| Author |
Message |
KalgoorlieGreg
Samba Member
Joined: August 21, 2016
Posts: 45
Location: Kalgoorlie, WA, AUS.
|
 Posted: Sun Mar 19, 2017 3:06 am Post subject: Homemade exhaust, any rules? |
 |
|
Hi all,
I'd like to make my own exhaust for a fairly standard 1600DP because I want the exhaust tips set wide, not in the standard position.
It's a big topic, I have looked and come up dry. Are there any rules to what you can or can't do to get a decent exhaust system without causing more issues for myself?
Cheers, Greg. |
|
| Back to top |
|
 |
FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
|
| Posted: Sun Mar 19, 2017 3:38 am Post subject: Re: Homemade exhaust, any rules? |
|
|
Exhaust design is always a compromise. Where are you willing to compromise? Noise? Power? Torque? Money?
Your best solution might be to route pies from where the pea-shooters enter the silencer to wherever you want them to exit.
Otherwise, you could become an exhaust engineer, work ten or twenty years in the industry, and still not know everything there is to know about the "perfect" exhaust. There's a lot of litterature and a few calculators out there on the web to help.
Without more info, I can't say more, and anyways, I don't know that much on the subject. If I had to build one from scratch, I would try to build a stepped tri-Y setup with sequential mufflers, but it's a pipe dream (geddit, pipe dream?). |
|
| Back to top |
|
|
KalgoorlieGreg
Samba Member
Joined: August 21, 2016
Posts: 45
Location: Kalgoorlie, WA, AUS.
|
| Posted: Sun Mar 19, 2017 5:39 am Post subject: Re: Homemade exhaust, any rules? |
|
|
| I've seen 4 into 1 exhausts, and seen dual unmerged (one for each bank) exhausts. Would a dual exhaust merging the rear cylinder from one bank and the front cylinder from the other bank (with the idea of keeping header lengths similar), and a balance pipe joining each side, be feasible? |
|
| Back to top |
|
|
catahoula lou
Samba Member
Joined: August 30, 2008
Posts: 594
Location: south of Silver Springs, NV
|
| Posted: Sun Mar 19, 2017 6:35 am Post subject: Re: Homemade exhaust, any rules? |
|
|
The way I understand it, make sure that it's "tuned", meaning that the individual tube lengths are correct and that each burst of exhaust from the individual cylinders do not "hit" each other.
In other words, each burst should come out between the other bursts, at the same intervals, so that the exhaust is extracted(?) smoothly and efficiently.
This is for single 4/1 or dual 2/1 systems. I was told by a qualified mechanic that the dual 2/1 systems do not provide sufficient back pressure(?), may cause problems over the long haul, and that he strongly recommended the single 4/1 systems for that reason.
You may want to measure an existing tuned exhaust (along the tube center lines, for accuracy) to get a good start on lengths/ratios...
Best,
Thom
_________________
1 great wife
2 Catahoula Leopard Dogs (Mahogany Star and Spartan) - RIP Lucy, Braveheart, & Dusty!
1 1959 mango green Ragtop Bug (the "Mango")
1 1958 pantina red Lowlight Ghia (the "Chili Pepper")
Still looking for:
(1) My Dad's 1955 356 (he raced it amateur-class at Riverside and other courses during 1950s),
(2) My parent's black 1955 hardtop bug (CA license plate FWC 201 or FWG 201), and
(3) My parent's agave green 1957 ragtop bug (CA license plate LFK 734).
Last edited by catahoula lou on Sun Mar 19, 2017 6:42 am; edited 1 time in total |
|
| Back to top |
|
|
Q-Dog
Samba Member
Joined: April 05, 2010
Posts: 8698
Location: Sunset, Louisiana
|
| Posted: Sun Mar 19, 2017 6:36 am Post subject: Re: Homemade exhaust, any rules? |
|
|
| KalgoorlieGreg wrote: |
| I've seen 4 into 1 exhausts, and seen dual unmerged (one for each bank) exhausts. Would a dual exhaust merging the rear cylinder from one bank and the front cylinder from the other bank (with the idea of keeping header lengths similar), and a balance pipe joining each side, be feasible? |
Feasible? In what regard? Looks? Noise? Performance?
If you are looking for better performance then no, your proposed design would not be optimal.
The 4 into 1 merged is popular because it works. If you want to do 2 and 2, optimal would be to pair the fronts to each other and the rears to each other.
_________________
Brian
'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle |
|
| Back to top |
|
|
jpaull
Samba Member
Joined: February 22, 2005
Posts: 3459
Location: Paradise, Ca
|
| Posted: Sun Mar 19, 2017 7:29 am Post subject: Re: Homemade exhaust, any rules? |
|
|
You have a stock 1600. You dont have that much to gain or lose. If you make something worse then a $80 header then you must try really hard to mess up.
