nicolaselias

Hi everyone... I need advice on where I purchase a test pipe to suit my exhaust system and also what gaskets would I be required to purchase...

--
To get you up to speed, my Accord is a non-US model, therefore has no cat..

I purchased the APEXi WS2 exhaust system (which is a catback) and now need to mount it to my DC 4-2-1 header...

First thing, should I use test pipe or flex pipe to join the header to the catback..
Stock on the car is some 2" flex pipe which is too small for the new exhaust..

Which would be a smarter solution and more performance oriented, test or flex. Also, the whole point of buying the WS2 was because I didn't want the exhaust to be too loud, raspy or ricey.. so what can I do to keep the original WS2 sound...

Where can I get a flex or test pipe that will give a size match to my 60mm (2.36") exhaust..


Next, any of you have info on what gaskets come with a new DC 4-2-1? I inherited one from a friend and the only "gasket" I can see is the rubber attachment on the bottom end..
Do I need to purchase a gasket to attach the header to the test pipe.
Also, did the two piece DC 4-2-1's come with a gasket between the pieces? If so, mine didnt come with it from my friend's wreck..

Finally, where do I position the O2 sensor.. How many sensors does this car have? If its one, can I run it from the header? If its two would it be best to put a bung on the test pipe (or buy one with it already)...

I'm sorry for the extra long question but I haven't really been getting answers on the other threads that I have been posting to...

Thanks to everyone in advance and keep the good advice coming...

nicolaselias

BUMP because I really need advice on this...

Anyone here who did a Cat delete or someone without a cat should be able to help me..

PLEASEEE??

nicolaselias

Bump once more... Can someone please help?

joc1394

I have heard an Apexi WS2 catback...and thats about all the experience I have with the pieces you're talking about. However, to answer your question about where to find flex and test pipe...I'd check Advance Auto. I seem to remember they had some generic exhuast pieces of flex and straight pipe. You'd probably need to weld on the appropriate flanges.

As for the O2 Sensor question, I've got no idea. I had a 1992 with an F22A6, stock 4-2-1 headers and a factory cat...I replaced the whole exhaust once, muffler and downpipe twice. My 1992 with headers had 1 O2 pre cat, post downpipe. My dad has a 1991 Accord LX with an F22A1 with factory manifold and an O2 sensor in the manifold. Basically, I'd be looking up a repair manual for a car with the engine you're running and find out where the stock O2 was located.

Sorry I can't be of much help... Good luck with the project.

nicolaselias

So, I emailed about the Megan test pipe and apparently its 2.25"... could that be a potential weak link in my exhaust seeing as the catback is 2.36"


Anyone have experience with these megan test pipes?

nicolaselias

So back to begging for help....

I know that exhaust diameters are measured in outside diameter...
Knowing this, and the fact that my catback is 2.36", should I be considering a 2.25" test pipe or a 2.5" test pipe...
Ideally, I just want what will produce the most power at a reasonably low rev range...

Also, what brands can you all reccomend? Are the Blox adjustable test pipes any good?
Should I consider megan instead?

nicolaselias

Once again, anyone care to help?

What would the sound difference be between a resonated and a non resonated test pipe?

civichb20

thats a lot of questions just take it to a shop and call it a day. gl

nicolaselias

It isnt really that many questions...

Basically it comes down to this... I am getting a 2.25" test pipe...
What I want advice on is, should I get a resonated test pipe (such as megan) or not (such as blox)...

I do not want anything to mess up the sound from the apexi ws2 or to make it buzzy or raspy... The only catch to the megan is that it doesnt have the hole for the O2 sensor, so I would have to weld that in myself...

I don't really want to leave it up to a shop to do that piece as I have been using top quality components all the way through..

helldriver88

Im sure the WS2 will still be quiet even with a test pipe. OBX, or Megan test pipe would be the way to go. 2.25 won't hurt your performance at all. honestly, i would picture that as being way better flowing than any catylatic converter even at 2.36". should be all bolt on. as far as gaskets go, I've never had an aftermarket header on an F or H series so i don't know if the collector is any bigger than stock or not. i wonder if the OEM donut would fit on the DC header. cause on some cars, the gasket is sometimes much bigger diameter than the size of the exhaust pipe (at the header) so try one of them. if that doesn't fit, than see about getting one through DC Sports or Vibrant. they may make them. they make any other exhaust part lol.

nicolaselias

Thanks for the reply helldriver... with the exception of joc and yourself it seems that no one wants to reply to this thread...

I think I'd be fine going with the megan, I just need to figure out how to weld on a bung for the oxygen sensor... I don't want to have to simulate it and end up throwing codes etc.. Easier just to do it right the first time.. Do you know anywhere that sells the bungs to weld on?

