jwood_06TSX

Mod Edit: Everybody, PLEASE fill out the poll and post up some info for me if you have a AT with Comptech headers and if you have the rattle, at what RPM range and more importantly IF you have a CAT or exhaust! This will really help me out, thanks!

Hey guys,

Well after having them in my room i finally got around to installing them and i will give you the shorter version as there a lot of threads on these and install manuals as well. I used JTso instructions along with the regular comptech ones, although it didn't prove to be difficult at all. I am pretty mechanically inclinded, although i have not done headers before, it was very simple.

Install-
I only have 7500 miles on my car so the top header bolts were really easy and i did get stuck on the one hard to reach CAT bolt, but finally got it loose. A breaker bar will SAVE you a TON of time on this, i will say that. All in all, it took me just over 2 hours to do it including like 10 mins just clean the header to insure no finger prints

Performance-
I set her down and started her up to listen for leaks and let it warm up so i could take her for a spin, luckily i had no leaks! I took her out and honestly i was not impressed initially at all. It sounds slightly louder (only other mod i have is a custom comptech icebox) and i could feel a slight difference in the higher RPM range but nothing special, i was alittle dissappointed. I thought to myself though, i know the ECU needs to learn and adapt so i will run errands the next day with her and do a few turn on and offs and such to give it some time. Well, the next day i wake up and head to the gym and i immediately see the RPM's flow up a little more freely, it seemed like the engine wasn't working as hard. I didn't hit VTEC as the gym is not far away and the car was still cold but i could def feel a slight more pull between 2-3k. I leave the gym and run some errands and then i get to the part of the road where i like to hit VTEC and i make a go at it. Well, to my surprise, it DEF made a pretty noticeable difference!!! I used to have this lag at around 5-5.3k before hitting VTEC at 6100 but now, MAN, this thing jumped from about 5.3k to 6.6k MUCH faster and then right into VTEC where it takes off like a bat out hell and i almost hit the limiter. It seriously revved up much faster than before. I can now tell the difference across the whole power band, the car def has a little more pull down low and a decent amount of pull up top!

BAD news.....the rattle....
Well, with my luck with my 04 and now this rattle track 06, i new i would get it, and yep, i do but its very strange. Here is what happens.....
The car ONLY seems to make a noise between 650-700 RPM's no matter whether the AC is on or off, drive or reverse but needs to be engaged. This noise is not loud and it comes from the back of the car on the left exhaust pipe. I think the new resonating frequency at this point, makes the CAT and exhaust act like a tuning fork and it just vibrates slightly. I can deal with this. If i actualy turn the wheel to the left or right while at a stop in drive, it raises the RPM's and it goes away. Or, i just pop it into neutral if it really bothers......now...

the WORSE rattle.....
If i am in drive at a stop and i turn the AC on and the car idles in at ONLY between 660-690 RPM's (i need to check this again because i haven't been using the AC recently, its nice out), the WHOLE header and CAT SHAKE like crazy. They vibrate so badly its ridiculous but its in a very small range. I haven't investigated this much further but i am really hoping that it doesn't do it again, or it wears itself out because if you get under the car and look at it, it was BAD! It is a seriously natural resonance if i ever seen one and i'm worried that it might actually shake the engine, which could then in turn affect motor mounts, etc. So i need to look into this.

Do you guys think that if i got the RT CAT that it would change my air flow enough that it may make the natural resonant frequency different? How about hondata, i heard that it makes your car idle slightly higher, which would get rid of this problem.

Also, i'm asking that anyone that has this header, please post up what else you have with it and if have the rattle and at what RPM range, i plan on trying to figure this one out if possible....its the engineer in me!



So this was no where near as short as i was hoping but there it is. Replies are wanted and i want to start a discussion about this header again!

chuson

lol, the RT Cat and Hondata will only let you drive your car faster or louder (cause of the HFC), not quieter or reduce the vibration.

I knew a member who had the CT Header got a rubber header hanger from Acura dealership for cheap, once he swapped it, the vibration is 90% gone. I guess result might vary tho.

