NA6 vs NA8 vs NB8a vs NB8b exhaust differences?

jerrah · Postby **jerrah** » Thu Jan 27, 2011 4:02 pm

Hangers and headers aside, what were the pipe size differences between these models?

Did the 1.8's use a 2 1/4 exhaust stock?

Steampunk · Postby **Steampunk** » Thu Jan 27, 2011 4:14 pm

- Little difference between NA6 & NA8, the main one is two different cat lengths. Fair chance that later model NA6 (don't know what year onward) share same cat as NA8. So in short, virtually no difference between late model NA6 and all NA8.

- I think early NA6, or it could be just the Eunos Roadster, came with a removable axle-back system, whereas NA8's are all one piece from the cat-back

- NB's pipework considerably different from the axle-back, and different enough from the headers to the axle for it to NOT be interchangeable with NA's.

- NA8 (and probably NB's) have 2" piping.

jerrah · Postby **jerrah** » Thu Jan 27, 2011 4:43 pm

I currently have NB6 headers which are 'apparently' compatible with NB8 exhausts except for the hangers. Was wondering if I could have a cheap upgrade and a quieter exhaust. My current exhaust is 2 1/4 but drones too much on the highway for my liking.

I believe stock Na6 is 1 3/8"!

hks_kansei · Postby **hks_kansei** » Thu Jan 27, 2011 4:52 pm

you have an NA6 don't you? with an NB6 engine? (per sig)

and I guess that means you've got a custom enhaust system then?

the NB6 headers probably do bolt up to NB exhausts, but to fit the NB exhaust to an NA will mean pretty much every hanger needs to be changed, the NA exhaust pokes out the back just to the left of the diff, the NB is far off to the left side of the car. I think under the car it may also route a slightly different way too.

the easiest, and likely cheapest solutions sound like.

a: possibly an NA8 exhaust may fit. Not 100% on this but worth looking into.

b: get a different muffler that is quieter (less drone) or maybe see if the exhaust shop can add a hot-dog or something to help reduce the drone. Ask their opinion, they will know more about it that I do.

jerrah · Postby **jerrah** » Thu Jan 27, 2011 5:21 pm

Changing the hangers isn't a huge task if the pipework and exhaust fits to the headers.

I already have a hotdog etc. I'm going to talk to MX5plus on the weekend and see how well a NB8 exhaust might fit up. I just wanted to get an idea of the OD/ID of the pipework to see if I'm going to take a performance hit if I run a stock exhaust off a larger engined car. My car produces more exhaust than a standard NA6. (and probably a NB8)

I know from experience NA6 exhausts (stock and aftermarket) don't fit the NB6 headers and the NA8 exhaust is the wrong length I've been advised previously.

I have the NB6 engine but it's just a B6 engine with solid lifters, but the 4-2-1 exhaust from the NB6 is a different length to the NA6.

My current exhaust is a hacked up bitsa exhaust that came with the car that was then hacked up from NA6 length to NB6 length when I changed the headers.