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3 Inch Downpipe |
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| Pictured to the
right is the 3" JT stainless steal downpipe plus adapter. The downpipe and
adapter replace parts 2 and 3 pictured below. Installation is very easy,
unbolt the stock catalytic converter and flex pipe and bolt up the new
downpipe. This setup does not contain a catalytic converter. I was
planning on purchasing and installing one myself, but upon installation it
became clear that there is not enough room to install a catalytic
converter. With my current setup of the Saab 2.5" cat-back exhaust and the 3" downpipe without catalytic convert I am very happy with the sound of my exhaust. It's a nice rumble that is not so loud as to turn heads, I have even gotten some complements on it. |
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| The benefit of a
3" downpipe is to eliminate back pressure. The performance gain should not
be focused on the 10 or so horsepower increase, but instead on the reduced
spool up time. Spool up is now much quicker. I performed a test before I
installed the 3" downpipe; traveling at 40 mph in 3rd gear with boost at 0
psi, I floored it and counted the seconds to full boost (15 psi). It took
just under 4 seconds to reach max boost. After installing the 3" downpipe
I performed the same test, spool up time now takes 1.5 seconds to reach
max boost. There is one problem with this downpipe, it does not have a spot to screw in the second oxygen sensor. I was surprised to discover this when I received the pipe, however this was not a big problem for me because I have access to a machine shop where I cut a hole and welded on a bolt for the oxygen sensor to screw into. Running without the second sensor with cause a check engine light. I inquired at a local exhaust shop and was told that the charge for a bolt to be welded on was $25, also that it could be done with the downpipe already installed with the Saab on a lifter. The 3" Downpipe should be installed after or in conjunction with a sport cat back exhaust. Cost: $314 From Engstrom + ~$25 To Weld On Bolt Time: 45 min Difficulty: Easy |
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| The most cost effective way
to purchase the JT downpipe is to buy it without a cat and have one
installed later. I also found that it was too loud without a cat. I drove
around a few weeks before I had a cat installed and the noise level was a
little embarrassing. The smallest 3” catalytic converter that I could find is 14” long and oval shaped. This is still too large to safely fit in the same location as the stock cat. To fit the new catalytic converter it must be installed further back on the exhaust system. I have indicated the location where I installed the cat on the picture to the right. The cost of the 3” cat was $45 and a link is provided below. A local exhaust shop at a cost of $50 performed the installation and they were able to install the cat without removing the exhaust. The final step was relocating the second O2 sensor behind the cat, otherwise a check engine light would illuminate. The exhaust shop also installed a bung after the cat but the O2 sensor wires are not long enough to reach. The wires must be extended but it is a very simple task. |
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