Old school is cool. Even een vergelijk throttle bodies en dubbele carb's. Auteur noemt
ong. 5% meer vermogenstoename in het voordeel van TB's.
Bron:
http://www.pumaracing.co.uk
INDUCTION SYSTEMS
There are so many designs of standard carburetor or injection system that it is impossible to list all the permutations of power gain that are possible from replacing one type with another. We'll look at two representative examples which give an idea of the power gains available.
Twin DCOE Webers
These are usually used to replace a standard twin choke downdraft carb such as those fitted to Pinto, CVH and many other types of engine. Expect about 10% increase in power on a standard engine and up to 15% as the engine is tuned and the standard carb gets more and more restrictive.
4 butterfly throttle body systems
The fuel injection equivalent of the DCOE, these are usually used to replace a standard single or twin butterfly plenum injection system. Expect about 15% increase in power as an average with up to 20% on some engines. It all depends on how good the standard system is of course and how heavily the rest of the engine has been modified and therefore how restrictive the standard system has become. The Vauxhall 2 litre XE engine for example is particularly responsive to having throttle bodies fitted and you can expect to see about 180 bhp instead of the standard 150 bhp (20% extra power) with just these and a decent exhaust system in a Westfield or similar. Claims of well over 200 bhp with just throttle bodies on this engine abound though and you can make your own minds up about those now. I've just had some engine dyno feedback on a 2 litre Zetec where our 45mm TBs increased the power from 174 bhp to 201 bhp on a modified engine in a back to back test against the standard plenum. Copyright David Baker and Puma Race Engines
I'm often asked how much extra power a 4 butterfly TB system gives over DCOEs. Usually around 5% in terms of peak power but there are more benefits than just this. Using really big carbs, or big chokes, to get the best peak power leads to poor low rpm operation and high fuel consumption. TBs can be sized for best power and still give excellent economy and good low rpm torque and they usually enable a hotter cam to be used while still retaining tractability.
