QuartKa Mile

T

he original Ford Ka is no slingshot hot hatch, at least in terms of performance - using a 1·3 Endura-E with 60 PS puts paid to that idea. Although it has excellent handling, if you’re up against another car with similar handling abilities, it’s almost certainly going to be quicker.

So one might think that taking the Ka down the drag strip to see just how slow it is, might seen a bit silly? No, I don’t think so, and you can read about my opinions on this here.

We’ve managed to slice 1·2 seconds off Kermit’s quickest quarter mile time, even if the reported terminal velocity is still around 70 mph. This document details the quarter mile runs we’ve put Kermit through.

So how do I measure my own car’s quarter mile time?

First off, go to a “Run What You Bring” drag strip. They have these dotted around the country, but the two most famous ones do appear to be Crail and Santa Pod. Turn up, pay your money, get your tickets, and head out to the queue for the drag strip.

The Queue

Whilst in the queue, there are a few things you can do to help your car, since if it’s a busy drag strip, you might be in the queue for some length of time. To keep the engine cool, many competitors open their bonnet - thanks to KITS I know how hot Kermit’s underbonnet and airbox are getting, and after a few minutes queuing, the temperature is already climbing. Lifting the bonnet simply removes a lot of the heat from the engine bay, and if the fan is running, the hot air has somewhere to go. Of course, you probably shouldn’t tackle the drag strip with the bonnet open, so don’t forget to close it!

The Burnout

Immediately before you go to the start line, you’re invited to “burn” the driven wheels. That means wheelspinning on a specially prepared bit of tarmac or cement, although in the case of the basic, vanilla Ka, there’s probably no real benefit to doing this, so I have typically avoided this. Then you’re invited forward. Inch the car up to the line, using the Christmas Tree to guide you. When you’re getting close, the top row lights up. When you are in the right spot, both rows light up, but if you’ve gone too far, the top row goes out and the bottom remains lit. When both competitors are lined up, and everything checks out, the controller starts the countdown.

Launching

There are various launching techniques that one can try, and to get it right it depends on the car in question and how sticky the launch pad is. The Santa Pod Raceway’s launching pad is especially sticky, so you need to absolutely nail it off the line, whereas Crail’s launch area isn’t so sticky.

When launching, getting the right engine speed and careful clutch control is very important. Too many revs and you wheelspin the excess power away, which means you don’t get a very good launch - in the absence of a limited slip differential, just one tyre tends to spin the power away. However, too low an engine speed and it gets bogged down, so the revs drop and you lose your acceleration.

Santa Pod’s sticky launch pad means that it’s possible to dump the clutch with the engine at full speed (after the Bluefin recoding, around 6,000 rpm) and get a good launch. At Crail, using 4,000 rpm gives a better launch.

You’re On Your Way

Changing up is achieved as quickly as possible and I’ve found that the difference between a clutch friendly upchange (easing off on the power) and not (keeping it nailed!) is around 0·2 seconds to the quarter mile. It’s quite possible to change gear very quickly in the Ka, thankfully. Using 5,500 rpm, I’m in second at 27 mph and third at 47 mph.

For the Ka, with or without the benefit of the recoded ECU, the optimum change up engine speed is 5,500 rpm. Hold out to 6,000 rpm and you add another 0·2 seconds to your quarter mile time. Change up at 5,000 rpm and you add 0·2 seconds.

Deceleration

If you’re sane, as soon as you’ve crossed the finish line, you’ll lift off and get on the brakes. It may seem like you’ve a long way to go before you have to pull off the runway, but at terminal velocity the car covers this distance pretty quickly.

The Results

There are three primary sets of figures.

Standard and Unprepared

This really does mean turning up and running, without any sort of optimisation of the car. So, the tank is usually full of petrol, and you might even have some luggage onboard too! The tyre pressures are standard, and there were no modifications to the Ka.

The best time to sixty feet was 2·688 seconds, and the fastest quarter mile time was 20·408 seconds.

Very Minor Tuning, Prepared and Optimised

After replacing Kermit’s air filter and exhaust (for the Janspeed back box), I did many runs to experiment with different launch techniques and the best change up engine speed. I also increased the tyre pressures to reduce rolling resistance.

In combination, these made some reduction in times. The best time to sixty feet was 2·716 (marginally slower than the above data!), but with the vast majority of runs between this time and 2·800 seconds. The quickest run down the strip was 19·800 seconds.

Chipped, Exhausted, 185/60/13 Tyres

After having the ECU recoded, replacing the exhaust with the Powerflow cat-back system, and switching to XR2i rims wearing 185/60 tyres, and full optimisation (one quarter of a tank of petrol, high rear tyre pressures, nothing else in the car), and running several times down the strip, we’ve further improved things.

Now, the quickest time to sixty feet is 2·682 seconds and the fastest time to the quarter mile point is 19·239 seconds.

Some Observations

There are a few observations to make from the data I’ve collated.

One, the time to sixty feet is very consistent at 2·7 seconds, give or take a few tenths. There’s no more traction available from the 185/60 tyres compared to the 165/60s, at least, if there is more traction it is not significant. There is enough power (and torque) to cause wheelspin using either set of wheels, but if anything there is less wheelspin with the 185/60/13s rather than the 165/60/14s. But neither the different wheels nor greater engine output materially influence the initial sixty foot marker.

So why can’t I get it much quicker? Looking at the times afforded by more powerful front wheel drive cars, these tend to be around the 2·5 second mark. I’m not that far off these times.

The time to the quarter mile marker shows a considerable reduction as we first optimise the technique, and reduce weight, and then modify the engine. Nevertheless, the reduced quarter mile time makes no difference when up against something like a Saxo VTS.

There is still room for improvement. At the bottom of the strip, the speedo is showing an indicated 78 mph, which is essentially right on the limiter in third gear. From the evidence I have so far, the Ka is quicker if one changes up at 5,500 rpm rather than hold on for a higher engine speed, and so in theory I should be in fourth gear at this point. However, by the time you’re almost at the quarter mile point, changing gear will be of little benefit to your time, or probably slow you down a bit.

With taller gearing, but not much taller, one should be able to improve on the time. Swapping Kermit’s 4·06 final drive for a taller one, such as the 3·82 unit from the Puma, will raise the gearing such that at 78 indicated in third, the engine speed is 5,650 rpm. This is better than 6,000 rpm! Using the 3·59 final drive, the engine would be turning over at 5,300 rpm, better still, but with this level of gearing I can expect the acceleration to be noticeably lower in first and second.

Why Drag the Ka?

It’s been asked of me - why bother taking the Ka up the drag strip when it’s slow. I suppose one could ask the same question of any vehicle - why bother taking an RS Focus up the quarter mile spring when you’ll be quick? Or a TVR? Or anything else?

The reason why I take Kermit down the strip is because I’m academically curious as to how quick, or not, he is.

Sometimes, other drivers are genuinely surprised at how quick the Ka is off the mark. Providing you get a good, clean launch and your reaction time is respectable, the Ka is capable of surprising other drivers during the photogenic bit of the track - that is, where everybody stands to watch, and where most pictures are taken. Whilst the time to sixty feet is slower than most other front wheel drive vehicles. The reason for this is simple - the limiting factor over such a short distance isn’t so much power or torque, but is in the traction afforded by the tyres and the road surface. In other words, how much of your engine output you are able to transmit to the road. During those first 18·29 metres, you’re in first gear and in the Ka you’re likely to only wheelspinning for the first few of those.

Once they can apply the power, they’re significantly quicker.