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Individual throttle bodies (I.T.B.'s or multi-barrel/choke throttle bodies) are a very good way of getting more power from an N/A engine.  The benefits are twofold, not only do they allow for the least possible intake resistance, but they allow for intake resonance tuning. This is a condition whereby pulses in the intake tract can be tuned to reflect back towards the valve and increase cylinder fill/volumetric efficiency at certain rpm ranges (or, put more simply, it forces more air/fuel mixture in). For this reason they are unsuitable on a pressurized intake system. Turbocharged/supercharged engines/manifolds use the pressure in the plenum chamber to force air into the cylinder, resonant pulses get disrupted. They are an unnecessary complication on boosted engines.
I.T.B.'s always require re-tuning for mainly because the drivers modulation input sensor (or load sensor) is almost always different. Most normal engine management systems use either mass air flow or manifold pressure to determine load. I.T.B.'s utilise minimal air flow resistance so the fitment of an airbox with a mass air flow meter (M.A.F.) would produce undesirable resistance to flow (though airbox setups without M.A.F. sensors can be beneficial, through cold air ducting and mild positive pressurizing through ducting). Additionally, manifold absolute pressure (MAP) sensors determine load from negative (<1bar) pressure in the intake manifold (or higher with boosted engines). With I.T.B.'s the pressure in the intake manifold drops/raises (depending on how you look at it) to near atmospheric the moment you blip the throttle, so pressure sensing becomes unsuitable. The answer is to use throttle position sensing (T.P.S.) for determining load, or a combination of MAP and TPS. It is therefore usually best to run I.T.B.'s with an aftermarket E.C.U. such as those found on our E.C.U. page
We can supply, or custom make, any and all parts required to convert your car to multi throttle intake, such as throttle brackets, manifolds and fuel rails. We can determine the length and cross-sectional area of intake runners required to produce the most useable power from your engine and the demands you have of it
Pricing, given ECU is re-programmable for such use (obvious discounts are available as both ECU prices and the prices below include tuning, and if fitted together would only require tuning once):
Supplied, fitted and tuned:
.From £1475 for typical 4cylinder engine. (including bigger injectors)
Using superbike throttle bodies on custom manifold:
From £750 (using standard injectors)
Cbr1000 fitted to honda engines, including ecu and tuning:
£1000 |
