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Penryn
Dodge Dakota
JOIN HERE
8/17/2004
05:48:40
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 Subject: Losing low end torque?
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Message:
I keep hearing that if I open up the induction, put a better flowing exhaust on, I will lose low end torque on my 3.9.
Why is this? What causes the low end torque to disappear if you're flowing more air throug the engine (creating more power?)?
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GB2000
GenIII
8/17/2004
06:06:41
|  RE: Losing low end torque?
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Message:
You won't lose low-end for doing the intake side...but you may if your exhaust is TOO free-flowing. Why? Not enough backpressure.
Josh
http://www.cardomain.com/id/sentenced
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greyDAK
Dodge Dakota
JOIN HERE
8/17/2004
08:49:46
|  RE: Losing low end torque?
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Message:
also, if you increase the intake bore of the TB, you may loose some low end too, but its more apparent on the exhaust side. Stick to an exhaust system that is designed for your truck/engine size. On my 3.9l, with its 2.5" exhaust, I got the Midas Raven 77 series catback system (expensive, but I love it). It takes the 2.5" pipe (after cat) and expands it to 3" - through the muffler and out the back. Its a nice sounding muffler and I can really feel the extra power. I also have a 5 speed, so I dont see any low end loss at all.
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Penryn
Dodge Dakota
JOIN HERE
8/19/2004
03:32:59
| RE: Losing low end torque?
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Message:
Ok, *flipping through my exhaust book*, I understand the vacuum differences in the TB, how to get more low-end, or more HP..
I haven't gotten to the section on back pressure.. but here's where I'm stuck. A better flowing exhaust = the air moves faster, so when the exhaust valve opens, more air is sucked in through the throttle body.
Why is any back pressure at all a good thing?
Sorry guys, I can read ahead and check it out, but I wanted your opinions.
Also, if I port/polish my stock TB, will I lose some of that vacuum? I've got a dremmel that's dying to eat up a TB.
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GB2000
GenIII
8/19/2004
05:25:13
| RE: Losing low end torque?
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Message:
Engines need a certain amount of backpressure... I am far from a car buff so I can't explain why, but I do know they need a certain amount or else they won't have jack for low-end torque. Too much is bad though. And yeah, I forgot that if you go any larger than I think it's 48mm on the tb, you will lose low-end.
Josh
http://www.cardomain.com/id/sentenced
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