Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Center mount carb preheat question help
Page: 1, 2, 3, 4  Next
Forum Index -> Performance/Engines/Transmissions Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
This page may contain links to eBay where the site receives compensation.
Author Message
Hnoroian
Samba Member


Joined: October 27, 2013
Posts: 535
Location: Bakersfield
Hnoroian is offline 

PostPosted: Wed Feb 24, 2021 10:16 pm    Post subject: Center mount carb preheat question help Reply with quote

Been playing around with this for a little while and have almost found the answers but not really. Looking for anyone that has tried or experience.

Would this work with a insulated exhaust wrap to help the manifold from icing up? I do not live near the cold nor really plan trips in the cold with it (open top Baja) camping in higher altitude but never in a really big rush. Running rough for a little bit is okay. Have the battery and amperage to cover the drain.

100-200w 12v silicone heating wrap
https://www.ebay.com/itm/233873965627

I was gifted a cheap setup where the preheat ports in the manifold do not go all the away through to the other side. Yes I know exhaust preheat to the manifold is the best, efficient, and quickest and I can eventually weld the preheat tubes to the headers.
_________________
Stupid people do stupid things.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
FreeBug
Samba Member


Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
FreeBug is offline 

PostPosted: Wed Feb 24, 2021 11:46 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Back in the previous millenium, in the UK mags, there was an add for what was called an IMDU, an "Inlet Manifold De-icing Unit". It was just about what you are envisionning. I'm not sure if they worked, but I haven't seen those ads in years...
Back to top
View user's profile Send private message Gallery Classifieds Feedback
oprn
Samba Member


Joined: November 13, 2016
Posts: 12632
Location: Western Canada
oprn is offline 

PostPosted: Thu Feb 25, 2021 6:54 am    Post subject: Re: Center mount carb preheat question help Reply with quote

It would make very little if any difference. You are far better off spending the time to get the factory one working correctly.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Vanapplebomb
Samba Member


Joined: November 03, 2010
Posts: 5387
Location: Holland, MI
Vanapplebomb is offline 

PostPosted: Thu Feb 25, 2021 7:25 am    Post subject: Re: Center mount carb preheat question help Reply with quote

Yeah, I can’t imagine 200W would be enough juice to make any noticeable difference.

Can you modify the manifold so that the exhaust gas can pass through? Drill through the manifold to Connect the two side of the heater tube, then trill/tap the hole on the outside with a pipe plug?
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Cusser
Samba Member


Joined: October 02, 2006
Posts: 31266
Location: Hot Arizona
Cusser is offline 

PostPosted: Thu Feb 25, 2021 7:50 am    Post subject: Re: Center mount carb preheat question help Reply with quote

Hnoroian wrote:
Been playing around with this for a little while and have almost found the answers but not really. Looking for anyone that has tried or experience.

Would this work with a insulated exhaust wrap to help the manifold from icing up? I do not live near the cold nor really plan trips in the cold with it (open top Baja) camping in higher altitude but never in a really big rush. Running rough for a little bit is okay. Have the battery and amperage to cover the drain.

100-200w 12v silicone heating wrap
https://www.ebay.com/itm/233873965627


I've thought of such myself, but haven't tried, would be interested in the responses.

I have a single Weber 40DCNF on a matching intake manifold that never had any pre-heat tubes at all (purchased 1976 from Claude's Buggies/CB) on my 1835cc engine, and mine definitely runs better in the first 5 minutes in summer than in winter. Note that the 40DCNF has no choke either.
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Hnoroian
Samba Member


Joined: October 27, 2013
Posts: 535
Location: Bakersfield
Hnoroian is offline 

PostPosted: Thu Feb 25, 2021 10:51 am    Post subject: Re: Center mount carb preheat question help Reply with quote

Thanks for the replies.

I’m willing to try, but by the time I get to it it will be spring and summer again, so next winter it will be ready. I have a few more things I’d like to do first and then worry about the preheat.

It is a cheaper 44IDF I have had for a while, cleaned and rebuilt and actually did pretty good. It is on a 1915cc. For the maybe once a year or so that I may need it seems like a bandaid alternative for free/cheap parts that will get by, and not out much money or length of time.

