CobaltSS313

CTI longtube has my vote. Ordered mine today.

CobaltSS313

whats the benefit of ceramic coating

Rage915

right now the header is on sale with the exhaust, header is for 399 and the exhaust is for 499. they arnt available with ceramic coating but you can call and ask brad if they can fab u some that are.

OUTPR4MZ

the vibrant header has a good design

Vman81

Just know that if you get an aftermarket header, GM will void your powertrain warranty if something ever happens to your engine. Otherwise, I would get the ZZP Header/downpipe combo.

Later,
Vince.

kenhebe

No they won't because I spend over $60,000 a year with my Chevy dealer in parts for my body shop. I am really, really fortunate there. They have looked the other way on my other cars and just got things covered.

Vman81

Lucky for you....at least your not like 89.9 percent of the people on this site who have told me what a horrible person I am for trying to get my car fixed under warranty...lol.

Later,
Vince.

player_1

thats a nice header, but I've heard it doesn't fit properly.

check out the JBP equal length header, it yeilds the gain of a long tub header.

www.jbodyperformance.com

pierre

Hey Skykapp,

Let me pick your brain a little. Yes the 400 series stainless steels will rust but they are quite a bit more corrosion resistant than plain old mild steel. Catalitic converter housings are made of 400 series as are a lot of OEM exhaust systems. They seem to last 8-10 years even up here in the North East. It could be a good price performance trade off.

300 series stainless suffers from carbide precipitation at temperatures above say 900-1100 F. This leads to stress corosion cracking. Using Low carbon stainless will prolong service life but will not eliminate the problem.

Of course Inconell 625 is the premium material but no one but race teams can afford that.

What are your observations on the life of these materials used on a header.

Thanks

Pierre

Rage915

wow, what this guy said!

joeworkstoohard

the other "hidden" benefit of ceramic coating is underhood heat. a steel pipe can often get hot enough to damage underhood paint and harm hoses and rubber.

skykapp

Pierre,

Without getting into the science of the steels, I can say you are right on track. Where things differ is in material thickness, preparation and source. Imported steel headers are almost always made from 18-gauge (0.049”) 400 series material that is then polished. Polishing makes the header look nice, but it requires material to be removed. 18-gauge is thin, mandrel bending makes it thinner and polishing it makes it thinner again. 1D bends are common in headers and tight bends like that make for a very thin material wall. It’s expected to have half the thickness on the outer wall on bends 75 degrees or more. A good header design can lower the chance having thinner walls by using larger bend radii and lower angles, but this isn’t always the best performing solution or possible with available tooling. The Asian steel used by most header companies (imported product) is of a lower quality than what is produced in the USA. Our materials testing guys (at my 9-5) regularly see our steel vendor try to sneak 304 Asian steel under our noses and every time we catch it. It breaks at lower loads, takes fewer elastic cycles and corrodes faster than American steel. It guess it’s All Natural.
Now when you talk about OEM exhaust and materials, almost everyone uses 400 series material, but it’s a thicker gauge and neither prepared with a polished finish nor built with the tight bends found in a header. In the Saturn community the header of choice is the OEM ’91-92 header and its crush bent 400 series steel. They are usually rusty on the outside and ugly as heck, but even today you can find them on junked cars or eBay 15 years after they were produced. The material is actually 16-gauge 409 and much thicker than imported aftermarket headers.
There is no doubt that 400 series material is the least expensive steel and using it is a matter of price vs. performance. I’m just of the opinion that this is not the way it should be in the aftermarket community.
Addressing any “stainless” embrittlement issues is a whole other problem that is completely impossible for us to get around. Mild steel is about the least susceptible to this, but it’s also the worst for corrosion resistance. With 300 series and even Inconel you still have problems getting from raw steel to a header and in that process the material has to change from malleable to hard and heat resistant. The problem is that you can’t have it both ways and expect to get a product anyone can afford. In theory a header shouldn’t see carbide precipitation temperatures ever. There should be a thin boundary layer near the material wall that insulates the core exhaust gas temperature from reaching the steel itself. (GENERALLY) If the exhaust gas velocity is near the 240 ft/sec mark and the header does not neck back on itself at no point in the header will it see temperatures that promote embrittlement. However overheating of the material during welding can permanently lower that threshold causing an accumulation of carbide and sulfur around the welds. This over time will cause a header to crack even one that is ceramic coated.

