Quitest Cat-Replacement Pipe
06-22-09, 09:54 PM
#1
Quitest Cat-Replacement Pipe
I know that's kind of an oxymoron, but I want to free up the rest of my exhaust (currently just have an N1 Evo cat-back). At the same time not making my ears bleed when I'm DDing my car. I've been looking at the Bonez Race Pipe from Rx7.Com as well as the racing beat downpipe/presilencer combo. My engine is stock ported, and going to be left that way for a while. So any suggestions are apperciated, videos/sounds clips of similar setups would be awesome. 
06-22-09, 10:18 PM
#2
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the rb presilencer is really nice, thats the only one i have experience with. are you keeping the stock mani or going with headers?? i kno you said the presilencer/ pipe combo, but w/ headers you will see the most power increase (like 10hp just from the addition of the headers seems like the consensus?) but then you will get VERY noisy. i used to run rb headers and presilencer to an apex'i GT spec on my NA.....LOUD AS F**K....with the mani inplace tho i think any presilencer will be fine... that stock manifold just kills airflow and consequently noise, of course the noise part is subjective..
06-22-09, 10:43 PM
#3
the rb presilencer is really nice, thats the only one i have experience with. are you keeping the stock mani or going with headers?? i kno you said the presilencer/ pipe combo, but w/ headers you will see the most power increase (like 10hp just from the addition of the headers seems like the consensus?) but then you will get VERY noisy. i used to run rb headers and presilencer to an apex'i GT spec on my NA.....LOUD AS F**K....with the mani inplace tho i think any presilencer will be fine... that stock manifold just kills airflow and consequently noise, of course the noise part is subjective..
What about headers and a high-flow cat, instead of a pre-silencer.
06-23-09, 06:54 AM
#5
I just had a "test pipe" made at a local exhaust shop- deleted the pre/main cats ('91 NA).
Runs from the stock manifold to the RB cat-back system, made of standard aluminized steel, no presilencers or anything.
Surprisingly, noise did not increase substantially...there is a bit more rasp and the overall tone has gotten decidedly more two-strokish, but nothing really obnoxious.
The engine revs much more freely and gas mileage has improved a bit (although this is difficult to quantify since I find myself revving much higher before shifts, compared to the "stock" setup).
This was Stage 1 of an experiment I'm running.
Since I just passed (albeit barely) CO emissions and have two years till the next test, I decided to save my still intact main cat till needed again.
Stage 2 will be to replace the manifold with a header (either Corksport or OBX, since they both will accept the stock cat) and have the test pipe cut and reflanged to fill the gap (this was part of the deal with the shop, so cost will be minimal).
I made too many other changes simultaneous with the cat delete to attribute all the improvement to just the exhaust, but the noise issue seems not to be a big deal...at least with the RB cat-back system in place.
Runs from the stock manifold to the RB cat-back system, made of standard aluminized steel, no presilencers or anything.
Surprisingly, noise did not increase substantially...there is a bit more rasp and the overall tone has gotten decidedly more two-strokish, but nothing really obnoxious.
The engine revs much more freely and gas mileage has improved a bit (although this is difficult to quantify since I find myself revving much higher before shifts, compared to the "stock" setup).
This was Stage 1 of an experiment I'm running.
Since I just passed (albeit barely) CO emissions and have two years till the next test, I decided to save my still intact main cat till needed again.
Stage 2 will be to replace the manifold with a header (either Corksport or OBX, since they both will accept the stock cat) and have the test pipe cut and reflanged to fill the gap (this was part of the deal with the shop, so cost will be minimal).
I made too many other changes simultaneous with the cat delete to attribute all the improvement to just the exhaust, but the noise issue seems not to be a big deal...at least with the RB cat-back system in place.
06-23-09, 08:31 AM
#6
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Replacing the big, heavy 1980's era catalytic with a modern 3 way catalytic should free up the exhaust.
Look into the brick of a modern cat. You can see through it.
I have a Racing Beat streetable (collected) header run into a 2.5" catalytic converter then into a 3" XS Power Catback. It's quieter than, yet still flows better than stock exhaust with cat delete pipe.
I have a feeling that the noise level will change when I pull the silencers out of the mufflers.
Look into the brick of a modern cat. You can see through it.
I have a Racing Beat streetable (collected) header run into a 2.5" catalytic converter then into a 3" XS Power Catback. It's quieter than, yet still flows better than stock exhaust with cat delete pipe.
I have a feeling that the noise level will change when I pull the silencers out of the mufflers.
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06-23-09, 11:59 AM
#8
I've got the RB cat-replacement/pre-silencer, with the OEM y-pipe still in place and stock manifold. The power gain was substantial - the claim of 18hp seems entirely reasonable, maybe even conservative. The exhaust is moderately louder, without being raspy or harsh sounding. It's not even as loud at WOT or cruise as my wife's Saturn, which still has its cat, but I replaced the silencer and muffler with freer-flowing aftermarket pieces (and put the aftermarket silencer in when the straight pipe I originally had in place of the factory silencer made that car too noisy).
