RX7Club.com - Mazda RX7 Forum - s5 vs s4 questions

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s5 vs s4 questions

1)If you were to take the OMP off an s5 car would it affect how it runs?

2)If you were to mild SP an s5 engine would it be better to use the stock intake mani with VDI and port it or use the s4 intake manifold?

Re: s5 vs s4 questions

Quote:

Originally posted by Net Seven
1)If you were to take the OMP off an s5 car would it affect how it runs?

2)If you were to mild SP an s5 engine would it be better to use the stock intake mani with VDI and port it or use the s4 intake manifold?

ad 1) you must have electrical OMP hooked up to harnes, but it could be hidden somewhere in corner....motor does not need it if u will go premix, but stock s5 ecu needs it...otherwise it will not run or will but really shitty (limb mode?)

Quote:

Originally posted by Net Seven
If you were to take the OMP off an s5 car would it affect how it runs?

If the OMP is removed the ECU will go into limp-mode and the engine will barely run. If you remove it to premix (I presume that's why you ask) it must remain plugged into the harness. Premixing will have no affect on engine output.

Quote:

If you were to mild SP an s5 engine would it be better to use the stock intake mani with VDI and port it or use the s4 intake manifold?

I don't know why you think the S4 manifold would be any better than the S5 one just because of a street port. The VDI is responsible for a big chunk of the power advantage the S5 has over the S4.