Hotpipe material

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bgilbert

VE Guy
Joined
Jun 20, 2007
Messages
515
This may have been beat to death in the past, but I'm just catching up;). I'm building a set of twins in a 1st gen with a s300 and s400. I just picked up a schedule 40 4" 90*elbow. This thing is huge and heavy. 4" id and 4.5" od:doh:. I think I have the space for it, but getting the 4.5" pipe to match the flange for the s4 might be another story. My question, should I use a 3" schedule 40 (3.5"od) elbow or can exhaust tubing be used? Thanks.
 
Schedule 40 is the norm. I would stay away from the exhaust tubing, it is too thin.
 
The 3'' will help keep the velocity up to aid in your primary spool up. The 3'' is perfered. Big rpm and gross amounts of fuel will call for the 4''. Thats what i have found.
 
GRotman said:
Schedule 40 is the norm. I would stay away from the exhaust tubing, it is too thin.
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Really?? source automotives looks like and most the ones I have seen have been exhaust pipe....I think MPI uses regular exhaust pipe for his hot pipes to??

I know sch40 would be stronger..but I thought lots of company's used regular exhaust pipe?
 
I have always used schedule 40 for all mine. Never had an issue. I have always worried about using exhaust tubing with having header wrap around it.
 
For those of you using sch.40 what are you using for the flange for the V-band side of the hot pipe?
 
How hard is it to box end the Schedule 40 pipe to weld fit lets say a T-4 of T-6 adapter plate? Just heat it up and bend it in a vise? pretty thick stuff
 
9 LIVES said:
How hard is it to box end the Schedule 40 pipe to weld fit lets say a T-4 of T-6 adapter plate? Just heat it up and bend it in a vise? pretty thick stuff
Click to expand...

it's not too bad... heat it w/ a torch and form it w/ vise, hammer, vise-grips, etc.
 
Bponci said:
The 3'' will help keep the velocity up to aid in your primary spool up. The 3'' is perfered. Big rpm and gross amounts of fuel will call for the 4''. Thats what i have found.
Click to expand...

Dang you are "The MAN" handing out that kind of advice at that time of the morning (0555) :clap::clap: I know what I'd have been doing........hope you were too!! :woohoo::woohoo:
 
lol!!!!

wonder where the 3" number came from?

Back to the material....exhaust tubing can be used, but make sure to either preheat the workpiece prior to welding, or at least anneal the welds after welding to keep the pipe from cracking (a rosebud works very well)

If the primary is supported by a bracket, sched 40 is overkill.
 
the thicker material of te sch 40 should help keep heat in and keep up the thermal velocity of the exh gases, correct? that is the thoguht behind using header wrap. lloyd and i used sch 40 on both of my sets that we built and both are still performing fine.

i like you avatar lloyd! looks kind of like mine, only mine is a bit closer to my speed!
 
I hate to drag this out of the weeds but I need answers.

What is the drawback to using 3" exhaust tubing if you properly anealed the welds, Jet Hot coat, header wrap, and supported the primary?

Only ask because this would be far easier for what Im doing than the sch 40.
 
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