The tapered throttle body system which Richard Jenvey and Steve Broughton of SBD Motorsport have developed back in 1995 for the 2.0L XE originally at that time for a touring car project which has been so successful, even spawning many copies.
We decided that the fact that the 2.0L XE was still very popular, that is was time to look at the design again which everything that we had learnt in developing the Hayabusa and Duratec high specification throttle bodies. We contacted Jenvey Dynamics again, who have helped us to develop all our own special throttle body projects over the years and started designing a new intake system to suit the 2.0L XE as well as it’s larger capacity versions, 2.2L, 2.3L, 2.4L & 2.5L which are now being built.
We incorporated all the latest designs and developments into the system and the first prototype was ready for testing for the beginning of December. One of our main dealers had a test engine ready that could have the throttle system tested immediately, so it was shipped to Ivan Orr at Cormeen Motorsport and fitted to his 2.3L XE engine. He carried out back to back tests with our original throttle system in the morning, then fitted the new system and carried out the same tests in the afternoon. The initial results are even better than we had hoped, we saw an increase in peak torque of 14lbft and an increase in bhp of 13bhp, in fact the torque curve had improved everywhere from 2500rpm upwards. Ivan is now getting a 2.0L XE engine ready to carry out a similar test and has already sold the first system to one of his customers.
The tapered throttle body has a 54mm entry tapering down to a 52mm butterfly. The taper then continues on through the throttle body then into the manifold and down to the cylinder head. The size of the inlet duct where it meets the cylinder head is 48mm wide x 32.50mm high. The port shape we have developed to match up with our high specification CNC ported cylinder head, this means the inlet manifold should not require any porting when mated to one of these cylinder heads. Please download the pdf at the bottom of the page for the TP-VX-2.0-K3 dimensions.
The injectors are now mounted underneath the throttle body pointing at an upwards direction at the correct angle so that upon butterfly opening high gas speed is achieved allowing very fast throttle response. Because the injector is mounted much higher up the inlet track, this allows improved air/fuel mix, which we have found in many tests to give identical improvements to that seen with an 8-injector set up but also allows for reduced complexity. Great care has also been taken to ensure that the package is very neat and compact as possible, which means we can use a flat air filter back plate without the need for any complex stepped back plates.
The system comes with a build in single cable throttle linkage mounting assembly, but we have designed options that will allow the use of the more traditional single or twin cable Jenvey throttle linkage kit, see below.
The overall length of the system including airhorns is identical to the length of our earlier system TP2K. This means that any customers using the original system with 90mm air horns can easily upgrade to the latest system.
The kit includes inlet manifold, throttle bodies, air horns, fuel rail and throttle cable bracket. It will come assembled, but without the injectors or water elbow TP5 as these depend on your installation.