Twenty Tech Tips

While it's not done very frequently, it often makes more sense to install a new plenum chamber rather than to persist with a chamber and throttle body that's located in the wrong place. A fabrication that attaches to the original runners (or includes new intake runners) can be produced, or in some engines, different design intakes were available on different models. So, have a good think before you end up with weird intercooler plumbing that weaves all 'round the engine bay, just so that it can get to the original throttle body!

When very short springs are being used on struts, the possibility always exists that the springs will unseat themselves when the car is jacked up or lifts a wheel over a large hump. That's fine - but the fact that the spring may not resume its former position when the car's weight comes back down isn't so good! Short 'keeper' springs like this have little rate on their own (ie they're really soft) but still have enough tension to keep the main spring in place, even with the car's weight off.

Slippery pedals can be dangerous and also make driving jerky and imprecise. One way to overcome this is to use screw-on replacement pads like these Momo items, which also look pretty good if you're into showing the car. Make sure that they are less slippery than the originals before shelling out the cash for them, though!

These days intercooler cores are just so cheap that there's no excuse to have a non-intercooled turbo car (or a turbo car with non-upgraded core!). However, space can often be a bit of a problem - both for the plumbing and for the new core. Removing the whole grille and then making a replacement (thinner) item can be one answer - this car's halfway there!

Extractor exhaust manifolds on turbo cars are certainly not an early mod - more likely, done when the turbo's being changed as well. While they allow the engine to perform better in its off-boost ('naturally aspirated') mode, they also have the potential to cause turbo lag and place a huge expanse of radiating red-hot pipes under the bonnet. Pick the extractor design with care - especially in making sure that you keep the runner diameters fairly small. Heat shielding is also worthy of consideration.

If you want to precisely measure intake restriction (ie pressure drop) and don't want to make or use a fluid manometer, this ultra-sensitive gauge can be used instead. Full scale is just 10kPA (1.45 psi) and that's a sensitivity that will let you measure the different restrictions of different airfilters, for example. Buy new from Dwyer Instruments or secondhand from used machinery warehouses.

Placing a section of high-temp glass tube (about $10) in the radiator hose can tell you fascinating things about the cooling system performance. Like, what're all those bubbles doing in there? In addition to showing when pump cavitation is occurring, the clear tube can also show flows and coolant condition.

By far the worse aspect of people testing out new products is their lack of record keeping. They'll say something like "muffler A is heaps better than muffler B", but when you ask how much the differences were (in power, sound or flow) they'll wrack their brains trying to remember the numbers. It's boring at the time writing stuff down, but you'll be glad later that you did.

Kit cars and other homebuilts often show great ingenuity in the mix and match of other cars' bits and pieces. Look here how the owner/constructor has used a fuse box from one car, an airbox from another - and a host of off-the-shelf but well-labelled relays. The result looks good and works well.

Wool tufting (covering the car with small lengths of wool stuck on with masking tape) is the best way of showing the pattern of airflow over a car. With the car bedecked in wool, all that you need do is go for a drive, while watching (and photographing and videoing) the car from another. Attached flow lays the tufts down flat, while turbulence causes them to whirl round and round.

Boost control can use a combination of both wastegate exhaust bypass and plenum pressure relief approaches. Taking this dual method can allow the very quick building of boost by holding the wastegate shut for as long as possible, with any over-spikes bled off by the plenum pressure relief valve. The plenum valve used on most early Nissan turbo engines can be adapted to this purpose - the internal spring is easily changed.

All vane-type airflow meters have a mixture adjustment mechanism hidden under that black cover. Changing the spring pre-load allows alteration of the air/fuel ratio, even at high loads. But don't go fiddling unless you know that you can find your way back to the starting point, and/or have an accurate way of reading tailpipe gases.

A turbo timer - a must-have accessory, or - the biggest waste of money since turbos were invented? We go for the latter judgement, but then we've never seen it as an onerous strain to sit in an idling car for a minute or so! As well as costing money, a turbo timer is also a nice and prominent ignition key bypass...

While it's human nature to look for power panaceas, low cost products that pledge high power gains often fail to produce the goods. The only exception that we know of is a turbo boost control - that's something where for $50, you can get more power! But miniature electric supercharger fans? You make up your own mind.

Cleaning alloys can be the biggest pain... especially if they're of an intricate design. But it's important that you do keep them clean or you'll find that the brake dust has permanently marked the surface. Using a spray-on wheel cleaner followed by a high-pressure spray is easiest; if that doesn't work, use a stiff bristled brush as well.

Heat in an engine bay is a bad thing - it warms intake air (decreasing power), cooks wiring (self explanatory) and can fry the brake fluid (where's me pedal gone?) In this club sprinting Alfa, the owner has lagged the extractors and has also insulated the master cylinder with a neat alloy and insulating tile shield.

The simplest way of adding door speakers without fighting your way through a nightmare of internal clearances, aiming angles (and other trivial problems that always end up taking hours to sort) is to screw on a pair of door pods. Check the speakers for fit before you buy though - 6-inch speakers, for example, can vary widely in actual outside diameters and mounting depths.

Varying the fuel pressure is an easy way of getting more (or less) fuel through the same injectors that are still being controlled by the same ECU. In some systems, richening the high loads a little will be compensated for at low loads by the oxygen sensor feedback loop, meaning that even economy doesn't suffer.

Removing overspray from windows is dead-easy - just use some steel wool in a gentle circular action. Make sure that you get rid of the steel fibres that fall off though: otherwise they can disappear under the trims and into the doors - only to re-appear later as rusty smears.

Single enormous turbos look pretty impressive and can crank out huge power numbers. But on road cars, a single big turbo is always gonna have a heap of lag. Unless the ECU uses anti-lag (a bit anti-social/illegal with those exhaust flames and pops and bangs) or you have a bottle of nitrous in the boot (illegal), anyway.

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