Heat riser pressure

alien8 Wolfsburg Wizard

521 posts · joined Sep 2008 · 15 Jun 2009, 6:27 pm

#718651

I noticed on my aftermarket headers the heat riser inlets where not drilled. I was reading some old posts that suggested that headers don't have pressure but they pulse instead. If I were to drill the inlets out should I drill a smaller hole on one side or just try and drill them as large as possible?

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 16 Jun 2009, 7:05 am

#718745

drill as large as possible so the gas flows n wont block up the tube

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 16 Jun 2009, 7:05 am

#718746

drill as large as possible so the gas flows n wont block up the tube

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 16 Jun 2009, 7:32 am

#718749

The gas will only puls as both the tap off points are at the same pressure.

If you look at stock ones the RHS take off point is next to cylinder #2 where as the LHS connection there is actually a tube that takes it to a low pressure point near the collector
This means the exhaust "flows" from right to left

Common headers have RHS take off at #2 and LHS at #4
So at best the gas "pulses" back and forth

Be carefull drilling as the blanked off bit is on a curve

Also most of the take offs are not welded properly and are not fully sealed

Personally - living in Qld i would think it is all THAT important
But yes - it is better if you can do it properly

Futue te ipsum!!!

alien8 Wolfsburg Wizard

521 posts · joined Sep 2008 · 16 Jun 2009, 11:51 am

#718781

So, a return to a stock system is sounding pretty good.

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 16 Jun 2009, 12:14 pm

#718783

Depends what you want

Is you carb icing up??

Headers will/should give "some" gain over stock

As i said before, i would be surprised if there wasnt enough conduction of heat to warm up the risers.
mine doesnt "sizzle" when moisture is placed there but it is hot to hold
I am running the stainless steel VW type header thing that fits in the stock position

I dont get icing and it was single digits here in Sydney this morning

Futue te ipsum!!!

alien8 Wolfsburg Wizard

521 posts · joined Sep 2008 · 16 Jun 2009, 1:35 pm

#718794

I had a aftermarket Thunderbird quiet system on my 1600 tp for the last month and a half and it never seemed right. Not that there is a fault with the headers as they are pretty well made I think. It just dosnt seem to run well. I have noticed condensation around the manifold and bottom of the carb. I guess it must be the cold humidity up here or somthing.

Anyway I put the stock system back on last night and cleaned out the riser pipe. I must say its running like a dream. I have been driving it all morning and the missus noticed the difference straight away when she did the school run. It seems to have more pickup.

I must add that this is only my experience with my car as I am sure other people have had good success with aftermarket systems but I think I am going to leave the stock setup on there for now. Maybe I should drill the riser inlet on the headers and test that. Nar I think I'am done.

Anyone want a Thunderbird quiet type system?

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 · 16 Jun 2009, 1:36 pm

#718795

alien8 wrote:I noticed on my aftermarket headers the heat riser inlets where not drilled. I was reading some old posts that suggested that headers don't have pressure but they pulse instead. If I were to drill the inlets out should I drill a smaller hole on one side or just try and drill them as large as possible?

On My VW muffler the exhaust flows from the left at the exhaust port across to the RHS where it exits into the muffler via a pipe..

LEE

- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 16 Jun 2009, 2:09 pm

#718800

if you look at the heat riser take off on the RHS it is tapped into where #2 exhausts

On the LHS you can see the pipe weave its way down and disappears near where the gasses exit to atmosphere

1 attachment · Log in to view

Futue te ipsum!!!

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 16 Jun 2009, 4:57 pm

#718833

Semi autos use the mex style with the exit on the rightside for ATF pump clearance

Brad you would need to do some slight jetting changes to make the best of that exhaust
its the same thunderbird quietpack i run and its 1.5" which is enough to warrant a jetting change

properly tuned and setup you shouldnt have dramas with icing, there will always be a bit of sweating below the carb, thats normal
i ran a quiet pack on a stock 1600 for years and im only an hour south of you so no change in climate and never had probs with icing
naturally its not as good as a stock muffler setup but i was happy enough with the performance and economy gains that an occasional rough idle didnt worry me

colonel mustard Son of Jim - Creator of Good

2,829 posts · joined Feb 2009 · 16 Jun 2009, 5:13 pm

#718838

alien8 wrote:Anyone want a Thunderbird quiet type system?

Photo's and how much...

alien8 Wolfsburg Wizard

521 posts · joined Sep 2008 · 16 Jun 2009, 5:21 pm

#718842

Hey Joel, Yeah I played around with the jetting, a lot. Convinced myself that it was cause of the 009 so I got a SVDA, which was the best thing I could do regardless.Thought it was a bad coil, dud carb, vac leak, point, plugs etc, etc. Just couldn't get it to run just right. I did eliminate a lot of the problems I was having. I mean it wasn't running totally bad, just enough to be annoying.

When I first got the car it ran great. It had a worn 34/3 and a 009 with a stock exhaust and stunk of petrol but it ran really well. Better than recently and with all the money I had spent on "upgrades". I will try a different system in the future but for now the stockie rules!

alien8 Wolfsburg Wizard

521 posts · joined Sep 2008 · 16 Jun 2009, 5:48 pm

#718847

colonel mustard wrote:
alien8 wrote:Anyone want a Thunderbird quiet type system?
Photo's and how much...

Pics tonight.
$130

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 16 Jun 2009, 5:50 pm

#718849

generally with a stock carb the stock exhaust works best

if u want to go extractors on a stock 1600 then 1 3/8" works best just stay away from empi systems