'90 to '91 Comparison...

What are the differances in say the Engine, Ecu and Electrical Harness?
Then what can I change to make it compatible with 91-96 aftermarket performance parts? Thanks Kev

The control system and top end are the largest items to be changed.

1990 featured RENIX - pre-OBD, bulit by Bendix, and rock solid.
1991 featured OBD-I compliant ChryCo SBEC system.

The cylinder head was changed in 1991 to raise the intake ports, and allow for more efficient cylinder filling.

The EGR system was deleted for the 1991 model year.

There are a host of other changes, but those are the big ones. What performance parts are you thinking of adapting? Knowing that would help us to help you - since that's a pretty open-ended question you asked...

5-90

There are headers avalable for the Renix motor. Clifford, Pace Setter and Banks or Borla. (One of Banks or Borla may not have a header for the Renix, I forget wich one.)On the Clifford it has the bung or boss for the EGR tube, but needs drilled out. They also don't supply the cross over tube.
XJ-Armour carries some stuff. Also, Artsounds on E-Bay bores out the Renix TB to 59.5mm. I think he's $100, plus your TB. You can probably do most the other mods. Some use Ford 5.0 injectors with good results. You can adapt the HO TB's with some work.
Valve covers will fit. I put a '95 VC on mine and did the 99+ big tube CCV update. I had to splice the tube to get more length.
Tom

5-90 said:

The control system and top end are the largest items to be changed.

1990 featured RENIX - pre-OBD, bulit by Bendix, and rock solid.
1991 featured OBD-I compliant ChryCo SBEC system.

The cylinder head was changed in 1991 to raise the intake ports, and allow for more efficient cylinder filling.

The EGR system was deleted for the 1991 model year.

There are a host of other changes, but those are the big ones. What performance parts are you thinking of adapting? Knowing that would help us to help you - since that's a pretty open-ended question you asked...

5-90

Click to expand...

So the big changes were in the head, OBD-1, no EGR... So did they get there power increase in '91 with new timing and fuel maps in the ECU, or was it more involved like a new cam lift and duration on top of having the new head? I guess my big question is am I going to have to rip everything out of the engine bay and start over, or can I replace the head, wiring harness, ecu, sensors...etc. and have a 91- motor.

Same cam - they changed management strategies, and the airflow and cylinder filling is better (more air = potential to burn more fuel.) I'm sure you could make much the same power with the RENIX controls - just a matter of changing things a bit to flow more air.

I'm still wondering why you'd want to change over the whole damn system - but if you do, I've got a project (RENIX Decoded) that I'd like to talk to you about getting your old parts - particularly the ECU, any other control electronics (the ignition comes to mind,) and any wiring you remove (since I'm redesigning the wiring harness as well.)


I honestly think you're opening a can of worms here, and it's going to be a lot of work for little gain - especially when you can gain the power with less work. I'd look into the idea of swapping the RENIX top end out for the OBD-I top end, centred around the #7120 (1991-1995) cylinder head - which is probably going to be the best power gain you can find...

5-90

Here's a link to put a HO TB on a Renix motor:
http://www.rockmodified.com/2003/april/TB/tb_perf.htm
I agree with 5-90, you can open a can of worms and there are many ways and levels to do this swap. Also, since your in CO, I believe you have emmission checks. If so and if they are strict then you will need to retain your EGR setup or change to a newer electronics. SO figure about the cost and time. I hear the Renix system get a bit better MPG though.
Tom