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I keep reading differing opinions on the topic.
Wrapping is said to cause the headers to melt , and rust away but is also said to improve exhaust flow and protect the intake and bushings .
I drive 80mph for 30 mins at 5000 rpm daily , heat is a concern .
I used header wrap on a Pacesetter (*cheap, thin) header and the 12a power it was enough to burn a hole in the inside, trailing, tight-turn bend. I wouldn't do it again. The risk of heat retention is too high, and driving it at 80mph for 30min nonstop shouldn't cause overheating of the exhaust, but that's steady state, lean burning cruise that tends to heat up exhaust components. If the engine ran rich or you were able to duct some fresh air onto that side of the bay, it might help with heat. The performance improvement is nil.
The only thing I found header wrap to be marginally effective at doing was slightly reducing the exhaust port clatter due to cheap, thin steel headers, and that only lasted about 10k miles before it ruined them.
Buy quality Racing Beat header, tune the engine properly for cruise speeds, and duct some fresh air pointed at the header and catalytic converter stack. Done,
I used header wrap on a Pacesetter (*cheap, thin) header and the 12a power it was enough to burn a hole in the inside, trailing, tight-turn bend. I wouldn't do it again. The risk of heat retention is too high, and driving it at 80mph for 30min nonstop shouldn't cause overheating of the exhaust, but that's steady state, lean burning cruise that tends to heat up exhaust components. If the engine ran rich or you were able to duct some fresh air onto that side of the bay, it might help with heat. The performance improvement is nil.
The only thing I found header wrap to be marginally effective at doing was slightly reducing the exhaust port clatter due to cheap, thin steel headers, and that only lasted about 10k miles before it ruined them.
Buy quality Racing Beat header, tune the engine properly for cruise speeds, and duct some fresh air pointed at the header and catalytic converter stack. Done,
I should have stated I purchased a whole RB set up , No cat's just a presilencer. My carb will need to be tuned again but it was already running ace at that speed so I just plan on making it run a tad richer and jacking the idle speed up 200 rpm ( It dropped 200 Rpm with the test pipe and no muffler ) .
I should have stated I purchased a whole RB set up , No cat's just a presilencer. My carb will need to be tuned again but it was already running ace at that speed so I just plan on making it run a tad richer and jacking the idle speed up 200 rpm ( It dropped 200 Rpm with the test pipe and no muffler ) .
Would a wrap harm the RB headers ?
Witnessed a set of RB mild steel headers sag and break at the collector after a season of racing. It was at the last race of the year and header dropped so low that the exhaust hit the track and came apart. So not melted but structurally compromised.
Even without wrap I had a set of RB mild steel headers crystalize and crack 6 inches from the port. That was after 3 seasons of racing. I bought a set of used stainless steel headers to replace the RB headers. That was like 18 years ago. Street driving isn't racing but in my opinion if just speeds up what will happen eventually on a street car.
If heat is an issue it is better to insulate everything around the headers rather than the headers. So spend the money on a carb heat shield. You can also apply heat barrier material directly to the intake manifold and the bottom air cleaner. Regarding the air cleaner - feed the carb cold air from outside the engine compartment because it helps reduce temps and adds HP. I have dyno tests that prove that!. Another strategy is to duct cold air into the area below the carb using a bilge blower and some hose.
I've never seen any independent data that proves that header wrap does anything regarding power. Now in the engine bay, reducing temps should benefit an engines performance. But this can also be mitigated by taking the steps I outlined above.
Witnessed a set of RB mild steel headers sag and break at the collector after a season of racing. It was at the last race of the year and header dropped so low that the exhaust hit the track and came apart. So not melted but structurally compromised.
Even without wrap I had a set of RB mild steel headers crystalize and crack 6 inches from the port. That was after 3 seasons of racing. I bought a set of used stainless steel headers to replace the RB headers. That was like 18 years ago. Street driving isn't racing but in my opinion if just speeds up what will happen eventually on a street car.
If heat is an issue it is better to insulate everything around the headers rather than the headers. So spend the money on a carb heat shield. You can also apply heat barrier material directly to the intake manifold and the bottom air cleaner. Regarding the air cleaner - feed the carb cold air from outside the engine compartment because it helps reduce temps and adds HP. I have dyno tests that prove that!. Another strategy is to duct cold air into the area below the carb using a bilge blower and some hose.
