Individual runner intake ECUs

[BBPanel]

Hmmm, so then, just to play devil's advocate for a moment, you believe that the "localized" pressure perturbation caused by the IAC on the MAP in a common block (because of their close proximity) would be much stronger than if they were separated?

Would you expect the MAP to see a lower than actual pressure when the IAC is operating? Wouldn't the IAC only impact MAP readings during idle - and during that time wouldn't the IAC effect be fairly constant? If that is the case, it seems that the percieved lower pressure by the MAP theoretically could be tuned out by adjusting the fuel requirements?

And if that is possible then a common block technique would greatly simplify the plumbing issues. Since the conversion of stack units to EFI is not that common there may not be any actual testing to draw conclusions from to verify or refute which way is better or necessary.

Just trying to reason this through - I have no EFI experience to base it on. -Bob

[camcojb]

Thing is that IAC is moving around at idle which I would THINK would create an unstable idle due to the map fluctuations, but maybe not. It also changes related to temp and even off idle will "park" at some opening value, so it's virtually always open to some point all the time other than if you have the idle stop adjusted too high for the commanded idle speed and the IAC is trying to slow the idle down.

I'm sure the car would still run with the two connected, just doesn't make a lot of sense to me to do that when you can eliminate any issues by keeping them separate. If it sat still at certain points or rpms you could tune around it, but it's "alive" constantly doing something at idle, and moving to a park setting off idle and will also move on throttle shutting, acting as a buffer to prevent stalling on decel.

Jody

[Tom]

Thanks for all the input.

If a distribution block is all you need to make the MAP sensor work with IR intake, I wonder why Roush had trouble getting the Accel unit to work? Of course, I heard this from someone else (reputable, I'm sure) and I don’t know how they got that information.

TWM's IR system comes with this vacuum accumulator which should solve the issue. (see attached picture)

Jody, the system you referred to is the Cobra set up? Did you tune it on an engine or chassis dyno (or both)?

To circle back to the question of which EFI to use, I still haven’t found consensus on which are “best.” But, if Accel, FAST will work w/ IR systems they may be the most cost effective and user friendly.