Individual runner intake ECUs

[Tom]

Has anyone had any experience using individual runner FI intakes (TWN, Kinsler etc.) ? Specifically, I’m interested in the EFI units used to run these IR systems.

(Notes: Motor is an early SBC. Looking at IR systems for the visual “pop” over TB systems.)



I’ve been reading and talking with as many people as I can and this is what I’m hearing:

Electromotive: good, but hard to set up and work with, poor support

Accel DFI: good overall, but hard to get to work w/ IR systems b/c needs a MAP sensor and it is difficult to get a vacuum accumulator to work correctly with 8 throttle bodies. (Apparently Roush had a lot of trouble getting it to work w/ their new IR crate set up.)

MoTec: the best, outrageous price, overkill for most street applications

I appreciate your thoughts.

[camcojb]

I ran one with a FAST that worked awesome. Any of the aftermarket units that are speed density like the FAST, Gen VII, and Holley Commander 950 will all work great, but they all need a map sensor. Not a big deal on a single plane manifold, but with IR you need to have a single line from each runner, tie them into a junction box, and then to the map sensor. If you want to run idle air control you'll need an additional line per runner, and the same for power brakes or pcv. PB and pcv can share a line, but the map and IAC need to be on their own circuit.

On my Hilborn setup I had three separate lines into each runner. Think nitrous system for how the lines were run and junctioned. What mine had though was the lines were hidden under the manifold with the junction block just like a hidden nitrous system. I then used a bulkhead AN fitting through the rear of the manifold to give a connection up top for the IAC, map sensor, and pcv/pb

Jody

[Fuelie Fan]

We've only had one customer so far do an IR setup, and we ended up doing it alpha-N. Worked as well as one can expect alpha N to work, he was quite happy

[tireman]

I'm going to try an Electromotive unit on my converted Hilborn. It has a feature that is interesting for IR setups. They call it Alpha blending. Essentially, you can smooth out your MAP signal at low throttle openings using the throttle position sensor output. On paper it looks like an interesting solution to the pulsing MAP signal issues encountered on IR manifolds. Unfortunately, I won't be able to try it until I get back to the states in November, so I don't yet have practical experience with it to tell you about. The other thing I really liked was their 60 tooth crank trigger setup.

From a software standpoint, I downloaded the FAST, Accel, and Motec software. I preferred the Electromotive interface. I also downloaded all the different manuals for comparison and was impressed with the Electromotive documentation. That might be because I already used an Electromotive system in college for an SAE Formula car, but it seemed clearly explained to me.

For right now, my Tec3 is running only the ignition on my car (I installed it on vacation in the states last year). It worked fine at first, but I did blow two of the coils for some reason. Electromotive was a great help in diagnosing the problem and replaced them immediately with appologies. With the two new coils it runs great again. I was very happy with their support. I just hope I don't have any more trouble. I never had trouble with their old system that I used before.

Hope this helps...

[OHCbird]

Ditto what Jody did (hidden underneath); DFI works no problem.

[BBPanel]

Why is it necessary to separate the MAP and IAC? Do they interfere with each other - how? Has anyone actually tried using a common block for these sensors/controls or is it just the "accepted" understanding that it won't work? -Bob

[camcojb]

Why is it necessary to separate the MAP and IAC? Do they interfere with each other - how? Has anyone actually tried using a common block for these sensors/controls or is it just the "accepted" understanding that it won't work? -Bob

The IAC is a controlled vacuum leak. The MAP needs to read engine vacuum. All the fuel adjustments are affected by that vacuum. It would cause instability every time that IAC moved positions to try to stabilize the idle. You just don't share the map signal with anything else. I also wouldn't share the IAC with anything else.

Jody

[camcojb]

I tuned it on a chassis dyno and then did the final blending on back roads. It requires a bit of fabbing as you don't want to pull your vacuum signal from just one runner, and since there is no common plenum you have to pull from all eight, run to a junction box, and then to the map sensor. Same for the IAC, eight more separate lines as you don't want the IAC pulling off only one cylinder either as it would always be leaner than the rest, quite possibly to the point of detonation and damage.

On the Accel difficulty, it is one of the more difficult systems to tune. Unless you have someone experienced with it many tuners get frustrated with it, they have lost a few dealers because of it. Not a bad system at all when tuned, but often more trouble to get there than it needs to be. The Holley and FAST will definitely do what you want and are relatively simple to tune. The new Big Stuff 3 is also a nice way to go, but I have not tuned it yet (sitting ready to go in my garage). It's the latest system from John Meaney who developed FAST and assisted in other EFI systems.

Jody