Header?

[JessZ]

Is it pointless to get a header for my L24 with a mild cam?

[evildky]

the header by itself isn't gonna net much power but they are pretty affordable and weigh less than the stock manifolds and look a lot etter, and if you keep with the same style head in the future you can carry the header over

[johnc]

Actually, didn't Tony D weigh a stock exhaust manifold and the MSA 6 into 1 header and find that they weighed about the same?

[Tony D]

Actually, the stock mainfold and headpipe to front resonator was lighter than the header...

 

But that goes in the face of internet myth, so it can't be true, eh?

[katman]

Yup, the big restriction was the stock exhaust from the headpipe back. Once that's fixed, as DAW suggests, we can talk generalities. In general, a header gets you about 4-5% peak hp over a stock manifold for most apps from a 4 cylinder Honda to a 454 Cheby. So that's like 6hp on the Honda (or 240Z) and 18 on the Cheby. For a good header. A bad one gets you no horsepower, a potential big torque valley, and lots of extra underhood heat. So for the $200 MSA/Monza/Whatever, you get another radiator under the hood. For $750 you get a Stahl with 1-1/2 primaries and maybe 8 hp. Your call.

[johnc]

The Stahl Model 28 is $775.00 plus shipping. It is a thing of beauty...

[bjhines]

I think whoever weighed the stock VS aftermarket exhaust manifolds and said they were the same is bonkers....

 

You can't comfortably pick up the stock manifold with one hand... you can pick up a tube header with 2 fingers...

 

But to dispel all myths...I have a jet coated MSA 3 into 2 header for a round port head... I also have a no name early style square port header .... in addition I have a bone stock 240Z manifold with AIRPUMP tubes and rail on it...all on the shelf and ready to weigh...

 

I will weigh them when my kid takes a nap...

[JMortensen]

Two different stock manifolds, FWIW. The early one that came on the 240 and maybe 260 is MUCH lighter than the 280 manifold.

 

I have a friend with a L28 mild cam and SU's and she put 2 1/4" exhaust on the stock manifold first, then put the header on. I was there for both installations. We didn't dyno, but there was a very big seat of the pants difference between the two. Of course that was an L28 using the L24 manifold, so maybe that's the reason...

[WHP]

I had the MSA 3-2-1 header and it fit terrible. The ports were way out of alignment and the collector was a hack job inside, so bad I never installed it. The header weighed about 12 lbs if memory serves me. A P79 (big 280 roundport) cast iron manifold was about 24 lbs. I laid an E31, N42, and P79 exhaust manifolds on the bench side by side for comparison and the early 240Z manifold while well designed looked too restrictive for a L28. The P79 roundport had the biggest volume runners and they are seperated inside the manifold, so I ported it out to match my square port head. I also worked on the area where the twin downpile connects with the grinder to smooth the transition and port match to the twin tubes. I then fitted a custom long twin tube downpipe with a 2.5" smooth collector to a 2.5" exhaust. The car runs very well and will never have an exhaust leak! I will live with the extra 12 lbs for the $$ as this is a daily driver. My exhaust now resembles a Tri-Y. The car does not feel like the exhaust is a handicap. It is a L28 bored 1 mm, flattops, with a ported E31 head with bigger valves and a .490 Isky cam.