When are 2" headers necessary?

[Motion427]

Why don't you get both 1 7/8" and 2".
I asked Kooks to make me a set.They sent me these signature series stepped headers 1 7/8" then it goes to 2".
Best of both worlds.

[HufferSS]

Originally Posted by MarylandSpeed

I think it is time for another test

Feel free.

I'd trust Janetty any day of the week though.

Using your analogy.....why do manufacturers make electric superchargers? They must work since they make them right.

[HufferSS]

Originally Posted by LashwayMotorsports

so you guys saying the 2" headers are the best way to go, would you also say based on your experience that a carb sytle intake or fast 102mm would be the best intake for a 5.3L LSx?

This isn't a 5.3L forum....it's a 6.2L + forum. Duh.

[jasycz28]

I guess I should of said that I am whippled and at 570rwhp stock everything else. Next step in my plan is full exhaust and cai. Then a cam. So I hope to break the 700 mark. Really looking at LG's full setup nocats $1900 shipped. Might have to wait for a 2" special to happen.

[SUX2BU]

Originally Posted by MarylandSpeed

This is a myth. One shop two years ago posted results of a test they did. If I remember correct, it was just they posted the peak numbers, not like a chart that shows power throughout the whole powerband.

I have been selling LSX parts now for 8 years, and have sold as many headers as anyone. 2" headers only sell for cars making 750+ rwhp. This is not my opinion..you call any major header manufacturer, and they will tell you the same. If 2" headers were better everywhere, why would header manufactuers bother making 1 3/4" and 1 7/8"? It would make life alot easier for everyone.

Everything you need to know about headers can be summed up in a garden hose. The idea of a header is the make the exhaust gas move faster. The faster the exhaust gas moves, the faster new air/fuel can replace it in the cylinder head, and the more efficiantly the engine can breathe.

Going back to the garden hose..if you replace your garden hose with a bigger garden hose...what happens? The water comes out the end slower because it is not as pressurized. The water will only move the same speed as the smaller hose if you turn the water up real high. Same thing with a header. If you put a big header on, it does not pressurize the exhaust gas as much initially, which hurts exhaust velocity. If the exhaust does not move as fast initially, you lose lowend power and TQ. You may see a same, or higher peak HP number witha 2" header, but that is because ones the engine is really wound up over 5K RPM, the bigger primary can flow it better.

Long and short is..you want the smallest diameter primary that can flow the maximum exhaust output of the engine efficiantly. if you go on LS1Tech, Corvette forums, or any of the other really technical LSX boards and say..I am gonan run 2" headers on my stock LS3, you will get laughed out the place.

I think it is time for another test

This reminds me of 5 years ago when people said a bolt on LS1 wouldn't gain anything going from 1 3/4" to 1 7/8" and most said I would lose power. So I dynoed my car with the 1 3/4", swapped them out on the dyno and dynoed again. Results? Everything under 4.5K was identical and I gained a few rwhp above 4.5K rpm.

Your garden hose analogy isn't very good. If you go to a bigger hose, yes the water will come out slower, but it will also come out in a greater volume. Pressure does not equal volume. You can open the hose and look at how fast the water comes out, put your finger over the end, the pressure goes up, speed at which the water comes out goes up but the volume goes down.

Companies make plenty of headers because people want choices. The same reason there are 100 different cold air intakes.

[Li0nel1234]

Originally Posted by SUX2BU

This reminds me of 5 years ago when people said a bolt on LS1 wouldn't gain anything going from 1 3/4" to 1 7/8" and most said I would lose power. So I dynoed my car with the 1 3/4", swapped them out on the dyno and dynoed again. Results? Everything under 4.5K was identical and I gained a few rwhp above 4.5K rpm.

Your garden hose analogy isn't very good. If you go to a bigger hose, yes the water will come out slower, but it will also come out in a greater volume. Pressure does not equal volume. You can open the hose and look at how fast the water comes out, put your finger over the end, the pressure goes up, speed at which the water comes out goes up but the volume goes down.

Companies make plenty of headers because people want choices. The same reason there are 100 different cold air intakes.

He is correct. The skinny hose does not help...
If you had the same volume of water in your mouth as a guy next to you. You both will attempt to squirt the water out as fast as possible. You both get to choose a straw. Will you choose the fat milk shake straw or the skinny coffee stirring straw? You choose the FAT straw to get the water out faster.

Or think of a cup with a hole at the bottom, the one with the bigger hole lets it out faster.

[SRT10KLLR]

Originally Posted by MarylandSpeed

Long and short is..you want the smallest diameter primary that can flow the maximum exhaust output of the engine efficiantly. if you go on LS1Tech, Corvette forums, or any of the other really technical LSX boards and say..I am gonan run 2" headers on my stock LS3, you will get laughed out the place.

I think it is time for another test

And yes, it is time for another test.

