LT Headers and stock exhaust

[skates15]

Will LT Headers pair well with stock exhaust on 23 Bighorn 5.7 crew cab? Or will stock restrict the LT headers and I'll need a new exhaust?
Thanks.

 

[Wild one]

The factory muffler isn't really what you'd call a high performance muffler,but it's better then alot of chambered after market mufflers. You want a muffler you can look through from end to end,which most baffled mufflers are

 

[skates15]

The factory muffler isn't really what you'd call a high performance muffler,but it's better then alot of chambered after market mufflers. You want a muffler you can look through from end to end,which most baffled mufflers are

Thanks. I was planning to go with Corsa Sport exhaust with the LT headers, but I'd prefer to add the exhaust later due to costs.
I was thinking LT and custom tune, then add the Corsa Sport later.

I can't imagine I would need a second tune when adding just the new exhaust?

 

[CanuckRam1313]

^^^ This!

My $0.02 on doing an exhaust upgrade and going LT's....

Have a great exhaust shop that specializes in custom exhaust put in a 3" system with high flow cats (or not if they're not required), an X-pipe, performance muffler of your choice (or go true duals ), remove the resonators and put a set of 5" tips on (if you have the dual out rear bumper).

Doing this set up and having a HP Tuners tune set up by a trusted source, you'll net some nice gains and one heck of a sweet sound out of your HEMI.

 

[skates15]

^^^ This!

My $0.02 on doing an exhaust upgrade and going LT's....

Have a great exhaust shop that specializes in custom exhaust put in a 3" system with high flow cats (or not if they're not required), an X-pipe, performance muffler of your choice (or go true duals ), remove the resonators and put a set of 5" tips on (if you have the dual out rear bumper).

Doing this set up and having a HP Tuners tune set up by a trusted source, you'll nest some nice gains and one heck of a sweet sound out of your HEMI.

What's the advantage of the custom exhaust? Costs or dialing in the sound you want? I didn't want to go much louder than stock, no drone, which is why I was looking at Corsa Sport, but I'm game for customization if better?

 

[CanuckRam1313]

I'm a junkie when it comes to exhaust functionality...lol

LT's, as we know, provide a nice gain in performance when paired with a great tuning product and tuner.

Yes, one can absolutely just bolt LT's up to a stock exhaust (edit..okay, not just a direct bolt up...lol...you'll need some custom exhaust work), perhaps change the muffler for a little bit more enhancement in flow and sound, but you're still rocking stock pipe sizing.

I went with a nice Magnaflow 3" cat back system (with their 14" performance muffler) that also deletes the resonators. Great sound and some miniscule gains, but my HEMI sounds better

I then had a custom y-pipe made, and that was a significant improvement on flow and sound, too. And then added 5" dual tips that provided a nicer deep tone.

If I could go LT's it would be done as I described it, to net as much of a gain as possible and to really get some nice sound as well.

A full custom exhaust is something else for sure and does provide performance gains overall. But it's not an inexpensive venture to go down that road.

If you're not looking for heavy gains and just want a subtle sound improvement and don't want to purchase the LT's, HP Tuners equipment and have it tuned...

Keep the stock manifolds until they fail (and they will), then put in some AFE shorty's...but... perhaps look at a custom y-pipe, a nice cat back system of your choice, and some nice tips in the interim.

 

[Wild one]

Not many shops are set up to do mandrel bends,and the last thing you want is an exhuast done with crush bends. Actually a big 3.5" single system will make more power then a set of 2.5" true duals will,as it not only will flow more exhaust,it also provides a better scavanging effect. To be an easy bolt on though that you can do on your driveway,a magnaflow set-up is tough to beat,as they use straight through mufflers that sound pretty decent.
You can run long tubes with out a tune,they just won't provide as big a gain as they will once tuned,i'd wait to tune it,till you have the complete system installed if you're going to add a catback system down the road

 

[skates15]

Main priority is HP gains hence the LT. Sound is a last priority...for some reason I thought adding a new exhaust would help with HP gains from the new headers, but it sounds like this isn't the case, in which I'd leave it with stock exhaust.
Yes to HP Tuner.

 

[Wild one]

Main priority is HP gains hence the LT. Sound is a last priority...for some reason I thought adding a new exhaust would help with HP gains from the new headers, but it sounds like this isn't the case, in which I'd leave it with stock exhaust.
Yes to HP Tuner.

The stock system after the muffler is only 2.25",it's not even a 2.5" set of pipes over the axle.So if you're looking at just chopping off the stock muffler an adding an aftermarket muffler,keep that in mind

 

[skates15]

'd wait to tune it,till you have the complete system installed if you're going to add a catback system down the road

Ah, okay. I'll wait a little longer and do it all at once, the LT, tune and exhaust.

 

[Wild one]

Ah, okay. I'll wait a little longer and do it all at once, the LT, tune and exhaust.

Are you going catless,or keeping the cats?

 

[Nick@GotExhaust]

You could always do a muffler kit with the LT's. We offer several options that would replace the stock restrictive muffler with a better flowing one and can get some better sound as well.

 

[skates15]

Are you going catless,or keeping the cats?

Cats, but MN and some counties in WI don't require smog checks. Pros/Cons of each?

 

[skates15]

You could always do a muffler kit with the LT's. We offer several options that would replace the stock restrictive muffler with a better flowing one and can get some better sound as well.

