New Type 9 Gearbox – BGH or ?
A trip to BGH Geartech.
The old adage of ‘ If you don’t try – you’ll never know’ holds true in so many ways when it comes to our cars, however I’d tried a straight cut gearbox and it just ‘wasn’t for me’. In fairness the ‘box’ had come with the car and although I managed to live with it for a few weeks before the car was sent off for winter mods comments from others ( notably Mrs G ) suggested that long term I ought to source something quieter, something a bit more civilised.
Whilst the ratios of the Quaife gearset seemed to really suit the car and style of driving, the noise was just too much, atleast too much for those that had been out with me as a passenger and so I started to think about swapping it out. Although I’m not ‘hands on’ mechanically I do like to try and learn about anything related to my own car or our type of cars in general – but gearing always gets me confused: I tend to mix up ‘short’ and ‘long’ geared and get in a muddle with differential ratios too. So I figured i’d better be careful with my research – otherwise it could prove a costly error!
The 2 Tigers I’ve owned have both been Zetec engined and the natural choice for many kit cars is to do the easy thing and use a Ford box, most commonly the Type 9: A relatively simple 5 speeder with 5th acting as an overdrive for motorway cruising. Of course the issue with this is that the Ford Engineers built it for a somewhat heavier and less sprightly car and as such the ratios are not ideal for a ‘kit’. First gear is very short at 3.65 – meaning the need to change to second at about 20/25mph and thereafter the spacing of 2nd and 3rd is not considered ‘close enough’ to prevent a pretty high fall off in rev’s at each change.
A typical Type 9 ‘box’
So what options exist for a like for like Type 9 replacement and is it a worthwhile avenue to explore? Actually the answers to both questions are pretty straightforward. If you don’t mind the noise a ‘straight cut box’ from the likes of Quaife will offer some good ‘close ratios’, whilst for those that aren’t racers and who like a more civilised drive SP Components and BGH both offer alternatives in the form of semi helical/helical gears – which to you and me means , quieter. Is it worthwhile? Personally I think this can be summed up with the style or type of driving – a kit being used to potter down to the local Show or Pub would equally suit any type of box, but for ‘drivers’ I’d suggest that a close ratio aftermarket box is worthy of a second thought.
Consider this. Many owners talk or focus on the powerplant and many bystanders enquire ” what’s the 0-60” – but no one really tends to ask ‘ how does it drive’ in reference to not the suspension/chassis but to the way that the car responds to a stab on the throttle and the delivery of the power. The key to the way that any car ‘goes’ is the harmony and matching of the engine, the gearbox and of course the final drive gearing ( differential) .
The gearing from the straight cut box in the car was excellent and really transformed the driving experience: With 1st at 2.54 and 2nd/3rd clustered close together the car pulled like the proverbial train and flicking between gears meant a far more miserly loss of rev’s. To amplify: Closer ratios means less rev’s drop during a gearchange, giving potential to maximize the engines power. So having sampled a close ratio box I was on the lookout for something similar.
Chris at BGH patiently and politely set me straight on a few questions and soon we were talking about the avenues and options open to me. After some debate we agreed that their E7 unit would be perfect. A helical gearset ( meaning it would be nice and quiet ) with a 1st gear of 2.66, 2nd/3rd clustered and with 5th at .086 giving a compromise between overdrive and continued acceleration. For those that don’t know BGH – they’re located down at Cranbrook in Kent and Brian Hill has a long history of developing alternative ratios for the Type N & Type 9 boxes as well as being involved in the design of the Caterham 6 speeder – clearly a man that ‘knows his onions’. http://www.bghgeartech.co.uk/html/bgh_home.html
A few days passed until I got the call ‘ pick it up when you’re ready’ . So last week I popped down and met with both Chris and Brian. After an exchange of pleasantries I decided that I could do with a swift lesson on the inner workings of a ‘box’……Chris outlined the basics of layshafts, roller bearings, oil pick ups whilst Brian talked about a few new ideas that they have for the future. Most informative and useful to know.
So the box has been dropped off at Snodhurst Garage where fellow members Dick and Jamie have now fitted it….and the expected net effect? Well aside from the quietness it’ll mean that the car is a lot more lively on a track day, with the rev’s falling between 20-30% less per change – helping the engine to carry on working where there’s most power available. To say I’m looking forward to it is an understatement!