82 replies to this topic

[manus]

I will try to post some of the latest updates of the on-going conversion of my car. Some changes have been visible on this site and in more detail (but Dutch language) on here: http://www.speedster...2619&start=1020
Project has started long time ago but now we're making big steps and the expectations of the car to be 'drivable on road and track' are high for second quarter of 2013.

Let me start with the wanahave specs:

Lotus GT3, 99-PR-XZ (road legal)

Engine: 530-625bhp at 8500rpm, weight: 825-855kg

Exterior and chassis

• Lotus Carbon Fibre Exige GT3 wide-body, shortened wheelbase
• Opel Speedster 2.0T chassis, sub-frame and engine

• Composite front-splitter, CF reversed wing, aluminium diffuser
• CF bottom panel parts, CF mirrors
• Lightweight interior panels, aluminium bulkhead
• Full roll cage

Engine and transmission
Air/fuel intake

• Upgraded air filter housing and fresh air intake, high-flow intake manifold, 62mm throttle-body
• Borg Warner EFR7064 twin scroll turbo
• Pro-alloy Charge cooler (strengthened for 2.5bar)
• Adjustable Water/Methanol injection
• 850ccm fuel injectors

Engine and head

• New engine (rebuild 2012): engine block, turbo, pistons, camshafts and others, steel crankshaft
• High performance push rods, crankshaft support plate, piston bottom cooling

• Lightweight flywheel, balance shafts removed
• Dry sump system (tank in front)
• Aggressive camshafts, solid valve lifters, flowed cylinder head, bigger valves, dual valve-springs

Twin scroll exhaust manifold (heat wrapped)

• Modified exhaust 76mm Ti, pre-cat removed
• Damper and cat combined

• Paddle clutch, limited Slip Differential (Quaiffe), 5-speed manual gearbox

Other engine related

• Engine mounts strengthened

• Dry sump tank in front (battery location). No oil cooler (oil tank and pipes/chassis will cool the oil)

• No electrical water pump
• Lightweight 70-90A Alternator (2.58kg) and bracket

Brakes and suspension

• Öhlins 2-way adjustable race version, Adjustable anti roll-bar, Polyurethane busses
• Road usage (Centre lock) wheels: Dymag Magnesium and Yokohama 048’s
• Slicks: Lotus sport magnesium 7Jx16 + Dunlop 200 580 R16 (12.3kg) 8Jx17 + Dunlop 235 610 R17 (15.6kg)
• GT3 spec brakes + proportional limited bias valve, Steel braided brake lines
• Aluminium (Nitron) Uprights with internal airflow
• Wishbones in 4130 steel

Other items

• 52 litre fuel tank, upgraded fuel pump

• CF seats, lowered (1-2cm) on L-shaped aluminium mounts

• 4-Point Harnesses
• OMP Carbon fibre steering wheel, airbag removed
• Dash rev-counter extended range, up to 8.500 rpm

• Racelogic traction control with digital adjuster, ABS signal filter

to improve input signal under 20MPH

• Lambda sensor monitor
• Stinger DSI, including laser shield front protection
• Racelogic Video VBOX 2 cameras and USB logging
• MIM01 Input module, to include in logging:
  
• GPS data (e.g. speed and position) and track logging
• RPM1: Engine RPM
• A1: Turbo RPM
• A2: Boost pressure
• A3: Traction control indicator( to visualize engine cut-offs/wheel-spin, pin 4 on the B connector – it sits at 5v but goes to GND when cuts are made.)
• A4: LMM Air mass meter value
• A5: Oil pressure
• A6: Lambda sensor
• A7: Water/Methanol injection status
• A8: Brake signal
• K1: Oil temperature
• K2: Air intake temperature

• Roof vent system (interior heating system removed)
• Improved tow-hook, Rear license plate on aluminium strips
• Integrated Fire extinguisher 2.25kg Remote Pressure Discharge Weight 3.09kg
• Cruise control

Electrical

• 2nd fan connected to fog light switch
• Front and rear clams with a single-plug (12/24 pin AMP) wiring disconnect
• Battery behind co-driver seat(?) Li-Ion 1,75kg, cut-off switch, located near front right-side door

Future/planned

• Lexan side windows (-6kg)
• Toe link upgrade (-1.2 kg)
• Long drive shaft, increased track width (might no longer fit on trailer?)
• Adjustable rear wing (http://aeromotions.com/news/ )
• Wider track (wishbones and drive shafts, http://www.driveshaft.co.uk/ )

[manus]

Cruise control... that can be a subject on its own....

Edited by manus, 06 December 2012 - 03:44 PM.

[techieboy]

Good to see you're still working on the beast, Manus.

[manus]

Most of the preparation work has been done and waiting now for the new engine to be ready and power-tested on the Dyno. My expectations of the Borg Warner twin scroll are high (wide power band) and the low-mass steel crankshaft might make it run like a motorcycle engine. (dreaming...). From there we (workshops doing the hard work and lazy me only the design and some testing) will redo most of the suspension. Lightweight wishbones and uprights are not yet on the car and the rear possibly needs longer wishbones to fit the 295/30R18 tires. Not yet on the list above are the cooling ducts for the front brakes. As there is this Exige body on top of this VXT I can remove the indicator lights (replacing a smaller version close to the main beam) and suck the air from there. Planning would be to get the engine fired-up around Christmas, finish up some mods in Germany in Jan/Feb and ship to UK to do the geo-setup finishing in March/April. But reality could be different... we'll see.