Knifey

Yup, that's it exactly. I have a 5AT, it's happens around ~750rpm. The vibration, when it really gets going, is a bit unsettling to watch, certainly doesn't seem good, but I don't know. I've had it about a year now, haven't noticed any additional problems, but no, it doesn't get any better.

The tuning fork like behavior was what I thought too - I think I even speculated in the original comptech header rattle thread - not so sure now though. It seems to me to be a lot louder near the rear seat hump and I wonder if that has anything to due with the pulse changing the sound from the resonator at that position. Since the header is shorter than OEM (vis-a-vis the length of the car), I was thinking of having the flex pipe replaced with a slightly longer one to see if that would make a difference. Pure speculation, I haven't done anything with it though.

clee109

hmm I have no rattle at any RPM with the CT header.

Setup: 2006 M/T
CT icebox
CT header
RT Cat
CT catback

No rattles or leaks of any kind. I just had a heck of a time with the lower right bolt on the stock manifold.

acn684

rattles only with AT because we stuck in gear at light.

moda_way

To those of you who have the 5ATs... get someone in there to hold the car in D at idle w/ or w/out A/C on and find the rattle. From what it looks like its the exhaust post CAT and not the header.

jwood_06TSX

So i think between this thread and along with all the others, we know its the following...

primarily 5AT due to a steady idling RPM with in D mode
only between say 650-750
worse with AC on-severe vibration
no AC, just slight noise from the rear end of the car


Ryan-i had my g/f do this quickly and that is when i looked under the car i saw it shaking like crazy. I plan on repeating this to see where it stems from and if it shakes the engine because that would NOT be good!


Possible solution would be to just get a RT CAT and a CT exhaust, but i rather not spend another $1200 just to get 10 HP and fix a rattle.....lol

jwood_06TSX

I know it will do that but i'm just saying that it might change the airflow or the idle RPM's just enough to change the natural resonance of either the header or the CAT.....i need to figure out a way to test both to see which on it is.....or the exhaust i suppose to.

Isn't there already a rubber hanger? That is what i hung the header on or are you talking about something else?

moda_way

have you thought about some poly exhaust hangers from NAPA?

jwood_06TSX

I hadn't gotten that far to inspect to see if that would make much a difference yet. Isn't our exhaust already on rubber hangers though?

Is this what you mean... http://www.napaonline.com/MasterPage...er+-+Universal

moda_way

no, this one:

https://acurazine.com/forums/showthread.php?t=26948

Reach

jwood, this is exactly what happened to me as well. I wrote on it extensively and never got a good solution. Also, I do already have the RT cat, so no that won't fix your issue.

The problem only affects 5AT owners, as the conditions which bring it about simply aren't present on the 6MT. You need to be at the lowest idle and in gear which the 6MT isn't at a stop (clutch out). A/C makes it considerably worse.

I also agree with the sentiment that it isn't the header per se, but the header is what CAUSES the exhaust to vibrate like crazy; a tuning fork is a good metaphor. The exhaust may be the actual source of the vibration, but the header is a primary factor that leads to it.

I wouldn't imagine the Comptech exhaust would reduce the issue substantially either, as it is very similar in design to the OEM setup. If I were to put my Comptech back on, I'd go with a single-outlet exhaust. The design should be so significantly different as to cause different resonation and less (hopefully none) vibrations.

I'm currently using a modified DC header that is working fantastic for me. For some reason, I wish I could go back to the Comptech (I just like it better, ok!) but without a clear resolution to this issue, I'm not putting it back on.

