Turbo header design, focusing on the collector.

The_Beave · 12-11-2009, 10:26 PM

Is it "better" to have maximum velocity or to have maximum pressure?

What I am wondering is that I see most turbo manifolds are merged heavily, fairly short, and probably produce a decent amount of velocity as long as they aren't too crappily constructed.

However, what I was thinking, after seeing the Bisi header and some other designs I have been studying from pretty darn advanced turbo systems on non-diesel powered engines (diesels require their own field of study that I am not really interested in), I see that there are efforts in producing maximum pressure at the inlet of the turbo, not just velocity, by increasing the volume post collector (or in the case of Bisi's, pre-collector, or, that is what I think of what he's done, i could be wrong) to lower the velocity and induce a higher pressure before the turbine.

Let me define "better:" capable of converting the potential and kinetic energy present in the exhaust gases into work (spooling the turbo) in the shortest amount of time possible, especially between shifts.

1SLOW93TURBO · 12-11-2009, 11:48 PM

Dang Beave thats alot of studying, sleep on it then throw the bottle on and dont worry about physics LOL.

remoer · 12-12-2009, 08:16 AM

i have wonder too beave but again it's only for the pleasure of learn not appling cause i am a N/A guy. here's what intrested me.

Originally Posted by remoer

are my eyes deciving me? that turbo manni is stepped, i've seen alot of turbo manni but this is the first stepped manni i've ever seen... there's more to more that meets the eye here ppl. wow. very impress...

Originally Posted by The_Beave

Remo- I've seen several, mostly Hytech stuff, with Hytech's typical anti-reversion chambers and other assorted voodoo. Bisi's D manifold is the first I've seen to use all that high-tech wizardry for the D, though.

Originally Posted by Bisimoto

Yes, it is. N/a meets turbo..lol.

No worries, Beave.
It is actually steps to assist with flow due to loss of exhaust mass energy, quite different from anti reversion...I let that happen at the head flange.

The_Beave · 12-12-2009, 10:31 AM

Originally Posted by 1SLOW93TURBO

Dang Beave thats alot of studying, sleep on it then throw the bottle on and dont worry about physics LOL.

I don't want to juice a boost build. I have no desire to use nitrous. I don't like needing to fill up another bottle and try to integrate it into control systems not setup up for it, and deal with all the many variables needed to actually pull it off. I know someone back in the 90s who went so far as to machine his own controlled expansion chamber for nitrous and integrated it into his plenum on an turbo A6 build, but that dude is seriously one of the smartest men I've ever met and could do the math for that kinda thing. He only used nitrous as a means to spool his turbo (not a whole lot of selections back then) and cool the intake charge, and nothing more. His bottle lasted a long time since he wasn't dumping a whole lot in. It was a totally awesome system that was well thought out and implemented, but, again, I have no desire to play with it as that would take too much experience to not blow it up that I don't have. I'm still a )(#$)(*#$ newb.

Remo-

Yeah, I got all that, but am still trying to figure out what he means. I am not sure why he'd want to increase the diameter to decrease the velocity and increase pressure so far away from the turbo.

remoer · 12-12-2009, 11:50 AM

Originally Posted by The_Beave

Remo-

Yeah, I got all that, but am still trying to figure out what he means. I am not sure why he'd want to increase the diameter to decrease the velocity and increase pressure so far away from the turbo.

and i might get flame for this but the difference of the ram horns on top vs mannifold piping going down like his design. i want to say it has to do with top end. but i'm guessing i know nothing about turbo. just asking.

The_Beave · 12-12-2009, 01:46 PM

That's not something I've really looked into, so, I don't know. Some people with more experience would better be able to asnwer that question. I've been studying 70's and 80's turbo tech, and starting to look at the WRC and earlier, crazier rally car setups. This stuff is waaaay head of just about anything these days, and that was 20-30 years ago.

I have no use for "typica' scenarios since my CRX has been anything but typical. I always look to incorperate advanced techniques and theory into just about anything I do, simply because it usually makes things work better, and inteh case of REAL advancements, simpler. Granted, a lot of what I ask is based on not so cimple concepts, but, the results will speak for themselves.

jebusama · 12-12-2009, 07:46 PM

does exhaust mass energy losses have to do with the exhaust cooling down and expanding?

The_Beave · 12-12-2009, 07:49 PM

Tha's what I'm trying to figure out, because an expansion lowers the velocity and increases pressure, converting kinetic energy into potential energy, with accompanying losses in heat, which makes for an overall lower energy package. I don't understand the step up in that section of the exhaust, unless there is more Bisi voodoo IN the piping that he might not want use to see?

jebusama · 12-12-2009, 07:52 PM

my physics are weak, but i am assuming it's not possible to increase the speed at which the exhaust exits but the idea is to keep them from slowing down right?

The_Beave · 12-12-2009, 07:55 PM

It is possible to increase the velocity. It's just hard. You have to use the exhaust energy farther down the header/manifold to send a pressure wave back up the other pipes at the right time to impart more energy into the exhaust stream "up-wind."