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Thor - Replacement AFM Heat Issues


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I am putting a Thor 4.6 into my 101 – it is a tight fit, particularly in the left side of the engine.  The air intake will take a 90 degree bend from the throttle body and run back to the rear on the outside of engine on the passenger side.  I intend to install the Megasquirt Thor AFM replacement unit for Manifold Air Temp (MAT) sensor and PWM Control.  The AFM Unit is fitted between the Plenum Entry and the Air Filter.

Now I might be worrying about nothing but this temp sensor which is on the bottom of the replacement AFM unit sits only a few inches above the exhaust manifold and there is little air flow in the area.  I can move the temp sensor to the top of the AFM unit by adding a new port but I still have a concern that the heat soak from the exhaust may give false readings from the MAT sensor.

Here are two pics – one with the engine in the vehicle and another showing where the replacement AFM sits.

So am I worrying about nothing?

InkedPXL_20210207_013645280_LI.jpg

P8040017_LI.jpg

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This is just an off the wall idea as I have no experience.

The throttle body looks to unbolt, could you use a cut down throttle body as a pipe fitting and relocate the actual throttle body behind or i front of the engine?

For that matter can you not route the pipe forward anyway and extend the pipe for the PWM control?

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1 hour ago, missingsid said:

This is just an off the wall idea as I have no experience.

The throttle body looks to unbolt, could you use a cut down throttle body as a pipe fitting and relocate the actual throttle body behind or i front of the engine?

For that matter can you not route the pipe forward anyway and extend the pipe for the PWM control?

Thanks for the input - yes the throttle does unbolt and piping for the PWM is not an issue as it is easily sorted.  Unfortunately with the Thor intake being on the left, there is no way the piping can be turned forward as the seat when it is in place will be in the way as going forward will be in the cabin.  I have already had to cut a hole in the cabin body work the feed the piping back to the air filter which its outlet pipe is in line with the back of the engine on the passenger side. (a bit hard to see.

Also when you say "cut down" throttle body - do you have an examples?

Appreciate your comments.

 

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1 hour ago, Bowie69 said:

Where is the air box going? Quite ok to put the MAT sensor in there.

The outlet from the airbox airbox is that dark shape to the left, about mid way between the yellow arrow and the green handled screw driver in the second pic. 

Based on your comments and those of Missingsid an idea is forming.

Remove the throttle body and mount a 90 degree bend to the intake plenum - mount the throttle body where the yellow arrow is in the top pic and mount the replacement AFM in the air box as you suggest - the air box is a cylindrical tube about 10" across and about a foot long - the air filter is nearly as large and the replacement AFM could fit inside the cylindrical air filter.

My main concern would be is what impact on the system would there be mounting the throttle body away from the plenum.

This is the air filter arrangement.

Cheers

Garry

air filter.jpg

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MAT sensor doesn't really mind too much where it is, it's not massively affecting the fuelling although it may see heat-soak after a long "run, stop, re-start" situation if it's above the exhaust.

I can't remember the thread (M14 fine?) but you can drill & tap and fit it into almost anywhere in the intake tract from the airbox to the plenum, it won't mind.

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18 minutes ago, elbekko said:

I wouldn't move the throttle body. I'd expect the volume behind the throttle body to be pretty precisely tuned, not sure what effect it'll have to move it.

Agreed with this, could cause all sorts of issues...

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  • 2 weeks later...

Thinking further on this and doing some measurements.  With the arrangement pictured above as you can see it is a very tight fit and part of the body work has to be cut away to make it fit.  I also have at home a old 3.9 with the 14CUX injection manifolds etc still on it.  I had decided not to use this as the inlet is only 65mm where the Thor is around 78mm so I thought would breathe better with a 4.6 engine.  However tinkering around yesterday I did some further measuring and while the inlets are different sizes, the actual butterflys in the throttle bodies are the same at 65mm - the thor inlet narrows down before the butterfly I guess to speed up airfow to push its way through the long bananas where the 14CUX is straight into the plenum and into the engine.  I dont know if the injectors are different but I think I could just fit the 4.6 injectors in if they flow more than the 3.9 injectors.

The other advantage is that I can turn the 3.9 plenum around so the intake is on the drivers side and run the air intake around the back of the engine.  i can then just use a 14CUX ECU to run injection and my mejajolt run the ignition.

Given that GEMs produces more power but less low down torque than Thor I assume it is the same with 14CUX - the torque difference is not such an issue as the 101 is so low geared anyway.

Any thoughts?  Any thing I have missed?  If 14CUX will work near as good as Thor, the ease of installation will be so much better.

Thanks

Garry

 

 

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