Catalytic Convert Confusion/Civic VX

[Davo53209@yahoo.com]

Originally Posted by Old Mechanic

A 94 VX was OBD 1. I don't think you have the ODB2 sensor that tests the exhaust after the cat. I would think that as long as the flow was not significantly different, the mileage should be close to the same, but much better than you are getting with a cracked manifold.

One reason why I am not especially interested in VXs at their present age is the availability of replacement parts, but that applies just to me. You might have luck at a pick and pull and statelaws vary a lot about what you can do for replacements.

There was a thread by a member here who could not find a manifold for his VX. It was a California version. Seems stupid to me to make used ones illegal or rebuilt ones, when you can't get one OEM. The rebuilt ones I remember were the original casing with new guts.

regards
Mech

It's definitely not OBD2; but I'm starting to think that I may be on the verge of debunking a myth that there's something special about either the exhaust manifold & catalytic converter for the Civic VX, which are thought to contribute to the cars high fuel economy.

For example, if in fact a CX exhaust manifold is interchangeable or if an aftermarket CAT works just as well, one would have more options in terms of finding parts at a substantially lower cost.

[user removed]

Did a little searching, the VX and CX manifolds have the same Honda part number, but both have been discontinued as far as new parts are concerned. I did not find any source for a new replacement and there seems to be quite a few people looking for a replacement for the same reason.

Probably a lot of them on riced take outs. Maybe some of them sre still sitting around or someone will chime in with an option.

regards
Mech

[California98Civic]

Yes, if the manifolds are interchangeable that is cool. Check out the wide-band O2 sensors details too. The wide-band sensors are definitely a requirement for the VX/HX lean burn capability. The CX would not have had the wide band sensor. I don't know of substitutes for the costlier versions people on here have seemed to regard as required hardware for lean burn to work properly. Ebay and such might be really poor guides in this area. Search here on EM for the best details. Here's an example: http://ecomodder.com/forum/showthrea...sor-21933.html

[Davo53209@yahoo.com]

Originally Posted by California98Civic

Yes, if the manifolds are interchangeable that is cool. Check out the wide-band O2 sensors details too. The wide-band sensors are definitely a requirement for the VX/HX lean burn capability. The CX would not have had the wide band sensor. I don't know of substitutes for the costlier versions people on here have seemed to regard as required hardware for lean burn to work properly. Ebay and such might be really poor guides in this area. Search here on EM for the best details. Here's an example: http://ecomodder.com/forum/showthrea...sor-21933.html

No, I don't believe that there's any way of getting around the 5-wire O2 sensor; but the good news is that it may work just as well in a used CX manifold. Frankly, I'm finding more options that way without the frustration and exclusivity of searching for a VX exhaust manifold.

[vrmouseyd15b]

I have the same exhaust manifold on my jdm d15b Honda motor.

It's cut off just behind the motor, and Goes to a short flex pipe.

Flex pipe to my "stainless cat test pipe" and then it goes to 3"stainless.

3"all the way back to a 4" outlet muffler. IT'S LOUD!

I do lean burn, and with the lx manual tranny my best tank was 43 mpg. I've just installed a vx tranny yesterday. I'm expecting about 50 mpg going forward. ..

[California98Civic]

Originally Posted by Davo53209@yahoo.com

... Frankly, I'm finding more options that way without the frustration and exclusivity of searching for a VX exhaust manifold.

A most awesome outcome for ya. Keep us posted as parts arrive and when you install. I'd love to see the outcome.

[vrmouseyd15b]

Yup yup. 3 stage vtec. 1st stage bwa, 2nd stage ha, 3rd stage HA!

[Davo53209@yahoo.com]

Today, I decided to go to the local Honda dealership, whereby I spoke with one of the techs and asked if either the exhaust manifold, or the catalytic converter made any significant contributions to the high fuel economy of the Civic VX. The short answer was, "No, they do not".

Additionally, it was also mentioned that both items were interchangeable between the Civic CX and VX, given that they both have the same part numbers and functioned in the same manner. The only significant difference appears to involve the 5-wire O2 sensor for the Civic VX.

For literally my money, that's enough for me and to be clear, I by no means expect anyone to solely take me on my word alone given that this appears to be a long held belief of VX owners for some time now.

What's encouraging is that I now have the confidence in knowing that I can at the very least utilize a CX manifold from a junkyard.

[Davo53209@yahoo.com]

Today, I just purchased a used exhaust manifold from a 95 Honda Civic Cx, whereas I'm also thinking about going with an aftermarket catalytic converter from Eastern Catalytic Converters, part# 40352. My only issue is that they're designed to last only 50,000 miles

If in fact it does hold true that an aftermarket CAT and a exhaust manifold from a Honda Civic CX would impact the fuel economy, then I will be saving almost $400 from new OEM parts. I will keep everyone posted.

In the meantime, what would be the best way to clean out the inside of a used exhaust manifold?

[vrmouseyd15b]

I ran water from the garden hose thru mine after grinding on it and stuff - I ground the holes for the heat shield off, and I ground off lots of the casting seams and webbing in-between where it breaks into 4 pipes.
also roughed up the inners on the manifold, since I run 3"all the way back I figured the littlest bit of extra back pressure there couldn't hurt me.