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Kooks Header Advice/Experiences

3K views 23 replies 12 participants last post by  RockyMtG8GT 
#1 ·
After a lot of reading, I think I've decided to go with Kooks Mids vs LT. My thoughts on this:

1. ~10hp difference is acceptable to me
2. Cost is way better than with LT and all the extra bits/work
3. Sound - A little louder is OK, a LOT is not unless only at WOT.

Some requirements for me:

1. Stay legal for NC emissions inspection - Someone please let me know
2. I have Solo Mach Catback and will be keeping it, so I want something that will mate right up. Can someone let me know if this assumption is correct or will I still need some kind of connection pipe? Was thinking the stock cats are just removed and replaced with the mids/HFC combo.
3. Internal engine sounds - Is this much more noticeable? I'm kind of picky about stuff like this and don't what to hear a lot of clattering valves, etc. Any input on this would be welcome.

If I keep this car long enough, I may turn it into a real beast (V8 supercar), but for the foreseeable future, need it to be a good DD as well, so nothing too extreme. I need to be able to do this in stages as $ permits like most I would imagine, so I want stuff that I do to carry over when I also get a cam later. Then I want the cam to carry over when and if I ever S/C the car. I know some will say LT if you ever plan on doing this stuff down the road, but from what I've read the mids will work just fine with cam and S/C but just might be leaving a bit on the table vs LT with same setup. So, any input on #3 up top and the 3 requirements would be appreciated so I know my assumptions are either correct or not. Thanks.
 
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#2 ·
I have kooks mids with solo shorty and have passed nc emissions with it. It will mate rightup to the solo. As far as sound... it is a little louder inside and you can hear the bacon grilling sound but it isnt too bad.

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#3 ·
I switched from stock manifolds/Solo HFC's/Mach shorty to the Kooks mids/HFC's. Long range plan was to go FI. Didn't give the long tubes much thought because I didn't want clearance issues.
I haven't noticed any appreciable increase in under the hood noise at all.
I did notice that the AFM/DOD noise seemed to be more noticeable, but you can shut it off.
Someone else will have to chime in on how well the Cortex tune will work with/support that setup.
 
#7 ·
Someone else will have to chime in on how well the Cortex tune will work with/support that setup.
Definitely won't be using that anymore (at least on the G8) after this work is done. Generally not a good idea to do so after headers or anything past that. Planning to get Rick C. to get the most out of the setup once I have the parts selected and purchased.
 
#5 ·
I didn't go w/ kooks mids I got JBA 1-3/4" long tubes instead...price was also a factor for me and I already had a custom pieced together catback so I didn't want to have to hack that up and retrofit kooks LT's + connection..and the JBA's don't hang low at all as theyr'e not as "long".

I can tell you on my setup (mods in sig magnaflows) - with NO cats, it is louder from outside the car on cold startup but sounds good, at partial throttle (like 1/3 cruising style) it is no louder in the cabin if not quieter since I had AFM tuned out. At WOT it sounds meaner/better - louder? yeah I guess, but not terrible.

You will hear the pinging of the headers but it subides some as they warm up and is less noticeable from inside the cabin.

Get them you won't be disappointed. As far as HP increase...by the way guys talk on this forum LT's get you 40whp....from my experience this is simply not the case. On the dyno I got my mods tuned on stock G8 GT's put down between 280-290whp. After the mods in sig I'm at 344hp/356tq (mustang dyno). A dynojet would probably read 10hp higher at least. It is the cumulative effect of the mods you will notice, it isn't like headers are a 30-40hp boost in themselves, they need the intake/tune/catback to see full results.
 
#6 ·
Thanks for the input so far. Good to know this setup will pass inspection.

Keep the advice coming...I need to listen to a car with mids in person to determine if I can deal with the increase in internal engine noise.
 
#8 ·
Its really not going to be that loud man, if you want the kooks mids get 'em. It'll be louder at initial startup and from outside the car, internal engine noise increase will be minimal and will sound sweet @ WOT.

Whatever "negatives" you may potentially incur by adding headers are far outweighed by all the benefits. I promise.

Also - in regards to inspection - even w/ my catless longtubes I can pass a "sniffer' emissions test @ idle, obviously I won't pass a visual test, but somehow or another my tuner is able to trick an emissions test into a pass even without cats
 
#9 ·
So what do you all think on coated vs. not?

