The Complete List of Factory-Fitted ITB Engines.

So, you’re looking to convert your engine from a single throttle body to individual throttle bodies (ITBs).

While there are plenty of aftermarket individual throttle body options out there from companies like Jenvey and EFI Hardware, some vehicles were blessed with ITBs as standard. If you can find any of these cars at a junkyard or the actual parts for sale online, you might have a cost-effective solution for converting your project car to individual throttles. 

The list of production road engines that use an individual throttle body system is surprisingly short, and dominated by BMW’s M cars. Nearly all of these motors are naturally aspirated, except for Toyota’s supercharged 4A-GZE 20 valve, Nissan’s RB26DETT, and the unique SR20DET found in Nissan’s Pulsar GTI-R. 

What are Individual Throttle Bodies?

As the name suggests, individual throttle bodies — or “ITBs” — refer to an intake arrangement in which, instead of one large single throttle body controlling the flow of air into an engine’s cylinders, we have an individual throttle body per cylinder doing the same job. This means, for example, that an inline-four cylinder will have four throttle bodies and a V10 will have 10.

In short, this allows for more precise control of air intake and reduced restrictions, which can improve throttle response and increase power output — however, this is highly dependent on the specifics of the engine and existing intake tract. 

ITB's biggest benefit (in the case of naturally aspirated engines at least) is the ability to tune power characteristics through the intake trumpets feeding each throttle body. Adjusting the length of these trumpets can increase power higher up in the rev range at the expense of power lower down, and vice versa, depending on what’s required.

This is something we dive into in more detail in this article discussing ITBs, as well as our ITB Tuning Explained webinar. 

Engines With Individual Throttle Bodies as Standard

Here’s the complete list of road-going engines that feature ITBs straight off the factory floor — if you know of any others, let us know and we’ll add them in!

• Alfa Romeo 1.7 16v boxer 4 (Alfa 33)
• BMW M88 inline 6 (M1)
• BMW M88/3 inline 6 (M635 CSi, M5)
• BMW S14B23 inline 4 (E30 M3)
• BMW S38B35, S38B36, S38B38 inline 6 (E28 M5, E24 M6, E24 M635 CSi)
• BMW S50B30 inline 6 (E36 M3)
• BMW S54B32 inline 6 (E46 M3, E36/7 Z3 M Roadster, E36/8 M Coupe, E85 Z4 M Roadster, E86 Z4 M Coupe)
• BMW S54B32HP inline 6 (E46 M3 CSL)
• BMW S50B32 inline 6 (E36 M3 Evo)
• BMW S62B50 V8 (E39 M5, E52 Z8)
• BMW S65B40 V8 (E90/E92 M3)
• BMW S85B50 V10 (E60/E61 M5, E63/E64 M6)
• BMW S70/2 V10 (McLaren F1) 
• Nissan RB26DETT inline 6 (R32, R33, R34 Skyline GT-R)
• Nissan SR20DET inline 4 (RB14 Pulsar GTI-R)
• Toyota 4A-GE 20-valve inline 4 (AE101 Levin/Trueno, AE101 Ceres GT, AE101 Marino GT, AE101 Corolla FX GT, AE101 Sprinter GT, AT210 Carina GT) 
• Toyota 4A-GZE 20-valve inline 4
• Rover K Series VHPD inline 4 (Lotus Exige, Elise)
• Honda E07A MTREC inline 3 (Beat)
• Ferrari F129 V8 (F355)
• Toyota/Yamaha 1LR-GUE V10 (Lexus LFA)
   

How Can You Learn More About Individual Throttle Bodies?

Once you’ve obtained individual throttle bodies, either from another vehicle or through aftermarket options, the next step is fitting, setting up, and tuning them on your car. This can present some unique challenges, but once you understand them, you’ll be well on your way to perfectly synchronised, howling ITBs. 

If you want to start learning check out the EFI tuning courses.

Start with "Introduction to Engine Tuning", then advance to the "EFI Tuning Fundamentals" course. Alternatively, bundle these together (along with “Understanding AFR”) and grab yourself a deal with the"Tuning Starter Package".