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Header wrap?

6.1K views 25 replies 5 participants last post by  musclecar64  
#1 ·
Hey everyone, first post here. I have a 94 Corolla base (1.6l 4afe, manual), and I'm going to be redoing the exhaust myself with bolt on aftermarket parts. Stainless headers, new cat converter, and stainless catback system. This is just a daily driver, but I'm worried about underhood temps getting out of hand with the bare headers. I'll most likely soon be ditching the factory air box for a short ram and cone filter intake. Would header wrap be necessary? I've heard that header wrap is dangerous, and can have bad side effects. Is this true? Should I bother with the wrap?
 
#2 · (Edited)
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Do it, it made a big difference for me and I've had no ill effects from wrapping the ebay stainless header...yet. quality was good on mine, welds were nice, and the stainless is actually stainless.

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My concern was about how close it was to the alternator and radiant heat cooking things
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As you can see its close to the alternator and the oil filter.
 
#5 ·
hmmm, i havent heard any ill effects of the wrap ( gonna do some more reserch also ).i also have a stainless steel header with 2.25"piping with custom resonator and 3" growler free flow exhaust and am also thinking of using the wrap cause ive read it increase hp a bit and keeps the heat withing the header which enabling cooler enginebay tempertures. plus as bitter suggest he has had no ill effects as yet, but is it wise to do so in a more temperate climate, the days can get really hot down here.
 
#6 ·
wrap WILL rot mild steel header/exhaust. Stainless though can handle it without issue from what I've been able to research.

I did notice a slight change in tone after wrapping and maybe just a hair of difference in how it drove but I think that was all in my head.
 
#7 ·
Header/exhaust wrap reduces the life of the tubing, and over time will cause mild steel to rust (as Bitter mentioned above).

If you can afford it then I'd strongly suggest getting your headers coated instead. This will do just as good a job as wrapping the headers, without the adverse side effects (and looks better too in my opinion).

As for the short ram intake, forget about it. If you're worried about engine bay temperatures then this is the last thing you want to do. I was running a short ram when I put my headers on, and could notice the pipe/filter getting a lot hotter than when I had the factory manifold with heatshield on.

You may as well spend the money on a cold air intake with the filter located outside of the engine bay. Either that, or go with the short ram but make a dividing shield from sheet metal (although even this will get heat-soak after a bit of driving). With my CAI installed, the pipe is cold to the touch and the performance has definitely increased. I'd never go back to a SRI on any car ever again.

If you are adamant on the short ram however, and can't be bothered making some type of sheet metal box divider, then at least wrap the pipe in heat reflective tape. This won't stop hot air entering the pod filter, but it will help stop things from getting hotter than they already are.

This is how my headers are in my engine bay. They were professionally high temp coated a number of years ago, but the top needs touching up due to careless mechanics dropping their tools on it when swapping out the engine (plus it doesn't last forever) -


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#8 ·
kiwi, where did you route your filter for the CAI? Where can I get a full kit?

The problem I have with the ceramic coating is the price. A set of JVT stainless headers off ebay costs about $100 shipped. those have an inlet diameter of 1 5/8" and an outlet diameter of 2''. I can also get a no-name ceramic coated (likely mild steel) for a little less from ebay. the inlet and outlet on those is 1.75". I don't know what would be best as far as sizing, but I know the in/out diameter of a magnaflow cat will be about 2''. It could cost me $200 to get a set of headers coated professionallly.
 
#9 · (Edited)
kiwi, where did you route your filter for the CAI? Where can I get a full kit?
I routed the piping down past the battery, and through the hole where the intake resonator box used to be so that the pod filter sits just in front of the front wheel. I cut a small amount of the splash tray out so that the air can rush up there and into the filter. I've driven in plenty of rain and through plenty of puddles, and hydrolocking definitely isn't an issue.

Unfortunately you can't just go out and buy a full kit to fit it. You have to make it yourself. All it takes is two 125-degree intercooler pipes, a few joiners and clamps, and a bit of patience. Just align the pipes, mark them where the cuts should be and then cut them to the right length. It took about one and a half hours to do all up, but it was worth it.

