Recently picked up a '94 JDM Eunos, 1.8 flavour, far too cheap from far too sketchy a seller, but it was an impulse-buy. Only had it a couple of weeks. I’ve been working my way through its assorted problems and just came to the exhaust blow.
The blow is at the catalytic converter rear flange, so I thought, right; fresh gasket, that’ll sort the blighter out.
Turns out the two flanges aren’t coming up flat together. The top side’s got a gap. When it’s all bolted up, the back-box’s hangers are canted over frontwards severely, but the midsection’s hangers drop straight. I don’t know if this means anything.
Standard (or at least Mazda-looking) exhaust, twin-box, 370mm cat with what I presume is a heat-sensor or somesuch, in the tail-end. Downpipe of unknown heritage. No known modifications to exhaust system, and all parts cat/forwards look original.
I’ve been told that a '94 JDM 1.8 should have a 440mm cat, but with a downpipe that matches it, so the rear flange comes out at the same point, but I don’t know if that’s true. Even if this was a 370 cat on a 440 downpipe, there doesn’t seem enough room for an extra 7cm of cat in there, but I’m stumped otherwise. I’ve been told all exhaust systems are the same after the cat, but parts suppliers do list separate ‘standard’ exhaust for early/JDM cars, it seems.
Pics aren’t the best but it’s a sod to aim a smartphone like that.
I’m open to the prospect that it’s just mullered flanges, and not some intricate and arcane mystery of the great Previous Owner Parts Carousel, but you never know. Any ideas?
Ta.
Edit: Apologies if this is the wrong section, but none of the others seemed preferable.
Your Eunos would have originally been fitted with a 370mm cat and bespoke front pipe. The cat is certainly an original and I would expect the front pipe to match too.
My theory is the problem relates to the catback which is a replacement. There are three varieties of catback for the MK1/Eunos 1989 - 1998. Two are the same length and will interchange. These are the ones for the 370mm Eunos/early MK1 cat and later MK1 440mm cat. I think the previous owner has tried to fit the third type of catback, designed for the longer 575mm cat fitted to the last of the MK1 cars. This is 2 inches shorter in length and would account for your problems.
If you can get a part number off the catback I will confirm. It doesn’t help when a well known resource such as the Klarius online catalogue still lists the longer cat with the longer catback and the shorter cat with the shorter catback. I did email them about this years ago but they appear to have ignored me.
If you are interested in purchasing the correct part, private message and I will point you in the right direction.
