The best downpipe for bnr
08-11-09, 02:49 PM
#1
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The best downpipe for bnr
Hi..
Whats the best downpipe for the bnr stage 3 turbo? to the fd3s?
I also whant a good midpipe but a catback that dosent make that much noise.
Whats the best downpipe for the bnr stage 3 turbo? to the fd3s?
I also whant a good midpipe but a catback that dosent make that much noise.
08-11-09, 03:04 PM
#3
For maximum flow, nothing is going to touch a dual downpipe.
MazdaSpeed
Knight Sports
Autoexe / Maxim Works
piping size
MS = 50mm x 2 = 100mm
KS = 60mm x 2 = 120mm
autoexe - 54 mm x 2 = 108mm
Most aftermarket downpipes range from 70mm to 80mm. Can't personally say if it is worth the extra money, but you will definitely see an increase in flow and thus an increase in HP.
MazdaSpeed
Knight Sports
Autoexe / Maxim Works
piping size
MS = 50mm x 2 = 100mm
KS = 60mm x 2 = 120mm
autoexe - 54 mm x 2 = 108mm
Most aftermarket downpipes range from 70mm to 80mm. Can't personally say if it is worth the extra money, but you will definitely see an increase in flow and thus an increase in HP.
08-11-09, 03:28 PM
#4
RHD or LHD?
Quiet cat backs include SMB and Racing Beat
As far as midpipe - does that mean you plan on running w/o cats? If so make sure it is a "resonated" or mufflered mid pipe if you want to keep sound levels reasonable. SMB has a good product for this as well but there might be other options from vendors in the EU or UK that are closer to you.
Quiet cat backs include SMB and Racing Beat
As far as midpipe - does that mean you plan on running w/o cats? If so make sure it is a "resonated" or mufflered mid pipe if you want to keep sound levels reasonable. SMB has a good product for this as well but there might be other options from vendors in the EU or UK that are closer to you.
08-11-09, 06:48 PM
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I think for RHD car those 2 piped DP is the way to go.. But for LHD FDs I think pettit or other DP should be fine.. LHD DPs don't have that square head.
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08-12-09, 12:23 PM
#8
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I have the rhd rx7...
But is there any use of the best dual pipe downpite if you have an resonated midpipe?
I was thinking about to have a catback that dident noise to much like the RB ... I tought that the catback was the best place to reduse sound and not conflict with the flow and power,am I right?
And what does w/o cats means ? Im sorry for not understanding this
But is there any use of the best dual pipe downpite if you have an resonated midpipe?
I was thinking about to have a catback that dident noise to much like the RB ... I tought that the catback was the best place to reduse sound and not conflict with the flow and power,am I right?
And what does w/o cats means ? Im sorry for not understanding this
08-12-09, 10:14 PM
#12
I have the rhd rx7...
But is there any use of the best dual pipe downpite if you have an resonated midpipe?
I was thinking about to have a catback that dident noise to much like the RB ... I tought that the catback was the best place to reduse sound and not conflict with the flow and power,am I right?
And what does w/o cats means ? Im sorry for not understanding this
But is there any use of the best dual pipe downpite if you have an resonated midpipe?
I was thinking about to have a catback that dident noise to much like the RB ... I tought that the catback was the best place to reduse sound and not conflict with the flow and power,am I right?
And what does w/o cats means ? Im sorry for not understanding this
By cats I meant catalytic converters.
Mufflers in the cat back and midpipe together help keep sound levels reasonable.
08-12-09, 10:29 PM
#13
Sure can, takes about 4 to 5 weeks to source,as with all Rx7 Boutique items, you don't pay a dime until we actually have sourced the item. If you want to be put on the list, shoot me a PM.
Last edited by purerx7; 08-12-09 at 10:31 PM.
08-12-09, 11:18 PM
#14
Original Gangster/Rotary!
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Quite frankly, any good downpipe will work perfectly fine on a set of BNRs. The restriction lies within the factory shared turbine housing. I ran an old school N-tech downpipe for many years when I was making 420+ rwhp with the BNRs.
08-13-09, 02:30 AM
#15
+1, I agree completely.... I have flowed all portions of the turbo, manifold & downpipe assy's and have quantitative data to support the foregoing contention. Furthermore, I recommend that the DP should be the aftermarket 3" version (not a modified stock one or the smooshed one used for RHD apps.
08-13-09, 07:54 PM
#17
For maximum flow, nothing is going to touch a dual downpipe....
