OBX headers on KA9

[KA Charliie]

I want to buy some headers for my 2000 RL. I want to get the OBX headers for a KA7. Will they fit on a KA9 without modification? Has anyone done it? Tried searching but didn't find anything. Thanks.

[The-Teej]

did you just ask on FB?

[BigCope923]

Originally Posted by The-Teej

did you just ask on FB?

No, that was me.

[Sovereign]

The OBX headers will fit onto the motor. Whether or not they fit within the car body, I do not know, but I do not see any reason why not. Being OBD II, you should have an O2 sensor downstream from the catalytic converter, so the test pipe would throw a CEL for you.

[OLD_HATCH]

Bringing this back from the dead.

They fit the head, but the y pipe needs to be modified. (currently installed on my car)

I'll post up the details at a later date.




*EDIT*

Well about a year ago I installed OBX headers for the 91-95 Acura Legend onto a 96-04 RL. I've been kinda lazy so I never posted up bit here is the basic jist of it. It works, but only kinda.

Here are a couple of comparison pics from the oem manifold y pipe to the OBX header.





That OEM collector though. lol



SO the headers themselves bolt up the the engine fine. Things you need to do are the following:
1. Make extensions for the 02 sensors as the bung is spaced father back.
2. Bend power steering line to clear header as the are wider than stock.
3. Pull the AC line to the strut tower with some sort of clamp to keep it from touching header. (reflective heat wrap is advised)


Now the Y pipe will not bolt up to anything at all. You need to cut it so it can bolt back up to the headers and the cat, then weld it back together.

I have yet to take pictures of what was needed to make the y pipe fit, but I am not happy with it so it will probably be remade. Hopefully sometime soon. Good thing is that it also comes with a straight pipe that I plan to install with high flow cat and resonator to replace the stock one. Performance increases..... butt dyno says maybe??? It definitely sounds different but I think it has more to do with the headers being a thinner material than the cast iron manifolds.

My recommendations is DON'T DO IT! Not really worth it, but I did it cause at the time I could so why not.

*EDIT*

[Vic Cardenas]

I've always wondered about this. I had my headers on my Legend for a few years but when I did my 3.5 swap into the Legend, the headers would not bolt up to the Y pipe. I had to cut and weld the Y and ended up making a new merge with mandrel bends leading into a Magnaflow collector. My Legend just sits now (long story, got red-flagged by inspector for a lack of PAIR pipe) and I started to part it out about a year ago but I still have the headers and full exhaust system that I re-welded up with mandrel bends throughout. I've always thought about putting all that stuff on my '96 RL but it's such a PITA to put the headers on with the engine inside. I'd do it if I had a reason to pull the engine though....

[OLD_HATCH]

So the same thing happened on the Legend body with the 3.5 engine?

I guess the heads/blocks aren't exactly the same as the 3.2 then.

At the very least I would have figured the y pipe would have bolted onto thte headers and then having to modify where it bolts onto the cat.

[Vic Cardenas]

Yeah, I had heard on here from a few people that the 3.2 to 3.5 swap on the Legend you would not run into issues with the exhaust system. Not the case for me. But at the same time it was not that hard to fix.

I guess the block is taller on the 3.5 so it never made sense to me how it would all just bolt up. I kind of anticipated it.

[Chrispy]

Originally Posted by Vic Cardenas

Yeah, I had heard on here from a few people that the 3.2 to 3.5 swap on the Legend you would not run into issues with the exhaust system. Not the case for me. But at the same time it was not that hard to fix.

I guess the block is taller on the 3.5 so it never made sense to me how it would all just bolt up. I kind of anticipated it.

I didn't really have a problem fitting the obx headers on my 3.5. The trick was to leave the headers slightly loose when lining up the y-pipe bolts. Once I got those lined up I left the y pipe bolts loose and tightened up the flange nuts for the headers, then tightened up the y-pipe bolts. It def took a bit of prying but I was able to get everything to line up and tighten down.

If you have to install these with the engine in the car, its WAY easier with a lift. I did it on jack stands the first time I did it, and that was 7 almost 8 hours of my life I can never get back On a lift I can install them in about 3 hours now, but I've had more practice. The easiest way by far is with the engine out of the car. With the engine in I have to make numerous contraptions with swivel sockets, universal joints, extensions, and wobble extensions to remove and install the lower flange bolts for the headers/manifolds.

Did you guys install new O2 sensors when you put the headers in? The RL probably doesn't see a lot of gains with it because it has AFR sensors instead of an O2 sensor with a rear O2 sensor. The fuel correction maps and spark advance cant compensate enough to make it more efficient. I'm sure the long term and short term fuel trims are all over the place and maxing out the correction it can make.