Seats crotch and Hans

I have been considering a safety upgrade to the Megabusa. I decided to invest in a set of seats that were more substantial than the GRP shells fitted and fit an additional crotch strap to the seat belts and Hans device for my neck.

If you want to know what a Hans device is then there is a very good explanation on Wiki (*).

The crotch strap is a simple addition to the existing Willans seat belts. It stops you sliding under the harness in extreme conditions.

The seats were ordered while at Stonleigh and are made by a company called Intatrim (*) and the product is called Endeavour. Although still a GRP seat it is a much more substantial product than the basic shell seats and they have thought about the crotch strap void in the design.

Hans adapter

A Hans device was purchased from JJC earlier in the year at significant cost. However I was never able to use it in the Westfield as the seat belt straps need to be precisely aligned with the seat apertures and the Hans device. This requires the attachment points in the Westfield to be radically altered. After some discussions with various scrutinisers at the track and after even more thought I designed and fabricated  a Hans adapter using the existing Westfield seat belt attachment points. You can see not only have the attachments been aligned horizontally with the Hans device but a 50mm elevation to the attachment has been applied because of the Hans thickness resting on your shoulders.

The adapter was fabricated out of 4mm sheet steel and bright steel studs taped and welded in place on both sides of the plate.

I propose to submit this for scrutinising soon at Kames.




Hans adapter

Hans device

Drivers seat with new belt attachments

Comparing drivers and passenger seat belts

Passenger seat belt points

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References (*)
Hans explanation: http://en.wikipedia.org/wiki/HANS_device

Seat manufacturer: http://www.intatrimtelford.co.uk/index.php

Engine prop shaft adapter

The Hayabusa engine normally has a toothed gear to transmit the power from the gearbox to the rear wheel of a motorbike. Wesfield in their cars mount a special adapter on the gearbox output shaft that adapts it to a split Sierra drive shaft. The adapter is normally made of mild steel and is rigidly attached to the gearbox shaft via a large M20 lock nut and a large washer. If you trawl the forums this nut comes undone with amazing regularity. Mine unwound at Croft on 7th June 2014. It was trailered back home as I had no chance of repairing it at the trackside. The mild steel adapter was badly damaged and I did not want the gearbox shaft to go the same way.

I took the advice of Andy at AB Racing. He has a special adapter made to his exacting requirements which is reported to solve the problem. It is designed to be loose fit on the gearbox shaft unlike the Westfield part and is made of hardened steel.

It is unfortunately about 10mm shorter than the original Westfield part so I had to make an alloy spacer in the lathe to make it all fit back together.

The M20 nut was also modified to make the adapter a loose fit on the shaft and I tightened it up such that it will not come off again. I used the permanent nut thread fluid to bond it up tight.

I have no idea if this will permanently solve the problem but is seams like a good approach. Time will tell.




Westfield adapter after failure

Gearbox splines

10mm custom spacer



Nut modified on right to remove some of the step



Reassembled

Update 11th Sept 2014

Kept a regular eye on this part of the car and it regularly gives an 1/8-1/2 turn between race events on the cap head screws no evidence of the 32mm nut loosening again. I decided to wire the bolts to ensure they don't come loose again. I drilled the cap heads in place using some carbide burrs (long job).

Wide carbon wings

I was having difficulty changing the tyres at the trackside with the standard Westfield wings. I was also having difficulty sourcing wider wings. Carbon Copies (Warren Sheridan) made me new ones in carbon. Unfortunately due to ill health he has had to give up his business. It took a long time to get these parts but he came good in the end with the help of his son. Top marks for commitment right to the end. The wings now match the headlights, see bottom image.



From front

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Dynamometer Test

The last open pit lane session at Knockhill with the Westfield club revealed some performance issues on the straight from Taylors up to Duffus. Every time I changed up the power was taking too long to build up again. I took the car to Sitech to find out what was going on. Simon revealed that in the lower (throttle openings) and high engine revs it was being over fuelled. The theory is that this was throttling the engine when lifting off to change gear. Simon completely remapped the Power Commander such that at all throttle openings and rev ranges the correct fuelling was being delivered. All I need now is a track day coming up soon to try it out. Simon did say tht the power sensor on his Dyno is playing up and could be 10-20% down in absolute numbers. I have pencilled in another session after Croft.

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Carbon effect headlights

After a moment of weakness I purchased these new headlight units at Stoneleigh this year, what more can I say!

 

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Shift advisory lights

Decided to fit another box of electronics made by a company called DRE (Digital Race Electronics). It is a computer that works out when to change up gears called an SDL5 Sequential Shift Light. The box measures 58mm x 16mm x 35mm and the idea is you are to mount it in your direct line of sight. This should avoid the potentially detrimental dependence of the rev limiter. It also wastes track seconds going into the rev limiter. I spotted this shift light box on a car at Doune this year.

The box worked well when directly connected to the Hayabusa ECU rev counter drive cct but refused to work with ETB rev counter connected to the same wire. I scratched my head and went back to basics with my electronics knowledge and made a cct that allows both to co-reside. The ETB rev counter appears to put a 5V offset in the ECU circuit when connected. I basically removed that offset with a capacitor resistor and diode to protect the DRE unit. The values of the capacitor and resistor are not that critical being 33uF and 2.2Kohm. If you require more details mail me, I doubt this is a common problem.

10/06/14: The signal to the unit was correct as designed above, however the setting for "Cylinders" should have been 2 to match the ECU signal of one pulse per rev. Now working fine.

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Tonneau

There are no dependable people around central Scotland to get a Tonneau made. I pondered the issue for some time and came across some favourable references to a company called Soft Bits for Sevens. As they reside in West Sussex then a template was the obvious answer. I made an accurate template from Toolstation tarpaulin. After several months the finished product arrived from Softbits. I made some time ago a special tool for riveting the buttons in place while the tonneau is in process of being fitted. This is a much more accurate way of fitting a tonneau as you can drill each stud position one at a time and fit both half's of the stud fastener without removing the Tonneau from the car. The tool is made in part by a Rolson crimping tool with alternative stakes and anvil on each side.

I used the spare seat belt attachments to locate the Tonneau with brass eyelets.

I also took the opportunity of fitting a Longacre racing (rear view) mirror saved me thinking too much about the mounting brackets. It gives a 14" panoramic view a good safety feature for the track.

 

Soft bits logo and attachment eyes

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