Knifey

Just put it in Drive and set the parking brake, and you can watch it shake all day long - it will. I don't recall it really having much impact on the engine, even when it's at full swing (though one wonders what kind of stress it's putting on those bolts...). It's really just the header and cat which vibrate like mad. The oscillation is damped somewhat at the rear of the exhaust, the mufflers don't move nearly as much, maybe due to the extra hangers.

moda_way

Well obviously Honda/Acura knows about it and that is probably why there is that extract bracket on the motor to the header for the OEM one. Just a shame becasue I love my Comptech header and couldn't imagine not having it.

jiggaman

i have 6MT 2004 and comptech header caused same problem at idle with AC...i ended removing it..

jwood_06TSX

THAT is exactly what i was thinking the main reason for the a majority of the resonating. I was thinking of trying to design a connection that would keep the comptech header tied to the frame somehow, but there is no way to do it without welding, which i wanted to avoid due to possibly reselling or trading in the car. I will look into it some more, but i don't think that a second connection is an option.

i also looked into those exhaust hangers, and i really don't see how that would help all that much. I would tend to think that with the more vibration, the more rubber you would want to allow the vibration to dampen out of the system as a whole. If you put a shorter, less flexible hanger in there, it won't have as much "play" to help the dampening of the vibration....just my theory on that anyway but i need to inspect a little more, which i will do this weekend.



Reach- i did read that thread a lot actually and i think you had some good points although, most of thread ended being about that bracket the that 06's have that hte 04-05's did not. That is not he cause of any of my noise as far as i can see so far. Seeing as you have the RT CAT and still had the vibration, that combination obviously doesn't change the resonating frequency, so that idea is out. The design you have now is strictly a two piece design just like the other Topspeed you had too correct? Do any of the two piece designs have the same connection to the frame that Ryan mentioned? I didn't think it did but maybe the two piece design is enough to allow a little flexation in the system whereas comptechs solid one piece does not. If that is the case, then there is most likely nothing we can do to resolve that other than find a way to keep the idle higher.....

Also, Reach, did you notice a performance difference form the Topspeed to the Comptech? Just curious as if this gets to be too annoying for me and i can't figure it out, i may switch however, i have almost 9 months before i will be using the AC heavily again, so i have some time.


I will inspect this more and gather some more data to try and figure this out. My agend as of now is to try and identify where most of the vibration occurs and what else vibrates a long with it. Maybe try and narrow down the exact RPM range as well.

Tsx536

Hey Jordan, how about some type of spring loaded bolts between the header and CAT. The OEM setup has that. If you made a custom setup I'm wondering if it would work with the Comptech.

curls

Do not weld or affix the header to the frame. There are motor mounts for a reason -- the engine does move, and affixing the header (which is attached to the engine), to the frame (which is isolated from the engine via the mounts), will cause something to break. Something would have to give. Odds are it's the most expensive piece that breaks, too. Murphy's law and such...

I can't remember, but doesn't the OEM header connect to the block of the engine? If so, THAT would be a viable option. Take the piece from the OEM header that makes this connection, get it measured precisely, and attach it to the CT header in the right spot. Bolt to block/wherever, and see how it goes.

What I think this would do is prevent much of the vibrations from resonating through the header and thus through the exhaust. By connecting the header not only at the runners, but also part way down the downpipes, you'd create a vibration-free zone between those two connections. Might be enough to stop the massive vibrations from happening, since every time the ehader moves currently, it moves the entire exhaust (on rubber hangers), which probably resonates at just the right frequency to amplify itself when the engine is at the rpm level you're experiencing this at.

I have a DC V1 (w/ upgraded welds) + a 6MT, so I am more than happy and have no noises or vibrations to deal with... but the above are just my rambling thoughts transmitted through my fingers.

jwood_06TSX

Eric, i meant connect the header to the block like you are saying. I thought that bracket connected to the frame but i forgot it was the block. I am trying to think of a way to use that bracket and some other type of pipe fitting around the header so i don't have to get anyone to weld it. Like maybe get a heavy duty hose type clamp and connect it to the OEM header bracket, if that makes sense. Again, i need to get under it and take a close look but this weekend is booked solid so i may not get to it until next week.

curls

That makes sense. Just make sure to do some research on the materials you use, for a few reasons:
- reaction to the stainless (?) header, and possibility of scratching the header
- heat resistance / possibility of fusing itself on there if not a suitable material and fastener
- sturdy enough