.....piping size
MS = 50mm x 2 = 100mm
KS = 60mm x 2 = 120mm
autoexe - 54 mm x 2 = 108mm
Most aftermarket downpipes range from 70mm to 80mm. Can't personally say if it is worth the extra money, but you will definitely see an increase in flow and thus an increase in HP.
.....piping size
MS = 50mm x 2 = 100mm
KS = 60mm x 2 = 120mm
autoexe - 54 mm x 2 = 108mm
Most aftermarket downpipes range from 70mm to 80mm. Can't personally say if it is worth the extra money, but you will definitely see an increase in flow and thus an increase in HP.
However, any gains are probably going to come from improvements in the transition from the turbo flange exit to the pipes' inlet. Here's why more is less:
50mm pipe x 2 does not equal a 100mm pipe, rather it equals a 70.7mm pipe in cross sectional area. (Because this is geometric, it is calculated as the root of the sum of the squares.) Similarly, 2 x 60mm = 84.9mm and 2 x 54 = 76.4mm equivalent diameters--almost. Two pipes, when joined in parallel for the same effective area as a larger single pipe, will have much greater surface area relative to their combined cross section, and as a result, have more frictional loss and resistance to flow; i.e., they're less efficient than one single larger pipe.
08-13-09, 08:57 PM
#19
Al, I agree, the dual arrangement looks cool as hell....
However, any gains are probably going to come from improvements in the transition from the turbo flange exit to the pipes' inlet. Here's why more is less:
50mm pipe x 2 does not equal a 100mm pipe, rather it equals a 70.7mm pipe in cross sectional area. (Because this is geometric, it is calculated as the root of the sum of the squares.) Similarly, 2 x 60mm = 84.9mm and 2 x 54 = 76.4mm equivalent diameters--almost. Two pipes, when joined in parallel for the same effective area as a larger single pipe, will have much greater surface area relative to their combined cross section, and as a result, have more frictional loss and resistance to flow; i.e., they're less efficient than one single larger pipe.
However, any gains are probably going to come from improvements in the transition from the turbo flange exit to the pipes' inlet. Here's why more is less:
50mm pipe x 2 does not equal a 100mm pipe, rather it equals a 70.7mm pipe in cross sectional area. (Because this is geometric, it is calculated as the root of the sum of the squares.) Similarly, 2 x 60mm = 84.9mm and 2 x 54 = 76.4mm equivalent diameters--almost. Two pipes, when joined in parallel for the same effective area as a larger single pipe, will have much greater surface area relative to their combined cross section, and as a result, have more frictional loss and resistance to flow; i.e., they're less efficient than one single larger pipe.
08-14-09, 07:08 AM
#20
if the collector at the end of the dual downpipes ends in a 3" flange it will still flow like a 3" downpipe regardless if the dual pipes have more area, right?
with this in mind, my 4" smb dp tapers to a 3.5" flange connected to a 3.5" resonated midpipe connected to a 3.5" bent single tip catback...
with this in mind, my 4" smb dp tapers to a 3.5" flange connected to a 3.5" resonated midpipe connected to a 3.5" bent single tip catback...
08-14-09, 03:09 PM
#21
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What is the SMB4 " downpipe... were do I get it?
I was thinking about to have a larger downpipe together with an open midpipe w/o resonation or cat. and have an good high flow cat back that dosent make that much sound.
I would have gone for the single tip catback without soundreduction but if the local police see that and notice the sound I would be getting a quit large ticket
;( and thats alot in Norway
I was thinking about to have a larger downpipe together with an open midpipe w/o resonation or cat. and have an good high flow cat back that dosent make that much sound.
I would have gone for the single tip catback without soundreduction but if the local police see that and notice the sound I would be getting a quit large ticket
;( and thats alot in Norway
08-14-09, 06:18 PM
#22
if the collector at the end of the dual downpipes ends in a 3" flange it will still flow like a 3" downpipe regardless if the dual pipes have more area, right?
with this in mind, my 4" smb dp tapers to a 3.5" flange connected to a 3.5" resonated midpipe connected to a 3.5" bent single tip catback...
with this in mind, my 4" smb dp tapers to a 3.5" flange connected to a 3.5" resonated midpipe connected to a 3.5" bent single tip catback...
As to the 4" / 3.5" question, there is likely some flow benefit if you carry the 3.5" pipe all the way back.
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