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No real opinion regarding exhaust design for the street as my race car can be loud as long as it is not too loud. However, regarding materials, why not use stainless? it would be lighter and last longer than the mild steel you are wanting to use. I built the system on my car using stainless I sourced off of ebay at a reasonable cost and welded it up with my mig welder. It was easier to work with than the mild steel I had been using.
Rotary NA is just too loud. Put a turbo in your exhaust that will quiet it down just fine.
If only that were an option... someday, someday...
Originally Posted by mustanghammer
No real opinion regarding exhaust design for the street as my race car can be loud as long as it is not too loud. However, regarding materials, why not use stainless? it would be lighter and last longer than the mild steel you are wanting to use. I built the system on my car using stainless I sourced off of ebay at a reasonable cost and welded it up with my mig welder. It was easier to work with than the mild steel I had been using.
From what I understand, the thicker wall mild steel does a good job at preventing the pingy sound from leaking through, or at least that's what I've read. Otherwise it's just a convenient cost savings. If there's a benefit besides lightness (it's just a streetcar after all) then maybe I could be convinced otherwise. I usually do a quick coat of high temp paint (grill paint works great for the price) to keep mild steel exhaust components from rusting on the outside. The inside will be whatever it will be, although that's a fair bit of metal to rust through.
If only that were an option... someday, someday...
From what I understand, the thicker wall mild steel does a good job at preventing the pingy sound from leaking through, or at least that's what I've read. Otherwise it's just a convenient cost savings. If there's a benefit besides lightness (it's just a streetcar after all) then maybe I could be convinced otherwise. I usually do a quick coat of high temp paint (grill paint works great for the price) to keep mild steel exhaust components from rusting on the outside. The inside will be whatever it will be, although that's a fair bit of metal to rust through.
Just that stainless will outlast mild steel, even .250 mild steel. The enemy is not corrosion it is heat and stainless deals with it better than mild steel. I have no opinion or personal experience with respect to the sound quality of stainless vs thick mild steel...
Just that stainless will outlast mild steel, even .250 mild steel. The enemy is not corrosion it is heat and stainless deals with it better than mild steel. I have no opinion or personal experience with respect to the sound quality of stainless vs thick mild steel...
My RB sytem works since 1992 for me. I think the very thick mild steel muffler sounds better then the one that where making out of thinner stainless steel material.
My RB sytem works since 1992 for me. I think the very thick mild steel muffler sounds better then the one that where making out of thinner stainless steel material.
That sounds wonderful. Perhaps it's the porting, but for some reason RB mufflers have never come across that way in any video I've found thus far. Beautiful car as well.
Which system is it out of curiosity? I would assume long primary.
That sounds wonderful. Perhaps it's the porting, but for some reason RB mufflers have never come across that way in any video I've found thus far. Beautiful car as well.
Which system is it out of curiosity? I would assume long primary.
RB long primary. The more extreme the ports the more extreme the sound 😉 In the 80ties i was also searching for a good sounding system. The elford limited stainless steal exhaust system was sounding like an italian moto cross bike and i was going for the deep sounding RB exhaust.
Admitting that I am late to this post, I would like to add an experience I had. I earned a citation from Spokane's finest with the accolade of "loudest I ever heard" . The 7 had a stock 12a with a sketchy exhaust. I was nor have I ever been a loud exhaust guy. I appreciate tone more than volume. I bring this up to say you may get ticked, I was surprised when it happened to me.
As of now my planned setup is my current RB collected header, 1/8" wall 2.5" diameter pipe, an RB universal presilencer, Magnaflow cat, and an 83-85 Power Pulse muffler to finish it up. The thread might go dormant until I get my new exhaust parts in and then find time to install them, but when I finally do I'll be sure to update.
Thanks again for all the pointers and opinions.
you should look at RB's price on the pipe, its pretty good.
Ben, do you "need" a CAT? To meet emissions obviously, but is it your DD? I titled/registered mine as a Classic Car and it is totally exempt from emissions - both visual inspection and sniffer testing. I could have also tagged it as antique, but then I'm supposed to keep it mostly original equipment, which is getting harder by the year. With Classic plates in PA, it just has to "look" like an '85 RX7.... I could have anything under the hood I want.
The reason why the mild steel pipes sound less 'tinny' than stainless has more to do with material thickness than the material itself. Racing Beat prefers mild steel for the middle section of their exhaust because the greater tubing thickness helps to absorb the high frequency energy pulses which travel down the pipe. Their stainless steel headers are made from thick tubing, because this is where the energy pulses are concentrated as they make the 90deg turn from the peripheral exhaust ports to point toward the rear of the car - yet another reason why the RB exhaust systems last so long; thick AND stainless...
