| How To Get Traction (FWD) |
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| Written by Zuboo | |
| Friday, 12 August 2005 | |
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for anyone who does not know my back ground here it is, I have worked on fwd drag cars for 7 years now, all full chassis cars and I work with some of the best people in Australia’s drag seen. The basic thing you do not want to happen is weight transfer off the front wheels during launch, so for a start jack the back of your car up, heavy rear springs or you can fit those caravan towing aid rubber spacers into the coils of the rear springs, the stiffer the better, I now use two sets of bump stops, which the rear can only move less than an inch. At the front, you try to eliminate droop, in my case I have adjustable shocks so I wind the rebound to max, if you don’t have adjustable shocks then a cheap fix would be too install droop straps made of steel cable. Lower control arm position will effect dive or anti dive, so on my gti I fitted spacers between the body and the rear mount of the front arm(mine are 15mm long) Axle tramp is very much a killer of a good 60ft, so heavy urethane engine mounts are a must, my car has a very solid strut brace which has an equally heavy engine steady brace. All the power is trying to tear the front wheels off the car so it moves this action to the weakest area which is the lower control arm rubber mounts, at a minimum fit urethane mounts here. Axle tramp can be minimized if the front anti roll bar is as solid as possible connecting onto the lower control arms, minimum of urethane or for drags only go aluminum, solid. I think that covers the basics of the suspension, it wont really help if you don’t have sticky tyres, I use Toyo rai 205/60/13" for drags that require a street tyre they work well, but it is important to do a massive burnout. Here is what i have found with tyre pressures on 30psi i did a 2.6 60ft on 20 psi i did a 2.4 60ft and on 10psi i did a 2.0 60 ft this is not cold tyre pressures but hot, pressure was taken after the burnout, and when i went down to 8 psi, but i broke a drive shaft off the line which meant it was hooking up better. A lot of guys are worried about breaking gearboxes when they launch hard and so they should be , I’ve broken my share too!, but you have to decide what your aims are, if its to have fun then a soft launch putting power down gradually might be for you. The car I work on at the moment launches at 8,000rpm on the rev limiter at 28psi all the way, no slipping of the clutch, just dump it and mash the throttle and the tyres are hooking up well, it has the fastest 60ft for a full chassis street car in Australia which is a 1.59 60ft on slicks, it also had the fastest fwd street tyre for Australia, but we lost that at compack attack :cry: . When on street tyres we use the motec boost controller, which is setup per gear, we need to set this up at each track to get every bit of hp to the ground we can. With the boost controller the eases one to setup, is per gear, it will be the best for street use, the others take a lot of setting up, and you don’t always get what you can out of the vehicle for street use As for traction control andra don’t care about that, it slows you down more, but it is the sensors that go with it they don’t like, you could use the speed sensors to cheat in dyo racing, most of the big boys use the clutch as a traction control, that is why it takes a few runs to get there best time, working on what speed to get the clutch to come out per traction on the track For the record too, my car does a 13.1 at 101mph on street tyres, it has done up to 109mph but did not hook up, and it only has 180hp ATW. If anyone want vids posted let me know, i have a good one with us setting up the boost per gear, you can hear the difference each run. |