But as an engineer I'm sure you already knew that.

jwood_06TSX

HAHA....yea, i did know that which is what i'm trying to think of. I would assume i could get away with just using stainless steel, but then i know it would scratch it most likely. So i was then thinking about that high temp header tape to wrap it in first and then install a SS pipe fitting and mount it to the braket. But the issue with that would be movement due to the tape no matter how tight the clamp would be. I really need to think about how to do it without welding.....i rather avoid that but if i have to i have to. I could always just buy another OEM header bracket, they are only like $7, and use that one to weld to it if i choose that path.

I guess i just need to find out if that would even solve the problem first but i might try something temporary to test it out first.


PAGING JTso, i think his experience might help yeild a solution or at least ideas! Any thoughts on this?

JTso

iTrader: (2)

You can always try a custom bracket using different length/width and connect them together using nuts and bolts instead of welding. There might be other threaded holes on the block in addition to the header bracket hole. Then you can use a longer bolt and connect the custom bracket to the exhaust flange.

jwood_06TSX

I actually did notice there were unused thread holes in the block and i was wondering what they were even there for. That is one of my two ideas at this point actually however, what do you mean by connect it to the exhaust flange? The flage that gets connected to the CAT, because that is pretty far own there and i don't see any easy way to connect it down there?

MrHeeltoe

iTrader: (1)

It amazes me the lengths people will go to in order to cover up a problem like this. On one hand, good job for working it out...but on the other hand why mess with a product that has this known problem from a company that is so light on support after the fact?

jwood_06TSX

Ya know Marcus, you make a good point and its something i had asked myself prior to purchasing the header. Part of me wants to just put it back to stock and just make myself content with the TSX as is, and part of my wants to try and mod it to something its not and its never really going to be for me. I want more power and i guess that is why i bought it, in addition to the fact that i enjoy working on the car and doing this type of thing. However, you make a very valid point and i have a feeling that i will find myself giving up on modding and either keeping the TSX and making myself content (as i need to start thinking about saving for a house, which i am kind of doing already) OR trade it in for something faster to satisfy what i ultimately want. Although, i already turned down a VERY good offer on both a TL-S and an G35c of which i wanted both.....lol.

I will try and fix this once or twice with a lot of thought and after that we'll see what i decide to do. Until then, my search for a solution continues

moda_way

Again, we've documented the header itself is not the problem. So does a company warranty a downstream part? If I were to buy a trunk brace from you and I get the cross member supporting the rear deck to rattle, would you warranty that cross-member for me?

I've personally gotten great support from Comptech in the past. One of the exhaust resonators had a weak weld in it and they replaced it without question. Now that was the only issue anyone on this forum noted and the only one they saw at that point from the TSX exhaust.

I once had this rattle everyone is talking about, but to date, I can't reproduce it and couldn't locate the origin of it.

If anything, buying the DC Sport header and then taking it down to get a better flex pipe installed would tick me off just as much if not more. Why put a sub-par flex pipe in there to begin with when it is well documented as well.

Very admirable. I look forward to your results.

jwood_06TSX

So this may already be something you guys know and i have yet to find on here or figure out on my own but this interested me none the less. I was driving home yesterday and stopped at a light with my AC off. I took notice at the RPM's and they were at somewhere between 570-600 and it was as smooth as butter and i could hardly hear or feel the car running. This was something i had experienced the first morning after installing the header and had never noticed it idle that smooth. While i'm sitting at the light, i realize its starting to get dark and i think, turn on the lights. So i turn on the headlights with my fog lights on as well, and what do you know, the RPM's rise to about 675 in order to run the lights. As soon as i turn them on i get that small not bad rattle somewhere in the back of the exhaust. So then, i'm like let me try the AC and i do which then makes the RPM's rise to about 690-700 and it gives me that BAD rattle intermitantly. I then turn my lights off, and the they go down slightly but are still in that range of the small vibration. Then when going to turn the lights back on, i turn the wheel and the RPM's jump to like 750-800 and it goes back to being smooth. I turn the wheel back to being straight and the idle works itself back down to the 700 or so. I then turn everything off and the car goes back to being idled at around 550 and smooth.

