NA upgrades gains
12-31-2010, 05:51 AM
#26
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A note on race cars. Race cars are looking for performance. They have fitment issues too. Fitment issues (or packaging issues) are the area constraints that an exhaust system has to occupy. Usually these race exhausts are of a larger diameter therefore they take up even more space. Professional racing organizations all have sound restrictions. These are measured in a db or decibel rating. Usually it's around 100 db give or take. Usually the rotary cars (surprise) are the loud cars that push these db ratings. We have failed the test twice and replaced our mufflers with new ones and passed each time. Piston motor race cars usually run just one muffler and it works fine. Like I offer above, they have really straight systems. From the front of the car and engine right out the back. Some cars run them in front of the right rear wheel. This makes for a lighter system and weight on the right side of the car (passenger side) helps offset the drivers weight. All of the systems I know are made of stainless steel (S.S.) All of them use either a race muffler or a high performance street muffler (like I mention above). Most all of these cars DON'T run an under the trunk turn system that turns and bends and has two mufflers. These cars are also way too loud for the street and promote divorce.
Rotary exhaust differences: Heat, heat, heat. A muffler near the engine gets a ton of abuse. We run our cars (and other RX-8 Renesis powered cars do as well) at much higher rpm all the time. All the time. Data shows 5,500 to near 9,000 for 50 minutes. Without caution flags (yellow flags) the min exhaust temp just off the motor is above 1,500F (800+C). This is hot sports fans. Very hot.
Hope that helps. May I suggest you look into any of the zillion exhaust threads out there. Perhaps there are existing products like this that already exist.
Last edited by EricMeyer; 12-31-2010 at 06:15 AM.
01-01-2011, 10:03 AM
#33
Who cares what numbers it puts out? What matters is how it performs. Every time I see somebody review it, they rave about the car as a whole. That to me speaks volumes.
I don't need a car that's fast in a straight line. I want one that handles on rails.
05-01-2011, 07:18 PM
#36
100 points for you. You are correct. The end of our longer 3 primary pipes mate to a longer collector (3 into 1). This "collector" is long and gradual and therefore ends farther down along the side of the transmission, well past where a stock midpipe would mate.
We run a dual muffler system made by CoastFab in Southern Cal. These are rebuildable/repackable because the huge heat these crazy engines make cook street performance mufflers and they end up very loud. So loud that my crew guys use to not be able to hear me on the radio. We now repack our mufflers after two W.C. racers to keep the loud noise down on the radio. So we are getting about 4 races per muffler.
I do not know any longer merge collector mufflers out there other than one sold on the west coast by a well known company that mates to the stocker exhaust. The transistion for this (where 3 pipes go to 1) is much too abrupt. Air (like water) doesn't like to make a lot of turns and go around corners which is one reason the Renesis exhaust ports are sucky----they have way too many bends --- especially the center iron.
Since we're on the subject, we are now timing out our headers after each season. I have a fabricator making 3 sets (because setup time is long and 3 are much cheaper than 1). I already have 3 collectors from other exhausts and experimentation with various lengths, gradual bends vs. tighter bends, smaller diameters, etc. I think the collectors themselves were $700 each our cost in 321 S.S. You'll need lots of bends to weld together (X 3 primary runners). I think we are in the $1,400 cost each.
The original Grand-Am ST SpeedSource RX-8's used a similar but different header (which we have tested and exceeded their power curve) made by Howerton here in Indy. I think they are crazy expensive. North of $2K I beleive. They work iconel exhaust for the 3 rotor Rolex cars. Iconel is very expensive to work with. Superior properties but North of 10K for most muffler / exhaust (minus header). I recall a Porsche 996/997 Inconel exhaust being in the 15K range. Keep in mind that their engine is in the back and the entire system isn't long but it is compact.
Rumor has it that the SpeedSource Inconel Muffler is leased by Ianetti for something crazy like $20K / year. I've heard this from a few folks but have never been able to confirm it. I've seen the exhaust and ....... it looks like a muffler.
Old School rotary guys have been using Lava Rock (exactly what you think it is) in muffler packing for years. It is an option with some custom race muffler fabricators.
Enough of my trivia. Time for a nap.
Meyer out
We run a dual muffler system made by CoastFab in Southern Cal. These are rebuildable/repackable because the huge heat these crazy engines make cook street performance mufflers and they end up very loud. So loud that my crew guys use to not be able to hear me on the radio. We now repack our mufflers after two W.C. racers to keep the loud noise down on the radio. So we are getting about 4 races per muffler.
I do not know any longer merge collector mufflers out there other than one sold on the west coast by a well known company that mates to the stocker exhaust. The transistion for this (where 3 pipes go to 1) is much too abrupt. Air (like water) doesn't like to make a lot of turns and go around corners which is one reason the Renesis exhaust ports are sucky----they have way too many bends --- especially the center iron.
Since we're on the subject, we are now timing out our headers after each season. I have a fabricator making 3 sets (because setup time is long and 3 are much cheaper than 1). I already have 3 collectors from other exhausts and experimentation with various lengths, gradual bends vs. tighter bends, smaller diameters, etc. I think the collectors themselves were $700 each our cost in 321 S.S. You'll need lots of bends to weld together (X 3 primary runners). I think we are in the $1,400 cost each.
The original Grand-Am ST SpeedSource RX-8's used a similar but different header (which we have tested and exceeded their power curve) made by Howerton here in Indy. I think they are crazy expensive. North of $2K I beleive. They work iconel exhaust for the 3 rotor Rolex cars. Iconel is very expensive to work with. Superior properties but North of 10K for most muffler / exhaust (minus header). I recall a Porsche 996/997 Inconel exhaust being in the 15K range. Keep in mind that their engine is in the back and the entire system isn't long but it is compact.
Rumor has it that the SpeedSource Inconel Muffler is leased by Ianetti for something crazy like $20K / year. I've heard this from a few folks but have never been able to confirm it. I've seen the exhaust and ....... it looks like a muffler.
Old School rotary guys have been using Lava Rock (exactly what you think it is) in muffler packing for years. It is an option with some custom race muffler fabricators.
Enough of my trivia. Time for a nap.
Meyer out
05-01-2011, 08:31 PM
#37
I have been reading posts from the RX8 club daily, for hours at a time, even before I bought my car, or became a member, and have never learned so much in one thread.
This EricMeyer sounds like a very smart man and I am very happy to have stumbled across this thread
This EricMeyer sounds like a very smart man and I am very happy to have stumbled across this thread
05-02-2011, 03:10 AM
#38
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I have been reading posts from the RX8 club daily, for hours at a time, even before I bought my car, or became a member, and have never learned so much in one thread.
This EricMeyer sounds like a very smart man and I am very happy to have stumbled across this thread
This EricMeyer sounds like a very smart man and I am very happy to have stumbled across this thread
bravo ~!!!
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