JDM 4-1 Header, Carsound Cat, 2.5" exhaust - Install: How to
Thread Starter
Joined: Jan 2002
Posts: 2,186
Likes: 0
From: San Diego, CA, USA
JDM 4-1 Header, Carsound Cat, 2.5" exhaust - Install: How to
Here's all the parts I am putting in. There's a JDM 4-1 ITR header, a Carsound high-flow cat, an aluminum race skid plate and upper heat shield (for the header), and a custom 2.5" mandrel bent exhaust piping. (Resonator and muffler are being welded on by muffler shop)
Since the header is longer than the stock GSR header you need a shorter cat. Rather than doing that, I got a Carsound cat for a Type-R instead and the custom piping was off of a type R as well. I figured it should all match up correctly.
Jack up the car and get it on 4 jack-stands. I decided to rotate tires and change oil while it was in the air, so you can ignore the tire removal if you like.
Remove the heat shield from header. The bolts are very easy to reach and remove. I still manage to cut my hand. Gloves are now on!
I next removed the spring bolts from the header to the cat. They are a pain in the ***. I used a bunch of penetrating spray and lots of grunt. They came off...
Next I removed the bolts from the header mount. I first removed the ones circled in red, then discovered the ones under the blue arrows would be more useful. Either way, with all of them removed you can't go wrong.
Then I removed the header bolts and tried to remove the header. It started to come off but felt stuck. I kept pulling and pulling but it wasn't coming off. I looked up at the header from below the vehicle and saw to other bolts holding it in place. I was able to remove one of them but the other one was too hard to get to. So I removed this stupid plastic shield. The bolts are very easy to find. Just remember to keep all those little clip things that pop off when you pull it off.
Wow, now I could actually see stuff and reach it. That bolt was gone in no time.
I pulled the header off the head and pushed it down under the car. It got caught on some hoses a few times but after a few minutes I found a pathway out. That crappy old header was heavy, I discovered. Probably 1.5 - 2 times heaver than the much larger JDM one.
Don't forget to take the stock header gasket off and inspect it. Mine looked pretty good but I replaced it anyway. I'd rather not have leaks and have to uninstall everything I am installing.
I unbolted the axle back portion of the exhaust and removed it out the back of the vehicle. The rubber hangers were annoying but just work with them a bit and you'll get the exhaust off.
Now the cat and exhaust were suspended only by the rubber hangers. But before I could remove them I needed to remove the two o2 sensors from the cat. This was the hardest thing I've ever done. I didn't have a special o2 sensor tool so I tried a bunch of things. You can see the large amount of penetrating spray I used on that shield. I ended up removing the cat's heat shield and pulling it up a bit so I could access the lower portion of the o2 sensors. I put vice-grips on as tight as I possibly could and hit them with a big piece of metal. 30 minutes later they were removed. Down came the pipe!
Here's a picture of all the stock crap removed.
After a quick lunch break, I installed the new header. I installed from underneath. It was just as hard to wiggle this thing up, especially by myself, but it wasn't that bad. Don't forget to put the gasket in first! Next I torqued the bolts down to the 23ft-lbs spec. The header sure looks better than stock!
Then I installed the heat shield. No, the stock one won't fit. You have to order a JDM one. $$$ :-(
I only put the top 3 bolts in because the bottom two are going to be covered by the race skid plate.
You don't have to put a heat shield on, but it's a good idea since the header gets hot and in California the JDM header is illegal and this will easily fool the smog inspectors.
I was going to install the JDM bracket but realized this was impossible once the header was installed and I didn't want to uninstall it all. Most people say they've had no problems without it anyway.
Then I installed the skid plate. The header comes down lower than stock so this is a good investment. I don't want to destroy this nice bunch of tubes.
I put the 2.5" donut gasket on the header collector then I put the cat in and loosely bolted it up. I then got the exhaust in (with a new 3 bolt gasket by the way) on the stock hangers. This was easy.
I put the stock o2 sensors back in place. One goes in the header, the other in the cat.
Finally, I tightened it all down really well. I didn't use spring bolts between the header and cat because I didn't have them but you might want to do so. I am not sure how long these bolts will last.
