question on exhaust pressure.

twoguns simply aircooled

4,275 posts · joined Nov 2002 · 5 Feb 2006, 9:06 pm

#453856

hey guys. i dont know if i am thinking stupid or what.

for interest sake today i fitted a set of exhaust set that i had lying in the shed waiting for another ride. they are four independant exhaust pipes with just a small tip baffle on each.

anywya after fitting i started the car and yes besides being very loud, i was curious...

why is it that the two outside pipes being the ones exiting from the rear (closest to the back of car) of my engine heads produced more air pressure than the two exiting the front (nearest the gear box) of my engine heads? putting my hand to each of the pipes, i could feel a very noticeable difference .

is this normal or is it a sign of something not tuned right or something else, or nothing?

Simply Cruzin'...

Purple Martin Fahrvergnugen

913 posts · joined Feb 2003 · 6 Feb 2006, 8:16 am

#453921

Are they all the same length? If they are then I would have thought the pressures would all be the same.

I'm currently rebuilding my kombi's motor because one camshaft lobe wore out: the result was that the two exhaust valves which are controlled by that lobe (one valve on each side) didn't open, so the motor only ran on two cylinders. Maybe you should check all your valves: make sure the closed tappet clearances are right, AND measure how much each valve lifts.

1959 red & white Beetle
1975 Kombi camper

blup58 Officially Full-On Dubber

216 posts · joined Oct 2002 · 6 Feb 2006, 2:53 pm

#454010

Are all the pipes the same diametre?

shiftyvw Wolfsburg Wizard

523 posts · joined Sep 2002 · 6 Feb 2006, 5:44 pm

#454040

whats the engine like? a lot of kadron equipped motors tend to idle more on 2 cylinders, especially with anything much larger than a stock cam.

testing 1 2 3...

tassupervee That really hurts doesnt it!

1,171 posts · joined Sep 2003 · 6 Feb 2006, 5:45 pm

#454041

Indicates that the two pipes are different lengths to the others.
Whether its a good or bad thing can only be shown on a dyno.
Dont sweat it.
The eaxct same thing happens at the end of the collector pipe on my equal length, (and I mean, equal length) merged collector setup on the F-Vee.
Depending on the different tuned lengths, the tailpipe can actually appear to "suck"!!

However, the power difference is almost unnoticeable at the end of the day.

L8tr
E

Im not a complete idiot, quite a few parts are missing....

twoguns simply aircooled

4,275 posts · joined Nov 2002 · 6 Feb 2006, 5:57 pm

#454046

shiftyvw wrote:whats the engine like? a lot of kadron equipped motors tend to idle more on 2 cylinders, especially with anything much larger than a stock cam.

it is larger than stock cam, plus prted heads and kads. so you could be right. the pipes are same diameter but maybe a little diff in length. we its running though it is still going sweeet.

thanks guys.

Simply Cruzin'...