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Home » Hardware Components » Individual Throttle Bodies » IDA Type » PRO-RACE IDA 55/53/50 Tapered Bore Throttle Body

PRO-RACE IDA 55/53/50 Tapered Bore Throttle Body

55/53/50 - 55mm at ram tube face, 53mm across the butterfly & 50mm at the manifold face.
IDA throttle bodies feature 2 injector bosses per throat. Ram tube flanges are 70mm PCD (vacuum port for map sensor optional extra)

Product Code:

AUD $490.00 (ex GST)

Product Details


Every single throttle bore and throttle plate are measured and matched as a pair to ensure the most perfect throttle fit and consistency across every EFI Hardware throttle body.



IDA Throttle Body Technical Drawing




HP/kW Ratings vary from engine to engine.  The power ratings given here are only a guide, and are not absolute power ratings.  Engine power is determined by intake, exhaust, cylinder head design, camshaft design, compression ratio, fuel type and quality and many other factors.


55/53/50mm - 80HP/60KW* per throttle - with the tapered bore giving a potential for 5% above this figure.


*This number is a guide only and should be used in conjunction with real-world experience.




Tapered Bore Throttles have a clear advantage over Parallel Bore Throttles at increasing power and torque. By accelerating the air through a venturi (in this case a tapered bore) the air speed through the throttle body is increased.  This enhances the engine cycle's scavenging effect to provide more air and fuel in the combustion chamber and therefore more power and torque..


The Tapered Bore has 3 sections:

Inlet from ram tube - 55mm

This then tapers down to a short parallel section for the throttle plate - 53mm

There is a second taper down to the outlet flange of the throttle body - 50mm





In the past, 12° throttle plates were the industry standard.  The problem with 12° throttle plates, is that as the plates are moved off the closed position, the change in airflow is huge.  It makes it very difficult to drive smoothly at lower throttle openings.


At EFI Hardware, we only use 6° throttle plates.  This improves off idle and cruise driveability making your vehicle far more enjoyable to drive.


Manufactured from 601 Cast aluminum and heat treated before being CNC machined.

The butterflies are measured for each bore & precision machined to a 0.0005"" tolerance.

Butterflies are secured to centreless ground brass shafts with split screws to ensure reliability and serviceability.

All are fitted with bearings rather than bushes to eliminate axial shaft movement.

Low stiction bearings for sharp throttle response.


We now recommend

and use SKF bearings.

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