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Big Pimpin
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15,710 Posts
Discussion Starter #1
Typical rules apply here. No post whoring, this is not a chat thread.

The types of questions that belong here are the simple single response type of questions.

If you have a question asking which cam is better or how much power will I make please search your question first. Chances are it has been answered.

Ask away.
 

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Super Star
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343 Posts
I am currently running stock 2.5' exhaust pipe and 2.5' DC muffler with deleted resonator.. Its giving me a bad look and Im getting Skunk2 3' muffler and 3' resonator and 3' highflow cat... If i replace my stock cat with a highflow 3' cat and 3' pipe would I have to buy any special o2 sensors or adapters?
 

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Big Pimpin
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15,710 Posts
Discussion Starter #5
I am currently running stock 2.5' exhaust pipe and 2.5' DC muffler with deleted resonator.. Its giving me a bad look and Im getting Skunk2 3' muffler and 3' resonator and 3' highflow cat... If i replace my stock cat with a highflow 3' cat and 3' pipe would I have to buy any special o2 sensors or adapters?
Well, first the stock piping isn't 2.5". To answer your question, you shouldn't have to. The only reason people need o2 extensions is for a race header. Though I'm sure that whatever hi-flow Cat you go with will either come with the necessary parts or they will tell you that you need something. But I haven't heard of anyone needing any extensions or adapters for hi-flow cats.
 

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nerd bomber
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2,756 Posts
Ok so this is my current N/A setup on my 2002 Type S

Injen SRI,ESMM, ITR header/gutted cat, 2005-06 cat back exhaust.

Now my question is in the very near future I will be adding the Hondata reflash #4. Should I worry about my exhaust setup being too restrictive for the ITR header/gutted cat and hondata #4 reflash? Would I benefit from replacing my 05-06 axle back with something larger like a universal 60mm or 65mm axle back exhaust? Even though my current 05-06 midpipe is a 2.25 to allow for less restrictive exiting of exhaust gases with the newly added Hondata reflash# 4???

Any input on this would be much appreciated.

Correct me if I'm wrong but I would need to have a flange welded from the current midpipe to the larger axle back if I were to go bigger???
 

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Big Pimpin
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15,710 Posts
Discussion Starter #7
Ok so this is my current N/A setup on my 2002 Type S

Injen SRI,ESMM, ITR header/gutted cat, 2005-06 cat back exhaust.

Now my question is in the very near future I will be adding the Hondata reflash #4. Should I worry about my exhaust setup being too restrictive for the ITR header/gutted cat and hondata #4 reflash? Would I benefit from replacing my 05-06 axle back with something larger like a universal 60mm or 65mm axle back exhaust? Even though my current 05-06 midpipe is a 2.25 to allow for less restrictive exiting of exhaust gases with the newly added Hondata reflash# 4???

Any input on this would be much appreciated.

Correct me if I'm wrong but I would need to have a flange welded from the current midpipe to the larger axle back if I were to go bigger???
An axle back isn't going to do much, if anything, considering it's the entire piping that is going to be cause of any problems. To answer your question if it's going to be too restrictive...that's subjective. If you're worried about power, then yes. Otherwise, no it will be fine. You'll probably feel a difference with the reflash, sure, but not as much as you would with a proper header/exhaust.

Ya, I'm pretty sure you need a bigger flange welded on as well. Honestly, if you're going to get an axle back, just get the mid-pipe as well. Then you don't have to do any welding and you circumvent any restriction issues with the piping. After that it's all header and cat restriction.
 

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nerd bomber
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2,756 Posts
An axle back isn't going to do much, if anything, considering it's the entire piping that is going to be cause of any problems. To answer your question if it's going to be too restrictive...that's subjective. If you're worried about power, then yes. Otherwise, no it will be fine. You'll probably feel a difference with the reflash, sure, but not as much as you would with a proper header/exhaust.

Ya, I'm pretty sure you need a bigger flange welded on as well. Honestly, if you're going to get an axle back, just get the mid-pipe as well. Then you don't have to do any welding and you circumvent any restriction issues with the piping. After that it's all header and cat restriction.
Ok, I'm starting to get this all now, it is the whole cat back that is going to be too restrictive, and replacing just the axle back with something larger then then the 2.25 won't help performance wise becasue the exhaust exiting what was once the cat is still going to the b pipe that's 2.25 inches. In order to get the best flow the whole setup from the cat back needs to be larger then 2.25 inches.

