Ziggy682

I have an 86 N/A that I'm building up for SCCA Solo 2 E Stock. Basically, you can modify anything in the exhaust after the catalytic converter. I've pretty much decided to have a custom exhaust system made, but can't decide if I should go with single or dual mufflers. Here's what I want to know.

1. Which one makes more power?

2. Which one is louder?

3. Which one sounds better?

4. How big is the stock y-pipe, and who makes a bigger one?

Hmm, I guess that's about it. Thanks.

bcty

go single... go 2.5.. prob louder single.. so it sounds better and ditch the y-pipe when u go single

banzaitoyota

My engine builder Rob @ Pineapple, recommended that I run 2 1/4 all the way back. Single. Doing some research now on headers, presilencers etc.

rxspd

Go with Single.
1. Since the rules wont allow a true dual exhaust, duals at the y pipe arent gonna add any extra power.
plus a single saves tons of weight over dual.
2. single is gonna be louder, mufflers muffle the sound 2 mufflers will muffle the sound better than one.
3. i dont know why it should matter since your gonna be racing, but duals will be deeper and quiter, where single will be louder and higher pitched.
4.ditch it and go single

twiztedjeckel

so are you saying my 2.5" down pipe,2.5" race midpipe and apexi n1 single cat back is going to be loud once it gets installed?

rxspd

hell yeah it is

Silkworm

When did the RX-7 get moved to E-Stock? Isn't it in C Stock?

Well, my single 2 1/2" with a magnaflow sounds like a 2 cycle motorcycle engine.. Being a muscle car guy, it sounds like **** compared to my TA, but hey, it's a race car.. Remarkably quiet at idle, but the sound goes up exponentially as throttle is applied Real real loud at WOT

Anyway, G'luck!

PaulC

Evil Aviator

A single will make more power, but it's going to be loud. The SCCA does have noise restrictions, so this will be a factor for you. In most cases, if you look at what the points leaders are using, that will give you a good idea about which components are competitive. However, don't go by what the TII cars have, as turbocharged cars are a completely different animal when it comes to exhaust systems.

BTW, NA RX-7's race in C-Stock.

Barwick

might as well go single if it's only catback, to save weight I suppose, but for weight balance make sure it exits on the passenger side.

Matter or fact, does it have to exit at a stock location? Or can it exit off the side? Take out some weight (but make it louder) by removing unnecessary piping and exiting early.

AbecX

What the hell is duel exhaust?

Unless your on a turbo, exhaust isnt going to do much for you other then sound. Expect no more 10rwhp if even that. I'm sure it sounds like *** to, I'd get some quiet mufflers and spend the money on something that will actuall give you some power on them straight away's.

SoloIIdrift

Spoken like a true domestic owner....

1. Actually rotary's, even non-turbos, are very sensitive to exhaust, people on the dyno's have been known to gain over 60 hp on mod'd motors and even on stock motors true dual makes a big difference Mazdatrix's dual exhaust quotes 28% increase in torque, just ask any of the racers in the ITS class.

2. who cares about the "straight away's" the car wasn't really designed to be a mustang 1/4 mile drag machine.....

wpgrexx

that was great!!! true, they are more fun ripping through corners, when you have 50 50 weight distribution why not road race instead of straigh line. I have true duals and think they are awesome, would never go back to single, but it sounds like this guy is limited by the rules so he has to go single to save weight and get most power.

AbecX

Yeah, exhaust helps when your pushing the power, but I dont think this person is going to pushing a whole lot n/a, like I said, it'll help in a turbo app, but adding just exhuast isnt going to really give you anything besides a little more power up top and a different sound.

But when you come flying out of that corner @ 6500 rpms and rev it on up and dont go anywhere, whats the fun in that? I'd get some mods that would help you make the top in power, I mean if you just like to toilet bowl race the corners thats one thing, you might catch up a little around turns, but it wont take 2 seconds for a car with actual horsepower to come right back up and past you. A full exhaust system probably cost in the $500 range easy for these motors, there has to be other stuff out there that would produce and enhance the engine more for that price.

95R2-89TII Ground Zero

From what I hear, the single gives you better breathability. Therefore I would think that you extract more power out of it.

SoloIIdrift

Really? Explain that to the Porsche's I smoked this past weekend at Lime Rock (A real road race track) in a almost stock 140hp Integra.

I disagree, what besides Nos, or supercharger will provide more power "up top" for around $500?

I think the exhaust is a good upgrade, I mean FULL exhaust, such as header, midpipe and cat-back will provide N/A's with a good power increase with working 6-ports.

