Tbi swap build thread

[cjracing15]

Originally Posted by pancake

Hello again, I have a quick question.

If I use a adapter plate to bolt the TBI to a carb intake:

1) are there rules on whereto mount the sensors that were mounted to the TBI intake.

2) can I use a diffrent coil mounted to the firewall? what kind of coil do I need?

Thanks again.

1) I would put the sensors as close as I could as the factory did it.

2) As for the coil I am not sure. I am sure RF will chime in on it. He rocks on the wiring diagrams.

[rfmaster]

Originally Posted by cjracing15

1) I would put the sensors as close as I could as the factory did it.

2) As for the coil I am not sure. I am sure RF will chime in on it. He rocks on the wiring diagrams.

Thanks CJ

Pancake - you can mount coil on the fire wall (or in its original location). If you do so make sure to run a ground strap (braid) between intake and coil mounting bracket. Low resistance ground return path is required between EST and coil.

I have seen third gen boys mount monster sized coils (lots money) on the firewall. Generally, performance coils can be saver and trouble all rolled into one. The problem stems from current requirement that these coils place on EST module (inside dizzy). To get HV coil to deliver joules of spark energy (at 40 - 50kV) requires more current flowing through the primary (12 volt winding). EST module operates as a switch which turns on & off current flowing through the coils primary windings. More current = more heat. Semiconductor devices do not like heat and fail over time if subjected to operation beyond rated limits. For our trucks, with engines spending most of their lives below 3000 RPMs use of 'monster' coils is not necessary.

One of these days I'll setup experiment in my lab to measure primary coil winding current and publish my results. I have factory coils, but I do not have any 'monsters' for obvious reasons.

As to recommendation on coil - I have never used anything but stock, hence I can not recommend one.

Sensor placement. I prefer to mount my sensors away from heat sources for the aforementioned reasons. I mounted my MAP on the firewall, ESC module is mounted on fender skirt. All my relays are mounted away from engine. GM mounted the same sensors on a bracket bolted to intake manifold.

//RF