This raises a few new questions, from the research that I did in the ITR header thread the ITR header and cat only made 7 whp less on the dyno then a 02-04 type S with a RH ( I can't remember what brand RH) This was with a full working cat. I'm hoping that since mine is gutted (I do have to run the gutted cat with a defouler to keep me from getting a CEL) That I won't suffer from that 7 whp loss after the vtec cross over. Essentially with the gutted cat I do have a RH.

Now if that's the case, I'm wondering if I'm actually bottle necking at the end of the cat? With other RH's don't they also taper down to a smaller diameter? I was talking with drumnatural and he said his comptech RH was only 2 inches diameter at the end of the piping where the cat back would connect and he actually bored his out to 2.5. I have no idea what diameter the piping is at the end of the ITR cat but if it is smaller then the 2.25 inch b pipe then my flow should be sufficient? :run:
 

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Big Pimpin
Joined
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15,710 Posts
Discussion Starter #9
Ok, I'm starting to get this all now, it is the whole cat back that is going to be too restrictive, and replacing just the axle back with something larger then then the 2.25 won't help performance wise because the exhaust exiting what was once the cat is still going to the b pipe that's 2.25 inches. In order to get the best flow the whole setup from the cat back needs to be larger then 2.25 inches.

This raises a few new questions, from the research that I did in the ITR header thread the ITR header and cat only made 7 whp less on the dyno then a 02-04 type S with a RH ( I can't remember what brand RH) This was with a full working cat. I'm hoping that since mine is gutted (I do have to run the gutted cat with a defouler to keep me from getting a CEL) That I won't suffer from that 7 whp loss after the vtec cross over. Essentially with the gutted cat I do have a RH.

Now if that's the case, I'm wondering if I'm actually bottle necking at the end of the cat? With other RH's don't they also taper down to a smaller diameter? I was talking with drumnatural and he said his comptech RH was only 2 inches diameter at the end of the piping where the cat back would connect and he actually bored his out to 2.5. I have no idea what diameter the piping is at the end of the ITR cat but if it is smaller then the 2.25 inch b pipe then my flow should be sufficient? :run:
If you're using a stock 02-04 b-pipe it's smaller than 2.25". I think the inner diameter is around 1.9" from what some have said. But yes, you have the basics of it. Any bottleneck in the system is essentially (for arguments sake) going to negate any upgrades you do to your exhaust. The only reason to change axle backs is either for the different sound or, in the rare case, to get one that does flow better.

I'll have to see this thread before I comment on the ITR header business. But if you're saying that someone was using a DCRH with a cat, then that makes sense because the cat is the bigger restriction in that case, not the header. Also unless it was the same car, same dyno, similar atmospheric conditions and the same exhaust system then a test like that isn't reliable. Again though, I need to see this thread first.

I do not know the size of all the headers out there or anything like that, but I doubt that boring out the flange is going to make a difference because the rest of the piping in the header is designed around that 2" flange. My hytech was 2.5" at the collector (The biggest you're basically gonna get without coming into problems, according to John Grudynski of Hytech Exhausts) mated to a 3" exhaust. But the flange on the exhaust to the header was 2.5" and it flared out to 3" on the b-pipe. I still gained 10hp peak with that 3" exhaust on a DCRH over a 2.25" exhaust with no tune to compensate for the bigger exhaust. (keep in mind my setup was a bored and stroked motor, not your typical bolt ons). What I am getting at is, if his collector was a 2" diameter, boring his flange out to 2.5" wouldn't accomplish anything because he's still pushing out of a 2" collector mated to whatever size exhaust it was that he had.
 

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812 Posts
Ok, I'm starting to get this all now, it is the whole cat back that is going to be too restrictive, and replacing just the axle back with something larger then then the 2.25 won't help performance wise becasue the exhaust exiting what was once the cat is still going to the b pipe that's 2.25 inches. In order to get the best flow the whole setup from the cat back needs to be larger then 2.25 inches.

This raises a few new questions, from the research that I did in the ITR header thread the ITR header and cat only made 7 whp less on the dyno then a 02-04 type S with a RH ( I can't remember what brand RH) This was with a full working cat. I'm hoping that since mine is gutted (I do have to run the gutted cat with a defouler to keep me from getting a CEL) That I won't suffer from that 7 whp loss after the vtec cross over. Essentially with the gutted cat I do have a RH.

