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6.0 swap exhaust questions.


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Getting everything together to do the lq4 swap and I'm not sure what to do with the exhaust.

 

How does back pressure effect hp/tq?

 

Originally I was planning to do stainless shorty headers with true duals and 22inch glasspacks and keep the pipes 2.75in.

 

 

But after some reading I'm starting to worry that this setup might not have enough back pressure and cause some low-end power loss.

 

How will this effect my hp/tq/mpg?

Would adding an x-pipe make a difference?

 

I will be getting the truck tuned.

 

Any help or suggestions withhold be great, I want to be sure I know what im doing and get everything right before I start buying more parts.

 

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Less back pressure raises the peak torque band. Many guys have put large pipes on and lost peak torque.

The less back pressure the better. Back pressure is bad, that's a myth that it helps. The less, the better.

 

Looks like no one is really sure how back pressure effects engine performance.

 

I'm mainly worried about losing low end hp/tq. Does the lower compression on the lq4 make any difference?

 

Is a header wrap worth the money or should I just leave the SS bare, with no coating?

 

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Search utube, there are videos with an engine on a dyno stand and different sizes of pipe attached, from open headers to full quiet exhaust...the more open, less restrictive it is, the more power made.

 

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Search utube, there are videos with an engine on a dyno stand and different sizes of pipe attached, from open headers to full quiet exhaust...the more open, less restrictive it is, the more power made.

 

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I guess if you want to drive at 6000 rpms that's great but normal driving is at 700-2500 rpms and low torque is a much better fit for most drivers. Trucks are not a Corvette with 3000 lbs. weight. V/S 4800 to 5500 lbs.

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Less back pressure raises the peak torque band. Many guys have put large pipes on and lost peak torque.

 

Not because of back pressure. Because of the reduced velocity. They aren't the same thing.

 

You don't want ANY "back pressure", but you DO want maximum velocity. They lose power because they lost velocity. "Back pressure" is irrelevant.

Put too large a pipe on it and you lose the velocity and that's why anyone who saw a power loss from exhaust got that result.

 

Zero back pressure would be ideal, as long as the velocity is right. Back pressure being needed is a total myth.

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So it probably won't make much of a difference, at least not enough to worry about.

 

Has anyone here put SS shorty headers on their truck? Did you get them wrapped/coated or just leave them bare.

 

I'd rather leave them bare. Kinda like the look of the stainless and wouldn't mind saving a little money, but I'm worried about the heat.

Will I damage anything if I don't have any wrap or heat shields?

 

Thanks for all the help so far, I think the hardest part of this swap is going to be deciding what parts to get.

 

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If the stock manifolds don't damage anything, then shorty headers likely won't, either.

 

I personally would never wrap headers. If you want some extra insulation, get coated headers.

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Not because of back pressure. Because of the reduced velocity. They aren't the same thing.

 

You don't want ANY "back pressure", but you DO want maximum velocity. They lose power because they lost velocity. "Back pressure" is irrelevant.

Put too large a pipe on it and you lose the velocity and that's why anyone who saw a power loss from exhaust got that result.

 

Zero back pressure would be ideal, as long as the velocity is right. Back pressure being needed is a total myth.

I was just going post exactly what you said lol. I'm still wondering why GM thought my '11 6.2 needed a 3.5" exhaust pipe. Doesn't seem like it would have enough velocity although it sounds and looks good!

 

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Well the 6.0 I just picked up isn't a lq4 like I had thought. I guess I've got a ly6...

 

I'm not sure if this is a better engine or..? Is the swap going to be more difficult?

 

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Depends on what you are swapping into. If it is a 00-07 truck then it can be a pain in the ass. If newer then it will be alright

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