I'm running a RB 13b collected header going into the -SE (EFI) specific pre-silencer which has the pressure feedback port to operate the 6-ports properly, and from there using the stock (thick steel) Mazda OEM mid-pipe to a RB PowerPulse rear muffler, circa 1995. The main muffler has the 2x straight pipes out the back with chrome slant tips, and the venturi constrictions visible when looking up the tailpipes. This system sounds great at part-throttle when cruising, and even better under hard acceleration - and is nowhere near loud enough to get ticketed in over 30yrs of driving with this configuration.
Point being - exhaust systems are going to either sound wonderful or last a long time. Racing Beat has done the homework to try and meet both requirements, and 30+yrs of sounding pretty good is good enough for me.
Sidenote: OP may want to put his Magnaflow Cat in front of the Presilencer for best effectiveness, as the catalysts rely on high temperature to work properly, and the thermal mass of the heavy (20lb?) presilencer will suck up a bunch of that heat if placed in front of the cat.
I'd like to offer a different opinion on the sound of the RB system. I have the collected header full system on my 12a / Holley and it is loud A. F.. It is low-mile and all gaskets/hardware are good, but it just seems so, so loud inside the car (full interior). My wife can hear me cruising (3k rpm) when I turn onto our road from Main St, which is one mile away. I haven't turned the radio on since installing the exhaust, because there's no point.
That being said, when I put the new engine in I'll get RB's Street Port system. The systems are heavy and well made, and two pre-silencers Has to be quieter than one, right?
MW,not picking on you here,many others,myself included have used same RB system you have on your car and have no complaints as to tone and overall noise and all will agree it it to be be slightly louder but mellow. I would bet both of what i hold dear that replacing your presilencer and your RB muffler with another will make your car as quiet as any other running this system.
We've spoken about his previously in a post when you 1st were getting your car up and running and i responded to your stated symptoms about the car running way lean and combustion temps being sky high as a result from vacuum leaks that seriously overheated your brand new exhaust system evidenced in glowing header pic in your avatar. That pic is as header was cooling down,in the moment it would have been cherry/orange hot. I recall you saying the car was not run long in that condition. Also remember seeing a pic of the muffler off the car leaning on the wall by your garage door and commenting about the serious heat it had seen and how super oxidized it was for being brand new. I believe the exhaust presilencer/muffler got so hot and expanded enough that baffles in each became unattached so that sound is leaking by these pieces and the "loose" pieces are reverberating against inside of both giving you the marbles/angry bees noises. If you were to show pics of those parts to folks at RB they would concur lean running damaged the parts and if there was a warranty on the parts they probably would not honor it considering.
I have worked on "no run" 1st gens that had many similar parts ruined from excessively lean running,a couple that had cheap headers installed had the pipe burned thru like a blowtorch from inside out right where they make the 1st turn away from mounting flange.
You can't compare exhaust pulses of a piston engine to those of a rotary. Any rotary has much stronger pulses and more of them considering combustion events that make them louder than even a big displacement engine that fires once in four cycles. Any configuration piston turbo engine will not be as loud regardless of what type of system is behind it as the turbo in itself is a muffler of sorts. Apples/oranges...
Racing beat has changed the muffler on there street port exhaust system a few times. This is from 2017, V2 I believe. At that time racing beat told me they were having trouble with the supplier and were going back to in house manufacturing.
Wrapping the header like done here looks good,done to lower engine compartment temp? Will eventually cause header to crack at welds or burn a hole thru #1 tube at 1st bend prematurely. Have had this happen on a couple of cars i owned some time ago and and found same header lasted indefinitely unwrapped. For what they cost i'm ok with some blueing and surface rust over time.
GSLSEforme, I did replace the presilencer back when you suggested it. It made sense. But it did not improve the sound at all. I'm not going to drop another $300 on a new muffler because it "might" make a slight difference, especially since the presilencer made none. But your reasoning is sound.
GSLSEforme, I did replace the presilencer back when you suggested it. It made sense. But it did not improve the sound at all. I'm not going to drop another $300 on a new muffler because it "might" make a slight difference, especially since the presilencer made none. But your reasoning is sound.
Cut that old presilencer open and see what internals look like.
Wrapping the header like done here looks good,done to lower engine compartment temp? Will eventually cause header to crack at welds or burn a hole thru #1 tube at 1st bend prematurely. Have had this happen on a couple of cars i owned some time ago and and found same header lasted indefinitely unwrapped. For what they cost i'm ok with some blueing and surface rust over time.
100% On a bike exhaust wrap looks cool, but they soon rust... worth it for the look on a bike. But in a car heat shields are the way to go. I put heat shields in both of my RX7s. It keeps that header temp away from the carb.
