Kooks LT's installed now slower and less BOOST

[alexgg2]

I've just installed the new style Kooks headers with kooks high flow catted x-pipe, slp loud mouth catback exhaust and my car now feels like 30-40hp slower at mid to top rpms. Lower RPM's do feel quicker. I have Billet Flow 2.76" pulley and that thing used to whine loud and now you cant here it all with new exhaust setup. The old exhaust setup was stock manifolds, O/R X-pipe and Flowmaster Catback exhaust. I did notice a drop in boost guage around 2-2.5lbs of boost after install. I have been told that boost drop off is normal with header install due to less back pressure but is 2-2.5lbs of boost drop of normal. Would switching back to flowmaster catback give it more back pressure and add a little boost over slp loudmouth catback exhuast.

Kooks Headers 1 5/8" with 2.5" collector
Kooks Catted X-Pipe 2.5" Collector 2.5" Out
SLP Loudmouth I Catback Exhaust

 

[My96z]

Have you taken the car to the dyno or track to verify this? If the car is making less boost you have more airflow through the engine, thats a good thing. I think you have about the loudest exhaust set-up money can buy cept for the catted pipe lol.

I wouldnt add any different mufflers to add backpressure, unless you just want to quiet things down. I am not a big fan of the glass pack type mufflers like the magnapacks or the loudmouths. They dont sound good to my ear and they are loud. If you wanna quiet it down some go with a oval, full sized magnaflow or a dynomax ultraflow welded. They are a straight through design so they wont hurt flow and they are much quieter.

Is your blower ported? I dont think you can go to a smaller pulley to get your boost back. Do they make a smaller one for the eaton? Have you had the tune looked at to see if it needs tweaking now that it has the better flowing longtubes?

 

[alexgg2]

Have you taken the car to the dyno or track to verify this? If the car is making less boost you have more airflow through the engine, thats a good thing. I think you have about the loudest exhaust set-up money can buy cept for the catted pipe lol.

I wouldnt add any different mufflers to add backpressure, unless you just want to quiet things down. I am not a big fan of the glass pack type mufflers like the magnapacks or the loudmouths. They dont sound good to my ear and they are loud. If you wanna quiet it down some go with a oval, full sized magnaflow or a dynomax ultraflow welded. They are a straight through design so they wont hurt flow and they are much quieter.

Is your blower ported? I dont think you can go to a smaller pulley to get your boost back. Do they make a smaller one for the eaton? Have you had the tune looked at to see if it needs tweaking now that it has the better flowing longtubes?

I haven't taken car for dyno tune yet. I do have an Auto Meter Wide Band O2. In 2nd gear it reads 11.5 and 11.7 when its at 6000-6500rpms. In 3rd it reads 10.5 A/F ratio. I didn't have a wide bade O2 installed before so dont know the numbers b4 new exhaust install. The better airflow makes sense to why its building up less boost now I just have to add a 2lb lower Metco Crank Pulley to make up for the lost boost and/or port the supercharger. This is when I will take car in for a new tune.

The new exhaust setup really isn't loud at idle and normal driving, only at WOT the exhaust is insanely loud and could be why I dont here the supercharger anymore but not sure. At idle the new exhaust setup is quieter than with stock manifolds, o/r x-pipe and flowmaster catback. I did notice the engine runs smoother when idling and sounds quieter under the hood.

 

[99BOSS]

Port that blower and add the 2lb lower. The headers will really come into their own when you push more air into the engine. You'll get your boost back but more importantly, you've made your setup more efficient.

 

[mach1033]

You need to have your tune adjusted to your new set up.

 

[Blueline]

Yeah def. going to need a re-tune. You made the engine more efficient, so now you can up the boost and make more power. I would love to make 800rwhp on 1 psi of boost, if you get the idea. Im going with Kooks headers and x pipe in the very near future. How bad was the install?

 

[svtaddict]

i just replaced my gaskets last week for my longtubes same work as installing them it sucks. takes a whole weekend if everything goes well by yourself and taking your time one day if you bust ass the. invest in one of those cradles to hold the motor up i wish i did

 

[mach1033]

Yeah def. going to need a re-tune. You made the engine more efficient, so now you can up the boost and make more power. I would love to make 800rwhp on 1 psi of boost, if you get the idea. Im going with Kooks headers and x pipe in the very near future. How bad was the install?