I have switched over from dual carbs which was nice, (both require a rebuild as they have clogged with silt dust). But the darn linkages (hexbar) had too much slop and always tinkering with them. Don’t mind syncing them but getting covered with mud and whatnot always bugged me. After the rebuild considering putting on center pull as I continue to read about them.
_________________
Stupid people do stupid things.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
74 Thing
Samba Member


Joined: September 02, 2004
Posts: 7369

74 Thing is online now 

PostPosted: Thu Feb 25, 2021 12:02 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Best for a preheater set up is one that flows through all the way and one of the tubes is rerouted to the header collector so it actually pulls exhaust gas through.

With a header the air will not flow properly since the connections are at the #2 and #4 exhaust. There are many threads on this modification and aircooled.net used to offer headers with this modification (not sure if they still do). Here are some photos in the gallery of the modification to the header: https://www.thesamba.com/vw/forum/album_search.php...t_dir=DESC
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Hnoroian
Samba Member


Joined: October 27, 2013
Posts: 535
Location: Bakersfield
Hnoroian is offline 

PostPosted: Thu Feb 25, 2021 1:22 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

I realize that the connection needs to go all the way though in the manifold (positive and negative pressure) but I don’t think the one I have is capable of doing so, but will look again.

Might have solved my problem too. Some in thing that has crossed my mind is taking 3/8” or so stainless tubing and bending along the way to match the curves of the manifold and drilling/welding them in the header for a pressure and scavenger line. Then I would need to figure out how to attach to the manifold. Then again seems to be creating more work for my self for something I may never need/use.

My head spins sometimes from searching through forums, I have read and searched many...

Question, where would it start to ice up? Right below the carb, downdrafts at the manifold curves, or the???
_________________
Stupid people do stupid things.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Turnswrenches
Samba Member


Joined: May 02, 2019
Posts: 552
Location: Dawsonville, GA
Turnswrenches is offline 

PostPosted: Thu Feb 25, 2021 1:55 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Hooking up the preheat stuff as close to the factory design as possible will give best results.
As mentioned above... the aftermarket pipes with preheat flanges on #2 and #4 exhaust ports are worthless garbage. You need high pressure on one side and low pressure on the other for it to circulate. Two high pressure heat sources wont do it.
I found this out from personal experience.
I went from a cheap chinese muffler with preheat ports on #2/#4... to a nice German made Euro style stainless muffler with the crossover ports placed correctly.
The car ran 10 times better and it completely changed the jetting requirements too. A wideband O2 sensor was crucial in figuring all this out.
_________________
71 Superbeetle, stock 1641DP with Weber progressive
Railbuggy with 2332
Scat 4340 84mm crank
5.5 H-beams
Mahle 94mm pistons
AA jugs
Grant rings
CB2292 cam + straight cut gears
46/37.5 CNC Wedgeports
Pauter 1.5's
Big Beef intakes
44IDF's/38 vents
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Hnoroian
Samba Member


Joined: October 27, 2013
Posts: 535
Location: Bakersfield
Hnoroian is offline 

PostPosted: Thu Feb 25, 2021 2:20 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Lost in my bookmarks

http://www.vw-resource.com/heat_risers.html

In the end there is no real way to work this out like I would want or should.

Am I still understanding correctly? Generally wetter weather and <50*F or so starts to create this problem or around there?
_________________
Stupid people do stupid things.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
BFB
Samba Member


Joined: November 03, 2014
Posts: 1689

BFB is offline 

PostPosted: Thu Feb 25, 2021 7:13 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

i know its been discussed but cant remember seeing or hearing whether anyone has done it or not, but what about running engine oil through the intake heat channel?
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
stewartsoda
Samba Member


Joined: February 03, 2020
Posts: 88
Location: Treasure Valley, ID
stewartsoda is offline 

PostPosted: Fri Feb 26, 2021 4:01 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

richardcraineum wrote:
i know its been discussed but cant remember seeing or hearing whether anyone has done it or not, but what about running engine oil through the intake heat channel?


I heard someone mention this somewhere.

I've been thinking of doing it as part of my rebuild. I've got a Weber Progressive and I hear it (like any centermount) needs heat.

Aftermarket header, so it's either take it to the muffler shop and get it welded or I route oil through the manifold. I'm cheap, and the oil routing is just a brass fitting and some hose, so what is there to lose?
_________________
1972 Super Build
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dan the workingstiff
Samba Member


Joined: July 03, 2006
Posts: 824
Location: Downriver, MI
Dan the workingstiff is offline 

PostPosted: Fri Feb 26, 2021 4:29 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

stewartsoda wrote:
richardcraineum wrote:
i know its been discussed but cant remember seeing or hearing whether anyone has done it or not, but what about running engine oil through the intake heat channel?


