Anyone have tips for a 2.8 (MT) downpipe removal?
02-21-2009, 08:20 PM
#2
a comment....
<center><img src="http://i39.tinypic.com/2lxi9sj.jpg"></center><p>You might consider having the following handy:
1)torch(see pic)
2)swivel joints(3/8 dr)
*3/8's is a bit light, but 1/2 doesn't really want to fit in there.
3)lots of drive extensions of various lengths.
4)liquid wrench or the like
Comment: Its worth having a couple swivel joints around, I usually break one during that job. The down pipe removal is not that bad and its makes the trans drop so much easier with greater access. Generally, I convert the drive on the rachet end to 1/2 so it has more torque. Prep the hardware with liquid wrench and see if they will come off with just that. Take caution, not to break a stud. There's usually lots of corrosion and they are not that big. Generally if you can torch one of them off, it takes off enough tension that the rest roll right off with a socket etc. If you can, with the torch, aim the heat away from the engine block as much as possible. Mapp gas is fairly hot and can(and will) do damage if not used properly.
Regards
1)torch(see pic)
2)swivel joints(3/8 dr)
*3/8's is a bit light, but 1/2 doesn't really want to fit in there.
3)lots of drive extensions of various lengths.
4)liquid wrench or the like
Comment: Its worth having a couple swivel joints around, I usually break one during that job. The down pipe removal is not that bad and its makes the trans drop so much easier with greater access. Generally, I convert the drive on the rachet end to 1/2 so it has more torque. Prep the hardware with liquid wrench and see if they will come off with just that. Take caution, not to break a stud. There's usually lots of corrosion and they are not that big. Generally if you can torch one of them off, it takes off enough tension that the rest roll right off with a socket etc. If you can, with the torch, aim the heat away from the engine block as much as possible. Mapp gas is fairly hot and can(and will) do damage if not used properly.
Regards
02-22-2009, 08:14 AM
#3
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Forgive me for my naivete, but why are you removing downpipes on a 2.8?
I have driven over 350,000 miles on modded Audi 2.8l engines (12v & 30v) since 1996, and I know of no benefits to modding the down pipes on a normally aspirated 2.8, unless you are installing headers (which generally alter backpressure at a tradeoff to the powercurves).
Unless you have a multi-thousand hp dragster engine which starts to melt its spark plugs after about an 1/8th mile and diesels across the finish line, normally aspirated engines need a certain amount of backpressure to function optimally, and even the multi-hundred hp NASCAR and Formula 1 engines have a certain amount of backpressure engineered into the exhaust system.
The catalytic converters and down pipes have great importance to maintaining the proper backpressure given their proximity to the engine and hot exhaust gasses versus the mufflers which have less importance due to their distance from the engine and the fact that the gasses have cooled by the time they have traveled 15 feet to the exhaust tips.
What are you up to? Sounds like you intend to remove the cats which is a bad idea for myriad reasons beyond performance.
Unless you have a multi-thousand hp dragster engine which starts to melt its spark plugs after about an 1/8th mile and diesels across the finish line, normally aspirated engines need a certain amount of backpressure to function optimally, and even the multi-hundred hp NASCAR and Formula 1 engines have a certain amount of backpressure engineered into the exhaust system.
The catalytic converters and down pipes have great importance to maintaining the proper backpressure given their proximity to the engine and hot exhaust gasses versus the mufflers which have less importance due to their distance from the engine and the fact that the gasses have cooled by the time they have traveled 15 feet to the exhaust tips.
What are you up to? Sounds like you intend to remove the cats which is a bad idea for myriad reasons beyond performance.
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