Well, for now that's all I have. I drove home very slowly as the mufflerless, resonatorless, exhaust sounded like crap. It was so loud I think I could have completely lost my hearing if I revved over 3k. ASAP this thing is getting it's 14" Magnaflow resonator and stock-looking magnaflow muffler. I will post videos when that's all done.
edit: 9/15/03, Video is up with the muffler and resonator http://www.travisharrell.com/a...t.mpg
Modified by gtravsr at 2:34 AM 9/16/2003
Since the header is longer than the stock GSR header you need a shorter cat. Rather than doing that, I got a Carsound cat for a Type-R instead and the custom piping was off of a type R as well. I figured it should all match up correctly.
Jack up the car and get it on 4 jack-stands. I decided to rotate tires and change oil while it was in the air, so you can ignore the tire removal if you like.
Remove the heat shield from header. The bolts are very easy to reach and remove. I still manage to cut my hand. Gloves are now on!
I next removed the spring bolts from the header to the cat. They are a pain in the ***. I used a bunch of penetrating spray and lots of grunt. They came off...
Next I removed the bolts from the header mount. I first removed the ones circled in red, then discovered the ones under the blue arrows would be more useful. Either way, with all of them removed you can't go wrong.
Then I removed the header bolts and tried to remove the header. It started to come off but felt stuck. I kept pulling and pulling but it wasn't coming off. I looked up at the header from below the vehicle and saw to other bolts holding it in place. I was able to remove one of them but the other one was too hard to get to. So I removed this stupid plastic shield. The bolts are very easy to find. Just remember to keep all those little clip things that pop off when you pull it off.
Wow, now I could actually see stuff and reach it. That bolt was gone in no time.
I pulled the header off the head and pushed it down under the car. It got caught on some hoses a few times but after a few minutes I found a pathway out. That crappy old header was heavy, I discovered. Probably 1.5 - 2 times heaver than the much larger JDM one.
Don't forget to take the stock header gasket off and inspect it. Mine looked pretty good but I replaced it anyway. I'd rather not have leaks and have to uninstall everything I am installing.
I unbolted the axle back portion of the exhaust and removed it out the back of the vehicle. The rubber hangers were annoying but just work with them a bit and you'll get the exhaust off.
Now the cat and exhaust were suspended only by the rubber hangers. But before I could remove them I needed to remove the two o2 sensors from the cat. This was the hardest thing I've ever done. I didn't have a special o2 sensor tool so I tried a bunch of things. You can see the large amount of penetrating spray I used on that shield. I ended up removing the cat's heat shield and pulling it up a bit so I could access the lower portion of the o2 sensors. I put vice-grips on as tight as I possibly could and hit them with a big piece of metal. 30 minutes later they were removed. Down came the pipe!
Here's a picture of all the stock crap removed.
After a quick lunch break, I installed the new header. I installed from underneath. It was just as hard to wiggle this thing up, especially by myself, but it wasn't that bad. Don't forget to put the gasket in first! Next I torqued the bolts down to the 23ft-lbs spec. The header sure looks better than stock!
Then I installed the heat shield. No, the stock one won't fit. You have to order a JDM one. $$$ :-(
I only put the top 3 bolts in because the bottom two are going to be covered by the race skid plate.
You don't have to put a heat shield on, but it's a good idea since the header gets hot and in California the JDM header is illegal and this will easily fool the smog inspectors.
I was going to install the JDM bracket but realized this was impossible once the header was installed and I didn't want to uninstall it all. Most people say they've had no problems without it anyway.
Then I installed the skid plate. The header comes down lower than stock so this is a good investment. I don't want to destroy this nice bunch of tubes.
I put the 2.5" donut gasket on the header collector then I put the cat in and loosely bolted it up. I then got the exhaust in (with a new 3 bolt gasket by the way) on the stock hangers. This was easy.
I put the stock o2 sensors back in place. One goes in the header, the other in the cat.
Finally, I tightened it all down really well. I didn't use spring bolts between the header and cat because I didn't have them but you might want to do so. I am not sure how long these bolts will last.
