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Sun Jan 10, 2010 5:26 pm

Hi

New to the site, been reading a few months now though.

First question....I have just taken off my exhaust (broke during New Years visit to Ocotillo Wells :( ).

I have looked at replacements in all of the usual places in So Cal, but am confused by the extra small flanges on the top side of the exhaust, just adjacent to the larger rear flanges that fit to the head.

Most of the replacements do not have these extra flanges, can I just block of the small existing flanges or do I need to do something else?

Thanks in advance.

Sun Jan 10, 2010 5:51 pm

Those are probably your heat riser tubes. You can block them if you want but cold starts will suck.

Sun Jan 10, 2010 6:12 pm

vdub411 wrote: Those are probably your heat riser tubes. You can block them if you want but cold starts will suck.

Thanks for the quick reply. :)

So I can just make a small steel plate to block them and bolt it on then?

BTW Cold starts are not much of a problem here, unlike my home country at the moment, where it is bloody freezing cold!!! :P

Sun Jan 10, 2010 6:14 pm

If you mean the ones that come from a tube that goes to the carb manifold, as stated above you dont really need them, being in So. Cal. :) There are block off kits you can buy. They are heat risers, they provide heat to the carb for the purpose of warming up, If you want to run them you can fab up something.

Sun Jan 10, 2010 7:24 pm

Nicksan wrote: If you mean the ones that come from a tube that goes to the carb manifold, as stated above you dont really need them, being in So. Cal. :) There are block off kits you can buy. They are heat risers, they provide heat to the carb for the purpose of warming up, If you want to run them you can fab up something.

They are the very ones :)

Thanks for the information regarding being able to buy block off kits for them, just checked it out and found them for just over 4 dollars.

Not worth me fabbing them up.

Sun Jan 10, 2010 9:43 pm

Most of the headers you will find that have these heat riser connectors are not functional off the shelf. The fittings are just welded on, without a hole being drilled in the tubing in case you don't need them.
If you have dual carbs and don't need the pre-heat, then just cut them off.
If you have a single center-mount carb, you will want to drill a hole thru the tubing and then connect 'em to your heat risers.

Mon Jan 11, 2010 8:32 am

sxuxrxf wrote: Most of the headers you will find that have these heat riser connectors are not functional off the shelf. The fittings are just welded on, without a hole being drilled in the tubing in case you don't need them.
If you have dual carbs and don't need the pre-heat, then just cut them off.
If you have a single center-mount carb, you will want to drill a hole thru the tubing and then connect 'em to your heat risers.

I do have the single center mount carb, and the fittings do have holes in them, but the replacement exhaust systems that I have looked at do not have them, so I will just block them off.

I guess the times I am going to need pre-heat here are pretty negligible, so I am not going to worry about to much about that.

Mon Jan 11, 2010 12:22 pm

What carb are you running, not that it matters, because all single carbs need the heat risers to heat the carb to prevent icing. It's not just when the engine is cold.
The fuel needs to be warm to make the journey from the carb, down the runners to the head and remain atomized. If the fuel is cold it turns back into liquid form and is just wasted through the exhaust because it doesn't burn properly.

Dual carbs don't have this issue because they sit directly on the head, which is also hot, and the fuel vapor drops right into the cylinder.

You stated that your current exhaust has the fittings, are they hooked to the risers? If not, try hooking them up. You may find it runs considerably better.

I did plenty of research when setting up my single 44 Weber and had to fab my own preheat to ensure that it would run as good as a single can run.
Read more here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=333608&postdays=0&postorder=asc&start=0

Mon Jan 11, 2010 1:13 pm

sxuxrxf wrote: What carb are you running, not that it matters, because all single carbs need the heat risers to heat the carb to prevent icing. It's not just when the engine is cold.
The fuel needs to be warm to make the journey from the carb, down the runners to the head and remain atomized. If the fuel is cold it turns back into liquid form and is just wasted through the exhaust because it doesn't burn properly.

Dual carbs don't have this issue because they sit directly on the head, which is also hot, and the fuel vapor drops right into the cylinder.

You stated that your current exhaust has the fittings, are they hooked to the risers? If not, try hooking them up. You may find it runs considerably better.

I did plenty of research when setting up my single 44 Weber and had to fab my own preheat to ensure that it would run as good as a single can run.
Read more here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=333608&postdays=0&postorder=asc&start=0

Thanks for the tips.

The existing exhaust had them hooked up, and runs well.

I have been looking at a lot of the 'off road' exhaust systems and none of them have these heat risers points.

I am away out to buy the exhaust system today (The pleasure of living close to several dealers) and the block off kits, and will talk to them about it also.

Thanks for the help guys