RX-7Impreza

I got my new muffler back in yesterday and put it on (in the rain) it sounds better than the previous one (or maybe i am just a little deafer from open headers at the track)

its still a little "blatty" at high rpm and i think i am going to get a supertrapp "cap" to put on a bolt on tip. i want to bae able to go to an open exhaust at the track, so everything just comes off.

supertrapp

i just have to wait for Adam to post the pics of my collector on here, and if it stops raining tomorrow, maybe the assembled exhaust.

Justin

edit: this is the muffler i used Edelbrock RPM 3 in/out

mazdaspeed7

Ill get some pics when its on the car, but here is the header and the collector.

Rxmfn7

iTrader: (4)

Cool , but whyd you opt for the RR header instead of the collected in the 1st place, wouldve saved you some fabrication.

mazdaspeed7

Go read the last 2 exhaust threads I posted on. I explained it there.

Capn' Wankel

How is that edelbrock muffler working out for you? I just blew a hole through the top of the piece of **** and it promptly evacuated any and all ceramic packing besides for sounding like an open header after it blew up. Don't use Moroso spiral baffle mufflers either because I blew 3 of them up in various places throughout my exhaust system. Would love to see pictures of the mounted exhaust when u r done.

-Lee

PS- How is the architecture schooling coming along? I just graduated from SCAD this past year from that dept. Hated just about every moment of it that is for sure hehehe.

rotary>piston

your header is almost as discolored as mine . I like the mix of purple and gold though, looks much better than the original color.
I hate supertraps though. They just restrict the exhaust, and they sound crappy. My friend even had on on his bike and it sounded dumb.

Jimmy325i

Capn' wankel, What edelbrock muffler were you running? I just put one of the RPM's in mine also replacing the detonated moroso I had. (summit gave me a refund for it)

Capn' Wankel

That EXACT same muffler....the rpm series 3 inch in and 3 inch out.....the longest style they had....something like maybe 19 inches? You had purchased a moroso spiral baffled muffler too? I got both my mufflers from JEGS and they are giving my money back because I keep threatening them with false advertising law suits. In their catalog they say that the moroso is UNAFFECTED by heat and that the Edelbrock is good up till about 1800 degrees fahrenheit. I wanted to keep the moroso soo bad due to the nice low tone and high flow rate and tried different configurations and managed to break welds loose on 3 of them to the point that at stop lights it would rattle uncontrollably. After shelling out $$$ to keep re-installing mufflers I figured I would try the edelbrock which sounded absolutely wonderful (but cut my top end power a smidge compared to the moroso) until one day I took her up to speed and when done having fun I downshifted and had a flameless tiny backfire that ended up blowing a hole in the top of the muffler that eventually shredded itself apart.

JEGS betta have mah money HOEEEEE! (hehe)

I just put on a Ractive straight through 2.5 inch fiberglass packed muffler at the end of my exhaust and it has worked great for 2 weeks now (crosses fingers) it was free from a friend of mine too so I am happy.

-Lee

BDoty311

I have 2 ractive fiberglass packed mufflers on my car and they have held up for a year now. Probably the same ones you have.

BDoty311

MazdaSpeed7, Ive read your posts on the RB collected header, and my question is that what makes you think that you can make one better? Im not trying to be rude, just curious on what WOULD make a good collected header.

mazdaspeed7

My point is the location of the collector is what really matters. Like I said before, Ive talked to Jim Langer(co founder of RB) through emails a few times, and it left a bad taste in my mouth for their products. He told me that n/a motors are mild, and not even worth modifying. With a mindset like that, there is no motivation to make the best product he can. There is only a motivation to make something thats good enough to satisfy the most amount of people for the least amount of cost to him. That being said, their general quality of parts is outstanding. The welds are very impressive, and the fitment is near perfect. But I believe they are far from optimum for power. That explains my choice for using the road race header, with a custom collector afterwards.

I have a race ported exhaust, and I had to grind my headers to match the exhaust runners the best I could. But it is FAR from best. My only option is a custom set of headers.

And like I said before, porting, bolt-ons, and where you want your exhaust tuned for have a drastic effect on where the collector should be. A nearly stock motor would need the collector a different distance from the engine than a race ported motor with everything done to it.

Would someone with a RB street header(the collected one) measure the length of the pipes between the engien flange and the collector?

Capn' Wankel

It is about 29-30 inches I was told by the guy on the other end of the phone from flange to flange. I was informed by evil aviator that the consensus among autoxers is that for a stock ported NA 13b you should have 3" of straight pipe from the engine that flows in to your header(or is a part of it) and that collection should happen @ 27" from the block. From there you want to gradually open up the exhaust ie... 2" header, 2.25 pipeing, 2.5 inch piping, 3 inch outlet or resonator. Those that read this thread may be interested in this piece of info. You, on the other hand, are building this rotory to drag race? If so, then your shortened and large exhaust will give you all kinds of room to take advantage of some really really high rpm power....sbut would not perform so well on an autox course where midrange power and torque (if managed correctly) would be more advantageous.

We want some video footage with sound when you get this badboy heated up! From the looks of it, your car is gonna scream somethin ear piercing!

