Calling LS V8 Experts

"Smallbear wants a modern Syclone, local Maple Leafs spammer" (smallbear94) 02/01/2016 at 14:55 • Filed to: None

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I’m looking for a set of headers for my truck. I’m leaning towards shorties (can install myself, less $$$, still way better than stock).

What I want to know is, will any set of LS headers work, or will I have to make modifications to the rest of the exhaust system? I’ve had a muffler shop look at the stock exhaust, they said the stock pipes are big enough, the weak links are the manifolds and the muffler. They can deal with one, I’d like to do the other myself.

Truck is a 2010 Colorado with the LH9 5.3 V8.

Sweet Trav > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 15:10

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If you want my opinion, if you’re looking to make more power, I would skip the headers. Its a big investment for not a lot of power. The Factory 5.3L headers are pretty decent for cast iron pieces (Here’s a nice little build up on the 5.3 over at hotrod, only gained 10hp and 10 ft/lbs going from Stock Manifolds to Full Dyno Headers, which typically flow better than anything you can fit in an engine compartment)

http://www.hotrod.com/how-to/engine/…

Instead i would focus on a Cam Swap and re-tune the engine (LS1 cams work pretty well in the 5.3l) You may need to upgrade the valve springs too. Keep in mind that even if you put headers on it, to fully take advantage, you would want to re-tune the ECU as well. Also an LS1/6 Intake manifold might be a nice upgrade, if you can find a take off from an old F-body, or Corvette.

camaroboy68ss > Sweet Trav 02/01/2016 at 15:42

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Surprisingly the Vortec intakes flow better than a LS1 intake and are near the same as the LS6 intake. Really a ported throttle body is the only thing you can do to a stock intake to boost hp before going aftermarket. The LS intakes just look better than the truck units if your going for style.

camaroboy68ss > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 15:45

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If your going to do headers just go for long tubes. I had this same debate on my 98 Camaro SS and the gains between stock cast iron vs shorty is not worth the money and time. You could find a set of stock cast iron manifolds of a 02 Camaro or GTO, they would probably get you the same gains as shorties but a lot cheaper. Even a set of mid lengths are not worth the hassle.

Smallbear wants a modern Syclone, local Maple Leafs spammer > Sweet Trav 02/01/2016 at 16:08

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That makes sense. I guess I’ll hold off for now on the headers. Still on the table though :)

The muffler is definitely happening. I just have to find one that gives me the sound I want with as little drone as possible (I actually don’t think I’m going to find this. I think I’m going to have to add a Helmholtz Chamber to the exhaust). At the moment I’m tossed up between the Flowmaster Super44 and Super40. I’d LOVE a Super10, but the neighbours would hate me.

Cam swap is on the horizon. Two things on that though:

- My engine is VVT and I’d like to keep it that way. I need to find a VVT cam.

- $$$ sensitive here. I know a guy that does retunes free if he’s tuned the vehicle before, I’m thinking of doing the tune first.

When I do the cam the valve springs are definitely getting switched.

The tune is waiting at least to this spring. Reasons for this are:

- The guy who is going to tune it has tuned one other before. He said the engine was pulling spark quite a bit on 87 octane and the engine had potential for more if he’d used a higher grade. I tried 89 and sure enough I got better MPG. It was about 6% better MPG for about 6% more money, so the cost is a wash and I get better power and range. I’m still playing with the grades to see how much it can really take advantage of.

- I want to get it tuned on summer gas.

Intake is a good idea, but I think my stock one is pretty good iirc. Also iirc my heads are basically LS2 heads so no worries there.

Smallbear wants a modern Syclone, local Maple Leafs spammer > camaroboy68ss 02/01/2016 at 16:12

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My points against long tubes are $$$ (weak Canuckistan dollar) and installation.

Travis pointed out that the stock manifolds actually do flow pretty well, so I’m going to leave them for now. Thanks for the tip on the Camaro manifolds.

Same issue remains though, are all the LS manifolds the same length, or would I have to play around with exhaust pipe length?

Quadradeuce > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 16:39

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Google the Modern Mouse engine build sometime to learn what parts can make a difference in this motor. It’s a great read for 5.3 Vortec owners.

As a side note, I plan on using the 5.3 as a base for my Tempest build. It originally came in a 326 in 1965, so 5.3L is close enough to pay homage. The Modern Mouse basic build netted over 400HP, which is more than enough for a car that weighs 3k lbs.