Originally Posted by Li0nel1234

He is correct. The skinny hose does not help...
If you had the same volume of water in your mouth as a guy next to you. You both will attempt to squirt the water out as fast as possible. You both get to choose a straw. Will you choose the fat milk shake straw or the skinny coffee stirring straw? You choose the FAT straw to get the water out faster.

Or think of a cup with a hole at the bottom, the one with the bigger hole lets it out faster.

It is true up to a certain point. Try using a straw with a diameter the size of a paper towel tube and see how fast you can squirt the water out of your mouth.

So fill your mouth full of water then aim up then get a huge straw and try to squirt the water out. Next try the same thing with a narrower straw then finally the smallest one. The best will be the one in the middle(milkshake) not the smallest(coffee) or the widest(paper towel).

If 2" is better why stop there why not 3" or 4"?

Every application is different. On a stock motor the 1 7/8 might be better but on a FI motor the 2" may be the best.

[SUX2BU]

Originally Posted by SRT10KLLR

And yes, it is time for another test.

It is true up to a certain point. Try using a straw with a diameter the size of a paper towel tube and see how fast you can squirt the water out of your mouth.

So fill your mouth full of water then aim up then get a huge straw and try to squirt the water out. Next try the same thing with a narrower straw then finally the smallest one. The best will be the one in the middle(milkshake) not the smallest(coffee) or the widest(paper towel).

If 2" is better why stop there why not 3" or 4"?

Every application is different. On a stock motor the 1 7/8 might be better but on a FI motor the 2" may be the best.

You can't compare a fixed amount of water in your mouth to something that has a constant flow. Obviously you can't fit 3" or 4" primaries, but I think for what I am looking for (faster 1/4 mile times) the bigger primaries the better. Obviously you will see bigger gains the more power you make, but I don't think there is any reason anyone should go with less than 2" primaries besides cost.

[blazzin1]

I've always heard that, yes, unless you have a pretty radical set-up, you really don't need 2" headers. But I've also heard that they won't hurt your performance either. I'm never certain what direction my modifications may take down the road, so why limit yourself? In many cases (like Stainless Works) the 2" and 1-7/8" headers cost the same. Why buy something that may need upgraded at a later date? In my opinion, buy the 2" now, and never need to upgrade headers ever again!!! If someone could prove to me that 2" headers will hurt my performance (with something a little more substantial than hose analogies), then I may think differently.

[Kilo-9]

Originally Posted by Motion427

Why don't you get both 1 7/8" and 2".
I asked Kooks to make me a set.They sent me these signature series stepped headers 1 7/8" then it goes to 2".
Best of both worlds.

Maryland Speed, any chance we will see the 1 7/8-2" stepped Signature Series readily available from Kooks or are they going to be special order only?

[andredmg]

2" look pretty killer sittin under the hood, I made 703hp on the motor naturally aspirated if I was makin that at the wheels I would have went with 2" but my tuner and the manufacture recommended 1 7/8" no regrets, Im makin 610hp to the wheels.

[Sawyer]

Originally Posted by andredmg

2" look pretty killer sittin under the hood, I made 703hp on the motor naturally aspirated if I was makin that at the wheels I would have went with 2" but my tuner and the manufacture recommended 1 7/8" no regrets, Im makin 610hp to the wheels.

703 N/A??

[MarylandSpeed]

I really hate arguing on the boards. I honestly really don't have a horse in this race. You can buy 3" headers if you want (as long as you buy them from us of course..haha). My point I am trying to make here is that part of modding is choosing the right parts for your application. Same reason people sweat and pour over dyno's here about which CAI made 2 HP more in a dyno test. Can you put 2" headers on a stock/bolt on car thinking you may mode later? Sure you can. Just like you could wear a shirt 3 sizes too big thinking you are going to work out, or buy a 6 bedroom house thinking you are gonna have 5 kids down the road. My point is..it is best to chose the proper part for the application. Any header manufactuer will tell you unless you are going in the 700+ rwhp range with some bigger heads that flow a lot more air, or some extreme blower setup, 2" are unnecessary. Additionally, if you do some research on the more tech centric boards out there like LS1Tech or Corvette forums, you will see it is VERY rare someone runs 2" header...again..only in in the most extreme setups. I understand the bigger is better mentality. I also understand that there is a tendancy to think the Camaro is special or different, and what applies to other cars does not apply to it. However in terms of powertrain..your car is no different than any Corvette, G8, or GTO...and because of that, there is a wealth of information if you know where to look. You can either do that research..and I think you will come to the conclusion...or you can go by one dyno test that you are interpreting wrong..as even the shop that did the dyno test said in the test that 1 7/8" was the best all around header.

[DietCoke]

Originally Posted by MarylandSpeed

as even the shop that did the dyno test said in the test that 1 7/8" was the best all around header.

Not because it made more power (anywhere). Case in point.

Saying the 2" only makes significant gains over 4500rpm only furthers that its a superior choice. Do we race below that? Dur.