Exhaust swap 99 DX/HB to 98 B18C5

[webink_EK9]

Will my dx exhaust fit on the B18c5 stock headers? I plan on replacing the entire exhaust, but will it do that after the motor is in. I just want to make sure everything hooks up when I'm putting it in.

 

[civicious]

my b16 header bolted right up to my stock exhaust....but thats a b16....





tim?

 

[posol]

if the dx has the cat not on the header like the cx does (i can't remember), it shoudl bolt up, or at least be pretty close.

 

[civicious]

yeah...cx/dx/lx have the cats on the header.

 

[Incredib1e]

Yea it won't bolt up. The piping isn't long enough. You either need to get an extension which I don't think is a very good idea. I'm getting a custom piping and a new cat put on by mufflex.

 

[webink_EK9]

would it hurt if I just ran no exhaust after the header? Just to get the swap done and have the motor started...and maybe a trip around the block.

 

[E_SolSi]

youll be fine

i drove from CT to NJ open header last summer

 

[TWAN]

Originally posted by pissedoffsol@Feb 3 2004, 04:39 AM
if the dx has the cat not on the header like the cx does (i can't remember), it shoudl bolt up, or at least be pretty close.

Doesn't the C5 have a bigger collector where the cat would bolt up? I thought they did because the b-pipe is also a bigger diameter...

just my .02

 

[swapdohc]

You will need to get a test pipe or cat that will accept the 2.5" collector. hybridgarage.com offer cusom high flow cats for your specific aplication but they SUCK ASS!!!! I bought and paid (Paypal) for one three weeks ago and have not heard a word. I have sent at least a dozen emails and left 10 phone messages and nothing. But they are the only one that I have found that has anything that fits the jdm 2.5" type r header. Good luck.

I have a regular cat (Civic Si) that I had a custom flange welded onto that accepts the 2.5" collector. I will consider selling it, make an offer.

PS Running open header on this motor is EXTREMELY loud and also offers no back pressure, keep it under 8400!

 

[webink_EK9]

How about this...I'll buy it, name your price. I don't have a clue....but if you name your price, do it in the forum so if you're trying to put your fist where it shouldn't be, other people can watch you do it.

(Not saying I won't buy it if you do, but if I get ass f^*#ed it would be cool for people to see)

Let me know dude!!!!.

Oh yeah, whats up with the under 8400rpm thing...I don't know all that much about tuning and exhaust physics.

 

[Incredib1e]

Just take your car to Mufflex after you get your motor running. Or someplace like that, which does custom piping. Have them through on a new cat too.

 

[webink_EK9]

Drunkk as hell but that sounds like the best deal! Anyway can I give one of those plaes the cat I want them to use/?? or do they ahve to use what ehy got/?


Fuking sorrrry for bing so durnk!

Out
Luke

 

[Incredib1e]

I'm sure if you talked to someone they would let you use that cat you provide. Unless they are worried about the legality. Some places won't put it on if its not street legal.

 

[webink_EK9]

Thanks, I'll check around and find a place that'll do it. I'm going to have to take my car in for exhaust testing before I can get it registered. Do those places look at the exhaust or do they just test it? Can I make a pipe with two cats on it for testing and after that remove the cats with a streight pipe?

 

[swapdohc]

I'll sell it to you for $50 shipped ground. Sorry I didn't get back sooner I've been out of town.

The "Keep it under 8400" is about back pessure. When you run an open exaust there is no pressure on the exhaust side. When you run an exhaust system it has pessure on the exhaust side. This pressure helps to close your exhaust valves (Pevents floating).

I can accept pay-pal for the cat and will send you a picture if you want, just tell me where to send it to.

 

[webink_EK9]

Sold. I'll pm you a little later. Thanks man!

 

[civicious]

dude, how are you gonna bolt up that cat on a dx? on dx's the cat is a part of the header itsself, so the downpipe bolts straight to the exhaust pipe with no cat bolting on anywhere.


that cat aint gonna bolt right in...youre still gonna have to go to a muffler shop and get it welded on....

and it'd be cheaper to just get a flange that would bolt to the 2.5" collector on rather than buy a cat and get that welded on...


cliffnotes:

that cat will NOT just bolt up. waste of fuckin money.

 

[civicious]

The "Keep it under 8400" is about back pessure. When you run an open exaust there is no pressure on the exhaust side. When you run an exhaust system it has pessure on the exhaust side. This pressure helps to close your exhaust valves (Pevents floating).

WHAAAATTTTTTT?!?!?!?!?!!??! okay, who have you known to float valves because of open header? hmm....lets see...bisi? about 5 local guys (who have consequentally been running open headers for years)?

 

[swapdohc]

As far as the cat not bolting up Iwill be happy to send you full dimensions of the cat and the dimensions and sizes of the holes in the flanges. I am not trying to have throw away your money, just trying to help out.

As far as the comments that made that running an open header is safe goes. Do your homework, it is simple physics and well documented that running engines at high RPM's with no back pressure is dangerous. Besides that it draws the attention of the cops and kills your low end torque.

As far as who I know who runs a B18C5 who has floated a valve, no one. No one I know is stupid enough to turn up 9000+ rpm's open header with stock internals (Especialy on a $3-5000 engine). If you friend like abusing there valves so that they can have the loudest, most irritating, cop attention grabbing cars around with low torque, good for them. In a reliable high revving motor, back pressure is your engines best friend.

And as far as you coming back and blasting me with how smart and right you are. I Believe the proof is in what you drive. My full interior 94 Civic Si with a full system runs a 12.4 1/4 all motor b18c with stock internals and a littlle back pressure.

 

[civicious]

as far as the holes/flanges yeah...but unless the cat is like a millimeter long it aint gonna fit.


dx exhaust:

(o)))))===============[ ]======[cat]===motor
-------HEADER------------


everyothercar exhaust:
(o)))))===============][cat][ ]=========motor
-------HEADER------


on dx's, the cat is part of the header. you cant unbolt it. the exhaust bolts STRAIGHT ONTO THE HEADER. no room to bolt a cat in, no matter what header you use. on pretty much every other honda, the cat BOLTS in between the header and the exhaust.

And as far as you coming back and blasting me with how smart and right you are. I Believe the proof is in what you drive. My full interior 94 Civic Si with a full system runs a 12.4 1/4 all motor b18c with stock internals and a littlle back pressure.

you driving that proves.....shit. i dont give a fuck what you drive. on a dx, you can't bolt a cat on without modifying the existing header-back exhaust.