Archive for September, 2007
From a diesel perspective, anything that isn’t turbocharged is a waste of time from a tuning point of view. Similarly, anything that isn’t using electronically managed direct injection is a pointless tuning proposal so we are somewhat limited to modern Turbo Diesels.
Get rid of those two ointment bound flies and things get more interesting. A 2001 plated Peugeot 406 2.2HDi has been re-mapped from factory spec 136bhp (it’s pretty good in that tune with 235lbft to play with!) to a whopping 192bhp@4150rpm and 329lbft (yes, that’s right, we have NOT confused Nm with lbft) delivered from 2250rpm. This endows the car with mid-range thump that wouldn’t disgrace a Boxster or Audi TT with the silly engine option. NO stopwatch necessary, this is a genuinely rapid car now, it both feels quick and achieves the numbers to be quick.
The shocks are generally a piston inside a liquid and some have an additional gas chamber to absorb shocks (gas compresses whereas liquid does not compress under pressure.) Shocks can have a fairly complicated structure. Testing the shocks on your car you bounce the car – if you get more than one bounce then your shock are on the way out. Without shocks the car would drive like a thing on a spring and just bounce everywhere. read more…
Brakes – part of going fast requires that one is able to stop as fast. The brake works with a friction pad, which is pressed against a Disc – the friction converts the momentum of the car into heat which is then dissipated over the brake disk slowing up the car. Heat is a big problem with heavy braking and a racecar must be prepped to cope with the high heat demands placed on the braking system. The braking force goes from the pedal into a magic box called a servo, which uses engine power to amplify the pressure of your foot decreasing the effort you need to expend. The pressure is transferred to the friction pads by means of liquid (brake fluid) inside a tube. At the brake pad end, which is subject to high temperatures, the fluid itself can get very hot. The benefits of using a liquid, which cannot be easily pressurised, means that the effect of braking passes along the tube (brake pipes) almost instantly. A cable would stretch a little and needs constant adjusting – most handbrakes use a cable system so you are aware how inefficient the cable brake system is also cables are more susceptible to the effects of heat and stretching. read more…
Some rally style alloy wheels are lighter – (less weight = more speed) and also are designed to increase the cooling of the brake disks. Some designs hold up better to being curbed than others and some break very easily when hitting a pothole or curb at speed – always go for the best quality alloy wheel that you can afford and read the reports and reviews. If you do go for a different overall size you must get the suspension and tracking realigned to avoid uneven wear under acceleration.
Look at the car from a distance to see if the wheels are at the correct vertical angle then get a friend to drive the car while you stand at the side of the road (not directly in front of him!) and see if the inside or outside of the wheels lift up under acceleration, cornering or braking.
Fuel: this is regulated by a pressurise valve at the engine end – generally more fuel means more power but you also need more air as well – certainly an induction kit on larger engines and preferably a turbo or supercharger. If the mixture is too rich a catalyst would be destroyed as unburned fuel enters the catalyst and burns inside it melting the catalytic structure so there is a delicate balance to maintain. This balance is referred to as the air to fuel ratio or even AFR. High pressure fuel regulators should be fitted by a competent mechanic who can tune the engine to give the best fuel to air mix for your driving style and will keep the cat alive. A pressure reading will need to be taken before and after to give an indication of the optimal range of fuel pressure boost.
It was used in wartime to boost the engines in aircraft and later became a big hit in drag racing in the Pro Mod class. Not a flammable gas in itself it is injected into the intake manifold where it mixes with air & fuel. The main benefit of Nitrous comes as it burns and becomes an oxidiser releasing more oxygen into the engine. An interesting side benefit of using Nitrous is the cooling effect it has. It rapidly changes from a liquid to a gas and produces a cooling effect (when you get out of the bath the water starts to evaporate or turn into a gas vapour and takes the heat from your body) this cooling effect reduces the temperature of the air taken in by 60 degrees F. Colder air carries more oxygen which is flammable.
