Just a quick post to see if any you would recommend one over the others. Let me know. tks

 

You don't need headers unless you're building a monster. The stock manifolds are good to pretty high HP levels.

 

Just have your headers ported like a lot of us did. The stock headers are actually very good.

 

i use the AP headers, no idea on AFI. Fit is good, didn't have to enlarge any holes anything like that... my friend was following me one night, saw them glowing. wish i had a photo of that.

anyways to add to what others have said, be midful most aftermarket headers will lessen ground clearance. reportedly, changes tone of exhaust note.

Have read in more than one place on this forum that it's not a "need" until over 600hp or something like that, and even then, can port stockers. I dont have 600 yet but was sick with the mod bug at the timeit was an impulse buy (justified by bundling shipping costs... a "savings"), but happy with the purchase in anycase. everytime i change oil, it's nice to look at.

 

Thanks for the feedback.

The reason I ask is that I might be going with a GT3076 set up in the near future and have a choice between the AFI and Agency sets. If I'm getting it correct, it looks like about 6 of one and half a dozen of the other.

 

Do your homework. Compare the metal being used for the tubing. Stainless? Mild Steel? What is the type or grade of the metal? Thickness or tube? Thickness of the flange? Is the flanges joined or separate? The process of the weld, MIG or TIG? etc.

Remember, heat is a big form of energy or power that turns your turbo's. Thicker material holds the heat better. It also makes for a stronger header. Wrap will also help contain heat. Ceramic coating is good but in many applications will shead, fracture or peel. When you watch your headers glow ...... you are watching loss of power. That heat isn't turning impellers, instead it is escaping out the sides of your header.

Also, don't be fooled by header flanges that simply follow your gasket. There needs to be a slight lip protruding in a certain part of the header flange. If this isn't there and done properly that header will produce what is know as harmonic distortion in your valve train. This will rob power.

 

CJV - There are 2 kinds of Agency Power headers. 1 set is for stock turbos that we buy from overseas like many others. They are actually great. The other set is the set we build here inhouse for the Garrett turbo conversions like seen on my 997TT. AFI is a company that we use to work with and we had them build products for us. In the end, we have brought most all of our manufacturing inhouse so now produce these here.

Standard Turbo (304 Stainless, cast flange, robotic tig weld) -


Garrett Turbos (304 Stainless, Water Jet Flange, Tig Welded by Hand) -

 

Dan,

I am not promoting one header over another. I couldn't without having the specification of all the headers being compared. I know what I use, but without knowing what it is being compared against it would be a personal opinion.

Harmonic distortion related to flange design, a thick tube will retain more heat than a thinner tube, some grades of stainless are better than others, TIG is better than MIG and full penetration welds without protrusions is important, some collectors are better than others, tube size is important in relation to power and bigger tubes are not always better.

With that being said, cost is also important. Headers are probably one of the lowest bangs for the buck considering other mods. Ringing the last few hp out of headers can be costly.

Good quality material is probably the most important as this will help prevent headers from corroding when wrapped. Wrapping is cheap and will give the best return for the dollars when using headers. Keeping heat in the tubes is what really makes extra power. Why do the stock headers perform well? The biggest reason is their ability to retain heat. Other than their ability to retain heat well, they have a lot that can be improved upon.

 

Good stuff guys! I appreciate the info!!