Hi Nick, yes, please, you have my PM.

 

[Wild one]

Cats, but MN and some counties in WI don't require smog checks. Pros/Cons of each?

They are the biggest restriction in the exhaust system.
They make it tough to properly mount an A/Fr gauge,as most gauges want the sensor at least 18" from the last head port,and there's no point in mounting one behind them.
They're heavy and prone to being a theft item.
About the only thing they're good for is keeping the oder down if you start it inside,lol.
As you can tell,i'm no fan of them,and have been removing them since the 70's,lol.
Even my 300 which is basically stock,except for 6.4 exhaust manifolds and midpipes is catless,lol
I don't think you guys down south can get these,but i ran these on the 1320 with long tubes and no cats for over a year with no check engine lights,then i finally got around to tuning the back 02's out,my 300 is also running a set with no codes,and it's not tuned.

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304 Stainless Steel Universal Mini Catalytic Converter Check Engine Light Fix O2 Oxygen Sensor Adapter for Exhaust Downstream Pipe - 2 Pieces : Amazon.ca: Automotive

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Amazon.ca

I think these are still available south of the border.

O2 Simulator Mini Cat Cel Fix stainless steel Rear O2 sensor simulator.

O2 Simulator Mini Cat Cel Fix, Big Daddies Garage Mini Catalytic Convertor Rear Oxygen Sensor Simulator is the best and easiestway to clear p0420 / p0430 codes for bad or missing catalytic converters. Just screw it the o2 simulator mini cat into the existing exhaust then srew in the oxygen...

www.bigdaddiesgarage.com

 

[CanuckRam1313]

Main priority is HP gains hence the LT. Sound is a last priority...for some reason I thought adding a new exhaust would help with HP gains from the new headers, but it sounds like this isn't the case, in which I'd leave it with stock exhaust.
Yes to HP Tuner.

If the main priority is TQ gains (HP means pretty much nothing ), yes, do it all at the same time and go 3" to 3.5" mandrel bent exhaust all the way through, depending if you're going single or dual exhaust.

When you get it tuned afterward it'll really wake up, too.

If you're going all out and we're spending your money for you so you can achieve TQ gains.... slap a 6.4 intake on there as well and then have it all tuned

All this said... your transmission is going to warm up a bit more with your foot into the floor...lol
Recommend the @caulk04 transmission cooler bypass upgrade and perhaps even upgrade to a PPE pan as well.

The bypass upgrade will drop your trans temps by up to 30 deg/c and drop your engine temps by 3 to 5 deg/c as well.

Add in the PPE trans pan and you'll get even better cooling.

 

[skates15]

If the main priority is TQ gains (HP means pretty much nothing ), yes, do it all at the same time and go 3" to 3.5" mandrel bent exhaust all the way through, depending if you're going single or dual exhaust.

When you get it tuned afterward it'll really wake up, too.

If you're going all out and we're spending your money for you so you can achieve TQ gains.... slap a 6.4 intake on there as well and then have it all tuned

His bypass is installed and the temps have gone way down.
I don't know anything about exhausts and so pipe size makes sense.
I was previously reading about the 6.4 manifold, which doesn't seem too expensive.

So, next week I'm replacing the rear anti sway bar, end links and torque bar.
This is for towing, but really because of the death wobble when my wife drives and hits the corners too fast, among other scary driving habits.

She likes the TQ, so she will be happy, and I'm sure ill have to replace some undies.

LT headers, exhaust, 6.4 intake, 180 Tstat, hptuner custom tune with new fan curves.

Sound about right? I didn't include CAI or throttle body as I think stock should be fine.

 

[skates15]

And thanks for all the advice, much appreciated.

 

[Wild one]

His bypass is installed and the temps have gone way down.
I don't know anything about exhausts and so pipe size makes sense.
I was previously reading about the 6.4 manifold, which doesn't seem too expensive.

So, next week I'm replacing the rear anti sway bar, end links and torque bar.
This is for towing, but really because of the death wobble when my wife drives and hits the corners too fast, among other scary driving habits.

She likes the TQ, so she will be happy, and I'm sure ill have to replace some undies.

LT headers, exhaust, 6.4 intake, 180 Tstat, hptuner custom tune with new fan curves.

Sound about right? I didn't include CAI or throttle body as I think stock should be fine.

You'll need either the stock 6.4 airbox or an aftermarket CAI to run the 6.4 manifold,as it won't hook up to your factory 5.7 airbox.
Your stock throttle body is the exact same throttle body used on the 485 horse 6.4's.
You'll need injector spacers to reuse your 5.7 injectors,with those mods stick with your stock 5.7 injectors,it's easier to tune.You can get the spacers from either Matt at Moes or Byron at MMX

 

[skates15]

You'll need either the stock 6.4 airbox or an aftermarket CAI to run the 6.4 manifold,as it won't hook up to your factory 5.7 airbox.
Your stock throttle body is the exact same throttle body used on the 485 horse 6.4's.
You'll need injector spacers to reuse your 5.7 injectors,with those mods stick with your stock 5.7 injectors,it's easier to tune.You can get the spacers from either Matt at Moes or Byron at MMX

Doesn't sound too bad overall. I will check with Moes on the spacers, any brand recommendation for the 6.4 CAI?