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Header Tubing Size


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17 replies to this topic

#1 Do It Sidewayz

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Posted 30 December 2004 - 01:42 AM

Gonna make a header. I have some 1.75x.120 Tubing left around (roll cage tubing) which i was going to make the header out of.

that makes the ID about 1.5" that still too big?

i don't like the TWE stuff with the 1 7/8 ID. that's too big for me.

#2 NorthWet

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Posted 30 December 2004 - 02:37 AM

What are you using to bend it? Have you considered trying GM's trick of "hydroforming", filling the tubing with liquid, sealing it, and then bending the tubing?

#3 85 Gl

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Posted 30 December 2004 - 06:19 AM

What are you using to bend it? Have you considered trying GM's trick of "hydroforming", filling the tubing with liquid, sealing it, and then bending the tubing?


Q.

what does that do?

#4 BobBrumby

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Posted 30 December 2004 - 06:31 AM

i supose it would make the bend close to a mandrell, btw u would want a liguid that didnot expand any when heated.

#5 All_talk

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Posted 30 December 2004 - 10:13 AM

With the common port at the head and an equal length (or near) Y header what you get is a Tri-Y system, so the port at the head is the first collector. The ports are very large compared to the actual runners to the valves. If you look at the stock pipe you will see it necks down some from the port, as a collector should. For a turbo system you want to preserve exhaust velocity so an overly large primary can be detrimental. The stock heads don’t flow very well at high RPM so unless you have done some head work, sizing the piping for top end is kinda pointless. I would say that pipe ID matched to the port size would be max, and if you are looking to keep/build bottom and mid power, slightly smaller would be best. Whats the head port size (I don’t have a head loose to check)?

Just my thoughts
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#6 Myxalplyx

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Posted 30 December 2004 - 10:24 AM

With the common port at the head and an equal length (or near) Y header what you get is a Tri-Y system, so the port at the head is the first collector. The ports are very large compared to the actual runners to the valves. If you look at the stock pipe you will see it necks down some from the port, as a collector should. For a turbo system you want to preserve exhaust velocity so an overly large primary can be detrimental. The stock heads don’t flow very well at high RPM so unless you have done some head work, sizing the piping for top end is kinda pointless. I would say that pipe ID matched to the port size would be max, and if you are looking to keep/build bottom and mid power, slightly smaller would be best. Whats the head port size (I don’t have a head loose to check)?

Just my thoughts
Gary


I agree with your thoughts. I'm assuming our exhaust port size is 1.5" since that's the diameter of the stock exhaust piping. Hope someone finds out. If it is and the Techworks header/uppipe is 1 7/8, man....that's slowing down the velocity. On top of that, if you have a larger turbo, then it'll be even more lag. Our low compression, poor air flow and low displacement only compounds things. It'll be interesting to see what people experience with the parts.

Good luck on your custom build. Crush bends aren't the end of everything and can work quite well.

#7 calebz

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Posted 30 December 2004 - 10:41 AM

I just went and measured the exhaust port on a carb'd head. Came out at 1-7/8. I think its safe to assume that the turbo ports are the same size. That said, for my personal use, I would prefer a smaller header. Exhaust velocity is terribly important in these motors and IMO, 1-7/8 piping is a little too big. But then again, I don't care too much about top speed. I am more interested in how fast it can get there.

#8 MilesFox

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Posted 30 December 2004 - 10:45 AM

turbo ports are actually larger, if you get exh gaskets from napa they come with 2 sets, one is smaller than the other

#9 All_talk

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Posted 30 December 2004 - 11:01 AM

Good work Calebz. Now I can see why TWE went with 1 7/8" but given the stock heads limitations I agree its a bit large. The 1 1/2" proposed should work well.

Good luck on your custom build. Crush bends aren't the end of everything and can work quite well.


Right, the flow doesn't mind being squeezed a bit but abrupt changes consume large amounts of energy.

