Saturday, 25 October 2014

Ride height revisisted

Having now done a few miles to and from IVA centre, it was clear that the car seemed way to stiff at the front end. The springs were 200lb, and having now seen the axle weights, my guess is 200lbs is too much for 200kgs. Something needed to be done!.

In addition, I used an extension bracket to add an inch of ride height to the car to allow the front lights to pass the 500mm height requirement for IVA. This actually proved useful in that gave me effectively a 13" shock which suits the car better with the 13" wheels.

The bracket used was a) heavy, and b). borrowed, so it needed to come off. The solution was potentially to sell the 12" shocks and buy some 13", but a quick call to Gaz and a new set of shock tops were on their way to me with almost an inch increase in length...perfect and cheap solution.

That solved the ride height, but to also soften the front end a little, softer springs were needed. I put these on while replacing the shock tops. I've only gone down to 175lbs as I still want the car to be more track focused than road compliant, so we will see how the 175's perform.

This pic shows the different length of the tops, and the different colour of a 175lb spring!.
Another hot subject is the engine bay cooling :-)

not much in the way of free air flow with these rear engined cars. Look at any production car that has an engine stuffed behind the seats, and you will notice fairly sizable vents in the side to channel air in to either the engine bay or to a radiator / oil cooler. The J15 as standard offers very little in the way of air flow. Yes there are two small vents just behind the drivers and passenger ear, but that's about it. This means the engine bay (which of course includes the entire exhaust system) stays pretty.....bloody....warm. not so good on track days, and as the induction is firmly located behind the rear bulkhead, not so good for power as the warm air is far less dense than nice crisp cool air from outside the car.

So, what to do....Well, I've started by introducing some 'escape holes' into the rear clam. The first to be drilled are just above the air filter. The next step is to try and get some more air forced in. My plan is to place two NACA ducts and some tubes pointing at the air filter from below. That's the plan, and while I'm waiting for the DVLA to make a dream come true (and send me my plates), now seems like a good time to do these sort of jobs.

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