3" vs 2.5" exhaust ANSWER!

[MikeB]

Not a single "crush bend" in my exhaust system. I started off using a 2.25" mandrel bent kit from Heartthrob Exhaust. Nice thing was they sent me extra pipes for long wheelbase trucks (or maybe even the 164" wheelbase), so I had a few mandrel bent sections left over. I later used those to connect to headers. And the entire kit with crappy OE replacement mufflers cost less than $200 shipped through one of the their dealers, but I forget their name. Ended up using the Super Turbos I mentioned in a post above.

I'd be interested to see how 2.25" pipes & mufflers worked on that Engine Masters 345hp 350. I suspect my 355 with Vortec heads and RamJet roller cam has the potential to makes around that much horsepower.

 

[74 Shortbed]

I always do my own this is the first in a while I used actual exhaust pipe tho lol I usually use EMT that measures out to 2.75"ID.

I'd do my own too but I can't weld that good not steady enough, don't know why been that way all my life, sucks big time..

 

[spanky55amg]

Ill have to watch this show a little bit more. Im glad I watched it. This answers some questions I have had about what I would do with the truck. It sounds like I have an exhaust leak, either manifold/head or manifold/exhaust. So Im looking at cheap headers and redoing the exhaust anyways. I hate the straight pipe and 1 chamber flowmasters. Too loud for me.

I know that on an LS motor, you go long tube headers and 3" pipe. Going 2.5 doesnt give you the HP or TQ that 3" gives you. And that you always go long tube. GM manifolds are just as good as shorties and mid-length.

As for the truck, I am going to an LSx swap sometime, so I want to go the cheapest route for now as the truck is my DD. But I also want it to sound good

 

[Jrgunn5150]

Ill have to watch this show a little bit more. Im glad I watched it. This answers some questions I have had about what I would do with the truck. It sounds like I have an exhaust leak, either manifold/head or manifold/exhaust. So Im looking at cheap headers and redoing the exhaust anyways. I hate the straight pipe and 1 chamber flowmasters. Too loud for me.

I know that on an LS motor, you go long tube headers and 3" pipe. Going 2.5 doesnt give you the HP or TQ that 3" gives you. And that you always go long tube. GM manifolds are just as good as shorties and mid-length.

As for the truck, I am going to an LSx swap sometime, so I want to go the cheapest route for now as the truck is my DD. But I also want it to sound good

In my experience, cheap headers just leak and make me hate life lol.

 

[spanky55amg]

In my experience, cheap headers just leak and make me hate life lol.

Raining on my cheap header parade, HA. When I mean cheap, I mean like uncoated. Yeah, yeah, yeah, that pain is just for shipping and storage. But I only need two years out of them.

 

[Jrgunn5150]

Raining on my cheap header parade, HA. When I mean cheap, I mean like uncoated. Yeah, yeah, yeah, that pain is just for shipping and storage. But I only need two years out of them.

There's cheap headers on my truck, they've been there since I bought it two years ago. I expect they'll blow out in the next year or so, it's rarely driven and sat alot of that time. It's worth a shot for sure.

 

[78C10BigTen]

Watching more of their stuff... H pipe vs X pipe vs no cross pipe

xc_hide_links_from_guests_guests_error_hide_media

Very cool that you posted this, my 78 has a stock 350 with long tube headers no cats or crossover, just straights and a pair of flow master super 44s. Ive always been curious of this and i now think i wont add a cross over. Btw i also LOVE roadkill.

 

[78C10BigTen]

Very cool that you posted this, my 78 has a stock 350 with long tube headers no cats or crossover, just straights and a pair of flow master super 44s. Ive always been curious of this and i now think i wont add a cross over. Btw i also LOVE roadkill.

I forgot to mention my whole exhaust is 3"

 

[shiftpro]

Hold the presses boys!
Gather up your muffler bearings...

I have watched all these episodes and however entertaining they are, they are simply entertainment.
Yes there is good info BUT... it's never the complete picture.
For example the episode that is the excitement of the day...
Does 3" produce more grunt than 2"....?
Yes.... BUT ONLY starting around and over 5000 rpm.
It doesn't do a flip of difference at normal driving rpms. Nada. So unless your building a racing engine that's revving to the moon there is no difference.

But the point made about some mufflers necking down inside is good to know, and watch out for. I have a set of 2.5" mufflers that neck down to 2" inside. Now that would impede a big block for sure.

A big block daily driver would be fine with 2.5" as long as it was bent with a mandrel.
And yes long tube headers, easy on the diameter. Short headers again only benefit at high rpm, with the right cam.
Large tube headers are also for a racing engine turning 7000 and up. Terrible on the street, in most big tubes will negate torque.
Of course if your building a high revving race engine then your cam selection will have mitigated most of the low rpm torque anyway.
Everything in it's place...

Engine Masters wants to make a point, and a show worth watching. They can't get too specific (which is reality regarding engine
performance builds) or their viewing audience will go yawn. So for us by best advice is watch for the little details especially the ones
they don't mention. Sometimes one can learn a lot from what is NOT said.

 

[Honky Kong jr]

Where th

Hold the presses boys!
Gather up your muffler bearings...

I have watched all these episodes and however entertaining they are, they are simply entertainment.
Yes there is good info BUT... it's never the complete picture.
For example the episode that is the excitement of the day...
Does 3" produce more grunt than 2"....?
Yes.... BUT ONLY starting around and over 5000 rpm.
It doesn't do a flip of difference at normal driving rpms. Nada. So unless your building a racing engine that's revving to the moon there is no difference.

But the point made about some mufflers necking down inside is good to know, and watch out for. I have a set of 2.5" mufflers that neck down to 2" inside. Now that would impede a big block for sure.

A big block daily driver would be fine with 2.5" as long as it was bent with a mandrel.
And yes long tube headers, easy on the diameter. Short headers again only benefit at high rpm, with the right cam.
Large tube headers are also for a racing engine turning 7000 and up. Terrible on the street, in most big tubes will negate torque.
Of course if your building a high revving race engine then your cam selection will have mitigated most of the low rpm torque anyway.
Everything in it's place...

Engine Masters wants to make a point, and a show worth watching. They can't get too specific (which is reality regarding engine
performance builds) or their viewing audience will go yawn. So for us by best advice is watch for the little details especially the ones
they don't mention. Sometimes one can learn a lot from what is NOT said.

ameni think it's dead now lol.

 

[shiftpro]

I take it this has been discussed before?

 

[Honky Kong jr]

I take it this has been discussed before?

It just gets beat to death that's all. Your post summed it up if your gonna go above 5k or running big inches go big if not don't if you want the sound of big exhaust then do it. That's all lol

 

[yevgenievich]

And for a stock TBI a factory 3" single is just fine for the up 4k rpm shif point. To me engine masters proved that and that the clutch fan can stay and not matter too much on a stock tbi motor

 

[Honky Kong jr]

And for a stock TBI a factory 3" single is just fine for the up 4k rpm shif point. To me engine masters proved that and that the clutch fan can stay and not matter too much on a stock tbi motor

Agreed.

 

[74 Shortbed]

Where th

ameni think it's dead now lol.

Wanna bet, it'll be resurrected sooner or later, lol..