Response

More Spring Swaps

Re: Spring Swaps!. About 25 years ago I did a similar mod to my KE-25 Corolla (now I'm showing my age). The original leaf springs had sagged on the driver’s side and it was an expensive exercise (on an apprentice wage) to have the springs reset (few people back then did extensive mods to their small, 1200cc, cars). Originally I installed a set of K-MAC air shocks and modified the strut towers so that I could accommodate the air lines via the boot (K-MAC never made air shocks for small cars).  The problem with the air shocks was similar to the Daewoo springs...  A lot of noise was transferred through to the body when they were pumped up, and the sagging driver's side problem did not disappear. A guy from tech was scrapping a Corolla KE-20 wagon and I bought his springs for $10 each.  They fitted perfectly, increased the rear ride height by about 30 mm (perfect for a rally car) which allowed me to reduce the volume of air in the shocks, reducing the noise transfer to the body.

Malcolm Land
Australia

Negative Boost Fittings

I have previously enjoyed all of your articles on negative boost and I was excited to see this topic being visited again. The only thing that I thought the previous articles were lacking was a description of the actual connection to the intake when a factory location is not available. You have stated that you use a fitting and can then cover this with black silicon when finished but could you show exactly what type of fittings and how they were installed?

Chris Nichols
United States

It’s just a case of drilling a small hole (eg in the airbox) and then pushing in a small metal or plastic fitting (eg a miniature irrigation connector fitting) that the sensing hose can then push onto. Then when you’ve finished, pull the fitting out and wipe some black silicone over the hole.

Pick Up the Debris

Re: How Not to Die this Week. A great article! Also when driving in the rural roads, both black-top and dirt, motorists should be prepared to remove the occasional dangerous obstacles from the road such as truck tyres and fallen branches, especially when they lie in a potentially dangerous locations such as over a crest, around a corner, etc. Removing these obstacles removes the danger; and you may just save some unsuspecting motorist from having an accident and it will only take a minute.

Wayne Donovan
Australia

Diesel Turbo Boosting

Just read your Hyundai Santa Fe CRDi review and thought I'd chime in. I am a fan of turbo diesels and have bunged a T25g on my Mazda Van. Playing around with this has taught me a lot about what makes turbo diesels tick. When you open the throttle in a petrol engine, the exhaust gas increases almost instantly. Obviously the exhaust flow then builds as more fuel and cylinder pressure build and the turbo gets going relatively smartly. With diesels, having no throttle means that the same volume of air flows through the turbo all the time when off boost. Seeing as there is only a tiny amount of fuel injected at idle, there is little energy available to spin the turbo real fast. The answer, then, is to dump a load of fuel in quickly and get the exhaust gas hotter which in turns spins the turbo up quicker.

That's fine for me when I don't care about a big puff of black smoke when I stand on the accelerator off boost (in fact, there is no way to avoid it if your fuel pump isn't boost referenced) and I would hazard a guess that the slow Santa Fe response is due mostly to the electronics limiting the fuel that is delivered before reasonable boost is made in the inlet tract.

It took me a while to figure out how to get the turbo spinning quickly. Initially I had a turbo that had been modded with bigger housings for the SR20 U12 Bluebird that it was fitted to (actually was a feature car on AS years ago : Family Hauler). It was so late to make boost that it wasn't really good to drive, also it peaked at about 3 psi which wasn't what I wanted. I fitted a stock T25g and it now boosts at under 2000 rpm, and makes up to 10psi depending on how much black smoke I am willing to tolerate! Tuned for no smoke on full noise, it makes about 6 psi, add a little more fuel and it will make 10. The only other tuning (without boost referencing the pump, which is much more involved than doing so for a petrol engine) is timing, and a degree or two advance seems to keep the exhaust temperatures up and the turbo spinning quicker and sooner.

Murray Booth
Australia

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