I've never seen any independent data that proves that header wrap does anything regarding power. Now in the engine bay, reducing temps should benefit an engines performance. But this can also be mitigated by taking the steps I outlined above.
Wouldn't sag be prevented by having hangers ? I know many people don't use hangers in racing and just use solid mounts. That's Gnarly
Well I have decided I will wrap them until the heat shield comes in . If 6 days harms the headers they weren't very good to begin with .
I keep reading differing opinions on the topic.
Wrapping is said to cause the headers to melt , and rust away but is also said to improve exhaust flow and protect the intake and bushings .
I drive 80mph for 30 mins at 5000 rpm daily , heat is a concern .
For such short trips at low RPM you'll be fine with no wrap, says the guy who goes on 3-5 hour drives each way with 4.87 gears.
I had wrapped headers for a while, until I pulled off the highway one time to check something and noted that the headers were reddish-orange under the wrap even after the engine was shut off. Never had that with unwrapped headers.
And yes, the rust they cause is catastrophic.
At 80mph you have so much airflow going past the exhaust and stuff that there's no problem. Most of the airflow that goes through the radiator has to exit the engine bay down the right side since the left side is full of steering box and accessories. If you're worried about radiated heat on the idler arm, a heat shield over the idler arm makes more sense, as does a simple heat shield over the header. If you do the shield over the header, leave the front of it open so air can flow through.
I Cerakoted my turbo manifold (321 stainless) with a $35 Glacier C-7700. Shot with a small hvlp. Can’t recall the size at this time. Doesn’t require heat curing.
imo if you need to wrap a couple sections to keep other things cool its ok, but wrapping the whole header will shorten its life quite a bit.
the other thing that works is instead of wrapping the hot thing, you can insulate/wrap the cold thing. on my PP the header is bare, but the intake is wrapped
heat shields also work RB sells or used to sell one
Wouldn't sag be prevented by having hangers ? I know many people don't use hangers in racing and just use solid mounts. That's Gnarly
Well I have decided I will wrap them until the heat shield comes in . If 6 days harms the headers they weren't very good to begin with .
You know I honestly don't know if he had the exhaust system supported from the transmission on that car. The exhaust did have hangers at the rear, possibly under the middle of the car and certainly at the back. This was on an Improved Touring race car so solid mounts were not an option. What I remember is that the header was sagging at the bend just after the exhaust ports and he ran the car in the last race with only an open header. It was loud as hell! This was back when header wrap was a relatively new thing in the racing world so it was a one time experiment.
My current practice is to use OE engine mounts and a urethane trans mount in combination with OE cross member mounts plus a torque brace. I have an exhaust hanger off of the transmission tail shaft housing to help support the exhaust just after the header. I keep the tail shaft exhaust mount loosely connected to the exhaust system and it is designed to flex vertically. Its just there to contain the exhaust system and let it expand and contract as it heats and cools. The rest of my exhaust is also supported using flexible mounts.
Early on I had the transmission mount that was firmly attached to the exhaust after the collector but found out the hard way that this is a bad idea. A couple of off track excursions caused the header and collector to hit a curb which resulted in 3 broken transmission case bolts. Not a fun fix.
I use a chain myself, from the pipe to the mounting tab on the side of the tailhousing IIRC. It supports without stretching, and it can handle length changes when the exhaust expands in length with heat.
Having no mounts makes servicing a lot easier. I can R&R the transmission by myself in 40-45 minutes, if I had two helpers I could knock it down to ten.
I wrapped it but not the whole thing . The First curves are bare halfway through , then they are wrapped right to where the two tubes meet and bare from there on .
Why ? The original collector has the air hit it unshielded from the front and has no shielding for the connecting pipe.and the original collector wasn't exactly shielded all the way to the engine block but had a 3 inch gap
I think the rust claims are bogus to a degree . Moisture stays on metal cloth or not , obviously a damp cloth will hold moisture in longer but the header heat will evaporate it asap..
