Manifold piping size

General automotive discussion

Manifold piping size

Postby Afterthought » Fri Nov 09, 2018 9:04 am

I’m getting set up to make a manifold or two . I have some weld Ells in 1.5 npd schedule 10 321 stainless. Now that I have them in front of me they look awfully big.
.Wondering if I should be doing 1.25 or 1.5 ID sch 10 pipe for a medium HP I-5 Build .
Image
Last edited by Afterthought on Fri Nov 09, 2018 2:27 pm, edited 1 time in total.
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby DE80q » Fri Nov 09, 2018 10:46 am

That depends on what you are going for. If your looking to squeeze the last bits from the top end of a high reving motor, than stay with the 1.5". If your looking for higher flow, but trying to keep the exhaust vocity up, step down to the 1.25". The manifold that is being made for my 10v is using 1.25" runners.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (10vt project)
2007 Mitsubishi Raider(Dakota in disguise)
2014 Chevy traverse (It's what she wanted)
DE80q
 
Posts: 2212
Joined: Mar 4, 2013
Location: York PA 17403

Re: Manifold piping size

Postby Afterthought » Fri Nov 09, 2018 11:10 am

Nice you are doing a custom one for a 10V ?

Bad ass
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby DE80q » Fri Nov 09, 2018 11:53 am

Afterthought wrote:Nice you are doing a custom one for a 10V ?

Bad ass

Kind of, it's a stock location piece. Should have much better flow, and hopefully not crack. I've already repaired my factory one, and it has started to crack again.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (10vt project)
2007 Mitsubishi Raider(Dakota in disguise)
2014 Chevy traverse (It's what she wanted)
DE80q
 
Posts: 2212
Joined: Mar 4, 2013
Location: York PA 17403

Re: Manifold piping size

Postby Afterthought » Fri Nov 09, 2018 1:19 pm

Nice that’s pretty cool . So like the log header but tubular Instead of cast .

I guess regarding my header what I should do is look and see if there is any sort of calculators using like exhaust valve size and port size, desired HP or VE , displacement , no of cylinders etc. but all I can find is for NA

I was curious if there was any sort of accepted size , I’m assuming at some point there’s a volume vs velocity , like 1.25 may spool better but would max out at some point . Don’t know , maybe I’ll measure the exhaust ports . I mean if it’s going into a turbo it’s going through a collector anyways and necks down in size
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby audifreakjim » Fri Nov 09, 2018 5:11 pm

There was a comparison done at some point. The conclusion was, 1.25" is more than enough. Hank uses 1.25" on all of his headers, that's what I have on mine too. His 1.25" is almost 900 wheel and just trapped 154 in the 1/4. So that should work for ya :)
User avatar
audifreakjim
 
Posts: 2045
Joined: Mar 3, 2013

Manifold piping size

Postby Afterthought » Fri Nov 09, 2018 6:03 pm

audifreakjim wrote:There was a comparison done at some point. The conclusion was, 1.25" is more than enough. Hank uses 1.25" on all of his headers, that's what I have on mine too. His 1.25" is almost 900 wheel and just trapped 154 in the 1/4. So that should work for ya :)


10-4 thanks Jim. Holy sh!t he’s almost into the 8’s.
I guess I can use the 1.5 for the non Audi LS project I have .
It looks doable but the OD of that is like 1.9 so it’s a lot of pipe to fit in there
Now I have to figure out how to make a merge collector .
Need to identify and make a paper temple for this that I can overlay and scribe then make these cuts . Will report back in about a month
Image
Image
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby PRY4SNO » Fri Nov 09, 2018 9:26 pm

That's where your book of ordinates will pay for itself!
Find me on Instagram @pry4sno

|| 2010 Golf Sportwagen TDI /// Farmenwagen
|| 1992 80 quattro 20v /// Eventual AAN'd Winter Sled
|| 1990 Coupe quattro /// Because Racecar

|| Spare parts for sale
User avatar
PRY4SNO
 
Posts: 2099
Joined: Mar 3, 2013
Location: Edmonton, AB

Re: Manifold piping size

Postby Afterthought » Sun Nov 11, 2018 8:24 pm

It’s taken me forever, 2 scrap papers , the Internet , an old book, and probably wasted a lot of time but I think I understand now what I need to do.
Image
Image

