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Headers and High Flow Cat Convt

SwaintaN

Explorer Addict
Joined
March 15, 2008
Messages
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City, State
Carey, Ohio (Georgia Grown)
Year, Model & Trim Level
93 XLT
I was playing around with the idea of doing headers and an Hi Flo Cat since my cat has a nice lil hole in it from a while back, time i can finally fix it. How hard are headers on the explorer? when I did them on all the ricers.. lol... they were simple, but never a motor this big have ive even thought about doing that with.

any inputs? headers even worth the money?
 



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I know cybergasm had a set of headers on his 1st gen. He grabbed a set of stock manifolds from me to replace them..

I'm not sure which reason made him take them off but I don't think he ever got them to seal plus I think he lost the Carb label on them so he couldn't pass CA inspection anyway.

~Mark
 






well i dont live in Cali, so dont gotta worry about that part. Do we run on back pressure? Because if so, wouldnt headers w/ wider pipes, release pressure quicker and that would be less back pressure?
 






well i dont live in Cali, so dont gotta worry about that part. Do we run on back pressure? Because if so, wouldnt headers w/ wider pipes, release pressure quicker and that would be less back pressure?

Gonna need a bigger exhaust guru than me on that... I was more or less just pointing out that cybergasm may be a person to talk to, plus he never got his to seal (always leaked).

Another person I can think of that runs headers is Dannyboy.


~Mark
 






I might just do new manifolds with a new down pipe into the hi flow cat. i know there is a hole more then cat convt, and i know there isnt any leaks after the cat convt, i did all that my self, lol. how hard is it to do new manifolds and down pipe, raise the motor at all or can i do it with motor in place?
 






You don't need back pressure on any vehicle, that is an old wives tale and a common misconception. This comes from shadetree mechanics being confused as to why they lost horsepower when they would go to really oversized exhaust. What was really happening is turbulence would be created in oversized exhaust reducing or eliminating the scavenging effect of the exhaust.

I have no experience with headers on the explorer, however, like any other vehicle, they are probably a pain in their own way. Everyone has heard of Header tick before, which is of course a term for the exhaust leaks that are common around header flanges that distort after they are heated. Sometimes with the proper OEM gaskets in place, you will never have this problem, otherwise, I like to use copper high heat gasket sealant on any vehicle I do put headers on. A high flow cat is another wonderful idea for these vehicles, but, you won't get a lot of gain out of them, newer catalytic converters flow very well compared to the stuff from the early 80s so you are only really gaining a very small amount of additional flow and the larger tubing size. Also, look at the size of the aftermarket flowmaster system. That is about the biggest size tubing you are going to want to use for any exhaust system you put on your truck. Anything bigger than that, and you will be losing more than you gain.
 






If you do a search about headers on the 91-94, or even just on the 4.0L OHV in general, you'll find a few threads with performance results and even dyno numbers.

The short version is that the cheap junk headers (pacesetter) and usually okay headers(heddman) are just bent up mild steel, and have poor quality construction, especially at the head flange. The cost savings of cheap headers is made up for in trying to get them to fit on and not leak.

Even good stainless steel headers (Borla, JBA) only give a slight (+/- 2 HP, yes, that's 2 HP) gain on a dyno, but cause underhood temps to skyrocket. Yikes.

The only improvement-all-around is had by dropping the dough ($600) on a set of ceramic coated JBAs. They flow more, and the ceramic coating keeps the temps in check.

Of course, now that you have a set of high flow headers, you'll have to spring for the high flow stainless steel catalytic converter to go with it (either the magnaflow stock replacement ($200) or a universal single 3-way.

Then you'll need a catback system behind all that. It's a waste to do anything other than mandrel bent tubes, so you can either get a Dynomax setup for a 91-92 with the Ultra Flo straight-through muffler, or just get the Dynomax/Walker pipes and throw in your own muffler (Borla or JBA would be good choices here). Or go all the way and get a custom mandrel-bent system with your choice of muffler at one of the few exhaust shops in the nation that can mandrel bend tubes. Or have someone weld up a system with mandrel pieces.

After all is said and done, you'll have a $1000+ exhaust system.

OR you could just get the Dynomax Super Turbo cat-back (or the Flowmaster if you like those better for some reason), and/or throw some other muffler on the ride, and get a pretty big improvement over the stock or stock replacement muffler for $100-200.

The only reason to go all-out on the exhaust is when the engine has a lot of internal mods (cam, high compression from pistons/heads, port/polish, etc.), is tuned for torque/HP at mid to high RPMs (the stock OHV makes max torque at 2200-2500 RPM), or otherwise just needs to get exhaust gases out faster than the stock manifolds will allow.