Well, for now that's all I have. I drove home very slowly as the mufflerless, resonatorless, exhaust sounded like crap. It was so loud I think I could have completely lost my hearing if I revved over 3k. ASAP this thing is getting it's 14" Magnaflow resonator and stock-looking magnaflow muffler. I will post videos when that's all done.
edit: 9/15/03, Video is up with the muffler and resonator http://www.travisharrell.com/a...t.mpg
Modified by gtravsr at 2:34 AM 9/16/2003
Trending Topics
Thread Starter
Joined: Jan 2002
Posts: 2,186
Likes: 0
From: San Diego, CA, USA
Re: (xteg01)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xteg01 »</TD></TR><TR><TD CLASS="quote">nice post man...i would put those springs back on because there is wayyy to much pressure back there for those bolts to hold them...better safe than sorry 
</TD></TR></TABLE>
The problem is the cat seems like it would be leaking if it were any farther away from the header...I'll try and take another look later.
</TD></TR></TABLE>The problem is the cat seems like it would be leaking if it were any farther away from the header...I'll try and take another look later.
Thread Starter
Joined: Jan 2002
Posts: 2,186
Likes: 0
From: San Diego, CA, USA
Re: (Tweakmeister)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tweakmeister »</TD></TR><TR><TD CLASS="quote">good stuff 
it might have been something else, but take a look at the front of the oil pan...looks like the gasket might be going.</TD></TR></TABLE>
i think it was the oil I spilled a few minutes earlier when I was changing my oil...I'm a dumbass. But I'll take a looksee. Thanks for the tip.
it might have been something else, but take a look at the front of the oil pan...looks like the gasket might be going.</TD></TR></TABLE>
i think it was the oil I spilled a few minutes earlier when I was changing my oil...I'm a dumbass. But I'll take a looksee. Thanks for the tip.
Honda-Tech Member
Joined: Jan 2002
Posts: 1,987
Likes: 0
From: FL
Re: (Tweakmeister)
Some questions for you...
1. So you used a 2.5" collector's flange and gasket? Where did you purchase this?
2. With the ITR cat, did it come with flanges or did you have the shop weld some?
3. How much was the mandrel bent piping?
4. Who manufactures that skid plate?
Thanks.
1. So you used a 2.5" collector's flange and gasket? Where did you purchase this?
2. With the ITR cat, did it come with flanges or did you have the shop weld some?
3. How much was the mandrel bent piping?
4. Who manufactures that skid plate?
Thanks.
Thread Starter
Joined: Jan 2002
Posts: 2,186
Likes: 0
From: San Diego, CA, USA
Re: (EJ1)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EJ1 »</TD></TR><TR><TD CLASS="quote">Some questions for you...
1. So you used a 2.5" collector's flange and gasket? Where did you purchase this?
2. With the ITR cat, did it come with flanges or did you have the shop weld some?
3. How much was the mandrel bent piping?
4. Who manufactures that skid plate?
Thanks.</TD></TR></TABLE>
1. The flange was on the cat but I needed the 2.5" donut gasket. I purchased it from SMSP on this board. IM him if you need one.
2. I purchased a complete carsound ITR cat from someone on this board. It had the flanges on there already. I believe it was originally purchased from hybrid garage.
3. Mandrel piping was purchased used from a member on honda-tech for $100. I got the resonator and muffler new for $100 and they will be welded in for about $50. $250 for a 2.5" mandrel bent cat-back it pretty good I think.
4. I got the skid plate from heeltoeauto.com for $60 shipped. It's made by fastline performance.
1. So you used a 2.5" collector's flange and gasket? Where did you purchase this?
2. With the ITR cat, did it come with flanges or did you have the shop weld some?
3. How much was the mandrel bent piping?
4. Who manufactures that skid plate?
Thanks.</TD></TR></TABLE>
1. The flange was on the cat but I needed the 2.5" donut gasket. I purchased it from SMSP on this board. IM him if you need one.
2. I purchased a complete carsound ITR cat from someone on this board. It had the flanges on there already. I believe it was originally purchased from hybrid garage.
3. Mandrel piping was purchased used from a member on honda-tech for $100. I got the resonator and muffler new for $100 and they will be welded in for about $50. $250 for a 2.5" mandrel bent cat-back it pretty good I think.
