Overview

This blog is intended to document the build of my Gardner Douglas Mk4 Cobra; partly as IVA evidence, bit primarily to help others learn from my mistakes and/or successes.

I will endeavour to post as often as possible, with a view to entering a single post for a particular element of the build process, however inevitably some things may not be completed in one go. All posts will be tagged so it should be easy enough to find the information you seek.

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Showing posts with label Decisions Decisions. Show all posts
Showing posts with label Decisions Decisions. Show all posts

Tuesday, 2 February 2016

Gear Box Options

So the final decision of Orange with Carbon Fibre stripes has been made and the body is in the mould as I type.  I was hoping to pick it up this weekend, however one thing or another has delayed proceedings slightly, not to worry as there's still loads of prep and research to do.

Another decision I have already made is that I will be using an LS3 but as an engine and gearbox combination from new will set me back around £12k I've been exploring the possibility of a second hand unit.

LS3s are used in a myriad of American Muscle cars and a fairly readily available in the US, but after paying a minimum of $9k + shipping + import duty + VAT it's not that viable so I've ruled that out.  As far as I know the only UK sold car to come with an LS3 is the Vauxhall VXR8 which aren't exactly ten a penny, so finding a pullout is tricky, but I think I've succeeded.

There's a guy called Gary who runs a site called www.LSXV8.co.uk and is about the only UK breaker of Monaro's and VXR8s.  I got in touch and was surprised to hear that he had a low mileage (28k) 2009 LS3 with 6 speed manual available which has everything except ECU and loom, lovely.

Whilst I wait for him to put it back in a car so I can see/hear it run my thoughts turn to the gearbox and it's many guises.  He tells me it's a T56, however there seems to be about a million different variants with a million more gear ratio combinations and shifter locations, so I delve deeper....

After many hours/days of trawling Google and various forums, I 'think' it is either a TUET-2066 (T56), TEUT-2100 (T56) or TUET-10310 (TR6060) but am still waiting  back from Gary to confirm the correct part number.  In the meantime I have created a spreadsheet to compare the above three options and the T56 Magnum which GD use.

Tremec Transmission Comparison - Cruising

One of my considerations is the usability of 6th gear for cruising so you can see the relative RPMs at 80 MPH (not that I would actually drive that fast on UK roads!)  All are under 200 RPM so will offer reasonable full economy on long journeys.
Tremec Transmission Comparison - Speed
This time I've left the RPM the same so you can compare the speeds in each gear, the TUET2100 is my least favourite as I think 6th would almost become redundant so that is out.  The TUET2066 is a better set of ratios but reliability has been questions in the VXR8 community which is why Vauxhall ended up replacing a lot of them with TR6060s under warranty.

The TUET10310 is said to be much more reliable a less agricultural than the standard T56 so this would be my preference if it turns out that is what is currently attached to the engine, however both the T56 and TR6060 in a VXR8 would have a remote shifter so this would need to be repositioned.  Worst case I may end up having to get just the engine and sourcing a new T56 Magnum.

The spreadsheet automatically calculates everything by changing the ratios, RPMs or wheel and tyre sizes.  If anybody out there wants a copy let me know.

Saturday, 26 September 2015

GD Factory Visit

Today I visited the GD Factory to meet Andy & Meena, who greeted me with a cup of tea which is always a good way to get my business.  They are thoroughly nice people who have all the time in the world for you and Andy's passion for the cars he builds is infectious.  Being an engineer myself I was like a kid in a sweet shop walking around the factory looking at all the machinery and seeing cars in various states of build.

They had there Mk3 demonstrator as well a Mk4 on show and Andy took every one out for a spin which was fantastic.  I'd been out on the track at Castle Combe in June which was amazing, but it was great to see how the car performs on the open road as that is where is will spend most of it's time.  I was surprised to see how civil and comfortable it could be compared to the brutality on the track and that is a real selling point for me.

I presented my colour scheme which they loved and spoke about the option of replacing the grey stripes with carbon in lay and clear gel which (I think) would look incredible.  It  would difficult but achievable and Andy will knock up a sample panel to see how it turns out before I make a final decision.


So that's it, order form filled in and deposit placed which should have my body ready mid/late January, can't wait....

Chassis under construction
Two finished EURO chassis complete with LS3 engine ready for delivery
Body shell straight out of the mould
Fantastic gel coat surface finish even without any polishing
GD Mk3R demonstrator

Mk4 in background with Andy Burrows

Saturday, 19 September 2015

Colour choices

So, I have decided on the kit and have booked a visit to the GD factory next weekend to meet the team and place my order.  Due to funding, I have chosen to carry out the build body first as it's the cheapest 'big bit' to get started. The GD manufacturing process produces extremely high quality finished gel coats which can be polished up to a high shine which can save £2-3k on painting.

This does mean that I have to make a big decision prior to ordering and have to choose from any solid RAL colour.  I have trawled Google images for inspiration and found a lot of blue with white/silver stripes, grey with silver stripes, black with white stripes and red with white stripes.  These colours seem to have been done to death; and as I'm not intending to build a classic replica, I decided to keep it understated and chose ORANGE with GREY stripes!

Looking at RAL colours on line is pointless as every colour looks different depending what website and screen you are viewing it on.  I bought a RAL colour fan chart, picked my favourite colours and got B&Q to colour match some sample pots.  I then painted some scraps of plywood with the two chosen oranges (RAL2001 & RAL2010) to see what these colours would look like on a bigger scale.  It sounds daft but it does make a difference seeing it in big rather than a small swatch of colour.

RAL2010 (signal orange) appeared too light so decided on RAL2001 (red orange).  I the painted some stripes in 6 different greys on the orange for comparison and finally chose RAL7022 (umbra grey).  Below is how they look together on ply wood, only time will tell how they will look on the car.



After speaking with Andy from GD, I asked whether the stripes could be made in carbon fibre rather than grey and was delighted to hear that; although "tricky", it was not impossible. 

I have recently received a sample panel which shows the orange and carbon together (see attached photo) which I rather like, the black is there for reference.  The carbin in the sample is casually laid and will be at 45°for maximum  visual impact. 





Which kit?

I have been dreaming of building a kit car for many years and was originally set on the Tornado Sports Cars GD40 replica.  As time has gone on I grew more and more attracted to the Cobra for it's timeless looks and 'cool factor'.  The next decision was to choose a manufacturer, the main players being Pilgrim, Gardner Douglas, Dax and AK.

I want to use American muscle which rules the Pilgrim out and after reading many blogs and forums narrowed it down to Dax and Gardner Douglas due to their chassis designs, the CC&AR (Dax) and the Euro (GD).  While both have their own merits, more research suggests that the GD Euro chassis provides better track performance whilst still remaining civil on the roads.

I met with Andy and Meena from GD at the Castle Combe kit car show who were extremely helpful, and even took me for a spin around the track in there trusty demo car (see below picture, what you can't see is my Cheshire Cat grin under the helmet :-D).  This sealed the deal for me and I have arranged to visit the factory next week where I will no doubt be booking my build slot.


I have decided on the GD Mk4 with the Euro chassis, now I have to decide on the colour....