The rally car experiments

When you build your own rally car – at some level – you have no idea what you’re doing. Whether or not you meticulously plan it all out, at some point you’re going to have to just try it and see if it works. This is the only way you’ll ever get onto the stages.

One thing I suggest is not running too many “rally car experiments” at one time. Using a scientific method you should only change 1 major component at a time. Get some feedback, get some data – mark it off as successful or try again. This is one of the reasons we didn’t jump right into a turbo motor for this car. Lots of stuff to test and tune before changing the motor over to an SRT package. Here are the current experiments on the new rallynotes.com rally car:

LED Lighting
I figured that a car that was built in the 21st century would be able to snap in LED lights. But that’s just not how it is. I’m looking at LEDs for their longevity, durability, and power savings. Using resistor blocks that trick the relay is unacceptable. Turns out, weird stuff happens when you switch over to all LEDs and modify the relay. The car has circuits that rely on that power load, and a diode to ground confuses them. At this point, I am unaware of a setup without “load resistors” that will give the 2GN all LEDs. Right now I have a modified aftermarket relay and stock front turn bulbs. The rear lights are all LED. The experiment continues.

Power Steering Pump
As you have probably seen my work with a steering quickener, this experiment involves getting more fluid through the stock pump. A condition autocrossers are aware of is when you steer so much left to right that the fluid boils and then no-longer fills up the steering assist. You get a condition known as “pump catch” – this is where you’re working faster then the fluid can pump into the rack. So far, all that was done is a change to open the flow valve diameter a tiny .01″. Doing just this gets a lot more fluid through the pump. I haven’t changed any springs or shimmed any valves. Steering pump pressure is extremely high (1200psi) so be careful here. This experiment took a lot of research and appears positive on the street, but I’m not going to call it successful until a full rallycross workout.

Rallycross Springs
The first thing you notice when looking for suspension mods is that practically no-one RAISES their car. Searches always yield lowering springs, and “how much drop from stock” numbers. If you want to rally or rallycross your car you’re going to have to lift or raise it. Taking a page from the Subaru guys, I decided to test something out. You see the Forester (that fat little SUV) is built on the same platform as the Impreza. It uses the same strut design, yet has more ground clearance. Turns out Forester springs are a great start on an Impreza rallycrosser. The springs are “heavier” (spring rate in lbs.) to accommodate the heavier SUV and that means you get a harder spring with more ground clearance. The Forester version of this equation is the PT-Cruiser. PT’s take the same strut design (in the front at least). They are heavier and have more ground clearance. This weekend I changed the front struts over to OEM PT-Cruiser front springs. I gained at least 2″ of ground clearance and didn’t notice any adverse handling issues (not bad for $68). As for the rear, the clearance remains high here as the Neon is always sort of “nose down” from the factory. I’m entertaining ideas as this experiment unfolds. A full on rally suspension this is not, but I needed something while the budget recovers from 2GN rally prep so far.

All the major components are in place and tested for our trip to Prescott Arizona this weekend. Some additional wiring and safety items need to be installed, but I’ll have time this week to button it all up. See you there!

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One Response to The rally car experiments

  1. Mike Malsed says:

    I did something the same with the 1GN – I used the SRT-4 springs and it lifted it up quite noticeably, kept the same stance. Worked very nicely.

    It’s interesting following your experiments. It’s enjoyable reading your methodical progress through the various impediments you’re hitting. 😀

    Nice!

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