4. I got the skid plate from heeltoeauto.com for $60 shipped. It's made by fastline performance.
Honda-Tech Member
Joined: Jul 2002
Posts: 1,249
Likes: 0
From: Cville, VA, USA
Re: (b18bb0y)
nice install, nice pics, and nice explanations. thats the kind of thing i would like to see in an online how-to page, or in a book that could be referenced to. it would be nice to keep a journal with how-to's with pics and stuff like that on everything you do to your car. everytime you do something different, take notes on the install, take pics, and put it online or in the book.
props for a complete exhaust setup, not just catback and header.
props for a complete exhaust setup, not just catback and header.
Honda-Tech Member
Joined: Jul 2002
Posts: 1,773
Likes: 0
From: ATL
Re: (88civicHB703)
What didyou pay for the JDM 4-1? Get it from a member on h-t? I want that setup, except i'm running a GReddy exhuast right now which is 60mm. Would it F things up going from the 2.5 in 4-1 to 2.5 in carsound to the 60mm(2.36in) exhuast? Would I be better off dropping mad cash on a comptech 4-2-1?
Member
Joined: Aug 2002
Posts: 1,173
Likes: 0
From: NorCaL/SoCaL
Re: (Tim Maryak)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tim Maryak »</TD></TR><TR><TD CLASS="quote">What didyou pay for the JDM 4-1? Get it from a member on h-t? I want that setup, except i'm running a GReddy exhuast right now which is 60mm. Would it F things up going from the 2.5 in 4-1 to 2.5 in carsound to the 60mm(2.36in) exhuast? Would I be better off dropping mad cash on a comptech 4-2-1? </TD></TR></TABLE>
I'm in the same situation too although I have an ITR-catback. How much was everything?
BTW, great informative post. Make jobs easier for those who plan to do similar installs.
I'm in the same situation too although I have an ITR-catback. How much was everything?
BTW, great informative post. Make jobs easier for those who plan to do similar installs.
Honda-Tech Member
Joined: Jul 2001
Posts: 1,162
Likes: 0
From: East Bay/Pasadena, CA, United States
Re: JDM 4-1 Header, Carsound Cat, 2.5" exhaust - Install: How to (gtravsr)
nice detailed pictures/explanations of the install...I just took off the same setup (jdm 4-1 header w/upper heat shield &skidplate, SMSP carsound cat, 2.25" custom mandrel bent bpipe w/magnaflow resonator, Comptech muffler) today and switched it back to stock.
It's nice to have a quiet car..
It was a lot of fun though, you lose lowend, but a lot more high-end power!!! My car sounded like a wrx with the setup. enjoy.
Oh yeah, my parts are for sale!!!
It's nice to have a quiet car..
It was a lot of fun though, you lose lowend, but a lot more high-end power!!! My car sounded like a wrx with the setup. enjoy.
Oh yeah, my parts are for sale!!!
Junior Member
Joined: Sep 2002
Posts: 233
Likes: 0
From: tampa, florida, usa
Re: JDM 4-1 Header, Carsound Cat, 2.5" exhaust - Install: How to (99SiRacer)
i am pretty sure you can re-use the springs (just the springs) from the spring bolt from the stock cat & header bolts on your new bolts. i dont remember buying new springs, im about 99% sure i reused the stock ones and they worked.
also, i bought the JDM ITR 4-1 header with the race skitplate from marcus at HeelToe Automotive. i definately give him a for anybody who wants to do this themselves.
also, i bought the JDM ITR 4-1 header with the race skitplate from marcus at HeelToe Automotive. i definately give him a
for anybody who wants to do this themselves.
Thread Starter
Joined: Jan 2002
Posts: 2,186
Likes: 0
From: San Diego, CA, USA
Re: JDM 4-1 Header, Carsound Cat, 2.5" exhaust - Install: How to (spd18)
Someone asked what the header cost. I got it for $450 shipped with the carsound cat. Header had 1000 miles, cat was new. The whole thing was maybe 7 hundred something.
Update: Magnaflow resonator and muffler installed and a video is up. I think it's maybe a bit too loud but I'll either get used to it or throw a chambered muffler on sometime.
The video here ->http://www.travisharrell.com/a...t.mpg
Update: Magnaflow resonator and muffler installed and a video is up. I think it's maybe a bit too loud but I'll either get used to it or throw a chambered muffler on sometime.
The video here ->http://www.travisharrell.com/a...t.mpg
