brianw90

iTrader: (5)

what kinda power am i looking at with headers and stock cats/mufflers?
sound difference? i dont want to be heard a block away, just sound nice when revved up/taking off and free up a couple hp

or would i be better off with a catback? i was looking at getting a borla catback just that im on a lower budget

ericgrau

iTrader: (1)

I hear headers make a raspy noise, and they're somewhat loud. Plus they don't give you much power. Try a catback for 7-8HP. Be warned that it will definately be loud unless you spend more $ and get Racing Beat. Since you're on a budget you could skip the Y pipe and just get the mufflers. The Y pipe doesn't give much.

ohayou88

iTrader: (7)

too make some power you need to get rid of the cats. The problem with rx7s is the exhaust flow. So if you want Power I suggest getting Full Rb system. that or have a muffler shop fab u up a dual 2.5 in exhaust with as little restrictions as possible. Just get good mufflers to make it quiet.

I suggesting some Borla Xr-1

micah

WTF? The best mod to an exhaust you CAN do is the headers?

Most of your potential power is unlocked with full headers. The stock manifold sucks.

brianw90

iTrader: (5)

will aftermarket headers bolt up to stock cat?

Black91n/a

Corksport's header bolts up to the stock cat, but seriously, the cats are so old that they should probably be replaced anyway. You can get a Racing Beat header and Bonez cat combo from rx-7.com for $440.

zoominmyhead

so for a nonturbo you should remove the cat's. What about back pressure?

I love pop-up lights

s4 or s5? s4 you need back pressure to open auxillary ports s5 you don't...I think...

introVert

You can get the RB and Bonez downpipe/presilencer combo (as mentioned above)-Bonez has made a provision to retain the S4 port operation. I am running this setup, and have no aux port issues with my S4 vert.

Jager

iTrader: (10)

RB and Bonez make a combinations without a presilencer. It's a highflo cat (Bonez) and a RB header.

RB sells a header and presilencer for around the same price, which eliminates the cat.

Roen

iTrader: (2)

What about back pressure? That should really only come into play if you have an S4, which requries back pressure for activation of the 6PI.

glhs0867

My bud has a 13B rail buggy that had RB headers, on stock port S4 engine.

We built a set of headers and change the length out from the block to exactly 3" straight out, then proceeded to collect them as normal.

He was doing 7.6 in the 1/8 mile. all we changed was the headers and it went 6.8 in the 1/8 mile.

my .02 cents.

zoominmyhead

i have an 88 rx7 se, i have rb header with out the additional 6 port medal hookup on the header(bought for $40), is there a way to bypass the additional hookup on the header for the nonturbo 88 rx7 se? if not i will buy the specific rb header and use the rb presilencer that will then go to a cat back greddy exhaust(currently on vehicle). Will either of these options work? or do you have to keep the cats for back pressure?

Eva001Ikari

iTrader: (7)

You can waste your life savings like I did and get a full true dual racing beat system. It came out to 1000+ after i was finished. Sounds great looks great, wouldnt trade it for anything and it ensures that you're staying n/a because paying 1000 dollars for an n/a exhaust then throwing it away for a turbo is retarded.....(so much for going turbo LOL)

Jager

iTrader: (10)

That's a pretty easy fix.

You can block off the air tube (http://www.2751engineering.com) that goes back to the exhaust and remove your 5th and 6th port actuators, wire them open, or figure out a way to open them using some kind of actuator (you'll have to search for that way). Or you can buy the RB presilencer for your specific year of vehicle 86-88, and bolt that on for a fix. Look below for more details.

You can keep any 84-92 N/A header, the split air tube thing that actuates the split air tube however can be found on the 86-88 presilencer sold by Racing Beat. You can buy that and bolt it in and have your 5th and 6th ports working just fine. You can find this header in the classifieds or directly from Racing Beat.

Don't have to keep the cats, it's just the split air tube that you want for the 5th and 6th ports.

I hope that helps?

brianw90

iTrader: (5)

so rb header/bonez cat combo best pick over borla catback?

will they work fine with stock mufflers? be raspy?
i dont want it super loud or sound like a honda

super-rx7-71

iTrader: (5)

i just put a pacesetter on my car sounds awesome besides the leaking cat gasket but no probs with header fit great.

b20triz

i dont know if you want to do this, but i just recently installed a test pipe and wow, i was very very suprised. i knew i was going to get alot of power, but not this much. it seriously feels like i gained 20-25hp with the 60 dollar piece of pipe! as far as sound, it sounds like a true rotary, it also sounds kind of hollow, pretty different. however... it also smells like a rotary... but took 20 minutes to install, i saved my cat for my next smog.

Killert2

where you get that test pipe?

b20triz

http://search.ebay.com/_W0QQsassZrmtperformance he doesnt have another fc test pipe, but i would get a hold of him though ebay msgr, he's the cheapest i've found so far.

ericgrau

iTrader: (1)

Still waiting for a forum member to post before/after header dynos. So far I've only seen a forged dyno from a vendor, though they've cleaned it up a bit over the years. Racing Beat says their header plus cat replacement is about the same as just replacing the cat, unless you ditch fuel injection and buy their performance carbeurator. Headers don't do much in theory either: harmonics need to be tuned for certain rpms meaning you'll lose power at other rpms, and the restriction of the world's worse stock manifold (bends) is much less than a cat (screen) or muffler (2 sharp 180 degree turns). Plus if they really freed up so much HP for so little money and with almost zero technology needed, any Mazda engineer with half a brain would have added them. Headers are a scam.

cat replacement > mufflers > intake > other minor things. That's all the bolt on NA power there is. Oh, and be sure to mind the aux ports if you replace the cat. I didn't mention the cat b/c of all the cost & time & aux port control when the poster seemed to be fairly new and on a budget.

Roen

iTrader: (2)

All I know is that Racing Beat doesn't make the best header, just the most streetable ones.

All I gotta say is 174 whp from the Speedsource Full Exhaust and cone filter on a stock computer. For more info, contact C. Ludwig

Jager

iTrader: (10)

Just get them all.

Jager

iTrader: (10)

The before and after was done by Kahren on Fritz's car. Search.

https://www.rx7club.com/time-slips-dyno-128/tii-na-streetport-dynoed-186whp-482741/

He gives his .02 cents there.

incubuseva

iTrader: (13)

Gunna have to disagree w you here. Stock headers are horribly engineered. They're pretty much the size of 2 bricks put together. Extremely heavy. They barely even go out before they bend. Then the bends are practically perfect 90* bends, not even slow bends like good headers have.


I know that most will take this with a grain of salt, but when I first installed my pacesetter header I could feel it pull in 5th a bit more on the freeway. It was only that + an apexi cone intake.