And the bottom end is tough enough to run 400+ HP without any reliability issues there. It’s a great motor. Way underrated by LS folks, and GM made aluminum versions for their trucks (my 2011 Sierra’s is aluminum) and SUVs.

camaroboy68ss > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 17:00

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That I don’t know, But my thinking would they be all the same, but I’ve never had sets of LS manifolds out of different cars to compare. I’m going off my knowledge of traditional small block Chevy manifolds.

camaroboy68ss > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 17:06

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The VVT pretty much has to go if you cam swap. I currently own a L99 Camaro (VVT and displacement on demand) and looked into VVT cams as well. Texas Speed lists a grind but when you go to a forum like LS1tech there was a lot of talk on the cam but never any actual dyno numbers or talk from Texas Speed on the results of the cam. Leading me to believe it didn’t really improve performance or was unreliable. If you cruise through some forums you'll see the general consensus that to cam swap you have to lose VVT but your not losing much.

Smallbear wants a modern Syclone, local Maple Leafs spammer > Quadradeuce 02/01/2016 at 17:36

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Mine is aluminum as well.

Aaand modern mouse bookmarked, thanks.

Smallbear wants a modern Syclone, local Maple Leafs spammer > camaroboy68ss 02/01/2016 at 17:39

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I’m pretty sure I’ve found them before. Either way, it’s not priority at the moment, but it’s too bad if there isn’t one.

Sweet Trav > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/01/2016 at 19:01

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Your motor shouldn’t be a VVT engine, it has Displacement on demand, and if you want to make more power, you should remove that system and get it tuned out on the ECU when you do a cam swap.

Sweet Trav > camaroboy68ss 02/01/2016 at 19:05

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http://www.hotrod.com/features/1507-…

The LS6 makes a little more power up top and roughly the same amount of torque. However, the differences are so minuscule that its hard to justify the difference. You’re right on the LS1 Intake, However, depending on the year/RPO code, it may come with larger injectors than the truck manifold and might be able to tune a bit more power into it.

Sweet Trav > camaroboy68ss 02/01/2016 at 19:11

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Vs

Hotrod only picked up 10hp and 10ft/lbs going from the 5.3l factory manifolds to Dyno Headers (which flow better than damned near any in car header) on the dyno. (A $500-700 investment is better spent elsewhere)

Cast iron manifolds aren’t what they used to be. Unlike the old 3-1 manifolds, they keep the main diameter of the exhaust pipe through the main body of the casting, and the oval ports on the manifold are pretty closely matched to that of the cylinder head.

camaroboy68ss > Sweet Trav 02/01/2016 at 19:19

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I was mainly talking about swapping stock manifolds off say a Camaro and would bolt right into a Silverado without having to modify the exsisting exhaust. Those old manifolds were pretty much the same between all the models and could interchange, the early motors has ram horns and 55/56 had the only real one off pieces.

The old manifolds, like I have on my 68 Camaro, flow like garbage compared to headers. The biggest tell of that is on a first gen Camaro Z/28 302, those motors need the long tubes,

On the LS1 headers I know the 01/02 Camaro are pretty much the same as a shorty header in terms of flow and they can be picked up really cheap.

camaroboy68ss > Sweet Trav 02/01/2016 at 19:21

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You pretty much have to remove it and replace the lifters because they won't hold up to a higher lift cam.

Sweet Trav > camaroboy68ss 02/01/2016 at 19:34

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What about an L99 cam/Valvespring package?

Smallbear wants a modern Syclone, local Maple Leafs spammer > Sweet Trav 02/01/2016 at 19:41

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No DOD in the Colorado’s. The LH8 was had neither and was used in 2009, for 2010-2012 they switched to the LH9, the only difference was the LH9 had VVT.

http://www.355nation.net/forum/v8-engin…

It’s basically a Silverado 5.3 with a 4.8 cam, so a cam swap would really bring it to life.

camaroboy68ss > Sweet Trav 02/01/2016 at 20:00

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That could work, don't know the specs of the L99 cam, depends on what you gain to see if it's worth the hassle

TheD0k_2many toys 2little time > Smallbear wants a modern Syclone, local Maple Leafs spammer 02/02/2016 at 00:26

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my 5.3 swap is using stock headers flipped so that the will run to the single turbo I plan on adding eventually

Smallbear wants a modern Syclone, local Maple Leafs spammer > Sweet Trav 02/02/2016 at 08:01

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I believe the L99 cam phaser has a different mounting that other VVT cams, but I could be wrong. There was a 3-bolt and a 1-bolt mount. Not sure which the L99 is and not sure which mine is.

I guess if I changed the phaser/camshaft as a unit it would work.

Smallbear wants a modern Syclone, local Maple Leafs spammer > camaroboy68ss 02/02/2016 at 08:03

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That’s for DOD. They won’t take more than .295 lift.

Lift is no issue for VVT.