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Discussion Starter · #1 ·
I have a 1998 SSE (L36) and am getting a 3" DP put on tomorrow. Until next week (hopefully) it will be an other-wise stock exhaust system (I have a 3" Magnaflow Wide Open -not installed-, but that is too big of a low end torque loss -at least it was on my old 1994 L27 SLE and 1999 SSEi).
The only engine mods right now are CAI, TR55's gapped at .058", Belden Max wires, 180* t-stat drilled 4 x 1/16", removed MAF screen. Will the 3" DP be too big or should I wait until after I do rockers, PCM, and cat?
Also, what kind of power gain should I expect with the 3" DP and high flow cat? 8-10 hp and 5-8 lb ft?
 

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it should be fine.
and your muffler will not cause any low end loss. if anythign aftermarket intakes generrally cause more of a low end loss then exhausts.
if i were you i'd buy remote cut-outs....
 

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That's actually opposite of what I have heard. As I understand it having a set amount of back pressure (most often well below what the factory supplies) and a nice open intake (most often more free flowing than the factory supplies) is a good formula for good low end torque. Could you explain how you found out what you were saying?
 

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magilson said:
That's actually opposite of what I have heard. As I understand it having a set amount of back pressure (most often well below what the factory supplies) and a nice open intake (most often more free flowing than the factory supplies) is a good formula for good low end torque. Could you explain how you found out what you were saying?
You don't want ANY back pressure. You want scavenging (a vacuum), the opposite of back pressure.
 

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why do people race cars with open headers? why do people use remote cut-outs...

with a full exhaust if it is to large in diamiter can hurt performace, it's been proven, but if you are serious about speed and are going to continue doing performance upgrades, your new dp will become more and more usefull.

i say while your at the exhaust shop have em bend you a custom pipe. Which should be the same size as your cat, unless you plan on enlarging it to 3'' to fit your new dp. usually 2.25-2.5 is best for sub 300hp na cars. Get your magnaflow on the end of it and call it a day. i'm sure it will sound awsome...i say go without the resonator but you'll proably add one on later. just my 2 cents.

oh and an age old saying, 'your exhaust only flows as much as it's least restrictive part'

good luck!
 

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Discussion Starter · #6 ·
Well, I recieved my Magnaflow cat today (Magnaflow/Car-sound part # 94106), and have my Magnaflow Wide Open Muffler 3"inlet/dual 2.5" outs(Magnaflow part # 12267) in the trunk, and the shop is waiting for my car to build the 3" DP on Friday at 1:45. I can't wait.
Next it's TB, Series III plenum, ported lower intake, rockers, OR pushrods, LS6 springs, and then Intense PCM. It's not gonna be a 1 month process, but rather 6 months (no racing in the winter). After that it's suspension and tires (already have the light-weight 18" rims).
Ah!! Cars and mods!!! :D
 

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Discussion Starter · #7 · (Edited)
Sorry about the late response, but I only had them do the 3" DP and the cat. I wanted to see how much the DP and cat helped. I plan on putting the muffler on in the spring as I won't have any use for it this winter.

As for the added power with the DP and cat (along with dumping 180 lbs from behind the drivers seat) I managed to get a worse 60' (2.47 vs a best of 2.43 in this car last month), but my E.T and MPH were helped big time.
I dropped .55 from my E.T and gained over 3 MPH.
Previous PB: 16.458 @ 84.35 (2.43s 60')

NEW PB: 15.948 @ 87.52 (2.47 60')
 

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GoldmemberBonneville said:
Sorry about the late response, but I only had them do the 3" DP and the cat. I wanted to see how much the DP and cat helped. I plan on putting the muffler on in the spring as I won't have any use for it this winter.

As for the added power with the DP and cat (along with dumping 180 lbs from behind the drivers seat) I managed to get a worse 60' (2.47 vs a best of 2.43 in this car last month), but my E.T and MPH were helped big time.
I dropped .55 from my E.T and gained over 3 MPH.
Previous PB: 16.458 @ 84.35 (2.43s 60')

NEW PB: 15.948 @ 87.52 (2.47 60')
Good to hear your changes worked. Six months of winter? Dang.
 
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