My Stainless Manifold Build

Do y'all enlarge the bolt holes as you go outward from the center, and/or cut the flange between ports?

SS + solid flange equals some serious growing pains if provision for expansion/contraction isn't in place.

Looks great btw.


I know on my steel equal length header I made the outer 4 bolt holes bigger then the inner holes to alow for expansion. I had the 1/2" flange milled flat after all welding and use studs to clamp it down with a factory steel gasket, I have no leaks and it works great.
 
I know on my steel equal length header I...

where do you notice the power increase the most with your tuned header?

the only time we ever saw any benifits were when we played with the ex cam and collector dia for weeks on end

on a dyno

and the benifits only revealed themselves above 8000 rpm
 
Well thats a problem..... I built the header to gain clearance around my brake booster and steering shaft for the new twin turbos so its hard for me to say where I felt the power increase.

I have since went back to a single turbo (temporarily anyway) but I havent had a single on it since last year so its not a very good comparison but it feels like I gained a little faster spoolup and more power in the mid range ( 1800-3000 rpm) right where I wanted it (got lucky I guess). I dont need more low end tq since its just a half ton conversion and has plenty already for my 3900 pound truck.
 
Joefarmer,
I coped the fittings the ol' labor intense way, cut and grind, fit, cut and regrind, if I was to make a bunch i'd figure a way to machine them. As far as the undivided flange, no reason just made it like that for simplicity, i figure I'll just cut the divider out of the gasket.

Speedshift,
Adopt... haaha not that i know of, maybe i am though.....

Big blue24,
I've spent most of my free time since I was about 15 at the shop, now jeez i'm going on 24 shortly, I went and got my engineering degree at NDSU, went out to work in the oil patch in ND for a year to pay off college, now I'm back home working at the shop.

As far as the piping its standard 2", I thought about stepping the sizes, but the next size smaller is 1.5" at least to get standard stainless fittings I believe, not positive though. But 2" has a cross-section of slightly larger than the 12v ports measuring the gasket, where is 1.5" tubing is smaller, and I did not want to be necking it down right out of the head.

2wPuller,
man that manifold looks identical damn near, the discolored stainless is what i am shooting for, no real reason though, yours looks great! how does it perform?

Charles,
nope all the holes are the same, I will see what happens as far as the expansion contraction, its no problem though to chuck it up and mill the holes slotted or larger, I don't want to go to much larger though, it already cuts into the pipe a bit.

mondster,
Forest Lake, MN.
 
My motor I am building will be running a hamilton big stick cam, phatshaft sliver 62, dynomite 4's, cut fuel plate, A1 head studs, ARP main studs, moly pistons, and I am having it fully balanced also. I'm getting pumped up for the day she's going to run the dyno. I would like to compare the manifold against the stocker and something like an ATS or HTT for mine and everyone's knowledge.
Tim.
 
In the immortal words of all our grade school teahers


I HOPE YOU BROUGHT ENOUGH FOR EVERYBODY!!!
 
Looks nice!! Itg ought to work great, If it doesnt.......Oh well it still looks cool. Nice work.
 
Joefarmer,
I coped the fittings the ol' labor intense way, cut and grind, fit, cut and regrind, if I was to make a bunch i'd figure a way to machine them. As far as the undivided flange, no reason just made it like that for simplicity, i figure I'll just cut the divider out of the gasket.

Cool! I'm pretty sure I cheated... I used PVC the first go around to make it close, transferred the design and clearanced from there. I still had three 1/4" gaps at different places, but it turned out it was easier to port and polish with those mistakes in place.
 
Cool! I'm pretty sure I cheated... I used PVC the first go around to make it close, transferred the design and clearanced from there. I still had three 1/4" gaps at different places, but it turned out it was easier to port and polish with those mistakes in place.

Ya I thought about using pvc fittings for a template, but all in all it wasn't to bad. I only had one fitting that I screwed up. It went together good, and I was surprised how little the flange warped.
 
Wideopenthrottle-

If at all possible it would be awesome if you could compare stock and your manifold. Looking forward to seeing the results. Would really clear up some debates on this site.

Egts, dyno #'s, drive pressure

I have seen some guys put a carbide cutter in the lathe and the elbow in a vice and run the elbow into the cutter. Similar to notching a tube for a rollcage.
 
Looks GREAT! Nice work!

The only thing that I see that could use some improvement is you welded the stainless with to much heat.

When It turns black like that you are burning the nickel out of it.
Stainless should be welded slow and colder than carbon steel, and when done if you take a Stainless Steel wire brush and just give it a light scrub it will actually look gold.

Otherwise you did a GREAT job.

Are you interested in selling the flanges?
 
sdubfid, that is the plan, the engine dyno should record all of that info I think, it will take all of the guessing out of it. Side by side charts showing everything we/compD have been wondering about this type of manifold, well it will at least shine some light on the subject. Hopefully it will happen in about 1.5-2 weeks.

tony597fitter,
thank you for the review, I actually figured I was on the hot side welding it. This was my second experience with stainless tig welding, my line of work has always been aluminum tig welding and fab work here at the shop. Our creme and butter is aluminum CNC, and fab work, though it was fun to tig weld the stainless, a completely different animal compared to aluminum. It takes some getting used to. The pointers are great, keep'em coming.

Yep, I can make more of the flanges, let me know.

Tim.
 
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