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where to start with exhaust ?

EHB

EHB

New member
ok this might sound like a dumb question , but i want to start replacing my rusty exhaust system but do to my budget restraints , i'll have to do it one piece at a time , so my concern is with making sure that what i buy will match up with what is stock ( 2000 GTP) until i get to the next part. i'm not trying to build a drag racer , just maybe improve the fuel mileage and overall performance and have something that won't need replaced in a few years like regular mufflers do . so do i start at the manifold with a zzp plog (headers are to pricey for me) and then go downpipe ? or maybe start with a downpipe ?
 
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Try and start out with Speed Daddy headers. I run them and they're good. I think they cost like $217 shipped which really isn't much more than a plog/downpipe combo if anything it could be cheaper.
 
I didn't really have a problem. the only problem with the install i had was because the previous user of the headers had a 45* elbow on it and did some custom stuff. Coming new from speed daddy they shouldn't be too hard at all.
 
sd headers cost less then a plog and dp from zzp. headers dont come with a new cat, so if you need one have a hi flow one installed. they are like 50 on ebay.
 


Headers would be a good start but you'll need a tune once you get them installed. The tune will help with balancing the fuel curve/lean mixture throughout the RPM range. If headers and a tune are cost prohibitive, then a good downpipe that eliminates the "u bend" will be best as this is the most restrictive part of the exhaust system.
 
Start with the front and work your way back. If things don't line up, you can always adjust it as you go further back. I had ZERO problems with my SD install by following Bill's write up, it's worth reading. And NO, you absolutely do NOT need a tune after headers.
 


most likely i'll just go with the plog and downpipe .i'm just lookin to replace the rusted up exhaust system that's going to need done soon anyway. the plog looks like a lot less hassle than headers and as i stated i'm not trying to build a race car so i probably won't be going to far with the mods if i do any at all. my reason for starting this thread was my concern for what will bolt up with the existing exhaust system as i start replacing the system a piece at a time. i don't own a welder so does everything just bolt up ? will the 2 1/2 " downpipe just bolt onto the cross over and the piece behind it? should i get the catted downpipe ?
how many pieces are there ? what order do they bolt up ?
1 plog
2 cross over
3 downpipe
4 resonator ?
5 y pipe ?
6 mufflers ?
 
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everything is welded on a factor cat back.

do it part by part will end up costing more in the long run due to al the extra trips to the shop to weld parts in.

ebay has some cheap cat back, like 250 shipped.

cat back is a res, intermediate pipe AKA Y pipe, and 2 mufflers.
 
Anyone care to explain why a tune is not necessary? I put SLP long tubes on my GTO along with a cold air kit and had it dyno tuned afterwards. The car was loud before the tune... After 6 pulls and a drive with the lap top hooked up, it was more quiet and I gained about 20 HP. The tune helped lean the fuel mixture across the RPM band and tied all of the mods together to get the most out of them. I would assume that a GTP with headers or some other manifold mod, air filter replacement, and down pipe replacement would benefit from a tune of some sort, similar to any other car. Maybe a tune is not required, but very beneficial?
 


WickedGoat said:
Anyone care to explain why a tune is not necessary? I put SLP long tubes on my GTO along with a cold air kit and had it dyno tuned afterwards. The car was loud before the tune... After 6 pulls and a drive with the lap top hooked up, it was more quiet and I gained about 20 HP. The tune helped lean the fuel mixture across the RPM band and tied all of the mods together to get the most out of them. I would assume that a GTP with headers or some other manifold mod, air filter replacement, and down pipe replacement would benefit from a tune of some sort, similar to any other car. Maybe a tune is not required, but very beneficial?
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I agree with your principal statement: that tuning could be beneficial after headers/exhaust work. But unless you already have access to tuning software (ie.already own hp tuners or dhp) I wouldn't pay for a tune for just exhaust work and a Cai or Hai. Once you drop pulleys then definitely. But how much is a dyno tune? 500? Overkill pcm is 200 minimum still. Not worth it for just flow mods.

Drop pulleys, then tune at the same time. If your not doing that then roll as is.
 
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