Go to any junk yard and pull some from under a car. Then cut the shielding to fit. Should be said that I don't know of any auto producer that wraps their exhausts, but almost all of them use heat shielding. Maybe metal shields are better????
100% On a bike exhaust wrap looks cool, but they soon rust... worth it for the look on a bike. But in a car heat shields are the way to go. I put heat shields in both of my RX7s. It keeps that header temp away from the carb.
Go to any junk yard and pull some from under a car. Then cut the shielding to fit. Should be said that I don't know of any auto producer that wraps their exhausts, but almost all of them use heat shielding. Maybe metal shields are better????
I've wrapped exhaust on several customers' sport bikes,particularly aftermarket titanium 4-2-1 header/collector assemblies that throw off so much heat they melt and sag bodywork onto exhaust system scorching and catching fire on a few occasions. Lesser of 2 evils..
Metal shields still allow air to circulate around and under exhaust parts both keeping their temps down and protecting components in close proximity but they have their limitations. My Tacoma went thru 2 exhaust manifolds in 140k because it had a 3/4 coverage heat shield on it,both cracked in same place.Towing aggravated this condition. 3rd replacement was a Doug Thorley TRi-Y header jet hot coated that throws less heat into engine compartment than shielded manifolds did. Already had a Magnaflow muffler in place as oe muffler started to rust out prior to this and went with a hi flow Magnaflow cat converter to cure the dreaded PO420 code. Had a set of TRD cams given to me and sum total of all parts with a good valve adjustment got me @ 4 mpg more than previous and a bump in torque noticed when towing heavy stuff up hills where prior to needed downshifting. 213k on it and has more grunt than new and...it's paid for.
I've wrapped exhaust on several customers' sport bikes,particularly aftermarket titanium 4-2-1 header/collector assemblies that throw off so much heat they melt and sag bodywork onto exhaust system scorching and catching fire on a few occasions. Lesser of 2 evils..
Metal shields still allow air to circulate around and under exhaust parts both keeping their temps down and protecting components in close proximity but they have their limitations. My Tacoma went thru 2 exhaust manifolds in 140k because it had a 3/4 coverage heat shield on it,both cracked in same place.Towing aggravated this condition. 3rd replacement was a Doug Thorley TRi-Y header jet hot coated that throws less heat into engine compartment than shielded manifolds did. Already had a Magnaflow muffler in place as oe muffler started to rust out prior to this and went with a hi flow Magnaflow cat converter to cure the dreaded PO420 code. Had a set of TRD cams given to me and sum total of all parts with a good valve adjustment got me @ 4 mpg more than previous and a bump in torque noticed when towing heavy stuff up hills where prior to needed downshifting. 213k on it and has more grunt than new and...it's paid for.
WTF, everybody has an opinion! been on there three years now, NO rust, and happy to report no fires...
My setup definitely isn't the fanciest, but I'm a DIY guy and love making stuff myself. I'm about halfway though welding a full 4" using all 16 gauge 304ss pipe. Using 2 bolt flanges at all interface outside of the turbo housing to downpipe v-band flange. The midpipe will use the vibrant 4" ID x 9"L race muffler and the rear muffler is the vibrant 4"ID x 23" TPV muffler. I don't suspect either will have any significant muffling effect on the semi port motor, but I figure I'll get it sorted and see how it goes as I can always mod it later to add mufflers/more effective mufflers.
For reference, the skoal can is exactly 2.5" in diameter.
lwrobins,that quote you refer to in your last post references motorcycles and wrapping exhaust to keep from melting plastic/ABS bodywork to point of sagging onto exhaust components and catching fire. Any familiar with sport bikes that are tracked can attest to this.None of this translates to your car.
More than my opinion is my experience with my own cars regarding wrapping RB headers. One collected and two uncollected streetport headers-same as what's on your car. Cost me @1k in replacement headers to learn that unwrapped was better for their longevity,wrapping them makes them unable to shed heat that ultimately cause cracking/burnout. I'll try to find pics to support the evidence,been long enough ago they were taken with a camera,at least 20+ years ago.
I don't track my current car,i use it,sometimes hard. I have roads where i live that i can run car flat out for miles,125 mph+...Runs well,emissions stripped,ignition and air/fuel mods.It has same system on it as your car does and has been on car @ same amount of time yours has. Best guess 1500-2000 miles on system since put on.
Handful of pics showing normal heat that has caused header tubes(never wrapped) to blue and surface rust near mounting flange of header to engine and paint to burn off front part of pre silencers from heat from extended long pulls. These are normal pics of heat evidence on properly tuned car,curious to how yours looks after this amount of time.
01-24-20, 08:38 PM
