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blackglasspirate
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Joined: June 24, 2006
Posts: 1612
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 Posted: Wed Jul 06, 2011 1:44 pm Post subject: Anyone have feedback on the RMW stainless exhaust? |
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Hey Everyone,
I'm looking at getting my hands on a SS exhaust system from Rocky Mountain Westy. I know they're the same ones that tencentlife designed and I trust they are good quality.
I still wanted to see if anyone else has gotten one and has any feedback on the quality, ease of installation, etc.
Unfortunately, I probably won't be doing the installation myself, but I'd still like to know if it's easy. My old pipes are rusted to hell and I don't want to risk snapping the head off of a bolt when I don't have the tools to fix it. Unless I just have someone else remove the old one and then tow it home to install myself 
Anyway, if anyone has any input before I drop $1600, I'm interested. I'm trying to convince myself that this is my best option.
_________________
'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Wed Jul 06, 2011 7:39 pm Post subject: |
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Worth every penny.
No issues at all.
I only drove the van to break in the motor.
The exhaust sounded great! |
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msinabottle
Samba Member
Joined: September 20, 2005
Posts: 3492
Location: Denver Area, Colorado
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| Posted: Wed Jul 06, 2011 9:33 pm Post subject: Pictures of the Tencentlife/RMW Exhaust |
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I looked over the exhaust and talked to Mike Labate about this impressive rig. He said they're figuring a 15% performance increase at highway RPM's!
I drooled, but took a little pride in having been the one at the 2009 VW's on the Green to urge Greg to build Chris's design, having whined... er, talked to Chris about building and selling the thing:
As of our conversation in very late May, Greg was talking about $2K and a day installed for the full package.
I'm sure we're all very grateful to Mike and his company for offering such a wonderful and worthwhile product to our community:
I'm saving my pennies. +15% would be just about right for Winston and his faithful 1.9L.
Best!
_________________
'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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kamzcab86
Samba Moderator
Joined: July 26, 2008
Posts: 7915
Location: Arizona
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| Posted: Wed Jul 06, 2011 11:52 pm Post subject: Re: Pictures of the Tencentlife/RMW Exhaust |
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Oh, that is just beautiful!  And definitely on the wish list!
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~Kamz 
1986 Cabriolet: www.Cabby-Info.com
 1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Thu Jul 07, 2011 3:19 am Post subject: |
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Two improvements I notice from the system I was sent are appreciated.
Slip joint between the CAT and muffler.
Precut tailpipe.
Bravo.
dylan |
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D Clymer
Samba Member
Joined: December 22, 2005
Posts: 2978
Location: Issaquah, WA
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| Posted: Thu Jul 07, 2011 7:26 am Post subject: |
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Even forgetting the performance advantage, this system is a good value when you consider that a completely new stock system will be the better part of $900. And the "stock" parts at this point seem to be of lower quality than the original VW parts. From what I've seen, they're also more restrictive.
So I would say an extra $750 or so above that to get a system that is stainless, follows correct theory for optimal flow, and looks nice under the van is a good deal and a no brainer.
D |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Thu Jul 07, 2011 7:35 am Post subject: |
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Agreed.
The flow is better.
Still the most restrictive part of the equation is the intake elbow, located between the AFM and TB.
IIRC, Bostig flowed it years ago while working with Boston Bob on some upgrades for the waterboxer.
With it removed from the equation.....much more is possible.
Perhaps someone will dive into this and work out a much better intake solution.
The price of the stainless system is spot on for what is delivered IMHO  |
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D Clymer
Samba Member
Joined: December 22, 2005
Posts: 2978
Location: Issaquah, WA
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| Posted: Thu Jul 07, 2011 7:44 am Post subject: |
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| insyncro wrote: |
Agreed.
The flow is better.
Still the most restrictive part of the equation is the intake elbow, located between the AFM and TB.
IIRC, Bostig flowed it years ago while working with Boston Bob on some upgrades for the waterboxer.
With it removed from the equation.....much more is possible.
Perhaps someone will dive into this and work out a much better intake solution.