This all found me wondering about how this stuff would effect the RPM's differently. I know the engine needs to run alittle faster to run the AC and such but i guess i just really never noticed it when i turned the lights on without the AC. I guess its due to those SWEET BRIGHT lights Acura has!! It left me with these cases....

no lights, no AC = 570ish idle = no rattles
lights on, no AC = 670ish idle = little rattle
lights on, AC on = 690-700 idle = shaking rattle
no lights, AC on = 675ish = little rattle

my conclusion so far is that the natural resonating frequency of the severe rattle is around 670-700 where anything higher is smooth and then anything from 670-600 is a slight livable rattle from the exhaust pipe. I pulled the e-brake and put it in D when i got home and listened to the rear of the car for a minute and it sounded like there was actually a piece of metal inside the driver side muffler......strange! I will keep investigating this.

thought, comments?


EDIT: Thanks Ryan, i just hope i find something and give back a little to this community since its helped me so much

curls

You mentioned it sounded like a piece of metal rattling inside the drivers side muffler. Can you reproduce the noise if you shake or bang (lightly!) on the muffler when the car is off, but the exhaust system is still warm? The mufflers shouldn't be too hot even at operating temperature. Anything upstream might be, however.

Sounds like the 'sweet' spot , or should we say, 'rattle-inducing, I don't like this RPM range one bit' spot, is as you said, between ~670-700rpm. Must be a resonant frequency of the exhaust system. Changing to stiffer, or much looser, exhaust hangers just might fix this by preventing the exhaust from shaking in harmony with itself (resonance) within that rpm range. If it were something along the lines of the spring-mounted bolts ilke the OEM exhaust flange used, then you'd think the DC header and all headers that don't use spring-mounted bolts, would have the same problem. So it's probably a function of the Comptech header having the exact resonance, or effect on the resonance of the entire exhaust, that causes this.

I think your bracket idea just might work.

MrHeeltoe

iTrader: (1)

So does this rattle happen with other headers?

Do we know, physically, exactly, where the rattle comes from? What part hits another? Or the locality of the noise emanation? (do I need to read more?)

jwood_06TSX

Regarding your need to read more, yes and no. I have figured out the RPM range in which the 2 rattles take place and i only know the location of the lesser of the two rattles, which exists somewhere around the header and CAT connection but mostly from the rear of the car on what seems to be the driver side muffler. As for the main rattle, i have not yet be able to get under the car to take a closer look at that one yet, but plan on it this weekend if possible. I have only seen this main rattle at its worse, one time and it was basically the whole bottom section of the header and the CAT. The exhaust rattled a little bit but it pretty much dampened out the vibration that was occuring right in and around the flange of the CAT. Therefore, i have been thinking that a bracket somewhere closer to where the header meets the CAT would be better than mid span on the just the header. This is the part that i need to figure out!

As for the lesser rattle, i need to inspect the exhuast, the exhaust hangers, and the heat shield as i think those are what are causing the noise in the rear.


However, regarding other headers, i don't know. I have seen people with the DC header, the modified DC header, the newer DC header, and the Topspeed header that have not had this vibration. So it seems that when we go from a two piece design to a one piece design, something happens within this RPM range with the air flow.

Unfortunately, i have a feeling that if air flow is the "physical" problem, then no matter how we restrain the header, CAT, or exhaust, if the air flow is not changing then the vibration will need to be be damped out somewhere.....which could lead to other problems. This is my only concern in trying to find a solution! This applies to what you said Eric!

jwood_06TSX

My bold comment address most of what you were saying. I'm just worried that no matter how we bracket it, the air flow still remains unchanged and will want to vibrate somewhere or something. However, it could just be lack of support and needs to become a little more rigid and that may work too, this is why i need to look under the car more and get a better understanding of where it stems from!

