Different Catalytic Converter lengths?

Technical Area Engine, Transmission, Exhaust etc
1
  1. My model of MX-5 is: 1990 NA
  2. I’m based near: Chesterfield
  3. I’m looking for technical help or recommendations on: Exhaust Replacements

Hello,

I’m aware I asked a different question about my cat a few days ago.

I’m about to buy a cobalt exhaust, and a friend of mine has noticed some small print in the description that could potentially cause an issue.

I have an early UK-spec NA. Literally all the info I have. Does anybody know if the highlight part of the screenshot below is going to cause me any issues?

I am not able to jack my car up and measure as I’m away from home for another few days.

Cheers,

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The 475mm cat was only on later MK1’s your 1990 car wont have that size cat.

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Yours will be the 370mm one.

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4

Thanks all.

I know it seems like I’m a moron for not knowing this.

5

The cat back exhaust is the same for 370mm and 440mm cats. Only the manifold and down pipe is different.

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I only bought the mid pipe and backbox.

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not in my experience

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I bought a stainless cat back for my 1.6 that had the 370mm cat. Then turbocharged it, which came with a 440mm cat compatible down pipe. So had to swap the cat for a 440mm cat to make it fit. So, from the rear flange of the cat back, the exhaust is in the same position.