bliffle

I was reading the manual and it says the OEM exhaust header is double-walled because of the temps achieved in the header when unburned gases enter. But the aftermarket headers are single-walled, and I've read that they sometimes glow red. Since the intake is above the exhaust it occurs to me that this is a chance for gasoline to drip on the header with disasterous results.

mazdaverx713b

iTrader: (91)

i've used an el cheapo pace setter for a coupe months now with good results. the header will glow if you are really on it and through that, it has performed flawlessly. i would be more concerned with heating up the air and mixture in the intake and getting poor response due to a dense mixture. i would guess that you run the risk of dripping gas on the exhaust with either a manifold or header and expecting the same firey results. also, i would hope no one would be driving with a dripping carb.

kgray

glowing occurs most of the time with clogged cats. if you go header, go with new cat/ presilencer and muffler.

Edit: you are in CA, you will never pass emissions with that...

trochoid

iTrader: (6)

The oem 'log style' exhaust manifold is heavy cast iron, with a heatshield. Dripping gas will vaporize on it. Thou shalt not have leaky carb, unsafe on any vehicle.

As far as aftermarket headers go, some are thin wall, others, i.e., RB are thick walled. Dripping gas usually vaporizes on contact, a large fuel leak will ignite, with or without a header. Electrical leakage at a spark wire boot can ignite fuel vapors too.

Biggest problem with headers is the extra heat it adds to the engine bay, compared to the stocker.

nfld85GS

iTrader: (2)

How would one get an electrical leakage at the spark plug wire? My engine is having this fit where it loves to start on fire (3 times in last 2 weeks). It's getting really annoying! I have no idea where the fire would be starting from. The first time it was from a small oil leak on top of the engine, and i fixed that, but now i have no idea what would be causing this. Could it be my spark plug wires? They are less then 2 months old. Also would a MSD add to the chance of this occuring due to the hotter spark?

trochoid

iTrader: (6)

I've seen spark leakage at both where the boot mates to the plug wire and around the boot, due to a cracked coil tower. Usually doesn't show in up in the daylight. Looks neat at night though.

MSD may be part of it and/or cheap wires or boots that don't fit well.

85 FB

Are these good spark plug wires or cheapos? MSD should not make a difference, even tho there is a stronger spark duration. Just remember that anything is only as strong as its weakest link.

So, if you have outstanding plugs, MSD box, Blaster 2 Coils, and simple cheapo bought-in-the-back-of-a-guy's-van 6mm spark plug wires, then that ignition may be having some problems. BUT...that is my opinion, I've never encountered that issue. However, I figured I'd bring it up as just something to think about if all else fails. A few others who have had more experience in this field may jump in.

Bliffle - Sorry to thread jack this, but to answer your question, as long as you go with a good company's header (stray away far from Pace Setter/Monza), such as Racing Beat, you shouldn't have to worry about anything. And, yes, restriction in the cats especially will create more problems. Plus, the cats themselves will glow red. There are lots of members on here that are running headers and I don't recall them stating any problems with theres.

And do make sure your carb isn't leaking.

Latin270

All the more reason to wrap them header up with good'ole fashion header wrap!

Fire85GSLSE

iTrader: (29)

Yes, unless you drive the car in the rain alot. If so it will cause the header to rust sooner.

vipernicus42

iTrader: (4)

Header should not glow unless you're running lean or your timing is off.

Yes the header is hot. The stock exhaust manifold is hot enough to cause rubber to catch fire (don't ask me how I know).

Either way, both the stock exhaust mani and the header are hot enough to be troublesome with fuel.

As long as your fuel lines are hooked up properly, there should never be a time when gas gets out on that side of the carb and goes down to make contact with the header.

To give you an idea, a rubber hose (which I was using to hook my Air Pump directly to the cat) was left unhooked by my mechanic's stupid apprentice, and caught fire. When I opened the hood, the fire was up high enough that it was licking at the bottom of the air filter canister. Dangerous? Yes, but only if the fuel was on that side. The fuel comes in on the other side of the carb.

If there's something wrong with your carb so that gas gets out on that side, it won't matter whether you've got a header or a manifold.

Jon

t_g_farrell

iTrader: (1)

The only danger is getting tickets because you've now got some extra horses or its a lot louder:-)

Go for a header/tuned exhaust from a well known rx7 supplier ( RB, Mazdatrix ) and the exhaust note will be mellow, free flowing (enough) and thick walled so theres no surprised down the road. I have headre/exhaust setup from 91 supplied by Rotary Engineering thats still fine after 15 years of service, no breaks, no leaks and the muffler is still sound and sounds good. Back then it cost me $600.00 and it has been worth every penny because I've never had to mess with it again.

Get the el cheapo stuff and your gonna waste a couple hundred every couple years and it will end up costing you more in the long run and waste your valuable time.