Are you going 3 inch?

 

[Blueline]

Al I'm thinking 3" collector to a 3" x pipe which tapers down to 2.5 to keep my borlas. Who knows maybe I'll go 3" all the way out :banana:

 

[alexgg2]

Yeah def. going to need a re-tune. You made the engine more efficient, so now you can up the boost and make more power. I would love to make 800rwhp on 1 psi of boost, if you get the idea. Im going with Kooks headers and x pipe in the very near future. How bad was the install?

Install of kooks headers ways a pain in the a**. Lots of modifications to make them fit. I had to bend 1 header tube to make steering shaft slide in, I barely bent tube anything since I didnt want it to mess up the flow just enough to help but still steering shaft would not slide in. I even pried tubes apart and tried to slide steering shaft as per instructions w/ no luck. Finally It just came to me that I should just grind steering shaft knuckles down and make them round instead of square and steering shaft slid right in. Does not affect steering shaft knuckle strength at all since the knuckle is really thick metal even after grinding it round. Another problem I encountered was aligning EGR tube, Trick here is to install EGR tube 1st then bolt headers to head. You will struggle alot if you try to bolt headers to head then try to install EGR tube. Driver motor mount is also another problem, motor mount can not be installed without cutting one of the bolts shorter or notching the motor mount bolt hole so motor mount slides in. I notched mine since I had left the bolt screwed into motor so I wouldn't lose track of bolts and where they went. I couldn't remove bolt anymore since header was in the way so I just notched motor mount which is really thick and wont affect strength. This will make it easier if you ever need to change motor mounts as header removal will not be needed. After install I noticed the white plastic piece on steering shaft was touching one of the tubes so I just cut it off and it gave steering shaft plenty of clearance between header tubes. You dont want plastic burning under hood. Last issue was struggling to slide dip stick back in, kind of difficult but needs to be slid back in from top engine compartment with a little maneuvering. Passenger header no issues. Other people have had no issues with install but some have. I have the newer design kooks with collector that hangs a little higher than older style kooks headers. With a 1 3/4" primary and 3" collector you may have more issues installing. Get an engine bar from harbor freight tools, it will make it much easier to install, you dont want an engine hoist as the hoist legs will be in your way.

 

[dirtyCobra]

whats the easiest way to attach the engine to the engine support beam i cant seem to figure out a good way to do it the bst ive come up with is to just wrap a tow strap around the block and then run it up to the beam!??:shrug:

 

[alexgg2]

whats the easiest way to attach the engine to the engine support beam i cant seem to figure out a good way to do it the bst ive come up with is to just wrap a tow strap around the block and then run it up to the beam!??:shrug:

I used the chains that came with engine support beam and ran them down front of engine and used oil pan bolts to support block. You have to remove the rear crank belt for this or chains wont slide down straight.

 

[zincslowbra]

<slp L/T's wit 2.8 and loudmouth wit C/L and accu still see 14.5 #s, and yes a WOT is like a nascar wit the headers the blower is loudest cruising around 1500 rpms

 

[10sec89]

Chain it to the studs at the top inside of the cam covers, also holds the coolant crossover tube.

 

[Anabolic]

i was running 10-11psi with mac longtubes/offroad x and 3" chambered catback

switched to catted H with longtubes and 2.5" slp resonators..

went to 12-13psi... it's all the faster the exhaust releases the gasses.. less boost but more HP potential.. more restrictive system more boost build up because it's not releasing as fast,
make sense?

 

[earico]

i was running 10-11psi with mac longtubes/offroad x and 3" chambered catback

switched to catted H with longtubes and 2.5" slp resonators..

went to 12-13psi... it's all the faster the exhaust releases the gasses.. less boost but more HP potential.. more restrictive system more boost build up because it's not releasing as fast,
make sense?

^ This.

Boost is just a measure of resistance. It is not a measurement of power. Get the car tuned for the longtubes. You may only gain 5 hp with an Eaton though. You really need to move more air to take full advantage of them.

One thing that will help is a decrease in heat. Boost/resistance creates heat. Less boost will create less heat. This is a good thing especially on these motors that are known to run on the hot side.

 

[Anabolic]

^ you can say that again, mine's mad and spitting at me :-/