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I’d discovered that I had a cracked exhaust manifold when I’d decided to remove the heat shield. Bummed as I was, it then occurred to me that this was probably the reason why I was getting poor gas mileage on my 94 Civic VX.
As I was contemplating how I was going to deal with 20yrs. of corrosion on the bolts, it then occurred to me that instead of having what would ordinarily appear to be a catalytic converter, I instead have an exhaust manifold that connects to two down pipes. Additionally, the 02 sensor threads directly into the manifold as illustrated in the provided attachment.
I’ve seen the illustrations in the parts diagram for my make & model; but they don’t seem to match up to the exhaust manifold on my car, adding more to my confusion. I also can’t seem to find other examples of what’s currently on my car.
My question to the forum is two fold. Is this a stock exhaust manifold for a Civic Vx, where the catalytic converter is somehow integrated into the exhaust manifold? Or is this some apparent delete of the catalytic converter that was added at some point in the vehicles history? To be clear, I am not the original owner.
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thats VERY interesting, most aftermarket exhaust manifolds “headers” as commonly referred too are made of tubed steel, i have no idea why they would do this unless they are trying too acheave a duel exhaust which doesn’t look like the case, such a weird design. what kind of engine does hit have?
these are what the headers look like for your car and looky looky two too one design just like the stock manifold… which i am having a difficult time finding and replacing with headers i am not too sure if thats a good idea, eric can probably tell you he is a honda Guru!
I just looked up exhaust system parts for your car and found a totally different system. It shows the converter as attached to the manifold with fasteners and one pipe that connects with the pipe to the resonator.
Perhaps someone has replaced the manifold with the one you have. I know that I have seen your setup before but I don’t remember which Honda they are installed on.
I’ve apparently been able to establish what I have on my car. It seems to be known as a tri-y exhaust manifold. So the questions are whether or not this is a stock part, or if it’s any better or just as good as what I should have?
Someone mentioned it earlier, and seeing how he is a Honda Guru, maybe this is one for Eric.
Recently, Ive been shopping around on Majestic Honda.com and have come to realize that the part numbers for the catalytic converter & the exhaust manifold match up identically for both the 94 Civic CX & VX. At the risk of asking an obvious question, does this mean that they’re the same parts for each model and are interchangeable?
This may be critical, given the fact that it’s always been impressed upon me that there was something special in the design of the exhaust manifold & the catalytic converter, which contributed to the high fuel economy of the Civic VX.
sorry for delayed reply, no i don’t think you have headers, it appears your exhaust manifold is made of cast iron and most headers are made of tubular steel… the link i showed you at first where headers for your car as a example.
Within the past few days, I’ve finally gotten the answers to my questions. Thank you to all whom contributed to topic.
That is a stock Honda exhaust pictured. Not technically ‘headers’. I’m not sure if it’s the one for your vehicle however. If you don’t mind sharing the answers you found I’d love to hear about it.
Well it would appear that it came from a Honda Civic EX or SI, whereby it wasn’t initially meant for my vehicle. It would also appear that the reason why the former owner would have used this exhaust manifold, is that either the old one became worn out, or they were trying to add power. I would guess the old one was no longer any good, hence deleting the catalytic converter out of convenience.
There is this belief amongst VX owners that the exhaust manifold, in combination with the Catalytic converter, somehow contribute to the vehicles high mpg rating. This was the incentive I had to start with in terms of finding answers.
However, when I looked at the parts diagram from Majestic Honda for both the 94 Civic CX & VX, I’d noticed that parts numbers were identical. This lead me to believe that they’re isn’t anything significant to the VX exhaust manifold, or catalytic converter that would contribute to the vehicles high mpg rating, with exception of the 5-wire O2 sensor.
Would you agree with my theory Eric?
I don’t think having the catalytic converter as part of the manifold has anything to do with fuel economy. As you pointed out, the VX was not the only model to utilize that set up. Unfortunately, those manifolds were prone to cracking and often failed. Since the catalytic converter was a part of the assembly, this made the prospect rather expensive.
As for why they did that. Catalytic converters don’t work unless they are at operating temperature. The faster they get up to temperature, the better. The closer the catalytic converter is to the engine, the faster it will get up to temperature. The job of the catalytic converter is to lower NOx emissions. To summarize, they placed it there for ease of manufacture and better emissions.
I didn’t realize you could replace it with a different manifold. That’s interesting.
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