MrHeeltoe

iTrader: (1)

If resonance is causing the noise then you won't be able to fix that and indeed it is not a rattle at all. If resonance is causing the pipe to vibrate and physically hit something, then that should be fix-able. Actually, that would go to header design.

The only other thing I can think of is if there is a resonant frequency in the exhaust which reverberates with a resonant frequency of the heat shield of the exhaust or cat somewhere. Try removing the heat shields from the cat (4 10mm bolts, very easy to do.)

In the end we need to nail down exactly what is causing a noise. The exhaust moving is not in itself the issue at hand. To make a noise, it actually needs to hit something or have a loose part somewhere.

jwood_06TSX

That is exactly my point Marcus! If it is truly JUST air low, aka a certain resonanting frequency, then no we won't be able to fix it. If it is resonating with some other part (like your heatshield idea) or causing another part to rattle (like my exhaust sound i hear at the lesser of the two rattles) then we can try and track it down.

What i have a feeling is going to happen is i can figure out how to get the lesser of the two rattles figured out somewhere along the exhaust however, that main rattle i have a feeling is based strictly upon air flow. If this turns out to be the case then there really is not way to fix that. I originally thought that a RT CAT and an exhuast might be enough to change that resonating airflow but since Reach has a the RT CAT and i think he had exhaust, it wouldn't seem to matter.

I would be really curious actually.....Does anyone have a 5AT, with CT headers a RT CAT & exhaust? Please let me know if you fit this catagory and if you have a rattle or not!!

Tsx536

Can you adjust your idle and possibly raise it a little higher?
I wonder what RPM a 6MT idles at.

curls

~750rpm

curls

I still think a bracket might help, regardless of what is actually hitting something else. The reason being is that the 4-1 design might be acting like a tuning fork. By putting a bracket, or breaking the fork by not allowing one or more of the downpipes to rattle, you should basically stop the tuning fork action, which will do one fo two things: 1: Stop the resonance from occurring. 2: Stop something downstream from getting the vibrations transferred to it (at least somewhat reduce them), and thus stop the clanging against another part.

But obviously if its Part A hitting Part B, it's a design problem, and the easiest fix wuold be to separate Part A from Part B physically either by moving one part slightly firther away (adjust exhust hanger length in the area might be one easy fix?), or, by dampening the area with some thick foam or noise-suppressant taping to have less metal-on-metal sound.

jwood_06TSX

I think the 6Mt idles as the same as a 5AT in N, which is what Eric said, aroud 750 PRM's. Kenny, that is why i mentioned hondata, cause i though i remember reading something about how their idle was higher once they installed the reflash......can anyone confirm or deny that?


Eric - i acutally have thought about maybe even just applying some sound absorption material as well, IF that is the case. Again, i need to look into it once i get under there and throw different ideas around while watching it. Unfortunately, i think its going to be more than just making sure 2 peices aren't touching.....although, i hope that its it

moda_way

I did actually push my head sheild where the header transitions going to under the car, but I can't imagine that did anything. I do know for a fact that the header is not touching anything on my car and doesn't even come close, which is why I've said all along this is a resonance issue. The reason why other headers don't do it is materials and thickness. Cheaper SS isn't the same SS that Comptech uses and we all know that the DC header, under the ceramic coating is just steal.

Knifey

On my car the header isn't hitting any other part of the car. I've dropped the heat shield that goes over the cat, no difference. Never though to drop the heat shield(s) over the catback portion of the exhaust however as when I was playing with it I hadn't noticed the hum was louder at the rear.

And we should probably stop referring to the sound as a rattle, seems only to be a source of confusion.

Slammed89

I bought a DC header almost a year ago and mine rattles at part-throttle between 2500 and 3000 RPM. It drives me nuts. I've been under my car 4 times trying to identify the cause. My guess is that it's a pulse/resonation issue over that particular RPM range. I logged in today to see if other brands were experiencing the same problem. I guess DC isn't the only one.