Exhaust diameter question...
Thread Starter
Intermediate
Joined: May 2005
Posts: 37
Likes: 0
From: Post Falls ID
Exhaust diameter question...
Hi all,
Im new to this forum and appreciate all of the helpful information i have gotten here and have a couple of questions...
I just had a set of Hooker 2149 LT headers, high flow cats, and x-pipe installed on my LT1. The entire exhaust is 3" until after the x-pipe, where it is stepped down to 2.5" back to the mufflers because I had the catback done a year ago. The magnaflow's are 2.5" inlet and 2.25" single-to-duel-tip outlet diameter. My questions are:
1) What kind of effect is stepping down from 3" to 2.5" going to have since my motor is currently stock internally?
2) There are 2 standard, non mandral, bends in the pipes leading up to the mufflers. Will this be a big problem?
3) What kind of HP (estimated) increase can I expect from this set-up in combination with my existing mods (K&N, cut lid, TB coolant bypass, TB airfoil, magnaflow mufflers)?
Thanks in advance
Im new to this forum and appreciate all of the helpful information i have gotten here and have a couple of questions...
I just had a set of Hooker 2149 LT headers, high flow cats, and x-pipe installed on my LT1. The entire exhaust is 3" until after the x-pipe, where it is stepped down to 2.5" back to the mufflers because I had the catback done a year ago. The magnaflow's are 2.5" inlet and 2.25" single-to-duel-tip outlet diameter. My questions are:
1) What kind of effect is stepping down from 3" to 2.5" going to have since my motor is currently stock internally?
2) There are 2 standard, non mandral, bends in the pipes leading up to the mufflers. Will this be a big problem?
3) What kind of HP (estimated) increase can I expect from this set-up in combination with my existing mods (K&N, cut lid, TB coolant bypass, TB airfoil, magnaflow mufflers)?
Thanks in advance
Last edited by 96VettMan; May 31, 2005 at 04:37 PM.
Pro
Joined: Jan 2004
Posts: 707
Likes: 0
From: Syracuse Utah
I think your biggest problem is the 2.25 outlet size on the muffler. That will back everything up. The x-pipe will help some; the two bends in front of the muffler are not very relevent considering the outlet size; just guessing but I would surmize you are probably getting 20-25 hp gain from this combo.
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by 96VettMan
1) What kind of effect is stepping down from 3" to 2.5" going to have since my motor is currently stock internally?
Not enough to lose sleep over.
2) There are 2 standard, non mandral, bends in the pipes leading up to the mufflers. Will this be a big problem?
No, not a big problem. Not ideal...but no big problem.
3) What kind of HP (estimated) increase can I expect from this set-up in combination with my existing mods (K&N, cut lid, TB coolant bypass, TB airfoil, magnaflow mufflers)?
Since none of the existing mods make any difference in power production, I'll go along with hotred's estimate of about 20hp. Certainly no more than that.
Thanks in advance
Not enough to lose sleep over.
2) There are 2 standard, non mandral, bends in the pipes leading up to the mufflers. Will this be a big problem?
No, not a big problem. Not ideal...but no big problem.
3) What kind of HP (estimated) increase can I expect from this set-up in combination with my existing mods (K&N, cut lid, TB coolant bypass, TB airfoil, magnaflow mufflers)?
Since none of the existing mods make any difference in power production, I'll go along with hotred's estimate of about 20hp. Certainly no more than that.
Thanks in advance
Larry
code5coupe
Thread Starter
Intermediate
Joined: May 2005
Posts: 37
Likes: 0
From: Post Falls ID
Foolcrzy,
Yes, I had all emissions hookups modified to work with the 2149's, including AIR. Installing and modifying the AIR hookups was time consuming but worked well. I haven't taken pics yet, but will post one as soon as i get home tonight. The car getting the 2.5" piping and 2.25" mufflers removed right now and will have 3" all the way back this afternoon.
65Z01,
The mufflers were single center-in and single offset-out magnaflow's with a 2.5" inlet and outlet. The y-pipe that went from the single out to dual tips was only 2.25". This setup really made the car quiet considering it's mods and I am hoping that this new setup will make it much louder.
Yes, I had all emissions hookups modified to work with the 2149's, including AIR. Installing and modifying the AIR hookups was time consuming but worked well. I haven't taken pics yet, but will post one as soon as i get home tonight. The car getting the 2.5" piping and 2.25" mufflers removed right now and will have 3" all the way back this afternoon.
65Z01,
The mufflers were single center-in and single offset-out magnaflow's with a 2.5" inlet and outlet. The y-pipe that went from the single out to dual tips was only 2.25". This setup really made the car quiet considering it's mods and I am hoping that this new setup will make it much louder.
Last edited by 96VettMan; Jun 2, 2005 at 12:00 PM.
Burning Brakes
Joined: Jun 2002
Posts: 1,159
Likes: 0
From: royal palm beach florida
Originally Posted by 65Z01
Stepping from 3" to 2 1/2" on a 150hp (1/2 of 300 with duals) motor will not be a problem.
So your mufflers have a single outlet as well as a single inlet??
So your mufflers have a single outlet as well as a single inlet??
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You should WANT your pipe diameter to decrease as it moves towards the back, and 2.5" on that engine will not cause a power loss by any means. Only if you had something extremely radical would you really need the 3" or more going back. The 2.25" piece is probably hurting flow some, but if she puts out the sound you want, who cares, its not like changing that to 2.5" is really going to give you alot of power back.
I'd expect 20ish hp from the whole exhaust.
I'd expect 20ish hp from the whole exhaust.
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
i would guess about 20 at the wheels assuming everything else is in good working order. if you had a manual in ur 96 i would say maybe a hair over 25. thats what i am hoping for when i do my longtube headers the end of this month