I understand that they are not supposed to NEED it, but I know it will keep things cooler. I guess some do it so they don't get to looking bad after a while too. Just not really sure it's worth it or not.
 
#10 ·
Boston just did a thread with "coated or not" discussion and you might want to check it out.

I had my kooks dip-coated from Jet-Hot. They still "look new" after a year and a half (including winters, this is my daily driver) and the heat dissapation is amazing when they're coated. Since mine were dipped, it's a continuous layer of the ceramic coating, inside and out, completely. Others have done the spray-on-tan version, I do not have experience with this. The insides of the exhaust system after a little while will start to "carbon up" so benefits of coating the inside as well as the outside, donno.

I have heard reports for people who attempt the cheaper means of "coating headers" that sometimes that method flakes off due to the flexing of the stainless steel underneith with the normal heat cycles. I can confirm first hand that the dipped method does not flake unless you physically damage a section with a hammer or road debris or something like that.

Check out Boston's discussion from last week on coat-or-not-to-coat.
 
#14 ·
Boston just did a thread with "coated or not" discussion and you might want to check it out.
Thanks. I'll look it up.

Just remember to buy them from MarylandSpeed:)
Was planning to...I hear you can give great prices over the phone, but I just ordered something from you guys the other day so I better wait a bit so as to not call undue attention to my purchases lol!
 
#15 ·
I had Kooks 1-3/4 long tubes mated up with Kooks catted connection pipes to a Corsa cat-back on my GT. A combo I got from Maryland Speed back in 2009. I ran this setup for > 1 year before I sold the car, and had no issues with it at all. It was of course pretty loud but IMO no drone unless DoD kicked in.

I am pretty sensitive to drone as my 1st exhaust mod was a set of Pypes axle-backs mated to the stock system that droned noticeably and I had take them off after 2 weeks.

Also, I don't see a point int the Kooks mids. They really look more like shorties and all other things being equal, including a tune, your gains would likely be only about 10 WHP.
 
#16 ·
Also, I don't see a point int the Kooks mids. They really look more like shorties and all other things being equal, including a tune, your gains would likely be only about 10 WHP.
Wow, the Mids just keep going down and down in #s don't they? Pretty soon people will be saying they yield ZERO hp gains.

This is a false statement. I dyno'd around ~30 hp increase with the addition of the Kooks Mids to my set up. Not to mention a brand new handful of high end torque. Maryland Speed can chime in on their great results with the Mids on their GXP as well.

It's not just a Shorty header, it's a Shorty + Elbow Flange + HFCs.
 
#18 ·
1. Yes legal, I passed here with them
2. Cost wasn't bad, I think they had a price increase since I ordered them though, and they mate to all catbacks with no modifications needed.
3. I don't remember if you heard mine or not. It was increased a bit at startup and idle, sounded almost cammed. The WOT was impressive to say the least. I had the mach shorty though so a bit louder than your setup would be.

They will leave a little on the table if you do go supercharged or cammed or both, but there are quite a few G8's doing fine with all of the above.

My .02 on this setup was I absolutely loved it if you want to keep your exhaust from being cut up this is your best option. I can answer most questions you have PM me if you have to. Shame I still don't have the car so you can drive it and hear it.

My recommendations to get would also be a set of wire socks to protect your spark plug wires from the headers. I burnt one of mine and got them after learning the hard way.
 
#24 ·
I've also been pondering over this for a while and I continue to lean towards getting the Kooks Mids.
I love how my stock with Solo axle backs sounds, the perfect muscle yet not obnoxious sound levels. I'd rather spend ~$800 and be done than twice that much for LT's and mid pipe and then have to get rid of my solos because it would be too loud for me. Yes, I'll probably modify my stock mid pipe by getting rid of the crimped piping between mid muffler and hot dog resonators. I was thinking about keeping the mid muffler and putting an x pipe in place of the resonators.....
Anyways, I've heard nothing but great reviews for Kooks Mids and also heard you're only giving up 10-15 hp to Kooks LTs.... If I was all about being the fastest and chasing every tenth in the 1/4 then I'd go for LTs but I'm just a family guy with a modern day muscle car so I'm most likely going Kooks Mids.
 
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