Power for the People
“Hoekom skryf jy nie or; hoe om ‘n Enjin bietjie woema te gee?” I have been asked this Question a number of times and want to ask, “Why don’t you read my Articles more in depth? It is all there!” Ok before you heap abuse on me and tell me that stuff is alright for a MIT student, I will go through the Basic principles of Modifications and hope it will just get your Vehicle running right – as it should on the showroom:
Efficiency is what it is all about. Trying to make the most usable power out of the least fuel. The standard being 0.5 brake specific Horsepower (300 HP needs 150 lbs. Fuel an Hour).
Firstly get yourself a decent Workshop Manual. Then set up your Engine to stock specs, making notes of component changes etc. 2 things horrify me; Customers bringing engines in with timing and dwell way out of whack and expecting the “cam” to make a difference. Or people phoning me saying “My car ran good and now that I set everything up to spec it “hoeses en proeses”- when asking them before and after specs, I get told “Hoe moet ek weet”. Sorry Bud make notes !
Does your Engine get enough CLEAN and cold air. The amount of people modifying their Air intake systems for a nice Noise is staggering. Your motor wants cold Air and plenty of it- no need to Ram it in but remove all intake restrictions. You might need to jet richer if the stock system was bad. Yes even on your Stationary Motor it will help to put the Intake outside the Engine room to get COLD Air.
Now that your Engine gets all the Cold, Clean Air it wants- what about getting the Wastes out. A header (Piesagtakuitlaatstelsel) gets constructed according to:
Engine RPM where you want the Power
When your Exhaust valve opens
The remainder of your Exhaust should not be too restrictive, but beware of not running any kind of system. There are quite a few scientific theories, none though incorporate “Backpressure”.
Now it is time for my speciality, the head. It is most important to ensure adequate flow of Mixture into the Combustion chamber, without mixture separation. Whoever tries to impress you with before and after flow figures- wish him a good day and strike his name of your address book. Most modern heads flow Generously for street use but have weird contours and bad machine work done to them. Terms like Swirl and Tumble mean a lot to the professional but are sadly abused by the countless of Con men operating their “Flow centres”. The way the exhaust gasses flow in their port is of utmost importance and determine if you will have a bottom end or top end motor. Skimming the head increases compression and in the case of an OHC motor will get your cam timing out of whack.
Cams are the brain of your Engine, if the Intake opens to early you will get intake dilution and stand-off. Close too late and the Incoming charge will get blown back. On the Exhaust an early opening will bleed of exhaust gasses that could power the Piston. Late Closing will cause the intake charge to go out of the exhaust causing the racing Popping noises. Lift can really baffle our brains- try to find out at what lift your valve will spend most of its time, and it will not be at maximum. Also a Flow Bench will quickly determine at what lift you will have what kind of flow and how much. So what am I trying to tell you “Stop calling me and asking for a Stage 2 cam” as I have not got a clue what you are talking about and neither have you- show your Ignorance in a unique way please. A stage is where a band performs or a Stripper for that matter. I for one take serious time in determining what kind of cam works best with my modifications.
Now hat you have done all these Modifications, you usually have to Adjust the carburettor. Quite often I choose to replace the stock unit with something like a Weber. Not because the stock unit is too small but often because no Jets etc. are available. In the case of Fuel injection we can be lucky and be within the systems parameters. If not then we can either go to an Aftermarket CPU or we can go to a Piggyback unit that sits between the standard CPU and the pickups, modifying their signal. I am not in favour of “Chip Tuning”, by whatever name it goes unless a particular vehicle has its “Chip” adjusted on a Dyno by the particular “Electro Wizard”. The universal Chips you buy normally tend to run a little bit Richer (meaning maybe more Power) and more timing Advance (meaning maybe a Blown Motor). Factories build in Safety Margins for Reliability and fuel Economy and I need no “Hacker” to scratch around there !
Please remember that you cannot expect a Motor to perform to its optimum unless it is kept in Tune. It is surprising to see how many vehicles come in for a Carb or so with everything way out of tune. Also once a vehicle is modified some parameters change, such as Timing, plug range and gap and valve gap. By the way the next person phoning me asking for these values on a motor that was not done by me will get his Name mentioned here by means of “Abschreckendes beispiel”. How am I supposed to know how the original “Tuner” wanted the vehicle set up and then it is a groce Insult to me by having the Job done elsewhere and expect me to do the dirty work afterward !
When you do the tuning, remember what fuel is in the tank and think of what you are going to use in Future. Unleaded for now has a higher Octane level (95 vs. 93), which means it is more resistant to knocking. In other words it can take more timing and Compression. If you have EFI Beware of the fact that unleaded will etch into the needle, this by itself is normal and will not be really noticed. Leaded though will form a deposit on those etchings, throwing the metering way out of Whack. Therefore run 1 type of Fuel in an EFI system all its life. Technically speaking- Leaded is the way to go as it is Easier on the Motor considering Octane ratings to be equal. Seeing that Unleaded here is of higher Octane, and if it remains a good quality, then I would run my Vehicle on that from the start- of course if it were compatible. Avgas can be mixed into Leaded up to 50% to also increase performance, though no more than that is safe for your Motor in the Long run. Race Fuels = Race Motors- Simple ain’t it ? Those substituting Paraffin for Diesel will cause expensive damage to the Engine according to the SA Petroleum Industries Federation.
Also you sometimes get a particular vehicle that runs worse or better than another of the same Model. This is caused by variations in production tolerances and are generally not cured by us Tuners, as we often do not carry out work on those parts concerned. You can always do the push test by first pushing one and then the other vehicle and if the one is harder to get rolling you know you have resistance in the drive train. Same can be done with both cars driving along parallel each other at speed and then both have the foot taken of the accelerator simultaneously- the one slowing Quicker has another problem then besides the Engine.
Of course there are many products advertised that give you the ultimate Performance edge, such as; Zoom tube tips for your Exhaust, Air intake swirl devices, Fuel ionisers, additives etc. Guess why I don’t bother selling them ? Anybody using them stands out more than the pope in a Speedo- at least in my eyes ! Sorry I am conservative in my thinking, but that way I sleep easier. When working overseas I used to have a cure for the Overzealous tuners- the parts they Broke they had to wear around their neck like an Albatross.