The price of the stainless system is spot on for what is delivered IMHO |
Yeah, I've been looking at that intake boot with suspicion (and disbelief) since 1987. I think the reason no one has addressed it is because until recently there has been no reason to think about performance tuning for a Wasserboxer.
Of course just downstream of that you have the restrictive taper mount for the throttle body. As I remember it is significantly smaller than the bore of the actual throttle body.
D |
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blackglasspirate
Samba Member
Joined: June 24, 2006
Posts: 1612
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| Posted: Thu Jul 07, 2011 9:37 am Post subject: |
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Thanks for the input and confirmation. That system sure is a beauty. I had been figuring, since I never plan to sell this van I may as well get an exhaust that's going to last, instead of having to replace it in 10 years and end up spending more in the long run.
Plus the design is great, a performance boost is welcomed, and I get some bling
I'm hoping to put in an order today.
_________________
'87 Vanagon GL Westfalia
IG: @holidayatsee
FB: https://www.facebook.com/holidayatsee |
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10075
Location: Abiquiu, NM, USA
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| Posted: Thu Jul 07, 2011 10:04 am Post subject: |
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| Quote: |
| Of course just downstream of that you have the restrictive taper mount for the throttle body. As I remember it is significantly smaller than the bore of the actual throttle body. |
No, David, the TB and plenum spigot are exactly the same bore size, this is true with either engine size.
Awhile back I measured absolute pressure in the 2.1 plenum in real time, and at WOT, even with a stock TB, filter, AFM and all, it is atmosphere, indicating that all the air that wants to flow in can. Haven't done the same testing on a 1.9, but by the numbers the 2.1 intake is oversized as-built, at least as far as the plenum. The runners are correctly sized for the displacement and valve curtain area. It is actually a pretty well-designed intake tract considering the low-budget approach, at least as far as volumes go.
My conclusion about the stock intake is that at the existing engine displacements, limited rpm range, and OEM valve size and lift, there aren't any big volume gains to be had above the stock intake tract. Velocity is another question. If you wanted more horsepower, then cc's or rpm's or both need to go higher, and the heads would need a lot of work, along with different cam characteristics to shift the whole torque curve up the range. Gains may be available by changing intake flow dynamics, as in straightening out the flow pathway, but looking at volumes the OEM intake tract is well-matched to the engine size and rpm range, whatever limits there are are in the heads. Within the existing constraints larger valves and good port work could bring the hp curve up against the intake tract's limits.
And, I really appreciate the compliments about the exhaust design, but you guys always say it's better because flow is better. The truth is, the stock pipes aren't flow-restricted (the stock cat/muffler combo is a separate question). What the header design does accomplish, and where the stock system, like most, is utterly lacking, is in resonance dynamics. The whole design approach is to introduce strong resonance dynamics where they were absent, the rest is just sizing the flow path so as to maintain high gas velocity without impeding mass flow at the top rpms. I'm sure with enough money to invest in endless mockups and extensive dyno testing we could tweak this exhaust design here and there to wring a few more foot-pounds out of this engine, but as we have developed it it does a very good job of pulling the midrange torque curve upwards.
Our other goals were to incorporate high quality domestic-sourced materials and components, followed by excellent workmanship, into a comprehensive easy-to-install-and-service system, and I feel that's what we've done. So mission accomplished as far as Mike and I are concerned, we're very proud of the product. We're already brainstorming and are both looking forward to developing an analog for the Subarus later this summer.
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240Gordy
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Joined: May 15, 2008
Posts: 2354
Location: Vancouver, BC
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| Posted: Thu Jul 07, 2011 10:12 am Post subject: |
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but a little sexy on the top of the engine wouldn't hurt either would it?
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Tencentlife said,
"So, now that you know what you're doing, go to town."