Why not start with a done header, and fab your own exhaust AFTER the flange? I would not be anxious to fab a custom header for a stock 1600. There isnt enough to gain. Cause if you want more power, your gonna need to go up on your primary tube size anyhow later.
If you would like some ideas on custom after flange exhaust, I did a short how-to:
https://www.thesamba.com/vw/forum/viewtopic.php?t=641441&highlight=
_________________
[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg
Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth. |
|
| Back to top |
|
|
kangaboy
Samba Member
Joined: August 28, 2010
Posts: 1063
Location: St. Louis, Mo
|
| Posted: Sun Mar 19, 2017 8:37 am Post subject: Re: Homemade exhaust, any rules? |
|
|
| jpaull wrote: |
| Why not start with a done header, and fab your own exhaust AFTER the flange? |
I would do this. Buy one of those 4-1 headers that you can still use your heater boxes with, and then just by a three bolt flange and weld it on whatever type of muffler you want to create. Thats what a lot of people have been doing to create their turbo exhaust on the cheap.
_________________
-74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
| skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out  |
|
|
| Back to top |
|
|
mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
|
| Posted: Sun Mar 19, 2017 2:37 pm Post subject: Re: Homemade exhaust, any rules? |
|
|
| dont go too small dont go too big. IMHO a 2" is bigenough for a street 2386. and a 2.5 inch is too big for a street 2276. |
|
| Back to top |
|
|
Casting Timmy
Samba Member
Joined: August 04, 2012
Posts: 1221
Location: Kansas City, Kansas
|
| Posted: Mon Mar 20, 2017 4:05 am Post subject: Re: Homemade exhaust, any rules? |
|
|
| Most important....hide all your receipts from the wife |
|
| Back to top |
|
|
yamaducci
Samba Member
Joined: March 30, 2010
Posts: 2335
Location: Mount Airy, Maryland
|
| Posted: Mon Mar 20, 2017 9:23 am Post subject: Re: Homemade exhaust, any rules? |
|
|
Rule#1 Make all tubes the same length. Then make it a 4 to 1.
_________________
-John Cox
My 2498 Turbo Re-Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=5578697#5578697
3rd Brake Light Safety Stars- I still have a couple with blue light left. Email me if interested. |
|
| Back to top |
|
|
Boolean
Samba Member
Joined: January 19, 2012
Posts: 1712
Location: Stockholm
|
| Posted: Mon Mar 20, 2017 9:23 pm Post subject: Re: Homemade exhaust, any rules? |
|
|
Tube primary diameter: 2" for 9000 rpm/4 cylinder, 500 cc/ cylinder engines. Decrease or increase linearly with rpm and volume. Look for primary length on the net.
Use supporting hardware like heads accordingly.
_________________
I strive for perfection. Excellence will not be tolerated!
Build thread here:
http://www.thesamba.com/vw/forum/viewtopic.php?t=529379 |
|
| Back to top |
|
|
andk5591
Samba Member
Joined: August 29, 2005
Posts: 16757
Location: State College, PA
|
| Posted: Tue Mar 21, 2017 4:36 am Post subject: Re: Homemade exhaust, any rules? |
|
|
| kangaboy wrote: |
| jpaull wrote: |
| Why not start with a done header, and fab your own exhaust AFTER the flange? |
I would do this. Buy one of those 4-1 headers that you can still use your heater boxes with, and then just by a three bolt flange and weld it on whatever type of muffler you want to create. Thats what a lot of people have been doing to create their turbo exhaust on the cheap. |
That makes the most sense....Then you can do whatever you want with mufflers and tailpipes. Try to keep the bends as gentle as you can and look at existing systems for ideas on tubing diameters. as mentioned, since its stock, you dont need massive flow. OH - dont get a big tube header - stay 1 3/8" It will perform better and will make your life easier.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them... |
|
| Back to top |
|
|
earthquake
Samba Member
Joined: January 10, 2008
Posts: 3984
Location: SANDY VALLEY, NEVADA
|
| Posted: Tue Mar 21, 2017 9:59 pm Post subject: Re: Homemade exhaust, any rules? |
|
|
Check out these guys for bends...
http://www.mandrelbends.com/mandrel-bends.html
Casey
_________________
74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]
95 Chevy C3500 dually
98 Ford E150
Link to Kelly J. Nolte 3/20/53 - 11/6/08
https://time-zonelabs.blogspot.com/p/about-kelly.html
DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison] |
|
| Back to top |
|
|
|
