Mod planning

[Jobi-Wan Kenobi]

Alright, help me chart a path here guys.

A little background. Yesterday after work I was crawling around under my hood looking for an oil leak since my engine has been kinda slobbering on itself and seemingly dripping a bit onto the exhaust (thinking valve cover gaskets right now). I noticed two broken exhaust manifold bolts on the drivers side (front and rear most) so started thinking that this may be a good time for exhaust upgrades. Today now I looked at the passenger side and the manifold is actually split right in the middle on the flange and looks like its been that way for a while. So I have more justification now for upgrades.

Here's where I'm at now. I know I can buy different style headers or stick with a stock exhaust manifold. I wouldn't mind squeezing a bit extra power out. But this vehicle is also a daily driver so not looking to go crazy. And completely understand that the transmission is likely going to need some work since they don't seem like much power over stock. Regarding exhaust headers, shorties seem like an good upgrade since they would fit in place of the stock manifolds. Long tubes would be better performing but won't be a drop in replacement. I'd do a tune at some point. Maybe a cam swap. And probably not much more than that.

What kind of experience have you guys had here? What have you done with your vehicles?

 

[Marky Dissod]

My previous experiences are with mid-'90s LT1 Caprices / RoadMasters / Fleetwoods. Even so ...

Thinking about a cam swap or better heads - whichever is cheaper? or whichever is a better bang for the buck?
OE exhaust manifolds don't do well over the OE engines' OE redline. (The apostrophe is EXACTLY where it belongs.)
The OE exhaust manifolds are the major reason why 4.8L & the 5.3L & the 6.0L all share similar redlines.
If you're gonna do a cam swap, seriously think about upgrading the OE manifolds.

Same / Above goes for 'shorty' headers that keep the catalytic converters in the OE location.
If you want the engine to breathe better at highER RpM, OE manifolds / shorty headers are a compromise at best.

You should already have done a tune, even if you'll eventually need another. The difference is that big.
(Goes for literally ANYONE who owns a vehicle with a GM V8, damnit; people really don't know what they're missing.)

But for all my experience modding mid-'90s GM LT1 V8s, I regret not improving the suspension further.
Already got tuned.
Before I do any more engine mods - yes, out of fear of needing a 4L60E rebuild - I'll get more bang - and SPEED - for my buck improving the ride / handling balance with better swaybars / shocks / springs, than by modding the engine.

Traffic is just too freakin' dense in NYC. More horsepower is less useful than better handling.

 

[Fless]

I noticed two broken exhaust manifold bolts on the drivers side (front and rear most) so started thinking that this may be a good time for exhaust upgrades. Today now I looked at the passenger side and the manifold is actually split right in the middle on the flange and looks like its been that way for a while. So I have more justification now for upgrades.

Got news for you, they're made with the split. Not tryin' to ruin your justification, though.

 

[Jobi-Wan Kenobi]

Got news for you, they're made with the split. Not tryin' to ruin your justification, though.

View attachment 405955

Well look at that . I guess this isn't as serious as I was thinking then. Still got broken manifold bolts but since I couldn't see a split on drivers side I figured something was wrong with the passenger side.

 

[Jobi-Wan Kenobi]

My previous experiences are with mid-'90s LT1 Caprices / RoadMasters / Fleetwoods. Even so ...

Thinking about a cam swap or better heads - whichever is cheaper? or whichever is a better bang for the buck?
OE exhaust manifolds don't do well over the OE engines' OE redline. (The apostrophe is EXACTLY where it belongs.)
The OE exhaust manifolds are the major reason why 4.8L & the 5.3L & the 6.0L all share similar redlines.
If you're gonna do a cam swap, seriously think about upgrading the OE manifolds.

Same / Above goes for 'shorty' headers that keep the catalytic converters in the OE location.
If you want the engine to breathe better at highER RpM, OE manifolds / shorty headers are a compromise at best.

You should already have done a tune, even if you'll eventually need another. The difference is that big.
(Goes for literally ANYONE who owns a vehicle with a GM V8, damnit; people really don't know what they're missing.)

But for all my experience modding mid-'90s GM LT1 V8s, I regret not improving the suspension further.
Already got tuned.
Before I do any more engine mods - yes, out of fear of needing a 4L60E rebuild - I'll get more bang - and SPEED - for my buck improving the ride / handling balance with better swaybars / shocks / springs, than by modding the engine.

