16/03/09 - Trying out the RockLobster

We had a bit of an ad-hoc opportunity to try out the new Transfer Box this weekend as TV4x4 Club held a Training Day for beginners. This event is a restricted entry day just for beginners to try off-roading in a less pressured environment than a full meet. As James is just starting to drive he qualifies as a beginner so along we went, whilst it was his aim to practice his driving it was my aim to try out the car before Hogmoor.

First of all there was the short (1 junction!) Motorway trip. This was important as the RockLobster fitted in my SJ was very noisy and made any sort of journey to off-road sites a real pain. I am pleased to report that the Transfer Box in the Jimny is comparatively quiet. There is more noise that the original Jimny Box and there is a point on slight over-run where you can get it to become noisy if you feather the throttle. The good news is that is is comfortable to use. The really good news on-road is that the reduction in gearing in High Ratio is enough to make it very pleasand to drive again. It pulls away nicely and responds to the throttle well. It is never going to be a racer and with the Roll Cage, Winch and large tyres it seems to really max out at just over 60mph, which is ok.

I cross checked the speedo with a GPS unit. Although the Rocklobster does not affect the road speed (and hence the Prop speed and speedo reading) the larger tyres do affect it. Although I have bought an electronic kit to correct the speedo I have not fitted it yet, I have been waiting to complete my transmission conversions first. The little table below shows the effect the tyres have on my speed as measured against the speedo and GPS.

SpeedÂ	30Â	40Â	50Â	60Â
Speed0	30Â	40Â	50Â	60Â
GPS	 31.5	 42	 52.5	 63

This shows that the Speedo is reading 5% low. Now, in the UK, the law says that the Speedo is allowed to read between 0% and 10% High only, it is not permitted to be low. This is for the obvious reason that if it is reading low you can be speeding without being aware of it. Therefore I need to do something about it, but I am not overly concerned as the error is not great and the Jimny is not a speed machine.

Once at the site it was into Low Ratio and off we went. Again, the transformation was superb. In 1st the car will crawl along happily at an incredibly low speed (so slow that the driver can get out of the car with it crawling at idle, walk around the car and get back in the drivers seat again!). All of the power is now at the correct point for off-roading. Hill descents are a dream with the engine braking doing all the work, no brakes needed! Low Ratio 3rd Gear is now where 1st used to be so effectively I have two lower gears than I had before. This modification has the same effect on the Jimny as it did on my SJ, one of the most worthwhile modifications you can do.

Only one issue arose. When the Engine/Transfer Box is doing some work there is a loud "Tink,Tink,Tink,Tink" noise from underneath the car. This sounds like a bolt on the prop hitting something on the way around and it can be made worse by pressing on the main Gearbox lever. Since the event I have spoken to Rob at The Offroad Armory who says its the balance weight on the mini-prop hitting the gearbox remote when under load. Since he created the first kits a few weeks back he has added in replacement Transfer Box mounts into the kit which has the effect of correcting this, as I did not get these mounts with my early version of the kit he is going to send me some.

The rest of the day went pretty well with only a couple of issues. The car seems to have a tendancy to overheat and I suspect that the Viscous Fan is not working correctly so this needs investigation. Also on the way home the "Jimny Death Wobble" started so I have another KingPin bearing to change and, inevitably, I had no brakes left after the mud and sand had done its worst

Here are some pictures of it flexing

 

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The rest of the pictures from this event are in the GALLERY