Good size/Gauge Tube for building headers?

[sniper]

Just curious what a good gauge tube would be to use when building headers. I was thinking to use a 16 gauge Mild steel for my project 240. What do you guys think? I cant use Stainless because i cant weld that yet.

 

[cjsupra90]

16ga. it the typical for headers in both mild and stainless. one suggestion is if usuing mild, have them ceramic coated both inside and out. It will one cut some engine bay heat down, but the best bennifit is the corrosion pertection that the ceramic coating offers.

 

[Lextreme II]

I will be using 1.5" as primary, then 2" as secondary and 2.5" as tertiary. I will be using Mild steel with coating. Personally the stainless is out of my budget.

 

[cjsupra90]

Dave, are you build a TRI-Y set up? If so, not to say that this is the case 100%, but you might be better off with a 1.75" secondary. We built a destroked 283cid to 252cid chevy V8 and engine dyno'd it with different headers along with other items, but as for the header aspect, the 1.75 sec. yealded a brouder more usuable torque curve. Also on that note in talking resently to Burns stainless in researching the header design for my 1uz swap in my supra in the event of not going twin turbo, that is also the sizes that they suggested for a TRI-Y setup. To me, it makes sence to go in even step up increments like what you proposed, but I guess that is not the case. Either way, if you have heard otherwise, I'd like to hear about it.

Chris

 

[JDMfantasy]

the thicker the tubing that you go with the faster the exhaust gas velocities will be, which will yeild better spool up time, but also keep in mind the added weight of thicker tubing, in my opinion you should concentrate on getting a half inch thick flange for the header, then just use 16 ga tubing.

 

[cjsupra90]

You are sorta correct. It is true to an extent because of the nomenclature of piping and tubing. A tube as used in exhaust system is sized according to its O.D. where as pipe is sized according to it's nominal I.D.. So yes to get a smaller I.D. in exhaust, you have to go with a heavier gauge or thicker wall tube, but the thickness of the tube has nothing to do with velocity of the medium (exhaust in this case) flowing through it. The inside diameter is what controls this. When dealing with exhaust, from a flow standpoint, thinner wall is better if the I.D. is kept consistent because the larger the O.D. is, the more surface area it has and therefor the more heat it will give up to the surrounding air. Any lose of heat will equal a lose in flow velocity and therefor scavaging. This is the reason as to why just ceramic coating or wrapping an existing set of headers has showen horsepower increases numerous times in numerous dyno tests all because it keeps the heat in the pipe.

 

[Lextreme II]

Supra,

Thanks for that. Actually am using the cheap pipe right now. Mild steel is affortable and can be replace if mistake occur. I will be using 1.5" primary, 1.75" secondary and 2" turbo inlet. I just want to make some for the average joe. 2" up and 2.5" down. Its make for a twin T3 with .48 A/R with internal waste gate. Looking for about 300 rwhp with this setup. We are aiming for 6 psi on stock engine.