Thread: Early 4.6 P38 with THOR manifold

I have fitted a Thor to a 14CUX and it is possible but quite a bit of work.

1 Does the GEMS 4.6 have a normal thermostat in the top hose like a 3.9? If it does you have to have the front of the Thor manifold machined to take the Thermostat housing.
2 You may have a problem fitting your fuel rail under the Thor. The older 3.9 rail with the fuel pressure regulator on the RH side of the rail will fit but the later 3.9 rail with the regulator on the LH side will not. Even with my earlier 3.9 rail I had to grind the coil mounting points off the back of the manifold. The Thor manifold has higher pressure and shorter injectors and is one way only with no fuel return so you would have to maybe fab a rail and use your own injectors.

3The Thor TPS is different to the 14CUX TPS . I made up an adapter , but I suspect yours is more like the 14CUX than the Thor. Someone on the forum has found the Thor one would work but I didn't really try.

4 Of course the connection to the MAF will have to be fabbed. You may have to tap it for a pipe to run the IAC.

5 Does your 4.6 have a pin type stepper motor IAC or a Thor type cylindrical "sleeve valve " type. If a pin type stepper there is none in the Thor and you have to fab up a housing.

6 You will probably have to drill and tap a couple of holes in blanks on the Thor for the temp sender.

7 I think you have an electronic ZF so will not be faced with fabbing a kickdown cable. This is the most annoying part of the whole thing.

8 You have to fab up heater hoses so try to get a Thor with its heater hose as it is an Oring type and would be difficult to reproduce without actually buying one.
9 You will have to alter the length and termination of the accelerator cable
The conversion is well worth it and has transformed my 3.9 14CUX. GEMS should be even better.
Regards Philip A

Thank's for the reply Philip,I will check the thermostat situation in the morning as I have 2 manifolds to playwith.
About how much better did this conversion make your Rangie?
Thanks Brett.

Its hard to say exactly but the combination of Unichip with electronic advance control, self modded heads, and the Thor gives about 50% more "tractive effort" at about 1500RPM, tapering to say 20% at 3000RPM, witha loss of 10% over about 3500RPM.
This is ideal for towing as it holds on hills much better than a stock 3.9.

You may not gain as much as I understand the GEMS is much more sophisticated than the 14CUX with knock sensors and electronic advance map, but it should be substantial at lower revs.
Regards Philip A

The P38A, both Thor and GEMS, has the thermostat in the lower radiator hose (although, in my car, it's been moved to the normal position in the inlet manifold).

Sounds too much of a hassle to make it worth while, plus the fact that your vehicle looses it's originality. Also if you go to sell your vehicle in the future, most enthusiast may not approve of the change.

Just my opinion that's all.