Upgraded Cast Iron mainfiolds?

McRat

McRat

Diesel Hotrodder
Aug 2, 2006
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Rogue: I would buy a set if you can get them built.

Welded headers are a good option for those who can buy them. We can't. I've been trying for 3 years to buy a set of headers with zero results. Lots of promises, lots of Q & A sessions between me and the various builders, but zippo, nadda.

What really kills me, is that I crated up an LLY engine to ship to a company in Oregon to mass-produce headers for our trucks. Then I was talked out of it, because "We will have headers for you very soon!"

Is that just a characteristic of Header Builders? I heard that from 3 different shops. At this point, I give up on welded headers.

By the way, if you see "log style" headers for sale, that was the result of Q & A sessions between me and the shops. I told them before they started that collector headers ain't going to fit the need.
 
R

ROGUE GTS

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Apr 30, 2008
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McRat said:
Rogue: I would buy a set if you can get them built.

Welded headers are a good option for those who can buy them. We can't. I've been trying for 3 years to buy a set of headers with zero results. Lots of promises, lots of Q & A sessions between me and the various builders, but zippo, nadda.

What really kills me, is that I crated up an LLY engine to ship to a company in Oregon to mass-produce headers for our trucks. Then I was talked out of it, because "We will have headers for you very soon!"

Is that just a characteristic of Header Builders? I heard that from 3 different shops. At this point, I give up on welded headers.

By the way, if you see "log style" headers for sale, that was the result of Q & A sessions between me and the shops. I told them before they started that collector headers ain't going to fit the need.
Click to expand...

Collector headers absolutely won't get it done. A stepped log is the only reasonable way to do it.

I'm in SoCal as is my pattern shop and foundries. If it's something you're interested in I would love to work with you guys on getting them built. We can make them whatever YOU want them to be.
 
McRat

McRat

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Short-tube headers seldom make any power on a dyno unless the factory manifold is pretty awful. The length that long tube headers would have to be prohibits them. IIRC, about 60" primaries, but I'd have to check my notes.

Our factory manifold is pretty good actually. Long tubes on a car often increase the HP 10% or more, or about 50rwhp on a 500rwhp engine. Nobody is seeing that kind of gain with Dmax headers.

But for high RPM operation of larger turbochargers, having 1/3rd more flow in the manifolds, riser, and pedestal should net some good gains and drop EGT's and piston temps a little.

At least that's what I had come up with 3 years ago. Am I right? Dunno. Love to find out before I retire.
 
TrentNell

TrentNell

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what about the power gains from drive pressure reduction ? After running a set myself i dont think huge gains are on the table hear but i have to say that the gains were there none the less, and could be felt . Also on a local truck we saw HP gain just from up-pipes on Matt Larsons truck , i would think a upgrade to the manifold along with the up-pipes would have to show even more gains .

what are you thoughts Pat ?
 
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McRat

McRat

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Upgrading the manifold without upgrading the risers and pedestal to match won't be as effective.

I guess the question is whether a well-designed log manifold will perform as well as a well designed collector system. Historically, only "correct length" primary tube headers will see large gains over log systems. Yes, shorties can gain some power, but it's not much.

I'm just basing this off of dyno results over the years on NA gas engines, which is the only experience I can draw from. Does it apply to our trucks? Can't say. But headers have been out awhile now, and I haven't seen anyone show large gains from them, which lines up with what my past tells me.
 
TrentNell

TrentNell

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i really wish i would have dynoed the truck before and after , just didnt have enough time :(

the hard thing we all face is at our weight it takes a decent power increase to make a difference at the track and the SOTP meter . We also have to face the HP per $$ wich is really tuff for these type of mods . also as you stated the rest of the " system must be upgraded as well , so the A/R of the turbo could limmit showing gains till that restriction was removed ect......

BTW the up pipes on Matts truck if i remember correctly were in the 20-30 hp range improvrement. 2 week spread between dyno runs though but they were the only change to the truck .
 
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McRat

McRat

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I have no doubt the factory risers are the #1 restriction in our exhaust. I had PPE custom fab me up a set, but never got a chance to test them by themselves.

If I was on a budget, risers would certainly come before headers.
 
hondarider552

hondarider552

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Glad I made the right decison then, Got the risers before the headers. For me I dont see a need for the full out headers. up pipes go on next week, and im not gunna have fun. :eek:
 
TrentNell

TrentNell

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for anyone interested in these parts............... who ever makes them i will say that spooling was greatly improved with up-pipes and again even more so with the switch to full header . i am getting both chargers litt probably by just after the 60ft mark now . MPG is up also :)

back on topic look forward to seeing what you come up with for the cast versions . great to have alot of options for parts .
 
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03maxpower

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McRat said:
I have no doubt the factory risers are the #1 restriction in our exhaust. I had PPE custom fab me up a set, but never got a chance to test them by themselves.

If I was on a budget, risers would certainly come before headers.
Click to expand...

sorry for the stupid question but what are the risers any pics???
 
R

ROGUE GTS

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RE: Testing. Yes I have done some considerable testing in another venue and the results were surprising to say the least.

To start with, just like headers there are good and bad *cough* stock *cough* logs. "Bad" not only because of the undersized cross sectional area, but the lack of steps, reverberation canceling, etc.

Now the header vs log debate. There have been a million studies done on this and results vary. As I've seen the results can easily be swayed in whatever direction the tester wants them to. You can match a great header with a horrible (cast or fabricated) log and vise-versa.

In my experience a well designed, equal length true header/merge collector setup will make more peak power. But it comes at a cost. A log will almost always carry more power under the curve and as a result is much easier to spool a big charger. The logs are great at retaining the thermal energy and produce a lot of velocity for the given size. If you want to make the absolute most power possible in a small rpm range then a tuned header works well. But in my opinion and experience a well designed log will give up a very very small bit of power up top (>5% in most cases) and give back much more everywhere else.

I see there is a bit of interest here. I'm going to pull some measurements and start to model them up.

As well I will be talking to a few of the guru's here to get their wish list and see what we can work out.

I'm not sure if it's needed or not but a set of cast up pipes could be made as well. Given the various different chargers being used I'm not positive if it would be worth the effort but it's an option.

Any feedback is always welcome as it only benefits us all. I'll post some pics once I get a set modeled up and we'll see how it work out.


You guys wouldn't happen to have a solidworks model of the d-max head would you? :eek:
 
Brayden

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R

ROGUE GTS

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^ Yes, but definitely NO at the same time.

They are larger but from what I can see there is quite a bit of room for design improvement. Not only in flow/power but in the design of the casting.

Somewhat nice to see I'm not alone in my thoughts though.
 
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