Custom exhaust manifold design reference?

[Darius]

Does anybody have a good book or paper on turbo manifold design besides "Maximum Boost" by Corky Bell? I'm curious as to what thickness of tubing to specify, the minimum radius of bends, the type of welds, the type of steel, divorced outlet vs. single collector, wastegate positioning, etc.

Maybe if someone has experience they could do a technical writeup on the topic. I know Thagaard (sp?) hasn't been on here in a long time, but he was one that came to mind.

[002-M-P]

Generally speaking...use 321 stainless, tig welds, divorced outlet (twinpulse, twinscroll, divided, etc)...but only if you have researched exhaust pulses so you know which cylinders should go to which side of the outlet....the rest someone else can fill in because i'm not positive

[Chaos the Xile]

I am having one built that is a twinscroll design (divided flange w/ divided housing on turbo) and the lenght of the runners on one side of the dividen go to the 3 cylinders that fire first, and the others the the 3 that fire last. Also using twin wastegates I hear building them like this is optimal for response and power.

[Darius]

C'mon guys I know there are more people that know the technicalities of manifold design on here. What about guidelines for piping thickness, flange thickness, and manifold support at the flange. Maybe some tricks of the trade?

[Shocker]

Well heres my take on exhaust manifolds... equal length are better than logs. They might not spool as fast but seem to really help HP numbers up top.

Construction wise, the one I had gotten made for me, is nice and thick. I cant see it ever cracking. With that also adds weight.. its quite heavy but 1/4 inch thick tubing will do that. Also keeping the radius's as large as possible helps reduce constriction of exhaust gasses allowing them to flow more freely.

Twin scroll setups through a divided T flange also seem to spool better, by reducing exhaust pulses that disrupt the flow. Also aiding in more hp and better spool times.

heres a good thread on equal length vs log that full race did. The results are amazing. http://www.honda-tech.com/zerothread?id=925312

heres my manifold.

[gawdzilla]

how much did that cost?

[matafied]

That is NICE!!! i likey

[Darius]

Quote »Twin scroll setups through a divided T flange also seem to spool better, by reducing exhaust pulses that disrupt the flow. Also aiding in more hp and better spool times.[/quote]If your exhaust flange is divided, does that mean you have to run a divided inlet on your turbo to get the full effect or doesn't it really matter at that point?

BTW I'm so glad threads in this forum don't end up like the one above. I love how different the NICO community is from HT. The last 5 pages of that thread are a flame war...
Modified by Darius at 1:23 PM 6/21/2007

[Shocker]

no, my turbo is t4 regular. It would most likely help a little bit if it was divided through the hotside.. but on the dyno I was already making a few pounds at 1/4 throttle at 1500 rpms..... I shall see once my ECU returns.

[Yellow4g63]

hey shocker looks like there is some undercut on a few of those runners. Kinda hard to tell from the pics. Even the thickest manifolds will crack, usally at the weld. Nice work tho.

[Shocker]

undercut? as in to short? and not equal? the middle two are about 1/2" longer than the other 4. Not really a big deal. thanks.

I still dont see it failing, if it does happen to crack your right it will be at a weld most likely. Ill just remove it add some braces and fix the crack. Not biggy, the 35r isnt too heavy.. maybe if it was a 42 + Id have a little more concern.

[gawdzilla]

how much did that cost?

some info on where you got that made at least?

[Shocker]

some info on where you got that made at least?

check your email.

[Yellow4g63]

undercut? as in to short? and not equal? the middle two are about 1/2" longer than the other 4. Not really a big deal. thanks.

I still dont see it failing, if it does happen to crack your right it will be at a weld most likely. Ill just remove it add some braces and fix the crack. Not biggy, the 35r isnt too heavy.. maybe if it was a 42 + Id have a little more concern.

No no no undercut meaning the weld looks like it's a valley vs mound going around. look at this pic, http://www.3rdgearvtec.net/Protech/IMG_4741.JPG you see the outside runner going up from the collector? at the joint where the weld is it dosn't look like it's going in. In the pic you posted one of them looks like that but it's might be the angle it's at.

[Shocker]

No no no undercut meaning the weld looks like it's a valley vs mound going around. look at this pic, http://www.3rdgearvtec.net/Protech/IMG_4741.JPG you see the outside runner going up from the collector? at the joint where the weld is it dosn't look like it's going in. In the pic you posted one of them looks like that but it's might be the angle it's at.

oh yeah, they are like that, lol. I took it to my buddy who has been welding all his life, and he marveled at it. So no worries.

[Bwana]

Reminder to self: Hone tig welding skills...

[Chaos the Xile]

Hey Shocker can you email me some info on that manifold you got there?[email protected] i'd appreciate it.