Are the turbo heads larger, I would have guessed they were the same, can someone confirm? Could the smaller gaskets be for the EA-81 maybe?

Gary

#10 NorthWet

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Posted 30 December 2004 - 11:37 AM

I have heard of using the sand also, but had not heard of a commercial application that I could use as an example that it worked. I imagine that just as important as it being dry sand is that it *not* be sandblasting sand, which is angular enough to not flow well. Play sand would probably be better.

I was about to run out and measure my turbo port, but you guys have that covered, so I will stay dry! :grin:

#11 All_talk

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Posted 30 December 2004 - 12:37 PM

BTW, The frozen/semi-frozen water technique is the method used to make musical instruments like trumpets and trombones. I saw it on Mr. Rogers Neighborhood when I was a kid, I miss old Fred he was a great guy. :)

Gary

#12 Do It Sidewayz

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Posted 30 December 2004 - 12:46 PM

yes.. the ports on the head look MASSIVE!!!


For the bender....i've got one of the cheap rump roast Harbour Frieght benders. It works fairly well if you take your time, fill them with sand, and make sure the dies fit really well.

Welder...i've got a 110V mig welder, with shielding gas..so i can weld just about anything. Hell i welded the entire roll cage with it....so it's obviously good enough.

I think this tubing will work really well, as it will retain alot of heat because of the thick wall.

Bang bang....well.....if i can find a way without spending oodles of cash...maybe.

In the meantime..i'm just going to keep throwing fuel at it, till it backfires when you shift...It's a race car so i'm not terribly concerned with Fuel Mileage.

#13 Myxalplyx

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Posted 30 December 2004 - 01:36 PM

BTW, The frozen/semi-frozen water technique is the method used to make musical instruments like trumpets and trombones. I saw it on Mr. Rogers Neighborhood when I was a kid, I miss old Fred he was a great guy. :)

Gary


I wonder if Mr Rogers used this technique to fabricate exhaust manifolds on racing V8 in his spare time. :brow:

#14 calebz

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Posted 30 December 2004 - 01:45 PM

Heh.. Watching old fred right now.. They're having a birthday episode, which is cool since my daughter turns 3 today

/hijack

#15 All_talk

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Posted 30 December 2004 - 01:55 PM

DUDE thats where I saw it, Mr Rogers it was on maybe just a few days ago, they were making trumpets so I watched as Mr McFeely explained the process :brow:

That’s funny, and kinda spooky, but when I read you saw it on “a TV program”, I thought to myself… I bet it was on Mr. Rogers. Fred was single handedly responsible for make several generations of children better people… well him and Bert and Ernie.

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#16 Vanislru

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Posted 30 December 2004 - 02:26 PM

I haven't noticed any extra lag with the TWE setup on my wagon with the stock turbo, comes to full boost about 2500rpm. The top end is unreal, the difference is comparable to when I tore off the old melted DP and ran 2" all the way from the turbo back with my homejob DP. How much extra volume is there from the extra ID? one cylinders worth, maybe? I thought with the extra bit of piping the TWE setup has on the pas. side and the 1 7/8" ID would have meant more lag too but it hasn't at least not anything noticeable.

#17 Vanislru

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Posted 30 December 2004 - 03:07 PM

A smaller tubing setup built like TWE's would most likely have more low end/quicker spool times, I'm just chiming in to say... if you have a larger size tubing like 1 7/8" SS already then I wouldn't go out and buy a smaller size just for the sake of slightly improved exhaust velocity. Maybe instead of the wrap around style of TWE a better merge of the two pipes could be done to keep the volume of the header low?

#18 NorthWet

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Posted 30 December 2004 - 06:13 PM

Cool! I also have a Harbor Freight cheap-etc., and was planning on doing my own bending, trying the water and the sand method. I was also planning on using small diameter pipe, and double walling it (tube slipped over tube). I want to try a couple other things, but need to take baby steps first...

Let us know how things work, and what doesn't work.




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