zephyr07

iTrader: (2)

I have an 84 12a RX-7 all stock and was thinking of taking the stock exhaust off and putting on the bonez performance converter system i found on RX-7.com. I then going to leave the stock exhaust on from the catalytic back, because though I want a deeper, better sound I dont want the car to be much louder, the exhaust is in good shape as far as rust, and I'm trying not to blow all my money on the car. Just wondering if you guys had experience with this system and what your thoughts are. I believe the stock exhaust has 3 catalytic converters and I think it's a good idea to get rid of them. Thanks for any and all advice.

t_g_farrell

iTrader: (1)

This does not use a header from what I can tell it still uses the stock exhaust manifold. It won't improve the performance much if at all because the stock exhust manifold and stock muffler is where most of the restrictions are. Your wasting your money, save up some more and get a proven header/exhaust system from an rx7 specialty parts house. This will give you the biggest bang for the buck. That and a better carb will increase your HP by 40% typically.

iceblue

Your cat is old so it may be worth while just to get a less cloged up one. I would suggest just getting a RB header and presilencer. I did this on my SA and I am very happy. However the car is a ew tones louder and a good bit winyier high pitched as it winds up. I think the RB muffler quiets it down and gives a deeper sound over stock then just keeping the stock muffler.

zephyr07

iTrader: (2)

Thanks for the advice. Do any of you have a link to this RB exhaust and/or know about how much a full exhaust system would cost me? I'm more interested in a better sound than more power, as I don't think an exhaust would make a huge power difference, but more power would be nice. Thanks Again

cdrad51

Think again. Freeing up the exhaust is probably the single biggest power booster mod you can do on a rotary

http://www.racingbeat.com/FRmazda1.htm

Select and click on Hi-perf exhaust systems.

Rogue_Wulff

The Bonez system will help, as the stock triple cat system is very restrictive. It is also far cheaper than a full RB system. The cat is a high flow cat, and built to withstand the heat of a rotary. One added bonus, this system will pass almost any emmission testing requirements.
On a stock 12a, the header doesn't help as huch as just getting the stock cats off. I make more power with a stock manifold and free-flow pipe/muffler, and stock intake/carb than a freind does with a stock 12a, mikuni side-draft and full RB exhaust. Dyno proven, and side-by-side run proven. He now plans to get the engine ported, and change to the road-race RB system......

zephyr07

iTrader: (2)

I had about the same idea about the bonez as rogue wulff, but has anyone ever used this brand? It seems to be especially made for the 7. I'm hoping to order it this week if it is what i decide to go with.

cdrad51

Well if you wanna/have to pass emissions, get the Bonez cat. If not, and wanna get the most bang for the buck, get a cat replacement pipe from RB or get a custom piece made at a shop.

milton

i just put one on and i needed it to pass emmissions, but it works great easy to install. i also noticed a great soud esp if you drive it with noting but the manifold and the cat it is deep and throaty like a v8

zephyr07

iTrader: (2)

Milton, you are running the car with your manifold and the bonez system only? If it's not extremely loud it doesnt sound like a bad idea, otehr than loss of backpressure. Thanks for the advice guys hopefully I'll order it tommorow.

cdrad51

You mean without a muffler? I hope not.

milton

i had to for 2 days b/c i did not have the mid pipe between the bonez and the muffler and i was at my buddies house 20 min away from mine so i drove it home and then the next day i drove it to the exhaust shop to create mid pipe for me so yeah it is loud but befor this the hillbilly that owned my car before me just had a 2 1/4" pipe going right off the manifold so i didnt really notice a loudness difference but a town difference was noticable

cdrad51

omg dude that's hilarious, how can you take it. One time my exhaust pipe broke right after the cats so it was manifold to 3 cats to air, and had to drive it like that for 30 mins down the highway to get to the nearest shop. The sound nearly deafened me and I was shifting at 2k rpm!

milton

i dont know i did it with the hillbilly pipe for a year but i was at xollege w/o the car for a while but i just dealt with it and turned the music up to drown it out

blwfly

iTrader: (4)

buy a second hand header for 100$ get a shop to weld a 2.25or 3" exhaust and use a borla for the muffler
or use the borla as a presilencer and chose some kinda high flow mufler

zephyr07

iTrader: (2)

I ordered the bonex system today so hopefully sometime next week I'll get to tell you guys what it's like. In my experience, anything made by Borla is pretty expensive, are their products worth the extra money? I noticed this not only with rotary exhaust but domestic trucks and other sports cars as well.