dual 40 series!!!low back pressure????

Discussion in 'GM Powertrain' started by 1995 silverado, May 9, 2009.

  1. 1995 silverado

    1995 silverado New Member

    aloha everyone!! so recent upgrades include a set of hooker comp headers and dual flowmaster 40 series exhaust! all of this on a stock 305... the truck sounds good at idle, but get on the gas a little and it sounds like a train coming through! but at the same time, it feels as though it lost some power on the low end, the truck makes a whole hell of a lot of noise, but doesnt seem like its moving the way it should. any ideas??? did i go too big on the exhaust??? thanks!!!:confused:
     
  2. heavy chevy

    heavy chevy Epic Member 5+ Years 500 Posts ROTM Winner

    Did you run the exhaust all the way out. Also what gears do you have in the truck. You cant expect a 305 to just blow the doors off. You may not be getting as much air in as you a pushing out. I suggest getting a cai.
     
  3. 1995 silverado

    1995 silverado New Member

    the gears are stock gears, not too sure of the ratio... i have a k&n airfilter in it...did you change the gears in yours? i was thinking of doing the gears, but not sure what to get... i know i want to change it to a posi, but for the ratio, maybe a 383??
     
  4. 1995 silverado

    1995 silverado New Member

    oh yah, cai? what is that?? sorry, i think i have to do more homework on this stuff... haha!!
     
  5. 1995 silverado

    1995 silverado New Member

    :tussor:i got it!! cold air intake... hahahaha!!! what a rookie!!!
     
  6. 1_low_rider

    1_low_rider Rockstar 100 Posts

    i have the same problem, you need to google about BACKPRESSURE and read up on that. im not going to try and explain it but it can have some negative effects on torque when you change the exhaust from stock, depending on how its done.
     
  7. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    Are your headers shortys or long tube? How big of pipes did your run and how was the exhaust set up?
     
  8. 1995 silverado

    1995 silverado New Member

    thanks for the info! it just sounds like the straw is too big for the spitwad! haha! now how to correct that is another thing!
     
  9. 1995 silverado

    1995 silverado New Member

    the headers are full length, the pipe is a 3" up and over the rear end not quite a 45 to the tips. but it is a true dual. from the headers, both individual pipes run to the passenger side of the truck, then straight back. right behind the tail gate, the pipes split to 45s then down. does this make sense??
     
  10. 1_low_rider

    1_low_rider Rockstar 100 Posts

    2 options for correcting it, A) change the exhaust setup, or B) increase engine power to raise exhaust flow.......or do like me and get used to it cause u know you like the way it sounds and you dont wanna change it!!!
     

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