bobbitt

I'm considering ridding myself of the thermal reactor on my '79, and investing in the racing beat or mindtrain header set-up. I guess my question is, do I buy an entire system, or buy the header and all the other connecting pipes seperate? I've finally got some money to invest, and a long winter to work on it, so what I really need is the know how. Another silly question, is there any kind of installment instructions when you buy stuff like that spanking new? All signs point to header, but I thought I might as well throw it out there, get some feedback.
PS- Damon, if you're reading this you're probably LYAO, considering all the troubles to keep her stock.

damon

that is pretty funny, but if you really want to keep it stock now is the time to decide.

If you get the header get a high flow cat and presilencer
(I am running rb header with straitpipes to the stock muffler and it is loud as hell)

If you go the route of the header you can remove a lot of unneeded weight and horsepower lost in drag friction and will also open up a whole new world of modification for you

the downside is emissions testing, with all that removed it will be very difficult to pass an inspction if you have that in your state

good luck on whatever you decide

peace

Wankelguy

'79s had no cat. Racing Beat makes a header specific for the '79-'80 models that bolts directly to the stock heat exchanger, which does provide some muffling effect. RB also sells the mini-presilencer which will replace the stock heat exchanger perfectly and bolt up to the stock pipe. You'll also need block-off plates for the air control valve and the heat exchanger. Can't remember if the '79 has the EGR valve in the center housing, I don't think it does, but if it does you will also need a block-off plate for that as well. Good luck. -WG

NanaimoRx-7

Only the CALI models had EGR, IIRC

Manntis

Switch the header last if you want noticeable gains. If you swap it first, your system will still be choked by all the other stuff and you'll feel you've been had.

Wankelguy

I disagree. The installation of the header allows the removal of more power-robbing components than the mere presence of an inline heat exchanger. The '79s had no catalytic converter, what other stuff are you referring to? -Mike

joelwahid

this ,the header gasket, and the gasket that goes between the header and presilencer is everything they sent me.


this is all the **** i took off the car.


the holes circled in red are blocked off by the header gasket.


instead of making a block off plate for the pipe that goes into the thermal reactor i just put some thick rubber and a hose clamp over it. the red arrow is pointed at another place you have to block off.


this is a 14mm (i think) S bend that i had to modify with an oxyacetalene torch and a mallet to get the top left thermal reactor bolt off (top left if you are facing the engine on the passenger side of the car) that was the hardest part. i had to use this and a normal box end to get that nut off. it took about an hour of actually turning the bolt to get it off, like 1/16th of a turn with the s bend, then like 1/32 of a turn with the normal box end. haveing to bend over the side of the car, snake your arm to the bolt, switch wrenches every 1/32 of a turn sucks ***. i tried grinding sockets down, and bent the hell out of 2 of those bendy socket extension things, this s bend was the only thing that i had acces to that would work.

all in all its like body lifting a truck, it is pretty easy to do, it just takes a long time.

oh yeah, make sure you order the gasket that goes between the presilencer and the rest of the exhaust system if you only get the header/presilencer.

hope that helps, it took like half an hour to size the pictures and ****.

Manntis

The muffler, etc will still choke the system if it remains stock.

If you just replace the header and expect gains, sure you're removing the catalytic converter but you're leaving a few other bottlenecks in.

In the case of modularly upgrading exhaust components (e.g. replacing what you can afford, when you can afford it, instead of all at once) the marginal increase you'll experience by replacing the header first is nothing compared to opening up bottlenecks from the tailpipe and working towards the engine.

This is not to say that replacing the muffler gives you greater gains than adding a header, nor will it give you immediate results as bottlenecks are bottlenecks. But a header with stock muffler won't do much for you, and replacing the muffle is cheaper and easier to start with.

joelwahid

yeah i still have everything from the presilencer back stock, so i didnt get much of a power increase. but before i got the header my car used to backfire like a bastard, no backfire at all now.

Rex79

wait you guys are sure that there is no cat on '79 rx-7's?

357

Well, from what I know, there's no "cat" per se on the '79's. I believe that Mazda had on what is referred to as a "thermal reactor", and then switched over to conventional cats for the 1980 model year. Correct me if I'm wrong, but that's what I've read.

NanaimoRx-7

80 still had the thermal reactor, it was the next year that it changed over to cats.

bobbitt

Yeah, the '79 has a thermal reactor, instead of an exhaust manifold.And what acts (and looks) like a cat is a heat exchanger. I have removed from the car the headpipe from the T.R. to the heat exchanger, which would include what I believe is called the fresh air pipe, and the pipe that runs along the entire exhaust, which I guess just dispels more hot air? Of course the heat exchanger is stock, and from what I hear on this forum, I'm probably better off replacing that w/ hi-flow cats as well. I saw from RB that they have the hook up to bolt into the heat exchanger, but if it needed to be replaced, to purchase a mini power pulse presilencer. I really don't know if the heat exchanger needs replacing, but if it's traditionally known as being a restrictive piece of the exhaust, I will replace it. Unfortunately, shortly after buying the car, I also purchased a Monza Pacesetter Exhaust (muffler), but from what I've heard, that is junk. So far I've kept the stock muffler on. SO, that's whaere I'm at...should I even bother putting the Pacesetter on, or gow/ something more reputable. BTW, thanks guys, especially for the pics.

Wankelguy

Okay, for the last time, there is no catalytic converter on the thermal-reactor equipped cars. The thermal reactor performs the function of the catalytic converters which were installed starting in '81. The heat exchanger is mildly restrictive at most. One of the main advantages of installing a header is that it enables you to get rid of that damn air-control valve as well as the air pump that feeds it. That long auxiliary pipe? That's the outlet from the thermal reactor's outer jacket which is fed cooling air by the air pump. Once you yank that air pump off of there, you can cut off that auxiliary pipe if you want. All the motor needs is a PCV valve, tank vent, and a line for the vacuum advance. I just went out and took a picture of a bone-stock setup on my '80 to show that there are no other "bottleneck" components in the system once the Thermal Reactor and heat exchanger are gone. The muffler itself the only other component. Use that POS Monza muffler until it rusts out, which will be shortly.You wanna know how I know this? I've been into RX3s and RX4s for 10 years, and every damn one of 'em came with a thermal reactor.
I gotta get back to dropping this damn transmission.
-Mike

Wankelguy

Here's another pic.

k-oticrx-7

get the header from http://www.mazdatrix.com/ and mandrel pipes from any exhaust shop, get a high flow muffler, and be willing to spend about $500 total, not bad for the speed and efficiency you'll gain...and whomever said get a high-flow cat is retarded...just drop the cat (81-85), you don't need it, nor will you ever.