Now if that's the case, I'm wondering if I'm actually bottle necking at the end of the cat? With other RH's don't they also taper down to a smaller diameter? I was talking with drumnatural and he said his comptech RH was only 2 inches diameter at the end of the piping where the cat back would connect and he actually bored his out to 2.5. I have no idea what diameter the piping is at the end of the ITR cat but if it is smaller then the 2.25 inch b pipe then my flow should be sufficient? :run:
if you want power why are you going with 05-06 stock exhaust? why an itr header and not another rh? and why a sri and not cai? and why a reflash and not kpro?? if you dont want to much power than just stick with your setup.. but if your looking for optimal setup than why are you putting the weaker upgrades?? im not bagging on you b/c i did the same thing until i did the research but you need to decide what you are looking to get outta your car.. the bigger the better usually.. more air flow=more power
 

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nerd bomber
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2,756 Posts
If you're using a stock 02-04 b-pipe it's smaller than 2.25". I think the inner diameter is around 1.9" from what some have said. But yes, you have the basics of it. Any bottleneck in the system is essentially (for arguments sake) going to negate any upgrades you do to your exhaust. The only reason to change axle backs is either for the different sound or, in the rare case, to get one that does flow better.

I'll have to see this thread before I comment on the ITR header business. But if you're saying that someone was using a DCRH with a cat, then that makes sense because the cat is the bigger restriction in that case, not the header. Also unless it was the same car, same dyno, similar atmospheric conditions and the same exhaust system then a test like that isn't reliable. Again though, I need to see this thread first.

I do not know the size of all the headers out there or anything like that, but I doubt that boring out the flange is going to make a difference because the rest of the piping in the header is designed around that 2" flange. My hytech was 2.5" at the collector (The biggest you're basically gonna get without coming into problems, according to John Grudynski of Hytech Exhausts) mated to a 3" exhaust. But the flange on the exhaust to the header was 2.5" and it flared out to 3" on the b-pipe. I still gained 10hp peak with that 3" exhaust on a DCRH over a 2.25" exhaust with no tune to compensate for the bigger exhaust. (keep in mind my setup was a bored and stroked motor, not your typical bolt ons). What I am getting at is, if his collector was a 2" diameter, boring his flange out to 2.5" wouldn't accomplish anything because he's still pushing out of a 2" collector mated to whatever size exhaust it was that he had.
Let me clear things up.
My car is a 2002 type S
I have the 05-06 catback exhaust
I also have the ITR header and cat. The cat has been gutted, there is nothing inside it. This basically makes it a RH that looks stock and says Honda on it. The header also has equal primaries and mates better then an aftermarket header. It's made by Honda! :giggity:

As far as the ITR header all info was found in this thread... http://forums.clubrsx.com/showthread.php?t=461316

Here are some post supporting that the ITR header made 7 whp less on the SAME car as the DCRH...

It was dynoed from a k20a engine with the ITR header first and made the same gains when he switched to the DCRH up until the crossover at 5k. After that the DCRH made 7 more whp than the ITR header up until redline. The post was deleted after the website update because I would have posted the graph.
I made 208whp with mine on a dynojet with the following mods:

Fujita CAI
Hondata IMG
RBC
ITR header/cat (cat was punched out)
Buddyclub Spec III
Kpro + tune

EDIT:
dyno picture link: http://img444.imageshack.us/my.php?image=ryansdynographnl0.jpg
I had a DCRH which had garbage fitment with my buddyclub spec III. I put the ITR on for awhile and decided to just gut it when I got my RBC for maximum power. It still looks like its a stock cat, because it says honda all over it, it just doesn't have anything inside it :)
While changing my catback back to stock the other day, I measured the inside diameter of the flange at the cat of my ITR header and cat at 2 inches. Has anyone measured a different inside diameter? This would be where the exhaust connects to the cat.

luvmyrsx
Ok with all that there, and with now knowing that the flange at the end of the ITR cat is 2 inches, my question is as follows would the performance increase in going from the 05-06 catback exhaust to a 65mm or a 2.56 inch catback system be worth the cost of the upgrade or knowing that the flange at the end of the cat is only 2 inches should 05-06 catback offer good enough exhaust flow for my bolt on N/A setup?
 

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nerd bomber
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2,756 Posts
if you want power why are you going with 05-06 stock exhaust? why an itr header and not another rh? and why a sri and not cai? and why a reflash and not kpro?? if you dont want to much power than just stick with your setup.. but if your looking for optimal setup than why are you putting the weaker upgrades?? im not bagging on you b/c i did the same thing until i did the research but you need to decide what you are looking to get outta your car.. the bigger the better usually.. more air flow=more power
Well, I'm not really trying to make the most power from the N/A as possible, just trying to get the most out of the setup that I have chosen which is as follows and I'm set on.

