# Headers and midpipes



## campbellvt (Oct 26, 2010)

I've been looking into a solid header and midpipe solution for quite some time now. The only exhaust change made at this point was dropping the OEM mufflers completely and straight piping the gap to open her up. (funny how many compliments I get on just that sound as if I did something of great cost or effect) As soon as I return from my current deployment, I plan to have already ordered headers and midpipes because I intend to keep the stock resonator and entire catback. No real need to replace something that does exactly what it needs to. I've spoken with the guys at Kooks in NC where I'm from and considering the 1 7/8" headers with catless mids. I've also heard that you can tune out the rear O2s so I'm assuming my diablosport will handle that and I won't have to worry with codes, defaults etc. This will leave me with a fairly unrestricted system, but if it's too ridiculous I guess I can always pop in some bullet mufflers or something. Anyone have any thoughts or recommendations on my plan here? (We have emission inspection, but I'm hoping that tuning the rear sensors out will exonerate my guilt there.) Should I be looking at a different brand?


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## BWinc (Sep 21, 2005)

My only question is why do you want the 1 7/8" headers? Are you planning to go FI?


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## TheRedThing (Nov 2, 2006)

I picked up a set of Kooks 1 7/8" long tubes with the catted mids and it had a big impact on my performance and sound. The stock manifold is an anchor, not good for much else. With the long tubes, a CAI, and a dyno tune (stock cat back) I picked up over 35 hp at the wheels and about 37 lb/ft of torque. I got the 1 7/8" because I'm working my way up to a bigger cam and better heads, so I didn't want future airflow to be restricted at all.

The tune I had done removed the rear O2 sensors, so no CEL either.


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## svede1212 (Nov 1, 2005)

It won't made a lot of difference but guys seem to think that the bigger the pipe the less "restrictive" the exhaust will be and the more power it will make. Size really has to do with how much air you're pushing thru the system. You want velocity and too big of pipes slow down the gases. In headers it will make for less scavenging. Unless you plan on forced or big budget heads/cam/intake/etc and are going to drag the car with your RPM most of the time up in the 6,000-7,000 RPM range you'll be better off using 1 3/4" primaries. Even with that in the lower RPM ranges a smaller tube will make more power.


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## GuatoLT1 (Jul 22, 2009)

Hey save yourself $700 and get some jet hot coated pacesetter longtubes from maryland speed, they run $619 after the coating. Or texas speed sells them for $398 and $100 for them to coated by jet hot. Kooks will give you about 5 more horsepower when you have 400+ already 5hp doesnt matter. Im in the military too and we dont make that much to waste your money. Use some of that deployment money and get heads and a cam, youll love it.


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## GM4life (Mar 18, 2007)

svede1212 said:


> It won't made a lot of difference but guys seem to think that the bigger the pipe the less "restrictive" the exhaust will be and the more power it will make. Size really has to do with how much air you're pushing thru the system. You want velocity and too big of pipes slow down the gases. In headers it will make for less scavenging. Unless you plan on forced or big budget heads/cam/intake/etc and are going to drag the car with your RPM most of the time up in the 6,000-7,000 RPM range you'll be better off using 1 3/4" primaries. Even with that in the lower RPM ranges a smaller tube will make more power.


:agree

Smaller tube headers will make more torque on the lower end than large pipes will. Most think even with 1 7/8" with FI is best but most will never out flow 1 3/4" even with h/c and some FI.


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## svede1212 (Nov 1, 2005)

GM4life said:


> :agree
> 
> Smaller tube headers will make more torque on the lower end than large pipes will. Most think even with 1 7/8" with FI is best but most will never out flow 1 3/4" even with h/c and some FI.


The same "logic" is employed when people put 3" exhausts on stockish cars. For some reason velocity is never considered (or understood).


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## BWinc (Sep 21, 2005)

What's ya'lls take in stepped headers and what is the best application for them.


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## Poncho Dan (Jun 30, 2009)

Supposedly they work by reducing the sudden increase in pipe size when the primary reaches the collector to better maintain a scavenging/vacuum effect.

There's also two types of stepped headers - gradually increasing diameter primaries and 4-2-1 collectors (or tri-Y's some people call them).