If I remove all but 1.8849” of the pipe I will have 1.8849 x 5 which equals a 3” dia circle
So if my math is right (not for sure) I need to remove 1.89.
Which means each cut will be 72 degrees apart .
For he merge angle I think I can go anywhere from like 12-20 deg depending on packaging .
So , now I need this or something similar . Or make a jig using 1/2” square tuning that fits into my bandsaw at a set angle .
Image
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby Afterthought » Sun Nov 11, 2018 8:25 pm

It’s taken me forever, 2 scrap papers , the Internet , an old book, and probably wasted a lot of time but I think I understand now what I need to do.
Image
Image

If I remove all but 1.8849” of the pipe I will have 1.8849 x 5 which equals a 3” dia circle
So if my math is right (not for sure) I need to remove 1.89.
Which means each cut will be 72 degrees apart .
For he merge angle I think I can go anywhere from like 12-20 deg depending on packaging .
So , now I need this or something similar . Or make a jig using 1/2” square tuning that fits into my bandsaw at a set angle .
Image
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby audifreakjim » Mon Nov 12, 2018 12:07 pm

Hey Pat, when I built my header I did the collector first in PVC. At the end of the day it just took a little trial and error to get it right based on my chop saw I was using. Size doesn't matter, grab something close to it and test away. The angles are the same regardless.
User avatar
audifreakjim
 
Posts: 2045
Joined: Mar 3, 2013

Re: Manifold piping size

Postby speeding-g60 » Mon Nov 12, 2018 12:45 pm

User avatar
speeding-g60
 
Posts: 2141
Joined: Mar 1, 2013

Re: Manifold piping size

Postby Afterthought » Mon Nov 12, 2018 1:09 pm

I bought the PVC in 1-1/4 , it’s very close in OD .

That LPS piece is really nice , it says pre-order for 355.00 and ships this month .
Before I order I am going to experiment a little . Still waiting for the 1-1/4 pipe to show up so all I have now is 1.5” .

Wondering about the difference in spool between the two. Looking at header applications I see a lot of people using both , it certainly appears that 1.25 is enough and won’t be limiting .
Also working on drawing up some intake and exhaust flanges in Fusion360.

This will open up a lot of possibilities
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa

Re: Manifold piping size

Postby PRY4SNO » Mon Nov 12, 2018 1:58 pm

Pat, don't forget it's 1.25 x 5. Most people opt for a 3" turbo back exhaust. 1.25 ought to be plenty.
Find me on Instagram @pry4sno

|| 2010 Golf Sportwagen TDI /// Farmenwagen
|| 1992 80 quattro 20v /// Eventual AAN'd Winter Sled
|| 1990 Coupe quattro /// Because Racecar

|| Spare parts for sale
User avatar
PRY4SNO
 
Posts: 2099
Joined: Mar 3, 2013
Location: Edmonton, AB

Re: Manifold piping size

Postby dougkehl » Mon Nov 12, 2018 6:22 pm

Fushion360 is a great program. I actually have the base flange for the flange for the intake drawn out on 360.

Anyway, 1.25" pipe as others have said ought to be enough. Especially considering 1.25" schedule 10 pipe has an ID of like 1.44" which is not limiting at all!
dougkehl
 
Posts: 98
Joined: May 2, 2017

Re: Manifold piping size

Postby Afterthought » Mon Nov 12, 2018 7:03 pm

dougkehl wrote:Fushion360 is a great program. I actually have the base flange for the flange for the intake drawn out on 360.

Anyway, 1.25" pipe as others have said ought to be enough. Especially considering 1.25" schedule 10 pipe has an ID of like 1.44" which is not limiting at all!

I have a good start on some stuff but it’s a really steep learning curve . I mean when I get stuck on one tiny little thing I realllllly get suck.
I tried drawing the pipe intersection too which took forever but it’s all just practice.
Image
Image
Image


Sent from my iPhone using Tapatalk
****
Afterthought

1983 UrQuattro - http://theprojectpad.com/viewtopic.php?f=11&t=1819&p=72513#p72513
1983 Ur Quattro Amazon Blue / Zebra MC
GMC 2500HD
Afterthought
 
Posts: 845
Joined: Jan 16, 2014
Location: Bellingham, Wa


Return to General

Who is online

Users browsing this forum: No registered users and 1 guest

cron