I'd like to get the RB mufflers and cat-back to complete my exhaust - I've heard nothing but good things about the sound and performance of the RB components generally.
I'd like to get the RB mufflers and cat-back to complete my exhaust - I've heard nothing but good things about the sound and performance of the RB components generally.
06-23-09, 12:40 PM
#9
Corksport also makes a resonator/presilencer that is a direct replacement for the stock main cat. It's the same thing as RB's, except it's shorter, so there's a little less noise suppression. The upside is that, if you don't have an RB header or downpipe, you won't have to cut/weld anything to fit this presilencer. RB's is extra long, and goes past the stock mounting location.
http://www.corksport.com/corksport-p...pe-stock-.html
http://www.corksport.com/corksport-p...pe-stock-.html
06-23-09, 01:05 PM
#10
I believe the rb combo bolts to the factory ypipe as well.
Corksport also makes a resonator/presilencer that is a direct replacement for the stock main cat. It's the same thing as RB's, except it's shorter, so there's a little less noise suppression. The upside is that, if you don't have an RB header or downpipe, you won't have to cut/weld anything to fit this presilencer. RB's is extra long, and goes past the stock mounting location.
http://www.corksport.com/corksport-p...pe-stock-.html
http://www.corksport.com/corksport-p...pe-stock-.html
06-23-09, 08:37 PM
#13
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I had a presilencer from the XS power setup. It's the exact same length as the stock catalytic.
It was about 4 inches too short to hook up to the RB header... Hence why I had to put the custom welded catalytic converter on.
Exhaust shop wanted to cut my header, to which I replied, "Hell no!"
I had to sacrifice the XS presilencer for the flanges.
06-23-09, 09:37 PM
#14
I had a straight pipe before which go to 2 magnaflows, it was way too loud for me and on top of it the noise was very raspy.
I adapted the racing beat REV TII exhaust system presilencer (got it really cheap!) into my exhaust right where the cat use to go, after my RB headers. The headers, with this silencer and the magnaflows sound so sweet now, its nice and firm and when you step on it, it really opens up but not to the point its annoying either.
I haven't heard the standard racing beat silencer (the tube looking one) but since the REV TII presilencer is way bigger I would assume it absorbed more sound, either way I will never do a straight pipe again, way too raspy and loud for me.
http://www.racingbeat.com/FRmazda2.htm
I adapted the racing beat REV TII exhaust system presilencer (got it really cheap!) into my exhaust right where the cat use to go, after my RB headers. The headers, with this silencer and the magnaflows sound so sweet now, its nice and firm and when you step on it, it really opens up but not to the point its annoying either.
I haven't heard the standard racing beat silencer (the tube looking one) but since the REV TII presilencer is way bigger I would assume it absorbed more sound, either way I will never do a straight pipe again, way too raspy and loud for me.
http://www.racingbeat.com/FRmazda2.htm
06-23-09, 10:17 PM
#15
http://www.youtube.com/watch?v=34Qv0qoyKx0
I'm liking how that sounds. Any setups sound similar to that with no cats?
I'm liking how that sounds. Any setups sound similar to that with no cats?
06-23-09, 11:49 PM
#18
Just get the racing beat presilencer, it will definitely make you less stressed out when driving : ) You might want to look into getting the header and presilencer that goes with it if you are planning to do all this and not going to swap in a turbo any time soon.
06-24-09, 12:13 AM
#20
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I used to have an RB downpipe/pre-silencer and then put an RB header in. I didn't notice much increase in noise at all. It does give the sound a bit more edge though, the stock manifold does take some of the harshness out, but the header isn't bad by any stretch of the immagination.
06-24-09, 12:20 AM
#21
I used to have an RB downpipe/pre-silencer and then put an RB header in. I didn't notice much increase in noise at all. It does give the sound a bit more edge though, the stock manifold does take some of the harshness out, but the header isn't bad by any stretch of the immagination.
06-24-09, 11:06 AM
#22
You should also take into account that the RB downpipe is 2.5" pipe, while the stock exhaust manifold only has a 2.25" opening. I always developed an exhaust leak between the two when I had them on my NA engine. Off-the-shelf gaskets never fit totally right, and if I had to do it again, I'd make my own.
06-24-09, 11:59 AM
#23
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I have a buddy nearby that's selling the RB header. I'm not sure if a presilencer is included though.
06-24-09, 08:34 PM
#25
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i must like mine very quiet then cuz the rb header+presilncer+apex'i GT spec was too loud for me... and i run 3 IN straight pipe to a no name canister on my current turbo setup (also a bit too loud for my likes). then again, i did switch from a full stock (stock mani, 3 cats. etc) to that setup overnight. it didnt sound bad, just loud.