The advantages of using Taper throttles over the parallel type

Taper Throttles kit are made up from 4 single bodies (on a 4 cylinder engine) which is 66mm long tapering from a 48mm diameter hole at the ram pipe end down to 42.7mms at the manifold face, with a 45mm butterfly in the middle.

The main advantages of using a tapered singled body over parallel bodies & slides that we have found in tests are:-

1.        Being individually adjustable they can be perfectly set-up.

2.        We have found that the use of a taper that continues the shape of the ram pipe right through the throttle & manifold up to the valve, has improved torque through almost the entire power band.

3.        Also we have found that the use of a 45mm butterfly in junction with a taper has improved throttle response. We carried out tests quite a few years ago comparing a taper throttle body with a slide throttle; both being of a similar size, as it is had been suggested to us that an intake system such as slide or barrel throttle systems, would surely produce more power because there is no butterfly restricting the port. The back-to-back test showed virtually no difference in peak power at all, but the throttle response on the taper body system was significantly better than the slide system. We also have found more recently in tests the similar poor throttle response with barrel throttles.

4.        The peak BHP that we have seen from the tapers (with 45mm butterfly’s) is better than we have achieved in similar tests using 48mm parallel bodies or a slide throttle assembly.

This range of kits has been specifically designed for the XE & ECOTEC engine of 1.6L capacity of 16-valve design. All these kits come complete with an MBE Ecu which is ready programmed & ready to use, however for our higher specification kits we would recommend a mapping session to fine-tune the engine.

They are both smoother than the 2.0L throughout the entire rev range with comparative increase in bottom end torque as well as substantial increases in power at the top end.

We have run these kits in a closed cell Dynamometer with various different exhaust systems and manifolds, so whatever vehicle you put them into and whichever manifold you use, we are in a position to supply a programme that will run it.

The addition of the taper throttles to this management system, on this remarkable little engine is startling and produces a greater power increase than the same modification does for the 2.0L. We have achieved a genuine 164bhp (standard engine is 109bhp) and still have not touched the engine. The engine is on song at very low revs, and has a torque curve which is virtually flat from side to side of the graph, whilst the power curve simply climbs at a very steady gradient.

*The results have been achieved using a Corsa GSI, which has larger ports than later heads, if you are running any other cylinder head the results can vary. We have had reports of engines producing 10 to 20 bhp less.

We have also reworked the head and tuned the engine to race specification and achieved 241BHP. These engines have proved very popular with one of our customers who bought a new engine every year for the last 3 years. The results that they achieve are excellent.

The kits shown allow you the choice of one of three types of off the shelf wiring harness. These have been specifically designed to be as neat as possible and to cover as many applications. These wiring looms are kept on the shelf with a selection of coil adaptors, which will allow you to fit to a range of ignition coils or by using our coil (COIL-4 offered as a recommended option). If you wish to have a wiring loom custom made to your own drawing specification, this is no problem, but will take approximately 4 weeks to produce from receipt of your finished drawing. If you refer to the section on ECU's we have listed all the specifications and options available that you can add. The only optional upgrade that can done to the standard harnesses before dispatch is the addition of a barometric pressure sensor.

These kits will yield their true potential only when used in conjunction with of our exhaust manifold or one made to our design and a suitable exhaust system

Please note that most of the kits do not include oil system upgrades, this is because it will depend on the type of car & the rules of the Championship you will be using it for but it is recommended that a Dry sump system is used if possible. Please read the section on oil systems & ring for more details if you need help.

This is our 1.6L XE Display engine showing the upper & lower injector set-up of our Top of the range Taper Throttle Kit.