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## campbellvt (Oct 26, 2010)

Thanks for the feedback, it definitely helps. And I concur with the cost deal, but I definitely want something for the long haul and multiple mods further down the road. Sounds like the 1 3/4 is more than suffice even with loftier upgrades. 
Any further thought on the mids? Still want to go catless and hoping that my tuner will knock out the rear O2s. (Keep in mind that my resonator will be the only piece providing even relative "restriction".)


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## BWinc (Sep 21, 2005)

If it's legal in NC to have catless mids, go for it. I'd remove the resonator and throw an X or an H pipe instead. If your tuner can't turn off the rear sensors then you need a new tuner.


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## GuatoLT1 (Jul 22, 2009)

It's not legal in any state to take you cats off. And almost every company that sells the headers sells the mid pipes with them. Pacesetter doesnt make a mid pipe with cats only catless.


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## BWinc (Sep 21, 2005)

Misspoke about "legal". "Get away with" is what I should have said.


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## GuatoLT1 (Jul 22, 2009)

Thats more like it. When I got pulled over the other day the cop said "i know you youre that guy that everyone calls the cops on". I said "hmmmm idk". I was quickly stopped and the cops said "i really dont care just letting you know". Taking off your mufflers and resinator is not a good idea if you live in vacation central like me


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## aarons1k (May 23, 2008)

campbellvt said:


> Thanks for the feedback, it definitely helps. And I concur with the cost deal, but I definitely want something for the long haul and multiple mods further down the road. Sounds like the 1 3/4 is more than suffice even with loftier upgrades.
> Any further thought on the mids? Still want to go catless and hoping that my tuner will knock out the rear O2s. (Keep in mind that my resonator will be the only piece providing even relative "restriction".)


Get a custom tune and you will never look back!!!!! They run about the same price as a handheld ! Imoa the dyno is way better and i know they can turn your rear o2's off , as far as the handheld that im not sure....


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## campbellvt (Oct 26, 2010)

Not a bad idea. Well, probably going to roll with the 1 3/4" Kooks or Stainless Works LTs, go catless on mids and as planned keep OEM catback (minus the mufflers that I already dropped.) Should be good to go and if the Dsport tuner won't turn the rear sensors off, I'll find a way to keep that from being a huge a$$ pain. I appreciate the feedback.


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## aarons1k (May 23, 2008)

FYI they told me they would turn them off for 75$... So not bad if the diablo doesnt


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## campbellvt (Oct 26, 2010)

That's good to know. Yeah, I just need to make a decision on cats vs. catless. I want to go without personally, but I'm not sure that's the best option. If I go without, the resonator will be the only thing left to "quiet" anything coming out of her. (But I'm pretty sure I'm okay with that.)


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## aarons1k (May 23, 2008)

campbellvt said:


> That's good to know. Yeah, I just need to make a decision on cats vs. catless. I want to go without personally, but I'm not sure that's the best option. If I go without, the resonator will be the only thing left to "quiet" anything coming out of her. (But I'm pretty sure I'm okay with that.)


I like my catless mids (kooks) and that I don't have admissions testing


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## Leahburk714 (Apr 22, 2010)

campbellvt said:


> Not a bad idea. Well, probably going to roll with the 1 3/4" Kooks or Stainless Works LTs, go catless on mids and as planned keep OEM catback (minus the mufflers that I already dropped.) Should be good to go and if the Dsport tuner won't turn the rear sensors off, I'll find a way to keep that from being a huge a$$ pain. I appreciate the feedback.


Two months a go I put on my Kooks headers and Catless mids, with an H pipe and flowmaster 40's mufflers, it sounds great bought the o2 extensions for the front and haven't thrown any codes and have the diablo sport as well which i found to be pretty much useless after the car gets mods. Just my little bit of input


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## Poncho Dan (Jun 30, 2009)

For $600 you can get HPT and tune your car any way you want. Plus you get credits for up to three other vehicles, or the custom 2 Bar OS and two other vehicles. A wideband will run you ~$200 extra, but for even my humble mods, I'm happy I bought a copy and street tuned it myself. It runs smoother, more efficiently, plus more power, than stock. I never put it on a dyno... I didn't feel like being disappointed or getting into a pissing match with the house tuner over how much it'd make. I'm pretty confident it's running as best as it will, at least in a forced OL 100% MAF trim. Been a year on the same tune, no issues - no AFR change, mileage drop, or KR even...


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