2010 GOLF TRENDLINE 2.5
1985 GL now with more! a 2.1L
H&R SPORT(RED) Springs FRONT , SLAM SPECIALTIES RE6 AIRBAGS REAR |
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D Clymer
Samba Member
Joined: December 22, 2005
Posts: 2978
Location: Issaquah, WA
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| Posted: Thu Jul 07, 2011 10:57 am Post subject: |
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| tencentlife wrote: |
And, I really appreciate the compliments about the exhaust design, but you guys always say it's better because flow is better. The truth is, the stock pipes aren't flow-restricted (the stock cat/muffler combo is a separate question). What the header design does accomplish, and where the stock system, like most, is utterly lacking, is in resonance dynamics. The whole design approach is to introduce strong resonance dynamics where they were absent, the rest is just sizing the flow path so as to maintain high gas velocity without impeding mass flow at the top rpms. I'm sure with enough money to invest in endless mockups and extensive dyno testing we could tweak this exhaust design here and there to wring a few more foot-pounds out of this engine, but as we have developed it it does a very good job of pulling the midrange torque curve upwards.
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Hi Chris,
Can you elaborate a little more about resonance dynamics and how they help optimize scavenging? My understanding of resonance tuning is that the goal is to straighten exhaust gas flow and to thus make it flow more smoothly and with less resistance. Is this correct, and if so is the general idea that long, equal length primary tubes help accomplish this?
Also, tell me a little more about the Hushpower muffler you've chosen. I remember your earliest versions used a Magnaflow muffler. Is the Hushpower louder or quieter? I'm amazed by how compact the unit is.
David |
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SCM
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Joined: January 26, 2011
Posts: 3114
Location: Bozeman MT
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| Posted: Thu Jul 07, 2011 11:13 am Post subject: |
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| D Clymer wrote: |
[
Hi Chris,
Can you elaborate a little more about resonance dynamics and how they help optimize scavenging? ... David |
Yes, please. I would love a brief primer on just how a tuned exhaust improves performance.
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'91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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vanagonjr
Samba Member
Joined: October 07, 2010
Posts: 3430
Location: Dartmouth, Mass.
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| Posted: Thu Jul 07, 2011 11:19 am Post subject: |
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| Any dyno run figures? |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Thu Jul 07, 2011 11:37 am Post subject: |
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| 240Gordy wrote: |
| but a little sexy on the top of the engine wouldn't hurt either would it? |
Word Gord |
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10075
Location: Abiquiu, NM, USA
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| Posted: Thu Jul 07, 2011 1:07 pm Post subject: |
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| SCM wrote: |
| D Clymer wrote: |
Hi Chris,
Can you elaborate a little more about resonance dynamics and how they help optimize scavenging? ... David |
Yes, please. I would love a brief primer on just how a tuned exhaust improves performance. |
If you look up my earlier WBX-haust thread, we talked a lot about the various dynamic factors involved in exhaust design. Check that out and if you don't get it maybe I can point you to some other useful resources.
It boils down to two major factors that are almost independent of each other:
1.) Gas flow, which determines tubing cross-sectional area, but introduces direct conflicts in design goals between the mass and the volume of the gases that need to be exhausted. Tubing must be large enough to allow the maximum volume of gases the engine will produce at its highest operating rpm to flow without any restriction (which puts the lie to the notion of "backpressure", a smart-sounding but made-up and meaningless term tossed around by your beer-swilling neighbor to appear knowledgeable, but which has the opposite effect), while being small enough to maintain as high a mass velocity as possible (widening the space a given fluid volume can move thru causes it to slow down; think of a fast-flowing river becoming sluggish when the riverbed widens). Suffice it to say that most people choose tubing sizes that are too large.
Bends, joints, and irregularities within the flow path have some effect on velocity, the goal would be to have as few as possible but you still have to design a system to the engine and vehicle in question so they are a necessary evil.
