R Catback: 13 kg. Stage 1: 11.8 kg (saves 1.2 kg). Stage 2: 8.2 kg (saves 4.8 kg). Quicksilver Titanium: 5.2 kg (saves 7.8 kg)
S1 Weight Reduction
-13,4 kg Carbon fibre track seats (1,8 kg vs 8.5 kg) x2
-12.5 kg Titanium Exhaust system (std 16 kg vs 3.5 kg)
-11.2 kg MMC discs instead of iron disks (2.7 kg vs 5.5 kg each)
-11,1 KG TRM FSL001 instead of std AWI 5 spoke Wheels (20,7kg vs 31.8 kg)
-9,9kg Race battery www.voltphreaks.com (1,36 kg vs 11.35 kg)
-7.25 kg Lexan front window (5 kg vs 12.25 kg)
-6.8 kg Speedline Magnesium instead of std AWI 5 spoke (25 kg vs 31.8 kg)
-6.55 kg Alloy Fuel Tank
-4.4 kg Carbon fibre fixed seat frames(2 kg and 3 kg vs 0.3 kg)
-4.4 kg Remove the door reinforcement on 2 doors
-4 kg Remove radio and speakers (radio ~1.4 kg speakers ~1.6 kg)
-3.695 kg Soft top and mountings (Top 1.807 kg, siderails 1.888 kg)
-3.3 kg Lightweight Flywheel
-2.71 kg Cat Replacement Pipe (flexi stainless) (1.587 kg Vs 4.3 kg) mild steel 1.8 kg
-2.55 kg Lightweight alternator (3.35 kg vs 5.9 kg)
-2.2 kg Billet aluminium crankshaft pulley
-2.136 kg Back window
-2 kg Alu boot lit instead of GRP (Glass Reinforced Plastic)
-2 kg Alu top engine mount
-2 kg 2x Leather sill covers
-1.994 kg Rollbar cover
-1.697 kg Heat shield baggage compartment
-1,59 kg CF undertray insted of alu std
-1.388 kg Dressed baggage compartment
-1.329Kg Original Airbox and filter
-1 kg Eliseparts Lightweight Wheel studs
-1 kg Carbon fibre steering wheel (1.7 kg vs 0.7 kg)
-0,9 kg Elisparts solid 4-2-1 manifold (5,8 kg vs std 6,7 kg)
-0,9 kg Carbon fibre side mirrors instead of std
-0.872 kg Alu ball joint mounts (1.308 kg vs 0.436 kg)
-0.8 kg Footwell divider
-0,83 kg lexan back window instead of std glass
-0.6 kg Handbrake and gear stick cover
-0.562 kg Pair of Alu Verniers instead of std iron pulleys(570g v.s. 298g each)
-0.53 kg Passenger footrest
-0.5 kg Front Mud flaps
-0.4 kg Alarm siren
-0.23 kg Inner Rear view mirror
-1/2 of std Lightweight Starter Motor
-2/3 of std Polycarbonate / perspex rear/side/front screen
plastic boot lid stay 865g
2 x plastic floor mats 160g
passenger foot rest 535g
charcoal canister and pipes 625g
rear grills 310g
removal of fibre glass behind fog/reverse lights 370g
speakers including wiring 1220g
plastic speaker mounts behind seats 525g
plastic wiper motor guard 60g
rear wheel arch liners 2300g
plastic booy drain pipe 225g
front brake disc splash guards 210g
radio and surround 1760g
front grill 275g
handbrake trim surround 240g
Aerial and lead 160g
gear stick surround trim 325g
alarm siren 370g
rubber trim from rear wheel arches and boot lid 140g
interior side pads 2000g
boot bag 1435g
heat insulation/sound deadening in boot 1495g
boot divider Ali 1295g
rear under tray (homemade Carbon fibre) reduced by 900g
Rear boot tray 1620g
heat shield above exhaust (below boot tray) 1885g
misc nuts bolts cables ties etc 445g
passenger seat & belt 9725g
remove cat and replace with CRP 2725g
battery replaced by varley red top 6100g
battery bracket and breather piper 200g
I still have the roof to do but the car feels great at 860kg. I’ll be happy when I’m down to 840kg and still have a relatively comfy car to drive to and from the track. The rubber I had on yesterday was enjoying it’s last outing after a full year on track but on fresh rubber you can really feel the difference in the corners.
Could you replace the metal pipes to the intercooler with silicon hoses, as these seem pretty weighty, would this help with reducing heat soak too?
RLS light weight copies
Was thinking silicone hoses might be a bit cheaper?
I have the RLS IC pipes and they are about 1kg less in weight than standard well worth the cash 
What have you had done to yours to get down to 860?
Mine is 880 with 1/2 tank of petrol, carbon spoiler, redtop battery, 240R wheels and AP 4 pots.
All the carpets, rear engine lining, plastic thingy behind seats, battery, foam under roll bar, stereo, speakers inc looms, alloys, exhaust, foot rest, both seat rails, manifold, decat, eliminator kit. Loads of PROPER Carbon Fibre inc splitter, diffuser, rear wing, mirrors, engine lid, mog seats, then boot seal, parts from wheel arch liners and a few more bits I can’t think of and I’ve another list of things to do 
Cathode ray tube & Imax screen
Would have been cheaper to get a Katana SC
[quote=Rishie]
What have you had done to yours to get down to 860?
Mine is 880 with 1/2 tank of petrol, carbon spoiler, redtop battery, 240R wheels and AP 4 pots. [/quote]
My car is not an Exige, but I have also saved a few kilos. You can read more about it on my website : clicky
if you click on the orange numbers you can see the measurements
Would have been cheaper to get a Katana SC [/quote]
/tsk… not the point 
190bhp in a light car skilfully driven will embarrass most people. Only thing past me on my last track day was a 300+hp S1 and a GT3 driven by an instructor.
I know, I know, I was only having a dig at Jonny.
But while we are on the subject there are three elements here that need balancing - weight, power and driver skill.
So in my case i don’t want to spoil the car for general use by making it too track focused by removing every luxury and sound deadening. My skill level will never be high enough to get every drop of performance out of an Exige without putting at risk, so to get the balance I’ve added 40+ bhp with very little weight gain (it’s actually lighter than standard).
I think i have the same result as Jonny just taking a different route.
Having said that i could be completely wrong 
I think you are perfectly right. You can either drive a lower power car on it’s (and your own) limits to be quick or add power and be quicker out of the corners.
You can of course do both
On airfield days I drive at 95% and on tracks a lot less because of the associated risks. If I had more power I’d probably relax a bit more, either that or just crash faster!
Lol Mike…I thought your car was NA, 40bhp 
isn’t it? I will not make it any less comfortable to what it already is now (is that proper English lol). The only thing lacking is a stero and I never used it anyway. As for the seats and runners, well its just me who uses it. The Ohlins play a big part as it can be set up for wherever I drive including the journey. All sound deadening remains…as advised by JSR. I want the skill…it’ll take forever but I hope I can achieve it.
Tony ROCKS Mike could be GAY (like Pesky)
What are the main items that increased the weight of the S2 to be so much more than the S1. The engine and box must be a contributor but where are the other lardy bits!
I’m wondering if it’s worth swoping out the full ABS and servo system to replace with a non servo master cylinder as I run with no ABS anyway? Anyone done this?