I heard someone mention this somewhere.

I've been thinking of doing it as part of my rebuild. I've got a Weber Progressive and I hear it (like any centermount) needs heat.

Aftermarket header, so it's either take it to the muffler shop and get it welded or I route oil through the manifold. I'm cheap, and the oil routing is just a brass fitting and some hose, so what is there to lose?

I'm not cheap, but I'll save money where I can definitely. I've thought about this also. I was thinking of wrapping 3/8 tubing around the manifold. Exhaust is way hotter sooner....
_________________
'69 Beetle
'66 FG buggy
My other air-cooled's
'76 IH 1200
'75 IH 1200
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Alstrup
Samba Member


Joined: July 12, 2007
Posts: 7177
Location: Videbaek Denmark
Alstrup is offline 

PostPosted: Fri Feb 26, 2021 5:03 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Wrapping the header and the preheat tubes will make a difference, but it is not really worth it unless you are in a very cold ambient.
If you have a header with the pre heat hook up on 2/4 which goes directly to the exhaust, the way to make it work the best is to drill a 12-13 mm hole im the right flange and a 10 mm hole in the left. By doing that you ensure that the exhaust is mainly moving in one direction instead of just pulsing back and forth.
An extractor tube like the ones John@ Aircooled.net sells (or used to, I´m not sure he still hasém) is of course numero uno.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Brian_e
Samba Member


Joined: July 28, 2009
Posts: 3227
Location: Rapid City, SD
Brian_e is offline 

PostPosted: Fri Feb 26, 2021 5:09 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

I did this a long time ago. It made a huge difference keeping the carb and the top of the manifold warmer.
Image may have been reduced in size. Click image to view fullscreen.


Brian
_________________
www.type-emotorsports.com
Back to top
View user's profile Send private message Visit poster's website Facebook Instagram Gallery Classifieds Feedback
Alstrup
Samba Member


Joined: July 12, 2007
Posts: 7177
Location: Videbaek Denmark
Alstrup is offline 

PostPosted: Fri Feb 26, 2021 5:16 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Hehe Very Happy
Maybe you can start a new line of tupperware sales.

I´m imagining the sales lady: "And this model also works very well for your husbands vintage VW in the wintertime." - Wifey thinks, Hmmm, good excuse for spending a little money Cool

But I hear ya! I have seen a couple of redneck solutions too, which actually worked well.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
BFB
Samba Member


Joined: November 03, 2014
Posts: 1689

BFB is offline 

PostPosted: Fri Feb 26, 2021 5:22 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

oh shit! that is awesome! i love the tupperware intake, thats the coolest thing ive seen in a while.
wheres the intake hose attached to?

also about the preheat tubes, i bought a dozen or so of the small hole copper gaskets a while back and run one on one side and a normal on the other. i have no idea if its better or not but it does make sense to me...
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Alstrup
Samba Member


Joined: July 12, 2007
Posts: 7177
Location: Videbaek Denmark
Alstrup is offline 

PostPosted: Fri Feb 26, 2021 5:28 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

IMHO the hole in the copper gasket is too small.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Brian_e
Samba Member


Joined: July 28, 2009
Posts: 3227
Location: Rapid City, SD
Brian_e is offline 

PostPosted: Fri Feb 26, 2021 5:31 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

richardcraineum wrote:
wheres the intake hose attached to?


It goes down through the stock pre-heat hole and sucks in hot air from the cylinders and header area under the tin.

Brian
_________________
www.type-emotorsports.com
Back to top
View user's profile Send private message Visit poster's website Facebook Instagram Gallery Classifieds Feedback
QRP
Samba Member


Joined: April 27, 2008
Posts: 1703
Location: NORTH HOLLYWOOD,CA
QRP is offline 

PostPosted: Fri Feb 26, 2021 5:56 pm    Post subject: Re: Center mount carb preheat question help Reply with quote

Brian_e wrote:
I did this a long time ago. It made a huge difference keeping the carb and the top of the manifold warmer.
Image may have been reduced in size. Click image to view fullscreen.


Brian


That is great! . . Thinking outside the box or maybe inside the Tupperware or . . . LOL
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Performance/Engines/Transmissions All times are Mountain Standard Time/Pacific Daylight Savings Time
Page: 1, 2, 3, 4  Next
Page 1 of 4

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.