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The fastest accelerating Westfield in the world? The MegaWatt


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Build Diary: The MegaWatt

A bold claim? Yep. A true one? Oh yes, it will be.... over 1000bhp/tonne and around 2000ftlbs/tonne should be enough to see to that.


(Those who know me on Facebook have seen hints about this, but now the car is effectively finished, time to detail it...)


So, to do an introduction to this build diary. My good friend Dan Johnson has been coming out to Barbados helping support us ever since we used to rally the Westfields out here 15 years ago, he got hooked, has been coming back 2-3 times a year since, even selling up and moving here for various six month stints. I recently rebuilt a Hayabusa turbo Westfield out here, which Dan helped with (see the build diary on here) and got into the drag racing scene on the island. Currently, my car holds the outright 2WD record. But not for much longer...


A professional mechanic/motor engineer by trade, Dan recaught the Westfield bug, having previously built a MegaBlade kit about 10 years ago, and so, with one eye on creating a mobile CV and one eye on a worldwide record he bought Martin Atwell's old MegaBird on the island in December 2015. A car we used to rally with and know inside out, but since then it had been sold on and fallen into a terrible state. In the UK it would probably be scrap, but not here, it's duty paid and registered/licensed so time to resurrect!



I mean, the thing was in a state. It had been left outside for some time in this climate, chassis rust, bodywork a mess, all nuts and bolts rusted solid, engine dead, all the work that had been done on it since it left Martin seemed to be a total bodge job. Just awful.






And so the strip and debuild begins...

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1000bhp/ton is doable. What engine is he planning on using?

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Good stuff.  Having seen the state of it back in february, I can imagine how much work has gone in to this.



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So, in it's happier days, setting times up among the WRC cars and tearing round the rallysprint track we have the car in it's original setting... weight before debuild 515kg dry (Blackbird engined, no dry sump (anymore, *rolls eyes*), full CDS cage (T45 was against the rules out here back then), lightweight bodywork, heavy wheels with road tyres, allu uprights and hubs, Outlaw 4 pots, alloy Avo shocks).




And to save some time, as noone really cares about the debuild, here's a timelapse of the tear down... Dan finished the teardown in his first 3 month stint from January-March, taking slightly longer than normal due to some rum soaking, seized bolts, more rum soaking, a trip to Trinidad Carnival (which will now become a yearly pilgrimage), building a work bench, a little more rum and extracting from Bridgetown Port a rather large shipment of carbon fibre rolls of various weight along with associated strange pumps and materials (more on that later...).


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Gosh - I'm exhausted watching that - can you play it at extra slow pace (which would be about how long it'd take me to do all that work) :)


Also, is rum good for soaking rusted seized bolts....or have I misread that ?? :rolleyes:


Can't wait to see WATT you've done.....

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I saw (and commented on) your photo of the charge point on Facebook. Looking forward to seeing more about it!

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On stripping the car the state of the chassis became apparent - a couple of bars were rusted through and needed replacing (including those adjoining the rusted bars to be safe). The car really was moments from disaster.


Here are some shots from the diff area and damage being prepped:






The diff area, a consistent weak point, had been bodged fixed previously and aside from being absolutely hideous rat **** welding, it hadn't worked. The diff carrier had multiple cracks and required a lot of work. Knowing the amount of torque that is going to be put through this car (in the region of 1000ftlbs) this is one of the key areas that needed work.


The existing basic diff carrier area cracks/issues were fixed, bars replaced, bars were sleeved with an extra welded right angle of steel, all corners gusseted top and bottom, an extra mounting point added and then multiple triangulation bars were added. Will it be enough? Time will tell, but it will require a lot of monitoring. Countless hours, weeks even, were spent on this area, but it will still require constant checking.




The car is running a 7" Sierra LSD diff, which is another area for monitoring. Initially we'll run this, but as the torque is ramped up, the worry is the whole rear end might need replacing with something substantially stronger (perhaps even 4 link). 


Jumping ahead a little, here is the diff carrier at various stages through the build :-




Diff is debushed and hard mounted with an extra mounting tab (at the bottom).




The goal was to have the chassis finished so it could be sent off for powder coating while Dan was back in the UK. However, the arrival of the motors (info next post) was delayed which pushed the entire time-frame back. There were still vast amounts of other jobs to complete, not least the stripping, cleaning, checking of all the parts that came off to see which were suitable to go back on...

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So the powerplant, this is where my knowledge gets a little iffy and Dan's ingenuity completely takes over so forgive me if the details are not 100% and my technical knowledge is a little lacking.


Anyways, yep, it's going electric. I know it's been done, but so far, the one's we have seen were kinda tame and nothing stupid. So Dan decided to go full retard.




Twin series wound DC motors, good for 500ftlbs of torque each, potentially more if you want to push them. Going to be run in series, straight through to the back. Not bothering with 4WD, just means more weight and complexity, hell, the quickest drag cars in the world are 2WD right?


The aluminum discs and bar you see are the raw materials to machine the joining plates from - to pair the two motors in unison and enable the mounting of them to the chassis - as ever, all Dan's design.


And then the delivery of batteries arrives...




384 lithium cell batteries, 640kw power - about 50 times more power than a Tesla battery and the most you can legally import by air (99.9Wh). The battery pack will be a small lightweight 'drag' pack for the car, high power / low range. But easily swappable so can run a longer range pack, or, simply just add more packs as required.


And so now the chassis modifications begin in earnest...

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