2.) Resonant tuning, which determines the length of the tubing runners. The dynamic here involves harnessing the very intense sonic pulse that occurs when the exhaust valve opens. Sound waves in a fluid are rapidly-alternating higher and lower pressure phases travelling past a given point. The powerful initial report is a very high pressure wave in the gas medium, which will be reflected when it collides with the interface of a change in fluid pressure, which occurs where the cross-sectional area increases substantially (this is where tubing size selection relates to the resonance design. See: Bernoulli effect). When the pulses reflect they also change polarity, so when the sonic pulse travels back toward the exhaust port it has become a low-pressure wave. The length of the tubing runners determines the time it will take for the wave to travel out and back, timing it to arrive at the exhaust port as the piston dwells at TDC on the valve overlap phase. At that phase of crank revolution there is no piston movement to aid flow, so the low-pressure wave arrives just in time to extract the remaining spent gases from the combustion chamber, and at the same time to induce the air in the intake tract (since the valves are both partly open) to begin moving the air in the intake port so it has a inertial headstart before the piston begins its downward stroke and further accelerates the intake flow velocity. The net result is to have higher intake air velocity thru the entire intake stroke and hopefully enough that even as the piston passes BDC but before the intake valve closes the intake air's inertia of movement will stuff even more air into the cylinder against the upward movement of the piston. This results in the maximum charge mass trapped in the cylinder, a higher compression pressure, faster burn, more heat energy released in a shorter time, and consequently higher torque at the crankshaft.
The runners are of equal length so that this timed effect will be the same intensity and occur at the same rpm in all cylinders. In reality, the resonant effect has considerable time bandwidth, so it's not as if it creates a spike in the torque curve, but rather pulls the entire torque curve upwards around the target rpm.
| Quote: |
| Also, tell me a little more about the Hushpower muffler you've chosen. I remember your earliest versions used a Magnaflow muffler. Is the Hushpower louder or quieter? I'm amazed by how compact the unit is. |
The Hushpower HP-2 line is a fairly new product from Flowmaster, it's a hybrid of sorts between a straight-thru perf tube like the Magnaflow, and a baffled muffler.
http://www.flowmastermufflers.com/index.php?cat=1
Find one of the cutaway pictures on their website to see how it is different.
| 240Gordy wrote: |
but a little sexy on the top of the engine wouldn't hurt either would it? |
We call that "paint", my friend.
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Please don't PM here, I will not reply.
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10075
Location: Abiquiu, NM, USA
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| Posted: Thu Jul 07, 2011 1:11 pm Post subject: |
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| vanagonjr wrote: |
| Any dyno run figures? |
Nope, not gonna play the numbers game. I'm selling on quality.
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Experience is kryptonite to doctrine.
Last edited by tencentlife on Thu Jul 07, 2011 2:14 pm; edited 1 time in total |
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Mick Ord
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Joined: April 26, 2008
Posts: 203
Location: Vancouver, BC
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| Posted: Thu Jul 07, 2011 1:20 pm Post subject: |
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I have a 2wd Tristar that i will be starting work on shortly ( full resto ), it has the 112 hp DJ euro spec watterboxer and most definatetly needs a new exhaust system - would this system " suit" this engine and give similar improvements ???,
as it a 88 euro vehicle the stock system does not have a cat, if that makes any differance ???
Thxs
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1991 Syncro Westy- 2.5 Suby
1989 Syncro Tristar ( sold)
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10075
Location: Abiquiu, NM, USA
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| Posted: Thu Jul 07, 2011 2:16 pm Post subject: |
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| Mick Ord wrote: |
| I have a 2wd Tristar that i will be starting work on shortly ( full resto ), it has the 112 hp DJ euro spec watterboxer and most definatetly needs a new exhaust system - would this system " suit" this engine and give similar improvements ??? |
Yes on both questions.
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Shop for unique Vanagon accessories at the Vanistan shop:
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Please don't PM here, I will not reply.
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D Clymer
Samba Member
Joined: December 22, 2005
Posts: 2978
Location: Issaquah, WA
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| Posted: Thu Jul 07, 2011 10:25 pm Post subject: |
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Chris,
Thanks for taking the time to write up that explanation of resonance tuning. It was very comprehensive and informative. I think you're right. This is the aspect of exhaust tuning and design that most people don't realize exists. I actually have a beer-swilling neighbor down the street that sure doesn't 
Take care,
David |
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