New Exhaust Manifold?

Jun 1, 2020
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I bought a LMM with 80k & the heads redone to put in my 2006 Sierra. I was wondering if putting performance exhaust manifolds is worth the money & if so which ones. It is my work truck and I drive across the continent regularly. I am also about to expand to doing hotshot towing.
Upgrades I have now are 30% over injectors, stage 2 turbo, all the upgraded intake & headbolts, 4" exhaust, upgraded downpipe & a tune from Dirty Diesel.
Any info to help is much appreciated

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Jun 1, 2020
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At a minimum I would suggest a GM LML driver side manifold. The 01-10 trucks have a dent in them that's unnecessary.
I saw the "dent" fix when I was looking & those were pretty cheap. These were the 2 I was tossing around. What are people's thoughts on these 2?



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Bdsankey

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I saw the "dent" fix when I was looking & those were pretty cheap. These were the 2 I was tossing around. What are people's thoughts on these 2?



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Personally I would go one of two routes for a daily driver.
1) XDP or GM LML style driver side manifold with 2" up-pipes
2) DHD or ProFab cast manifolds with 2" up-pipes

Personally option 1 will be your best "bang for the buck" as you won't see a major gain from the aftermarket style manifold on your truck but it won't hurt anything either. They do flow better and are very resilient.

The HSP billet pieces are warp prone but do flow very well. WCFab also makes a billet manifold as they bought the design from Steed Speed.
 
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Jun 1, 2020
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Personally I would go one of two routes for a daily driver.
1) XDP or GM LML style driver side manifold with 2" up-pipes
2) DHD or ProFab cast manifolds with 2" up-pipes

Personally option 1 will be your best "bang for the buck" as you won't see a major gain from the aftermarket style manifold on your truck but it won't hurt anything either. They do flow better and are very resilient.

The HSP billet pieces are warp prone but do flow very well. WCFab also makes a billet manifold as they bought the design from Steed Speed.
It is my daily atm but won't be for long. I have a Sidekick diesel conversion going in the shop soon as the truck motor is swapped. The truck will be for pulling loads across the county & jobs I will be in the road for weeks at a time.
I don't want to spend money just for fun but if spending a little extra will keep my motor safer while hauling across the country I would rather spend it than toast a motor in the middle of nowhere. I do not have enough knowledge to know what best suites my needs

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Bdsankey

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I though the cast stuff was supposed to be as good as stock ones?
HSP's and WCFab's manifolds are not cast, they are machined then welded together.


It is my daily atm but won't be for long. I have a Sidekick diesel conversion going in the shop soon as the truck motor is swapped. The truck will be for pulling loads across the county & jobs I will be in the road for weeks at a time.
I don't want to spend money just for fun but if spending a little extra will keep my motor safer while hauling across the country I would rather spend it than toast a motor in the middle of nowhere. I do not have enough knowledge to know what best suites my needs

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At 1400hp a cast manifold (ProFab on my engine) have not been a detriment. On trucks making more HP than mine they haven't been a detriment. If you want to "buy-once-cry-once" I would go DHD or ProFab and be done with it forever if you have intentions of making over 700-750whp.

If it's something you need to count on I would avoid the billet manifolds as they are still warping. I've seen them all warp except Steed Speed's version meaning I've personally seen HSP and WCFab warp causing other issues.

I'd be happy to help when the time comes, I am one of the few approved vendors/sponsors on this page.
 
Jun 1, 2020
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HSP's and WCFab's manifolds are not cast, they are machined then welded together.



At 1400hp a cast manifold (ProFab on my engine) have not been a detriment. On trucks making more HP than mine they haven't been a detriment. If you want to "buy-once-cry-once" I would go DHD or ProFab and be done with it forever if you have intentions of making over 700-750whp.

If it's something you need to count on I would avoid the billet manifolds as they are still warping. I've seen them all warp except Steed Speed's version meaning I've personally seen HSP and WCFab warp causing other issues.

I'd be happy to help when the time comes, I am one of the few approved vendors/sponsors on this page.
I do not plan on building this truck more than it is right now. I plan on swapping to a 1 ton & building a LP5 to put in it. I listed what I have done to this truck. Since it will be swapped next week I just want to help keep it cool while towing so want to buy accordingly

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Bdsankey

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I do not plan on building this truck more than it is right now. I plan on swapping to a 1 ton & building a LP5 to put in it. I listed what I have done to this truck. Since it will be swapped next week I just want to help keep it cool while towing so want to buy accordingly

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Either option will suit you well. One option is ~$400, the other is ~$800.
 

PureHybrid

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Just change the drivers manifold to the LML style and run aftermarket up pipes. That's all that Rob ran for years on the MaxD Out race truck
 
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Chevy1925

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For a stock turbo truck like you have, I wouldn’t suggest larger manifolds. Lml manifold is a good upgrade though. Maybe towflow up pipes but that’s it

Larger manifolds require more “fill” from the exhaust to begin to pressurize the exhaust and get the turbo spinning. This means more lag. On a stock turbo truck, the manifold are not the choke point and won’t benefit you like you’d think.
 
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For a stock turbo truck like you have, I wouldn’t suggest larger manifolds. Lml manifold is a good upgrade though. Maybe towflow up pipes but that’s it

Larger manifolds require more “fill” from the exhaust to begin to pressurize the exhaust and get the turbo spinning. This means more lag. On a stock turbo truck, the manifold are not the choke point and won’t benefit you like you’d think.
I appreciate the info (cuz I don't know). Did you see at the beginning I listed most of my upgrades, including a (Powermax) stage 2 turbo?

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PureHybrid

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LLY will also have a pinched manifold and an EGR riser on the passenger up pipe. Federal LB7 will be the only one without an EGR riser.
 

JoshH

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Does that mean if I order something I want an LB7 manifold?

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Manifolds are the same from 01-10. The driver's side changed in 2011 to remove the pinch, but they are all interchangeable up until 2017. 2017 and newer are not the same and cannot be used on older trucks.
 
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Lennydmaxguy

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Does that mean if I order something I want an LB7 manifold?

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Actually, it's the up pipe you want. The passenger's side is the one with the riser. And you don't need to stick to GM for up pipes. There are better aftermarket options.

But if you decide to leave the driver's side up pipe as is, it will bolt up to an LML manifold.
 
Jun 1, 2020
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Actually, it's the up pipe you want. The passenger's side is the one with the riser. And you don't need to stick to GM for up pipes. There are better aftermarket options.

But if you decide to leave the driver's side up pipe as is, it will bolt up to an LML manifold.
I replaced the up pipes long ago (I forgot to add a few upgrades to my list apparently). I want to keep the heat down because my EGT's are always the first thing to make me back off. I was going to wrap or cover whatever needed to be but my mechanic said he doesn't like to because it can hold in moisture. Is this a concern, or should I cover parts? If I should cover things then what & with what?

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Bdsankey

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I personally run blankets on the manifolds, up-pipes, and turbine housings. I cannot comment on how it effects the lifespan of the up-pipes but I have to imagine it's not an insane amount of difference as the blankets rarely get saturated with water.
 
Jun 1, 2020
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I personally run blankets on the manifolds, up-pipes, and turbine housings. I cannot comment on how it effects the lifespan of the up-pipes but I have to imagine it's not an insane amount of difference as the blankets rarely get saturated with water.
Where did you get the blankets?

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