Open Down Pipes Bad???
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From: Chattanooga,TN
Open Down Pipes Bad??? I have an Incon TT kit and have open down pipes right now. The pipes run about a foot from the turbos. Will this hurt anything? I like the way it sounds and Im sure it helps performance aswell.
Thanks
Thanks
It shouldn't be a bad thing. The turbo may spool a bit quicker since it is shorter. On the GN's, guys with open down pipes have them about 4-5 feet long. I think as a rule (and I can be wrong) that the exhaust outlet has to extend past the flywheel to be NHRA legal.
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The reason why your supposed to have "X" feet of exhaust on N/A engines is so that your dont burn the valves up from lack of back pressure... since you got two turbos at the end of your manifolds creating back pressure you are good to go! I ran my GN open down pipe for a year before I got tired of it!
On my buddies whipple mustang we saw 22rwhp on the dyno from uncapping his dumps at the headers. Forced induction loves open exhaust!
On my buddies whipple mustang we saw 22rwhp on the dyno from uncapping his dumps at the headers. Forced induction loves open exhaust!
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I used to run an open downpipe on a 89 turbo trans am for years with no problems, just turbo noise.
I don't think u would run into a problem with an open dump. plus u will get quicker spoolup and possibly an increase in boost, keep an eye on it.
I don't think u would run into a problem with an open dump. plus u will get quicker spoolup and possibly an increase in boost, keep an eye on it.
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Oh and hey everyone, first post here, i popped on over from ls1gto.com
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im thinking of going the same, just a straigh-through pipe after the turbos, but I am wondering how loud the sound of that thing would be. I know single turbos tend to do a better job at contolling the sound level, but with small twins, I might need a muffler, or Ill have to work out a custom exhaust to utilize the stock butterflies to work.
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Two potential problems we have had that may or may not be to the open down pipe.
1. We think the down pipe is making the knock sensors read false knock
2. We think the down pipe being so short is burning out the wide band faster
Our down pipe is all of 8" or so and dumps in front of the cross member. Reason for the thought on number 1 is when tuning it was picking up knock even with a VERY conservative tune up and low boost (2-3 psi). Thought gas was the issue so we drained the tank and tried again, same problem. Checked the brand new plugs, nothing wrong there, so we concluded that it COULD be the issue. Reason for number two is the wide band is only about t2 inches from the end of the pipe. Couple that with it being a 4" pipe when you get off the throttle air is bound to go back onto the sensor. We built an exhaust for the car, that's why the sensor is so far down the down pipe, but had clearance issues so never put it on. Other than our not so common problems (that may or may not be from the short open down pipe) there really is no negatives. Its not as loud as you would think either when driving normal.
Sean
1. We think the down pipe is making the knock sensors read false knock
2. We think the down pipe being so short is burning out the wide band faster
Our down pipe is all of 8" or so and dumps in front of the cross member. Reason for the thought on number 1 is when tuning it was picking up knock even with a VERY conservative tune up and low boost (2-3 psi). Thought gas was the issue so we drained the tank and tried again, same problem. Checked the brand new plugs, nothing wrong there, so we concluded that it COULD be the issue. Reason for number two is the wide band is only about t2 inches from the end of the pipe. Couple that with it being a 4" pipe when you get off the throttle air is bound to go back onto the sensor. We built an exhaust for the car, that's why the sensor is so far down the down pipe, but had clearance issues so never put it on. Other than our not so common problems (that may or may not be from the short open down pipe) there really is no negatives. Its not as loud as you would think either when driving normal.
Sean
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From: Dubai
Two potential problems we have had that may or may not be to the open down pipe.
1. We think the down pipe is making the knock sensors read false knock
2. We think the down pipe being so short is burning out the wide band faster
Our down pipe is all of 8" or so and dumps in front of the cross member. Reason for the thought on number 1 is when tuning it was picking up knock even with a VERY conservative tune up and low boost (2-3 psi). Thought gas was the issue so we drained the tank and tried again, same problem. Checked the brand new plugs, nothing wrong there, so we concluded that it COULD be the issue. Reason for number two is the wide band is only about t2 inches from the end of the pipe. Couple that with it being a 4" pipe when you get off the throttle air is bound to go back onto the sensor. We built an exhaust for the car, that's why the sensor is so far down the down pipe, but had clearance issues so never put it on. Other than our not so common problems (that may or may not be from the short open down pipe) there really is no negatives. Its not as loud as you would think either when driving normal.
Sean
1. We think the down pipe is making the knock sensors read false knock
2. We think the down pipe being so short is burning out the wide band faster
Our down pipe is all of 8" or so and dumps in front of the cross member. Reason for the thought on number 1 is when tuning it was picking up knock even with a VERY conservative tune up and low boost (2-3 psi). Thought gas was the issue so we drained the tank and tried again, same problem. Checked the brand new plugs, nothing wrong there, so we concluded that it COULD be the issue. Reason for number two is the wide band is only about t2 inches from the end of the pipe. Couple that with it being a 4" pipe when you get off the throttle air is bound to go back onto the sensor. We built an exhaust for the car, that's why the sensor is so far down the down pipe, but had clearance issues so never put it on. Other than our not so common problems (that may or may not be from the short open down pipe) there really is no negatives. Its not as loud as you would think either when driving normal.
Sean
Single turbo or twins?