By far the biggest bottleneck in the system is the muffler and 2" cat-to-muffler and muffler-to-tail pipe. The stock manifolds, Y-pipe, and catalytic converter are good enough for stock to mild mods, and it's most cost efficient to replace the muffler and rear pipes based on your needs and preferences.
 






Don't buy the Dynomax

I've had three Dynomax systems and they all rotted quickly. Finally bought a Flowmaster system. Heavy gauge steel and welded muffler. This one will last a lot longer.
 






well i decided to not go with headers, im just replacing it all with stockish.. stock manifolds, new y pipe, new down pipe into a new cat convt from mag flow into my already newish flow master and cat back system. the price doesnt do justice on having headers plus with what i read and year of my ex that headers wouldnt really do anything for me... so hopefully this summer i cat the cat up done to match the cat back.
 






Recently added headers and cut the cat with a test pipe. What a difference. My 94 X also has a 5.0 Cobra MAF, K&N filter in the airbox and I did the airbox mod for improved air flow. Runs strong and has a great sound now.
 






i run headers and if you do have a stock system or dont have head work done,they are a waste beside for appearance.im going to have to disagree with some of the statement that Anime made,i have run pacesetter on everyone of my toys and they are just find headers.they are not cheaply made at all,i have had all three brands and compared them all and pacesetters had the best flange and welds(pacesetters,headmen,and jba,jba being the worst design)!!ps i would put the extra money out to get the ceramic ones either,the black ones are the best bet if you have an oven you can use.the black paint IS NOT HIGH TEMP,you need to strip that and ceramic paint and bake them yourself.this pic is after 3 years and about 6,000 miles and they still look new!
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i think for money wise and what i want.... stock will be ok, just want to get my mpg back and the muffler leaks fixed... plus while Ohio is not a ems check... some of the counties are emition check... and i just happened to get poped in one without my muffler...
 






i run headers and if you do have a stock system or dont have head work done,they are a waste beside for appearance.im going to have to disagree with some of the statement that Anime made,i have run pacesetter on everyone of my toys and they are just find headers.they are not cheaply made at all,i have had all three brands and compared them all and pacesetters had the best flange and welds(pacesetters,headmen,and jba,jba being the worst design)!!ps i would put the extra money out to get the ceramic ones either,the black ones are the best bet if you have an oven you can use.the black paint IS NOT HIGH TEMP,you need to strip that and ceramic paint and bake them yourself.this pic is after 3 years and about 6,000 miles and they still look new!
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No problems sealing at all.do you have egr?
 






No problems sealing at all.do you have egr?

no clue? lol dont know a lot when it comes to this, lol hints why im on the form, thanks, i forgot i even started this thread, i checked prices and blabla just like the economy prices always changing, its only gonna be 25 more to do the headers and high flo cat, so figured might as well, not sure if i have egr or not

figured i would have the headers wrapped (wet method) and sealed with the silicone.
 






Do you have one or two O2? If you have one you have no egr.they dont make headers that are a direct fit for the first gen non egr.you have to plug all three holes,i have part numbers for it,they use oil drain plugs and you have to have a O2 welded in front of the cat not in the ypipe for the single O2 of first gens to read right.also header wrap is not the best thing for heavy off road or a leaky engine.not a real big problem for off raod just need to be careful when washing off and need to run after washed to dry.ohv headers are hard to wrap,you need to know what your doing but well worth it,i can almost touch my headers!!;)
 






Ps you have to strip the black shipping paint,cermic paint them,bake them,wrap them,seal them rebake and i re cermic painted them and re baked them after.mine still look brand new!!! Paint on my heads look worse than the headers!!;)
 






I have 2 o2 sensors, someone told me to use the cheap header wrap because i go off roading, i know the wrap is just extra precaution. i ran headers on my geo storm wagon back (laugh now lol) and headers on the Cavy but the cavy was done way up, bigger pistons injectors turbo installed etc. i didnt run it on them but didnt know how it would work well with this, my ex is my winter dd and summer mudd runner
 






If gou have two you have an egr.cheap wrap????they make that? Header wrap is iffy,do it wrong and your rust or burn through the headers in no time!! Ive run pacesetters and wrapped every one of them for in everyone of my toys and had no problems.but i grew up in the pits of dirt tracks of va and Ohio ;)
 






I've replaced my cat on my old X with a Magnaflow. Only because it was clogged. I didn't feel any difference.
 



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thought i might run em a while without the wrap, and go from there. yeah he said cheap head wrap as in the thin stuff etc. but for now i might not wrap em.
 






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