Edited by manus, 06 December 2012 - 03:54 PM.

[ArticMonkey]

Some pictures?

[techieboy]

Who's doing the setup over here? Plans again? I assume you've gone for the R2 one piece wing and not the split version? Will be interesting to see how well that works. Theoretically it's the best of both worlds.

[techieboy]

Some pictures?

Should be some in here, though not sure how current they are anymore.

[ArticMonkey]

Did have a scroll. Looks like a great build, and with a reason/purpose for that amount of power.

[Nev]

Wow, sounds amazing. Saw a video of your car drive by - lovely and quiet !!

[jonnyboy]

How much work is involved in fitting the exige body to the V chassis?

[alanoo]

Interesting, pretty close to what I plan for my number 2 chassis sometime next year

[2-20]

_{Nothing to cool the gear box oil ?}

[manus]

Who's doing the setup over here? Plans again?

I assume you've gone for the R2 one piece wing and not the split version? Will be interesting to see how well that works. Theoretically it's the best of both worlds.

I think I would be looking for something with a more realistic price-tag first. Not sure if I can find that. The split version is my favorite though.
My engine-workshop tuner thinks its a waste of money with the projected power-output: "Just put it always on maximum downforce" He might be right.

[manus]

How much work is involved in fitting the exige body to the V chassis?

I don't know. But there are some thing to take into account:
a. For sure the wheelbase needs adjustment (or the bodywork extended) as the VX wheels ar approximately an inch further apart. Plans has solved it for me by modifying the rear wishbones. If anyone is interested in those, they will be available somewhere next year. (I will upgrade to extended ones in 4130 steel).
b. You can copy any detail or measurement from my car but the donor body on my car was an GT3 quick release. That is different from a standard mounting.
c. You'll need to exchange all parts, even the doors. Windscreen is the same.

[manus]

Some pictures?

I will soon post those. Have to sort it out as I have made hundreds/thousands over the years.Not all of them very interesting, not even for me.

[manus]

_{Nothing to cool the gear box oil ?}

Oil cooler was in there. But need to check if we did not scrap it to save weight

[manus]

Increasing tire width at the back will not be easy. On the picture below you can see the narrow gap when the car is mounted with 245R17. New tires are 295/30R18. Approach will be to use longer wishbones and driveshaft.


The Dry sump needed an extra plate to connect to the gearbox:


Steel crankshaft in there. If you really have a close look you can see that we've added material below the intakes. That way there are more options to improve the airflow.


Twinscroll that has to deliver at low revs. Hoping to extend power-band with 500rpm or more at the low end:


Wishbones giving massive reduction in (partly) unsprung weight:


Uprights improving unsprung weight even better:


Down there she'll have to prove the performance:

Engine needs to be tuned on torque. Keep it on 500Nm in an as wide range as possible. That way the gearbox might keep up.

[Exmantaa]

Increasing tire width at the back will not be easy. On the picture below you can see the narrow gap when the car is mounted with 245R17. New tires are 295/30R18. Approach will be to use longer wishbones and driveshaft.

I know you like to do things the long, hard and expensive way, but I assume simple wheel spacers are out of the question with your centerlock wheels? (Or alternatively space out the bearing pack?)


Can you not order the 18's with the needed low/negative ET value?

Edit2: You should modify your shock mount so the hose connection fits inside the chassis side. There are pics somewhere, but you have to file a small round gap there for the hose..

Edited by Exmantaa, 07 December 2012 - 10:11 AM.

[manus]

Increasing tire width at the back will not be easy. On the picture below you can see the narrow gap when the car is mounted with 245R17. New tires are 295/30R18. Approach will be to use longer wishbones and driveshaft.

I know you like to do things the long, hard and expensive way, but I assume simple wheel spacers are out of the question with your centerlock wheels? (Or alternatively space out the bearing pack?)

I would call it the proper way , perhaps even the only way of doing it.
Think you're right on spacers. I wanted to replace the wishbones with lightweight ones anyway. An extra inch of 4130 pipe will not kill the budget. The shocks can do with a little extra space a well. Want to upgrade to 46mm version but up till now there was no space for those.

[manus]

The engine will be detuned in low revs not to overload the standard gearbox. The F23 did not complain too much so far. But what if we want more torque to the wheels?

First day of surfing on the net gives me this list for transverse sequential gearboxes:
Brand ............Type ............Torque(lb/ft).........Torque(Nm)...........Strength(%)........Weight(kg)
Holinger .........MF-2WD.............516...................700......................224% ....................48
Xtrac ..............426 FWD.............480...................650.....................209% .................... 43,5
Tractive.......... SD90..................442....................600 ....................192%......................46
EP...................6/7sp..................369....................500 ....................160% ....................48
Sadev ........... ST90-14..............354...................480.................... 154% ....................42,5
Getrag ........... F23 ...................230....................312 ....................100% ....................42,8

However, it will take considerable time (if ever) to find a box that comes close to budget. You can buy a reasonably priced car for the price of one of those. Even better, a second VX220, and then you might want to add a "Geartronic paddle Paddle Shift system with sophisticated closed-loop semi-auto shift system".
Not sure if this is the way to go.

Edited by manus, 16 December 2012 - 05:20 PM.