<VV> Ultravan's new SuperTrapp, Vacuum/Boost gauge and O2 sensor

[Dan & Synde]

Figured I'd cross-post this here as well as the Yahoo UltraGroup as there
might be some tid-bits some regular Corvair owners could use. 

The exhaust was on its last leg so it was time for a replacement. I 
knew it needed replacement when the engine was rebuilt but it wasn't 
in the budget. The existing dual exhaust system took us 1300 mile 
which included a trip to the Ventura Convention but that was just 
about it. There was severe rot around the tailpipes and the rear of 
the mufflers. Stuff was rattling around inside of them. The old 
system didn't have a crossover pipe, which is not ideal for torque, 
which is what I wanted to incorporate into the new system. 

While at the convention, I picked up a couple of 140 u-pipes for use 
in the rebuild. I decided to flip the manifolds around so they 
point directly out the rear and then use a single muffler. I 
settled on a 5" SuperTrapp muffler because it can be tuned to the 
engine and is stainless for durability. The SuperTrapp muffler has 
a 2.5" inlet. 

Over the weeks following the convention, I worked on the exhaust. I 
took the two u-pipes, cut them in half and then flipped them to 
create two z-pipes. I ordered a y-pipe from a muffler shop that was 
made to combine two 1.75" pipes into a single 2.5". I used this 
along with the modified u-pipes to create a two into one system. 

I took the old system off the Ultravan and then removed and flipped 
the exhaust manifolds around. Now the exhaust manifolds pointed 
directly out the rear. I had to slightly modify old damper door 
outlets to allow the new positioning of the exhaust manifolds. The 
new two into one system combines the output from the exhaust 
manifolds and routes it straight out the center rear. 

I had never hooked up the oxygen sensor that went with the Safeguard 
system so now was the time to hook it up. I just welded the O2 
sensor bung into the y-pipe section of the new exhaust. 

I also decided after the trip to the convention that I needed a 
vacuum gauge for those hill climbs. Cyberdyne makes a digital 
vacuum/boost gauge. What's nice about it is that it is a standard 2 
1/16" but has a resolution down to 1/10 of an inch of mercury. I 
installed that too. 

With the new O2 sensor, I now realize that I'm running a bit lean in 
the upper rpm range. It's fine at idle and cruising below about 
2500 but as the engine speed increases, it leans out a bit. I'm 
running 53 main jets but am now thinking of increasing them to 54's. 
given the new information. 

The old exhaust weighed 30 lbs and the new one weighs in at 15 lbs. 
That just about makes up for the added weight added earlier to the 
rear a-arms. 

Here's a photo set of the new exhaust from beginning to end: 

[www.flickr.com
<http://www.flickr.com/photos/81412237@N00/sets/72157606393331127/>] 

That's about it for now. Until next time...... 



Dan Kling 
1961 Greenbrier Deluxe, 110 HP, 4spd, 3.89 stump puller 
1963 Spyder Coupe, restored, converted to 4spd Saginaw 
1967 UltraVan #299, The migration has begun, we're on the road
again......Save the Whales! 

Photos of our Greenbrier, UltraVan and work-in-progress @ 

[www.flickr.com <http://www.flickr.com/photos/81412237@N00/sets/>]