-Lee

AE_Racer

iTrader: (1)

cant wait to see it on the car

Jimmy325i

I wanted to get a pic of the inside of my moroso before i shipped it back but couldn't get any resolution off the BLACK internals.

I had half the baffle break off the center tube. (seeing as there are only two baffle pieces in the moroso) There was an initial weld and maybe 1" of material which stayed attached to the center tube before a very obviously heat cracked edge. My moroso rattled like mad also at idle and even made me embarrassed of my car at the time. I too loved the sound of the thing untill it let go. I called moroso first and they said they'd give me another one no problem, so then I called Summit and explained that moroso already agreed to replace it under warranty and that I didn't think another one would do any better. (only stayed under the car 3k miles and had been rattling for 3/4 of that time) Summit said that moroso would likely have them send me the new one anyways and asked if I wanted credit against another purchase or a refund onto my card. I couldn't have been more pleased with their response.

I'm running the RPM 2.5" I/O edelbrock about 8" from the back of my header (same location the moroso was) and also have a straight through ebay special HKS fake tip muffler as well. The car is simply too loud with just the tip muffler. If the edelbrock lets go its lifetime warranty'd so as long as I'm not swapping them out every couple weeks I'll be ok with it. I didn't notice a loss of top end power, but do notice that the midrange isn't as smooth. The split at the entrance of the muffler has some dynamic properties where I think there are reflections and stacking of pressure waves at certain frequencies (rpm) causing a reduction of flow. I was dissapointed to find the channeling inside the muffler was nothing but two halves of perf sheet formed over the packing. If it were actual tubes it would flow better and likely lack this acoustical flaw as it would act more as a y pipe than a brick wall.

AE_Racer

iTrader: (1)

sry, double post

BlackRx7

Yep I'd have to say my true dual setup on my 89 N/A gave me more power above 5k but had no torque below, and when I was driving arouns even between 1-3k it sounded like a stock rx7 at WOT and I wasn't barley moveing!!!! if you wanna make an N/A fast pm dvcn he's the one who ran a 13.9 on a stock port N/A motor...

mazdaspeed7

Good stuff, Capn wankel. Same thing I have been told. BTW, my exhaust will be tuned for around 6K rpm, but with my exhaust port, I need the collector about 33" from the engine. One more trick for more power is to angle the pipe up a little at the engine flange, to follow the angle of the port runner.

Justins car is just short of deafening. I think the volume is comparable to my old boss's race car. 350 motor, long tube headers, and one very large outlet on the pass side in frnt of the rear wheel. The only muffler was one of the circle track ones where the muffler case is about 1/2" larger diameter than the pipe, and abotu 8" long.


True dual sucks, I cant wait to get rid of mine.

sonic7

iTrader: (1)

where on the side of the car do the exhaust ends.... end? any pics

Turblown

iTrader: (12)

I want to see some install pixs, looks sweet tho! I will be running similiar soon, but coming out right infront of the rear passenger tire on my t2....

mazdaspeed7

Justins comes out right in front of the rear passenger tire. He just didnt have the exhaust on when I took the pics. Ill get more pics this weekend, or sooner if I see him.

chris_stampe

I have a single ractive 3 inch in 4.5 out muffler on mine. It costed me 129 shipped and makes it a hella lot quieter than 3 inch strait pipes. Ive had it on for 3 weeks. I love it!!

Jimmy325i

One highway run later and sure as **** my edelbrock is making more noise now.

I was playing cat and mouse with a 911 on the freeway at the time. He wouldn't run though. I wanted to see how badly he'd eat my ***, but everytime I tried engaging him he'd let me go.

Capn' Wankel

Aww man jimmy I am damn sorry to hear that! High rpm + strong-assed exhaust pulse + excessive heat up to 1800 degrees Fahrenheit = Edelbrock breakage. Well my Ractive muffler is still holding up like a champ after about 2 weeks now...Fiberglass packed 2.5 inch in/out...located at the END of my exhaust ( I don't think that the muffler would even pretend to last if it was right after the header.). You might wanna try that out. Thank you for reminding me to call JEGS today to see when my refund for the moroso and the Edelbrock hit my account.

-Lee

PS- Too bad you live so far away in Minnesota. It would be cool to hang out some time. Gimme a PM if you ever make it down to Florida near the Tampa area sometime. FAFracing will show you a good time =).

Jimmy325i

Yeah, My muffler is purple in the middle of it now and has some creasing from expansion. (I imagine)

I'm running a tip muffler but it's not enough to tame my beast's roar. I guess I'll have to cough up the 200 bones for a damn RB presilencer. The edelbrock hasn't popped yet, but she sure hums at 4K now.

rotarygod

iTrader: (1)

Capn' Wankel: I have the exact setup you described above. I went from a long primary to this much shorter setup and lost power everywhere. The first time I drove it I wondered what happened to all my power. The problem isn't the collector size but rather the collector location. I have a streetported motor and need it much farther back for best power.

mazdaspeed7: True duals do suck! I'm with you there. I hated the sound and performance of mine. Very happy when it came off.