A Trip Down Memory Lane – Part 2

Welcome to part two of our trip down memory lane – A peek into the pages of Modern Motor Magazine and the project car that started the ball rolling for Haltech. If you missed part one, you can catch up here.

In this instalment Modern Motor Editor, Barry Lake takes us further down the 1980s fuel injection rabbit hole, the challenges that the project car team faced with supplying fuel to the newly supercharged engine, and the custom solution they came up with.

Spoiler Alert: While Haltech is now best known for complete stand-alone engine management systems, Steve’s invention was actually a separate piggy-back fuel injection set-up.

Read this excerpt from Part Four of the Project Car build, as published in the June 1987 Issue of Modern Motor, to learn more. Republished with permission from ARE Media.

While our US experts advised us to fit larger injectors for each cylinder and to fit their complete replacement comput­er to control the fuel and ignition man­agement – this being the obvious way for a manufacturer to go when develop­ing a new car – Steve took a different route, but one which better suited our needs. He decided to stay with the Ford EEC4 (“Eek-four”) engine manage­ment system as it would still happily cope with most daily driving conditions asked of our car when full performance and supercharger boost are not re­quired.

To this system, Steve has added a second fuel injection system which comes on-stream when the EEC4 has reached its full output and can no long­er cope with the engine’s extra needs. 

This is where Ed and Steve had to work together, Ed selecting new com­ponents which could cope with the en­gine’s much higher output potential, and Steve producing an electronic man­agement system to suit. 

Ed’s calculations showed that the big­gest restricting factor of the standard system is the vane airflow meter. This is the air intake for the engine, produced by Bosch and commonly used on many makes of electronically injected cars all over the world. It contains the air flap valve which swings back as the air pass­ing through it (governed by the throttle opening) increases, operating an electronic potentiometer which sends a signal to the computer to tell it how much air is passing through. There is also an air temperature sensor which tells the computer the density of the air (air and fuel having to be mixed as a ratio of weight rather than volume for the most efficient mix).

By Ed’s calculations, the standard vane meter was barely adequate for the standard car’s needs, certainly nowhere near coping with ours. So he selected an easily-tracked-down larger version of the same thing, also by Bosch, from the BMW 635/735 series cars, which is actually larger than those cars’ needs, but large enough for ours. 

The injection system’s throttle body was not such a restriction to the stan­dard car but was still not big enough for our project. Ed’s investigations showed that the dual-butterfly throttle body from a Ford Bronco 4wd’s 5.8 litre V8 was just right.

We had a stroke of luck here because, with our projected overall costs already climbing in the usual fashion, a $500-odd part can be­come yet another accounting headache. But the PR department of the Ford Motor Company, whose engineers had already been helpful with advice from the start, found a little-used and no longer needed Bronco throttle body sit­ting on a shelf and sent it up to us. Who can ask for more than the right part at the right price? 

So, while Ed was manufacturing a plumbing system to fit these new parts in the best relationship possible be­tween the Sprintex supercharger and the standard Ford inlet plenum cham­ber, Steve was adapting sensors and computer to each other.

Fortunately, the electronic components in the Ford (Bosch) vane meter and the BMW (Bosch) vane meter were readily inter­changeable. Steve has readjusted the constant-force spring settings in the larger vane meter so that it has the same arm deflection. for the same airflow as the smaller Ford unit (even though the new unit’s cross-sectional area is much larger in the wide-open position), thus creating no new problem for the com­puter on that score. 

From there on Steve is designing and building his own computer which will interact with the EEC4 to provide the ignition timing changes required for our engine as well as the extra fuel re­quirements which, when needed (under part and full boost conditions), will be supplied via two additional fuel injec­tors mounted in the inlet plenum cham­ber. I will let Steve explain this in his own words in the accompanying panel. 

This is an exciting part of this project, one which puts us right into the elec­tronic and computer age. Steve and Ed and all of us here at the office are anx­iously awaiting the day when we run the car on the dynamometer again. Steve will reprogram the new computer to the car’s requirements under various con­ditions, then manufacture his own elec­tronic silicon chip to suit. 

Meanwhile, Ed has been work­ing on the car’s transmission, and we have upgraded differential, rear axles and tailshaft already underway. 

Join us for the next, final installment of our trip down memory lane, where we’ll see the finished car, its performance figures, and read Steve Mitchell’s own words on the computer program he wrote to make the proto-haltech piggy-back work with Ford’s own ECU.