HS/RGS was infamous for welding headers too hot, running multiple passes over bad miter cut joints and welding a whole assembly way too fast. The ignorant belief was that the mild steel could handle it and the ceramic coating would protect it from seeing the temperatures that promote cracks. Too bad that’s wrong and easily 25% of there products cracked in 11-14 months of use.
So weather its mild steel, 409, 304, or Inconel if it’s not built right it will not last forever and even ceramic coating can’t save a bad welded part. The thicker the material the longer it’s going to last, but at the same time having a thick product that is restrictive will generate excessive heat and fail eventually too. There is no simple answer and may never be, but it's always best to stick with a header that doesn't stick to a magnet and has some weight to it. 16 gauge 304 stainless steel TIG welded headers with a direct to the exhaust path will always out perform snakes having sex in both HP and lifespan.

pierre

Thanks sharing your experiance SkyCap.

Pierre

John

the JB header is top noch or the dc sport is a nice piece

zinner

DC sports is smaller than the stock SS/SC header, both the primaries and collect are smaller. It's good for a L61 or maybe the LE5 but not the LSJ.

I am going to order either the Hahn or CTI, I am not sure which yet.

martinsmu

DC piece looks preatty high quality, but new. SO I would either go with the HAHN or CTI.

Red2.4SS/SC

zzp header and downpipe is a good deal 450 with no cat

Rage915

you should add a poll to this thread

chipmonk212121

vibrant has a nice setup and comes with the DP

Cobalt_Supercharged

I'm going Vibrant if I get a header. Here's why:
-T-304 Stainless
-4-2-1 desing that promotes power in the mid rpm range (the most usable)
-Comes with a matching down pipe with high flow cat
-Bolts to the stock cat back or any other cat back for that matter.

pierre

One more question SkyCap

Working in the chemical process equipment field I've used plenty of Stainles and Inconell. We are always carefull to limit the interpass temeratures to below 300 F and we purge the backside of the weld with inert gas (Argon) to keep the weld from oxidizing in addition to the normal procedure of protecting the weld with the gass cup of the TIG torch. steel is not as sensitive to this problem. Is this issue adressed by header manufacturers? It costs money to do things properly.

Pierre

CobaltSS313

same reason why im getting CTI's header only no cat

skykapp

pierre,

HELL NO! This is a sad, but true fact that most (not all, but most) of the header/exhaust companies I have had the displeasure of doing business with do nothing in the way of controlling weld temperature or the quality of welding process. This ends up being reflected in the quality of final product and its failure to last more than 12 months without cracking.
Many welders believe that with proper environment control and a more aggressive mixture 304 can be welded without a back purge. This can even be the case with Inconel, but only about one tenth of 1% of all welders have the skill and patience to keep the material cool enough not to oxidize. Also the environment and material needs to be very clean and protected from the elements. There are even coatings available that actually prevent passivation in steels (300, 600 series), but when heated during welding evaporate away leaving a clean material to weld.

I'm in no way saying I'm a welder or a metallurgist in the slight bit, but I have been involved in exhaust manufacture for 10+ years. In that time I have seen everything from mild steel car headers costing under $200 each to complex jet engine exhaust manifolds costing over a million dollars each. Ironically I have also seen that same jet exhaust made from all composite in under 1/3 the price and time.

I guess my point is that in my experience it's not really possible to make a header that retails for $300 in the USA that considers all the factors needed for clean welds. The problem is that companies like HS/RGS fail to even put a roof over the head of the welder let alone try to provide a clean environment. When you are paid by the piece you are going to weld hot, fast, and ugly. If you don’t you’ll be back at Home Depot the next day waiting for the carpool.

I’ll go out on a limb and say that 90% of all hand welded exhaust parts are not properly treated before during or after the weld process. While this is not really any issue for exhaust systems, this can be a major problem for headers since they will see the heat levels on a daily basis which promote failure.

I think it's been proven enough times that looks mean nothing in header design. Also I'll say it again that N/A header theory doesn't apply the same with a supercharged engine. If you want to be safe let the dyno point you in the right direction, then look at the material and finally the mfg. source.

2K5SS/SC?

CTI's setup is a 4-1 design not a 4-2-1. Still awaiting mine as well!

player_1

those are the exact reasons why I went with the JBP header:

T304 Stainless Steel Flanges
- T304 O2 Bung
- T304 O2 WideBand-Bung (optional)
- T304 O2 Bung Plug (optional)
- Electropolished Finish (optional)
- Header Wrap for #2 primary
- Computer Tuned primaries 1⅝"
- T304 14 gauge Tube construction
- 3.0" T304 Stainless Formed Collector
- Bolts straight to stock down pipe
- Includes all mounting hardware
- Includes new stainles steel bolts




Thanks Skykapp

and I got mine polished, it looks great