Power is nothing, unless you have a way to apply it. I didn't see any of the race prep'd mustangs passing me at the track either, looks like to much $ spent on supercharging and not enough on improving there poor live rear axle setup

AbecX

Bad driver mod, slow car, old peice, it could be alot of things. Tell me why I beat cars with 75 more horsepower? Its all about the driver.

Junk Yard Turbo, hell you can buy the complete turbo engine from that fscs3.org website for like $1,000.

That will get you about 20horses, pause while I think about how much of a gain that is.

Its not the live rear axle, the fox chassis has been around since 1979, and its a drag chassis way more so then it is a road racer. Compare apples to apples, mustangs were made for straight line performance, bring your rx7 with exhaust and ports open and see how many cars back you'll be racing a stock 5.0, or 4.6, or a v6 for that matter.

wpgrexx

guy, have u ever driven an rx7 that runs properly?A v6 mustang will not be any car length ahead of you, actually he will probably be behind you by quite a bit. When I first got my car i raced a 5.0 mustang, his was probably mostly stock, but it was a little louder, not only did he not beat by multiple car lengths, but i kept up to him almost side by side. and i know he was trying by the sound his exhaust made, WOT. That was a stock 86 gxl with 115000 kms on it. go from a rolling start and the rx7 has an even better chance of winning

fuzzi

Undeniably the single most important modification you can make on an rx7 is intake and exhaust. Everyone knows that is the first thing you should do... Even if you have all the bolt ons in the world... your gonna be very limited without the two mentioned... Exhaust and intake are so fundamental because without them... you other mods wont even come into play... Before i did my intake i didnt even notice my streetport. The bone stock 2nd gen has 3 Cats !!!!!! 3 ! That is incredibly restrictive... huge huge ! gains can be made by doing the exhaust... thats my opinion...

AbecX

So your telling me your stock mid 16 second car can beat a high 13 low 14 second car? Lemme tell you about all the z06's I beat when I was all stock

Hell, even v6 5spd mustangs run mid 15's now days, all stock to the paper filter, some of them that launch like bob cosby run 14's. N/A Rx7's are slow even from a roll ( unless its turbo'd ).

Silkworm

wpgrexx

okay man, whatever you say, if you are getting beat by a v6 mustang, either
A) your car is not running properly or

B)you don't have a clue how to drive


I am saying these things because I have raced these cars before and know what kind of results I got because i haveeyes and i watched what was happening outside my car. I am sorry if you disagree with this, maybe the crapstang that you drive is different from the 500000000000000 other ones that i have seen being driven around by 75 year old women and 16 year old retards with heavy right feet. I have raced 5.0's and kept up with them, that is before any mods. That is my experience.u don't agree, fine, have fun going straight in your mustangs

AbecX

1999+ Mustang has 190 hp, your car has like 140 - 160. Get real.

My mustang will eat you alive even if I gave you a 10 car head start. I could care less what you think about mustangs, sounds to me more like your jealous of them, and actually it takes more skill to launch a 1.5 60ft then it takes to turn a corner.


Actually, my car will tear you up in the turns as well, even with your 50/50 weight ratio. Guess what, I have the lightest weight mustang ever made, I tip the scales at a whooping 3090#'s with driver and full interior backed up with ~300rwhp, you do the math.

rxspd

AbecX:what are you smoking?
1995 Ford Mustang 3.8 9.9 17.3

that's right 17.3seconds in the quarter

1986 Mazda RX-7 GXL 8.5 16.3

And the weird thing about it is, that most 7's run mid to high 15's stock, mazda just put out that # to be safe.

My sister owns a 5spd v6 mustang, and i smoked the living **** outta it in a automatic rx7.

Dont kidd yourself, Mustang owners always think they are so badass.
Jason

rxspd

abec: Im not trying to be an *******, but dont come on a rx7 forum talking **** about them, once you get that 7 going and take it around a corner at 60 you will learn to appreciate them more, Good luck with it by the way, any luck getting it running?

wpgrexx

1999+, mine is from 86, anyway, i am not trying to fight ya guy, sorry, i am definetely not jealous of them, whats to be jealous of, a solid rear axle car, that has pushrod technology(except new cobras) from like the dark ages, that everyone has, it is as plain as a civic, if you like your mustang good, if u love it, even better, I don't really care either way. All i said is that i have raced a 5.0 mustang, not your mustang,but the same body style as yours in the picture, i kept up with it, i have raced v6 mustangs and beat them. with 300hp i would hope your mustang can beat mine in a straight line race.

As for a stock mustang and a stock gxl, i am pretty sure a rx corners better. I think there would be someone on this forum that could back me up on that as well. and hey, if you think it is so easy to turn a corner, try autocrossing, it may open your eyes a little to a world outside the horsie