JimC comments (archive)

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1) I swapped a 735ia engine for the 533i and retained all the 533i's electronics and harness powering the 735ia's mechanicals with no problem. I did have to retain the 533i's flow meter and idle control system to run with the 533i electronics (they changed these quite a bit and are not interchangeable). The injectors though are still from the 735ia engine. I think as long as you change the complete harness with the computer (taking note or the compatabilities of the mechanicals as noted above)you would be fine. I did this 25,000 miles ago and still going strong! One last thing,, you can't just swap the computer alone since the 533is used a separate control for the idle system (the green or black box on top of the computer). In the 535i, it is integrated in the main computer.

2)Sorry I was a way for a while. No, I'm not the JimC of Conforti fame. But I did do the 3.5 mechanical engine swap while retaining the 533i electronics. I did this since the donor car was a 735ia with it's computer linked automatic. I feared this would be incompatible (I later heard from a mechanic friend that I could have retained the 7 series electronics and just ran the car with the extra electrical harnesses for the automatic unplugged...oh well). I did this work two years ago and just took my car if for it's bi-annual emmissions test in IL, where they use a more stringent dyno setup now to test the cars. It passed in flying colors. The car also gets about 20 MPG +/- 1. In my opinion it still runs well. Hope that sets things straight and sorry again for the late reply.

3)I have not measured the imps of either the 735ia, 533i, 535i or Mustang injectors so I can't comment. But I can state that I have run my car over 2 years with the 533i electronics with 3.5L mechanicals as described before with no ill effects. See my earlier post with my name in the subject line for even more info. I answered there first. Maybe it was a risk I took doing this "hybridization" of engines, but it seems to be working fine. No, I haven't tried the Mustang injectors yet, but if they are truely the same imp of the 735ia injectors...I would have to say YES from my 2 year experiment.

I hope that sets the record straight, as far as what I did with my car. No, I do not run a automotive business. I am not a ASE certified mechanic. I am a "shadetree" mechanic at best like a good number of people on this board who tinker with their car(s). Maybe on paper, what I did didn't folow the rules. But the car is running, and runs quite well. The rules also say I shouldn't speed...but that doesn't stop me either.

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