This is what I've always done. I've owned 5 Fabs on my lifetime and always done this to them.
Paint your header with a ceramic paint. As soon as you paint it get it on an oven or get it installed and run that car, at this point the paint will looks and feel like a powder. When the paint heats up it will create the ceramic coating.
Second, wrap the header tight.
After you got it like this, perfectly and amazingly looking wrapped like this😎 you spray this on....
After you spray this on you will run you motor again and this will heat and seal the webbing on the wrap and protect it from moisture, water and debris.....
Your header will last way longer doing this. I did this the first time on my first FB and I had it for 6 years, sold it and the person who bought it never complained about getting a hole on the header.....
That is kind of what I was thinking. If you didn't have problems before, you probably won't now. Not a guarantee though. I drove my Spec7 on the street for several years as a daily driver. It didn't have a header, but the heat shielding (whatever was originally there) was stripped away and I never had problems with fuel boiling in the Nikki. If you do have a problem, the RB heat shield should work fine as long as it fits. If it doesn't fit, I am sure you can fabricate something similar. You can even add insulation to it if you feel that is necessary. The pictures below are what I did when I started doing endurance races in +100 degF ambient temps. Under those conditions, the car is running essentially at WOT for 1.5hours at a time, followed by 5 minutes sitting in the pit. Repeat 3 more times. The setup below works fine now.
You may be right about the header tubing not "rusting" under the header wrap, but it absolutely will deteriorate rapidly. At least under racing conditions. I have direct experience with failures wrapped and unwrapped. Wrapped lasted about 1 year. Unwrapped lasted 4-6 years. Ceramic coated is 4 years old and absolutely no sign of deterioration. I recommend not wrapping.
The deterioration is most likely a result of high temperature oxidation. I cut the failed unwrapped header apart to try and understand what was going on. The deterioration defintely was coming from the outside. The outer 3/4 of the tube wall was "burned", black and granular. The inner 1/4 was clean and shiny. Oxidation occurs on the outside of the header tubing because it is exposed to atmospheric air which has 21% oxygen. The inside of the tubing has essentially zero oxygen (unless you are running an air/fuel ratio higher than 15, which I hope is not the case). As metal temperature increases the oxidation rate also increases at some "exponential" rate. The unwrapped failure was in the bends just downstream of the exhaust ports on the engine, which is of course the hottest location. Downstream 6-8 inches, the tubing was still pretty much "as new". If you wrap the header, you retain heat in the exhaust and thus have much higher temperatures over a longer length of the header.
Although I don't recommend wrapping the header, as a street driven vehicle, I suspect that it will take a few years for the header to fall apart if you do. At that point you can take the remaining RB inlet header flange to an exhaust shop and have them weld on some custom bent stainless header tubes ;-)
I am not sure any of that info is helpful, but it is the best I can do on a Friday afternoon.
Oh yeah. And as a combustion engineer working for 45 years in power plants I have still not figured out how to avoid burning myself on anything, including my coffee cup in the morning. :-)
I can't tell you how many times I've grabbed something that I just welded, too.
You'd think that pain would be an education reinforcement, but no!
I almost lost my finger to a pulley a few months ago. I told my self mentally to watch my fingers around the AC clutch and the first thing my body did was try to touch the belt. As soon as my finger touched the belt It bounced and got nicked by the pulley smashing my nail . No idea why My body did what it did when my brain was telling me not too. It's almost like target fixation when riding a motorcycle . Odd but funny. But yes the wrap it's partially due to the fact I know I will end up burning my self somehow.
Also Carl I saw your fab work in person and really liked it , I also liked your custom tail lights you made . Simple but oddly fitting . I might just buy some aluminum sheeting and make my own heat shield.
In a weird catch 22 situation I now have a job at a law firm and can afford things but don't have time to do them . I have been driving to RB on my lunch breaks just to pick stuff up since they open and close the same time I get in and out if work When I had time I had no money 😅 Guess that's just life.
Is it just me or does the header wrap make the car sound better. Swear it does!
Makes sense , It will insulate the sound and certain frequencies so it comes back out the pipe with another tone .Try insulating a trumpet tube and it sounds off
05-22-23, 02:46 PM