Thanks

AFAccord

So your stock exhaust had one piece that extended all the way up to the header, and now you have a 'converter length' gap between the header and the cat-back exhaust?

The stock setup uses a flex pipe that's built in to the header, from the header back it's solid.


Your smallest point in the exhaust will be your restriction (obviously). With the exception of Kamikaze 4-1 or a custom job from Bisi, I don't think any aftermarket header for the offers a decent sized collector. I don't think any of them are even over 2". But then if you told us what the engine was, it might open more options for headers...

EDIT: I believe your F20B should work with most H22 headers. High quality H22 headers are everywhere, but DC Sports is not one of them.

Your DC header should have a flex pipe already, unless it's designed with a spring-bolt donut connection, right? A resonated test pipe would be a safe choice to keep noise levels down.

Most headers i've seen come with the manifold gasket (to the head) and the gasket between the upper manifold and collector. The connection to the cat/test pipe is a 'stock' flange, and I haven't seen many headers include that one. Most people probably just reuse the existing gasket.

If it does have one, you can install that in one of the primaries, or down on the collector. Even though it's OBD2, I'm not sure why it would have two since the second sensor is to monitor the catalyst (which you say you don't have).


The collector on the header is your biggest restriction.

Not too much since most of them are small bottle style resonators. They don't have much packing, and therefore don't suppress the sound that much.


Again, your choice. It's not going to make much of a difference, but its safe to assume the resonated one will be quieter.

Doesn't the header have one bung on the primary, and one on the end of the collector? Most headers I've seen do. If it doesn't, you can tap the collector right before the flange. Most reputable exhaust shops will have O2 bungs in stock. If you can't find one, you can just use an M18x1.5 nut.

On another note, if your car doesn't use a cat, are you sure it actually has a secondary O2? On OBD2 cars that second sensor is simply there to make sure the catalyst is working properly.

POST EDITED: Checked your sig.

nicolaselias

AF Accord, that is the kind of help I have been so desperately seeking...
Thank you so much.... I have to admit that I am not the best at using the quoting but i'll still give it a try to address your excellent post...




That is correct, basically I'm missing piping for that exact length, and obviously using stock is not an option seeing as it will be the main flow restriction.


This is probably the case on mine as well but I mistakenly identified the flex pipe as separate.. So yes, from the header back I will be solid with 2 resonators before the muffler if I remember right.. Also, I think my stock piping starts at 2" but then drops to 1.75" after the first resonator (which might be in place of the cat??)


I don't think the H22 headers will work because I assume they have the VTEC engine exhaust ports 0-0-0-0 whereas my non-VTEC are more like 0-00-0

I think that my DC header has a 2.25" collector,.. .worst case it is probably 2" and while I understand that Bisi etc make supreme headers, I simply couldn't afford better than I purchased.. I decided to go for a solid mid-priced choice...

Correct, it is actually designed with the spring bolt donut.. I would have prefered flex pipe to be honest just because I would expect it to take the strain off the exhaust and hangers a bit more when vibration is applied...


My header uses the stock exhaust manifold gasket and I purchased a new one just to be safe.. It also uses two crush ring gaskets between the upper mani and collector. Finally, the lower gasket, I think is just the donut gasket to connect to the cat/test pipe/first resonated muffler (depending on set up)


Seeing as my car is back in the Caribbean, I told my cousin to take a look at it for me to see if there is a second O2 sensor.. Personally I cannot remember if there was one or not despite the car being OBD2.. As soon as he gets back to me on that it will make my decision easier..

Concerning the bung's, my header has one on the upper manifold just before it reaches the gasket for the collector section...
However, the header definitely doesn't have one down on the collector, but if necessary it might be easier to put it here as opposed to the test pipe.. Good suggestion!

Would this be exactly what I need? http://www.ultrarev.com/35-4005.html




I am leaning more and more toward the resonated one just because on a car like this, raspy exhaust isn't really a desirable sound from my POV.. A track car or a Ferrari is fine, but a DD accord I really just want it to be loud when im full on the throttle and going in the high revs.. Hence why I purchased the APEXi WS2


Once again, thanks so much for all the help and I genuinely appreciate it!

nicolaselias

Well.. finally went to the exhaust shop today....

Problems...

Apparently the DC collector which is supposed to be stock size and design does not fit onto the Megan test pipe....

Now, assuming the DC collector is correct, then why did megan sell me a product that clearly doesn't fit properly onto stock? After all, isnt it designed to replace the cat, which would fit stock onto the end of the exhaust mani and then onto the catback?

so, either I completely misunderstood how the megan test pipe works, or they made a pretty shoddy product..

So at this point im left with two options.... Somehow fabricate something and make the megan fit? Alternatively, I can just use a 2.25" length of flex pipe instead... The downside to this however is that I don't get the resonator which was part of the megan.. Really don't want my Apexi WS2 sounding raspy...