I should also mention that in order to get the pipe through the hole where the intake resonator box used to be, you must use a Dremel or file to make the hole slightly larger. I used 3" piping, but if you use 2.5" piping it won't take you as long. You'll also have to move the battery across a couple of centimetres if you use 3" piping, but you can still use the factory battery clamp and battery tray.

Here's some more pics (the plastic shield doesn't sit as close to the wheel as it looks, it's just the angle of the photo that makes it look like that) -



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#10 ·
That's sick! two question about that though, what did you do with the intake air temperature sensor, and where did you find 125 degree intercooler piping, I can't anywhere. I still don't know whether to go with the ceramic coated headers, or the jvt stainless. Don't know what the perfect inlet/outlet diameter size is for my 4afe application.
 
#11 ·
Thanks! I took the photos directly after I installed it so there are lots of visible fingerprints. Looks a lot better after wiping it down.

For the air temperature sensor, I had to drill a new hole and used a rubber bung so that it makes a snug fit. You can see it in the second picture in my last post, inserted in the pipe just before the throttle body ;)

I bought the intercooler pipes online from a NZ site that is similar to eBay. Try ringing around a few performance shops, I'm sure at least one of them will have intercooler piping for sale. If you can't find the piping in 125-degree bends, you could get away with using a straight pipe and 180-degree pipe, but you'd have to use more joiners/bend to make it fit.

As for your headers, go for whatever you can afford. You're still going to get a gain in performance no matter which ones you go for :). I have heard a few bad things about buying pre-sprayed 4A-FE headers off eBay so that's something to bear in mind. If you're going to go with ceramic coating then I'd suggest getting it done professionally. That will of course drive the price up, so it might be best to just go with the stainless headers and wrap it in heat wrap.
 
#12 ·
OK heres the scoop from the factory rep of DC headers that I talked to a few years back. I asked him why they had a disclaimer that the warranty was void if the headers were wrapped. His response is that it causes then to crack.

Well I tried it anyway on another car with a cheap header and found out... Gee that guy was right! After welding the cracked bits, I reinstalled the header with no wrap and never had another problem.

Header wrap may be good for a little extra horsepower that may be necessary for racing, but its a waste on a street car unless you want to be a racing poser and make people think it makes your car go faster.

-SP
 
#14 ·
So, I'm going to be ordering the headers in a couple of days. I can't get the rest of the exhaust parts yet, because I'm broke. :D The JVT headers I was looking at have a weird protrusion on the collector pipe outlet that I would think would not allow it to bolt to the oem type cat. So, the only other stainless headers for the 4afe left are the off-brand. They seem ok, and a couple sets just went back up on ebay, so I'm gonna grab one while I have the chance. I have a question though, the outlet diameter of the headers is stated as 2''. The inlet diameter of a magnaflow oem fit cat is stated as 2''. would the outlet fit the inlet of the cat? I mean, there would be enough clearance hopefully alowed for them to fit together?
 
#17 ·
because they're cheap :)

They're what I've been using on my 7A-FE and they work fine, sound nice, were great quality. the welds were very nice, the insides were ground and ported smoothly, the hardware included was good, its REAL stainless, and it bolted right up with only the addition of the gasket at the cat converter.
 
#19 · (Edited)
i'm not sure if the 4a and 7a have the same exhaust port size or not honestly. i'm sure the info is out there though. I do know that you should scrape the carbon when you install it, i had about 1mm around the whole port on each cylinder.

little larger runners won't hurt, but may not be ideal for the 4a.
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you can see how well finished mine was.
 
#26 ·
Also has anyone had any install issues with aftermarket headers and the stock cat converter? especially since a lot of the headers for either engine have a 2'' out pipe, and the stock cat (from what I gather) is about 2'' inlet diameter.
Sorry for all the questions, I'm just trying to pick which ones I may order tonight. :D