ok, so i'm not even sure this is possible.... but here's my setup for starters:
big single
3"downpipe
n-tech high flow cat (flows 96% of straitpipe)
tanabe g-power medallion catback

we are seeing exhaust restriction, we think its probably the tanabe not the hf cat. i'm trying to figure out what i can do to have the best flow possible as not to steal power, while maintaining as close to stock quietness as possible. while i'm not sure if this is do-able, i would like to get it as close as i can.
i know the rb dual is quiet, but not sure how well it really flows.
i think the greddy sp is excellent flow, and relatively quiet. what CB do most of you run?
the other thing i want to stay away from is the huge tip, i cant stand how big the tanabe is. i dont know if i need to, (or can) put another resonator somewhere in the piping to help either. anyone attempted this? or do i just have to live with the noise?

any comments/suggestions are greatly appreciated.
thanks!!

 

Just add this in line before the muffler.

http://www.quicktimeperformance.com/qtec.htm

 

yeah, i've seen that a few times. but i was going to use that as a last resort if i had to.
any other comments/opinions/suggestions?

 

racing beat exhaust is the one of the quietest you can get, and it flows very well

 

greddy power extreme or evo

 

i know the rb is quiet, but i'm worried about the flow, i have the tanabe g-power and getting restriction, so i need lots o' flow.

how quiet is the greddy pe?
or evo?

 

Hmmm quite, but still flows good? I'd have to go with the Apexi N1 dual. I'm kidding. I'm running a DP, non resonated MP, and a N1 on my big single and its a wonder I have'nt been arrested! CJ

 

lol, my point exactly, i had a my dual n1 on when my conversion project got done, and it was LOUD!!! like it didn't have any exhaust at all.
isn't there a poll or another thread with what exhaust all us single guys are using??
should i start one? i'd be interested to know the noise levels of the different catbacks.

 

I've heard that these are pretty good:

RS-R Exmag

I've got a DP, high-flow cat and RB dual (stainless) and I think it's droney and too loud. Attracts attention that I don't want. I'm thinking of trying an Exmag, but I haven't heard anyone on the list report in on them...

-ch

 

I would say for the most straight through exhaust get a catback with a muffler like the Apex'i N1. Others like this are the Kakimoto, JIC, and Greddy Ti. Although I have heard that with all the exhaust work done it sounds a little ricey. I love the tone of my PFS Catback. Very straight through too, just a larger muffler than the N1 type.

 

Where did you hear this? I have found even the best hiflow cats reduce flow substantually.

 

i cant remember where i heard it from, but i think someone did some experiments and the n-tech was the highest flowing out of all of them. i'll try to find out where i got it from. i could be wrong though...

 

when they compared the high flow to the straight pipe and found it to be "96% of straight pipe) did they happen to say what CFM that was at?

BTW - How much power we talking about making?

STEPHEN

 

i dont think i saw any cfm numbers wherever i read it. so maybe thats where i'm getting restriction. maybe i'll email nick at n-tech.

i made 409 (uncorrected, mustang dyno, i have the graph) at .80bar, so 10-11psi, and i'm shooting for 20psi, 500rwhp or so. i just need to figure out where we're getting held up.

 

i've got a PE for sale.. i'm single and the exhaust was very nice and quiet...not loud at all at idle or normal running, yet a really nice rumble when WOT... i actually wanted a little bit louder exhaust so i went with the greddy titanium.... lemme know... i've got it all boxed up and ready to ship.... i can send you some pics too...

oh and it flows real well... one guy (can't remember his name right now) ran 10's using this exhaust.....

harrison

 

Not to get off topic but what turbo are you running?

STEPHEN

 

I have seen dyno sheets with guys running the RB dual tip and single tip. These sheets were all over 400rwhp and no one complained of flow problems. I used to run the RB dual tip and loved the sound. I was still running the twins though so I wouldn't come close to running into flow problems where you will. The RB unit would still be my suggestion though. Best of luck to you in your decision.

Zach

 

well the tanabe is considerably more quiet than my dual n1. night and day actually. but i hate the huge tip and wish it was quieter still.
late nights in neighborhoods+loud exhaust= not good.

my dual n1 was reasonably quiet with my twins, but now that i've gone single, streetport, ect. it was like i didnt' have any exhaust at all with the dual n1.

anyone know how much the rb does flow?? anyone have over 450 with one?

i was asked to keep a lid on what turbo until we get solid numbers, it'll be soon though. sorry

that qtec thing is looking more promising though.

 

Reasons to buy a PE or EVO
1. It doesn't have the horrible highway drone of the Apexi 'mufflers' (snicker).
2. It sounds about 1/2 as loud as a greddy SP on a single turbo, except at wot. My friend and I swapped catbacks. I was astounded by the reduction in sound.
3. It has very little back pressure. Notice that the piping diameter compares favorably with the Apexi GT spec.


Type |Piping Dia |tip Dia
Greddy PE| 80-94 | 115
Greddy SP| 80 | 120x130
Apexi GT | 70-95 | 115

 

thanks ccarlisi, i've had my eye on this one for a bit now, any one have specs on the tanabe g-power?

 

I have no idea what kind of exhaust it was, but a buddy of mine had a 3rd gen with a 1/2 bridge port and he had an exhaust (Japan spec someting) that had dual 2 1/4" pipes from the down pipe all the way back to the tips. It had 2 presilencers (one for each tube) and two FAT round mufflers at the end with not too ricey 3" tips. Was WAY more quiet then his previous RB dual tip. Area wise, dual 2 1/4" is larger then one 3", but I dont know about flow, it was all straight through.

~Mike...............

 

racerxtreme7: damn, sounds nice and quiet,....could you ask your buddy if he remembers the name?

 

paximus,

I can't find out what it was, he volunteered to go to Iraq. Yeah, VOLENTEERED. He wasn’t even enlisted in the military at the time. He used to live down the street from me and he used to be on the forum. Silver 3rd gen or something like that, do a search in the 3rd gen forum, he should be listed in VA some were.

~Mike...........

Found him, I'll ask........... https://www.rx7club.com/member.php?s...fo&userid=1072

 

sweet, thanks!!

edit: i just looked at n-techs site and it says it on there too, but i thought i read it somewhere else first, i dunno... http://www.ntechengineering.com/inde...d=3&model_id=2

 

Actually, if you do the math it isn't that much of a flow benefit with dual 2-1/4" pipe over 3" pipe.

Area = pi * radius ^2

We'll assume we have ID measurements to make it even a little less complicated

3" is about 7.07 sq in
dual 2-1/4 is about 7.95 sq in

Comparatively, if you were to just go with a 3.5" pipe it equals out to be about 9.62 sq in. Dual 2.5" pipe is about 9.82 sq in. Choose your poison....

70mm ~ 2.76"
80mm ~ 3.15"
90mm ~ 3.54"
95mm ~ 3.74"

To get it super quiet I think your best course of action is to make your own and invest some time (research) and money into the muffler(s) you incorporate or just go with the RB dual tip. Quieting down a rotary with a good sized exhaust port is going to be pretty difficult, but I don't see how it could possibly be so very loud right now when you're running a cat?? Before you do anything I would first run a straight pipe in place of the catback just to confirm that it is indeed the restriction. Many people make over 400rwhp without a problem on many different types of ~3" catback systems so I don't see why you (or this exhaust) should be different.

I'm also very interested in hearing about this super secret turbo making 409rwhp at only 10-11 psi....AND with an exhaust backpressure problem??....now THAT is interesting.