Reflash #4, ESMM (eventually full mounts), ITR header and GUTTED cat, and exhaust

I went with the 05-06 exhaust because it is essentially the same exhaust as on the ITR the only difference is the ITR muffler has a flange inside that opens up at WOT for better flow, so I expected it to flow more then enoguh for my setup.

I run and SRI in the winter, have you ever been to Utah my friend hahaha? It snows here, and when I say it snows... I mean a whole fucking bunch! Most likely this summer I will run a CIA.

As far as the reflash vs kpro... for me I will not be adding anymore mods after the reflash, and possibly a larger diameter exhaust, if I find it to be necessary. I would only need kpro if I wanted to add the RBC intake mani or cams or if I wanted to go FI. I won't be doing anything that I'll need the kpro for other then It'd be nice to tune... but that's exactly why I'm trying to build my setup around the reflash... which is specifically designed for a type s with moderate bolt on mods ie intake,header,exhaust.

The ITR header with the gutted cat is pretty much a race header, just made by Honda it pairs better then after market headers and you get that Honda reliability! :giggity:
 

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Registered
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812 Posts
Well, I'm not really trying to make the most power from the N/A as possible, just trying to get the most out of the setup that I have chosen which is as follows and I'm set on.

Reflash #4, ESMM (eventually full mounts), ITR header and GUTTED cat, and exhaust

I went with the 05-06 exhaust because it is essentially the same exhaust as on the ITR the only difference is the ITR muffler has a flange inside that opens up at WOT for better flow, so I expected it to flow more then enoguh for my setup.

I run and SRI in the winter, have you ever been to Utah my friend hahaha? It snows here, and when I say it snows... I mean a whole fucking bunch! Most likely this summer I will run a CIA.

As far as the reflash vs kpro... for me I will not be adding anymore mods after the reflash, and possibly a larger diameter exhaust, if I find it to be necessary. I would only need kpro if I wanted to add the RBC intake mani or cams or if I wanted to go FI. I won't be doing anything that I'll need the kpro for other then It'd be nice to tune... but that's exactly why I'm trying to build my setup around the reflash... which is specifically designed for a type s with moderate bolt on mods ie intake,header,exhaust.

The ITR header with the gutted cat is pretty much a race header, just made by Honda it pairs better then after market headers and you get that Honda reliability! :giggity:
thats fine and all cuz its your build.. but you want to get a reflash thats meant for header and exhaust.. you basically reflashing a stock 05-06 type s without the box intake.. might as well get a bigger exhaust and ive had a dc sport header and test pipe and didnt get shit as power unitl i went to a rh i felt a big difference.. but your car your money your choice
 

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Big Pimpin
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15,710 Posts
Discussion Starter #18
Some people have. Some run nitrous on even bigger builds. There's nothing limiting you on running nitrous like there is with boost (I.E. compression and cam lift/duration).
 

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Big Pimpin
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15,710 Posts
Discussion Starter #19
Let me clear things up.
My car is a 2002 type S
I have the 05-06 catback exhaust
I also have the ITR header and cat. The cat has been gutted, there is nothing inside it. This basically makes it a RH that looks stock and says Honda on it. The header also has equal primaries and mates better then an aftermarket header. It's made by Honda! :giggity:

As far as the ITR header all info was found in this thread... http://forums.clubrsx.com/showthread.php?t=461316

Here are some post supporting that the ITR header made 7 whp less on the SAME car as the DCRH...









Ok with all that there, and with now knowing that the flange at the end of the ITR cat is 2 inches, my question is as follows would the performance increase in going from the 05-06 catback exhaust to a 65mm or a 2.56 inch catback system be worth the cost of the upgrade or knowing that the flange at the end of the cat is only 2 inches should 05-06 catback offer good enough exhaust flow for my bolt on N/A setup?
For what you're looking at doing, you'll see a minimal gain on changing the exhaust. If any. I'd go so far to say the only reason you should change your exhaust is if you want a different sound. Until you start modding for more power. In the mean time, save your money and just stick with 05-06.
 

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4,878 Posts
thanks keV I just was wondering about timing does kpro pulls timing when I'm using it and when I'm off goes back to normal
 
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