Traffic is just too freakin' dense in NYC. More horsepower is less useful than better handling.

If I did do a cam swap its something thats going to be farther off in the future. Not sure when that would actually happen since I've been focused more on fixing other issues with it that show up (I've had it home and driving it for a little over a month now). The tune is something I want to do but haven't had a chance to figure out what I actually want yet. Handling aspects are something else I want to get into with it as well.

 

[iamdub]

Alright, help me chart a path here guys.

A little background. Yesterday after work I was crawling around under my hood looking for an oil leak since my engine has been kinda slobbering on itself and seemingly dripping a bit onto the exhaust (thinking valve cover gaskets right now). I noticed two broken exhaust manifold bolts on the drivers side (front and rear most) so started thinking that this may be a good time for exhaust upgrades. Today now I looked at the passenger side and the manifold is actually split right in the middle on the flange and looks like its been that way for a while. So I have more justification now for upgrades.

Here's where I'm at now. I know I can buy different style headers or stick with a stock exhaust manifold. I wouldn't mind squeezing a bit extra power out. But this vehicle is also a daily driver so not looking to go crazy. And completely understand that the transmission is likely going to need some work since they don't seem like much power over stock. Regarding exhaust headers, shorties seem like an good upgrade since they would fit in place of the stock manifolds. Long tubes would be better performing but won't be a drop in replacement. I'd do a tune at some point. Maybe a cam swap. And probably not much more than that.

What kind of experience have you guys had here? What have you done with your vehicles?

Best bang-for-the-buck is a GOOD tune. You'll get more responsive operation, more power at the wheels and possibly prolong the life of your trans. Headers, etc. aren't worth it if doing alone. They're better as a supporting mod for major engine upgrades such as cam and/or head work.

Optimize what you have now by ensuring all the stock points are up-to-par (spark plugs, fluids, filters, sensors operating properly, etc.). Tune it for optimal operating efficiency. When this gets old and you're ready for more, might I suggest a NNBS intake manifold swap? This will be a feel-able mod that will support bigger future mods.

 

[Jobi-Wan Kenobi]

Best bang-for-the-buck is a GOOD tune. You'll get more responsive operation, more power at the wheels and possibly prolong the life of your trans. Headers, etc. aren't worth it if doing alone. They're better as a supporting mod for major engine upgrades such as cam and/or head work.

Optimize what you have now by ensuring all the stock points are up-to-par (spark plugs, fluids, filters, sensors operating properly, etc.). Tune it for optimal operating efficiency. When this gets old and you're ready for more, might I suggest a NNBS intake manifold swap? This will be a feel-able mod that will support bigger future mods.

So there isn't much of a benefit to doing headers unless I were to do cam? Since that's something that may not happen for a while if it even does I'm probably better off then keeping stock manifolds.

The tune I do want to do here at some point. That intake swap is definitely intriguing though.

 

[iamdub]

So there isn't much of a benefit to doing headers unless I were to do cam? Since that's something that may not happen for a while if it even does I'm probably better off then keeping stock manifolds.

The tune I do want to do here at some point. That intake swap is definitely intriguing though.

Long tubes... Sure. But, if you're keeping cats then that's even more $$$. Shorties, alone, no. You can do a larger Y-pipe (will have to have one made) to complement the shorties. Either long tubes or shorties really need to be coated as the extra heat they radiate will rot harness loom and, if your intake filter box isn't well-sealed, negate any gains they may yield.

Still, with the cost to do it right, a tune would be cheaper and have a better return on investment. Also, headers would be best optimized by a tune.

For now, enjoy the lower engine bay temps, not hearing exhaust pinging sounds and having cats so your exhaust doesn't stink up your clothes.

 

[Mudsport96]

Header dyno results on a 4.8

On an engine dyno with no accessories so numbers will seem high.
Shorties are not worth the time or effort spent..
And even long tunes aren't worth it in my opinion ( for a stock cammed engine).

Follow this guy's channel he has just about every test you can imagine for a 5.3.

 

[mountie]

Interesting read........ ( long ago, I spoke with my friend, Doug Thorley ( Thorley Headers)..... He said, unless you are highly modifying your engine, after market headers are a waste of money).

Anyway..... You people suggest a "tune". My '05 Yukon 5.3 runs... fine...... But is there a 'Black Bear tune" that just improves my performance a little better? I don't drive it like a hot rod. But a little better 'launch' would be nice. ( worth the cost?)