Thankfully we live in a world full of choices. Some of us choose big engines, and some small. Making ‘big’ power from big engines is easy, and for many it’s the easy and obvious choice. Some people though like to be different, be individual, and challenge the ‘norm’, so do we.
We received a request from a customer that wanted something different. A lot of the first discussions we had with the customer were on the phone, this because of the distance between us. With almost 500 Km between us, a quick visit was out of the question.
We discussed a couple of options, and gave the customer enough to think about. When he was ready, he came to visit us, so we could finalise what needed to be done.
It was simple, yet tricky. The customer wanted to extract as much power as possible from a 1600 DOHC v-tec, but wanted to be able to use the car everyday, use normal 93 octane fuel, and didn’t want to have to sit and repair the car every other weekend. Costs though had to be kept to a minimum, yet reliability to a maximum. The question though was how much power did he want from all this? The answer – 110-120 Kw at the wheels! That’s almost as much as some ‘bolt-on’ 2 litre V-tec combinations.
The reason why you are reading this, is because we accepted the challenge.
I got on to the phone to speak to my friend Larry Widmer and gather some ideas.
The following parts needed to be changed or altered for their respective reasons:
• the cylinder head – mildly ported – for extra ‘breathing’
• the cylinder combustion chambers – modified – for better ‘burning’ to use low octane
• inlet & exhaust valves – changed – for flow and reliability
• titanium retainers and springs – changed – for reliability at higher RPM
• cams – changed – ‘breathing’ and efficiency
• pistons – changed – maintain compression & efficiency
• con-rods – changed – reliability
• cam gears – changed – fine tuning
To keep costs down the work on the cylinder head was all done locally in S.Africa. To get the finish we wanted on certain parts of the head though, we had to buy some more equipment. This tough is not a set back for us, because we look at it as being better equipped for the next project, and being able to provide a better service.
The inlet and exhaust valves, retainers, springs, cams pistons and rods were all imported.
This is a comparison of the Endyn Rollerwave piston vs. the stock unit. Don’t be fooled with the height of the dome, the compression was not much higher than standard due to the amount of metal that was removed from the combustion chamber.
This is what they looked like installed in the bore. Note how deep the valve pockets are so as to accommodate the extra valve opening without any catastrophes.
The usual cleaning applies to all our work.
The foam is a reaction the chemicals we use have once they contact aluminium.
New seals were installed into the head once it was clean and dry.
And then the springs and retainers.
Note the thickness and the installed height vs. the non installed height of the valve springs.
This is a view of the finished combustion chambers.
The cam gears.
These are the Bumpstix installed in the cylinder head, note the width of the lobes for reliability. What you see on the lobes is not any sort of blood. It’s a lube to bed the cams in at start-up.
After some normal street driving to bed in the rings the car was taken to the dyno. Way before we even started tuning, we realised that the car needed much bigger injectors. This already told us the engine was flowing a lot more air. These were installed together with an aftermarket ECU to control the injector and the v-tec change over.
Tuning this engine was very interesting. It required different type of fuelling to what we normally use on other motors. It seemed that the higher it revved the richer it needed to run, and at lower rpm it preferred leaner mixtures.
The results at our altitude were 112 Kw / 150 Hp at the wheels. I wasn’t happy with the torque curve though, and after adjusting the cam gears we got a much ‘flatter’ torque curve, but the price for this was 110 Kw / 147Hp at the wheels.
An interesting fact that we noticed while tuning this car, was that above 7000 RPM the engine started pulling vacuum again! It pulled almost 2.5 psi at 8800 RPM! We discovered this was due to an induction system the customer had installed that could not flow what was required. We calculated that without this restriction the car would have run about 118 Kw at the wheels! and all this at almost 6000 above sea level!
110Kw at the wheels at 5, 557 ft above sea level.