Tuesday, March 12, 2013

IR EFI using Weber Manifold

After researching Weber carburetors extensively on the internet, talking to people who run them, talking to tuners, etc, I decided to look into IR EFI options with the same Aussiespeed manifold.  I thought for some reason that few made a throttle body for the IDF pattern, but I was wrong.

Weber carburetors are really neat, but independent runner electronic fuel injection allows for similar benefits without some of the drawbacks.  The general drawback to IR EFI is the cost.  However, I am pleased to show a couple options that reduce the cost of such systems.

Throttle Bodies

There are several EFI throttle bodies available for the Weber IDF setup, mainly geared toward the air-cooled VW world.  However, there is no reason why these throttle bodies wouldn't work on the Aussiespeed manifold.  For example, CB Performance has a set of two throttle bodies for $530 that are exact dimensional replacements for Weber IDF carburetors.  The throttle bodies feature integral injector bosses, vacuum/IAC ports, allow for the same linkage, and are machined to accept a throttle position sensor.  I wouldn't recommend their fuel rail as it appears to be too small for a healthy V8, but fuel rail blanks are easy to find and easy to have machined.  The nice thing about using a set of exact matching throttle bodies is that you could run Weber carburetors for a while and then switch to EFI without much work.  Your linkage would be the same, your height would be the same, etc.


Many of the well-known EFI systems out there will work okay with IR EFI.  TWM even recommended that I look into FAST EZ EFI, claiming that there are a lot of people running this EFI system without issue on IR EFI systems.  The downside to EZ EFI is that it won't control spark timing. The next generation, EZ EFI 2.0 reportedly will control spark timing.

Kelly Coffield likes the Electromotive offerings, stating that there is a speed density/alpha N blend feature that makes tuning finicky IR systems much easier.  Also, he likes to stay with systems that allow full sequential injector firing over bank fire systems.