Forced Induction Intake Manifold Design

[Mike Macie]

Im designing an intake manifold for one of my cars that is turbocharged. I purchased a book called Scientific Design of Exhaust and Intake Systems. Its a pretty good book but it doesn't cover forced induction and its a little old. Im mainly interested in how the resonances move around with boost and how to perform a wave analysis to tune the manifold. Does anyone know of any good reading material that can help

[Mike Macie]

Im designing an intake manifold for one of my cars that is turbocharged. I purchased a book called Scientific Design of Exhaust and Intake Systems. Its a pretty good book but it doesn't cover forced induction and its a little old. Im mainly interested in how the resonances move around with boost and how to perform a wave analysis to tune the manifold. Does anyone know of any good reading material that can help

[Mike Macie]

Does DE Winterbone's book, Theory of Engine Manifold Design, go into any detail of forced induction?

[Joy Pathak]

Hey....

I wouldnt know EXACTLy which books would help...

but there is a huge list of books posted somewhere in these forums... I am sure if u clicked search... and searched for books.. it would show up. They should have some stuff for Forced induction

I would definitely say.. from what i have heard/learn ... that go for smaller plenum volume... ifu go turbo.. to reduce lag?

Try get into contact with some ofthe Cornell guys.... They have been running a turbo effectively for quite a while..look for articles published by them... or maybe Helsinki polytechnic guys.. they run a turbo too if i am not wrong...

Ummm another would be the leaks that ppl get becuz of turbo(becuz of TB location) make sure.. u have seal kits.. ithink Garret includes this in the package... wouldnt be too sure. Make sure u check into all that...

Ummm wouldnt know what else to tell you man. I am still learning.. and dont knwo enough.. but that would be a decent approach.

[absolutepressure]

Maximum Boost by Corkey Bell looks like a good book. I haven't gotten to the good stuff yet, but there is a section on intake manifolds, and I saw some equations, and more importantly, ideal shapes of how the runners blend into the plenum. Ask drivetrainUW-Platt. He could give you a better review. From what I see, I would recommend it even if it doesn't have the exact equations you're looking for. He has a lot of hints, tips, facts, do's, and don't's in the book.

[raska]

Maximum Boost is a good read but it's a fairly general overview. It just brings to your attention some of what you should be considering and some rules of thumbs, where then you go read more technical books and papers.

[Homemade WRX]

I had looked into this and being the engine size I'm turboing while still trying to intercool, I'm left with well, one option...
intercooler as my plenum...
I've seen large and small plenums both makes gains but in different ways...smaller will reduce lag and larger increase peak power...

Maximum Boost is a good book for cutting your teeth on but doesn't do much in the way of real design work.

[Joy Pathak]

Sorry ... misread the initial post.

I tht it was FSAE cars related. Tehrefore i said it would advisable to go with smaller plenum volume ... and so on..

For cars... yes.. as 'Homemade WRX" pointed...

Large and small plenums both have their own pros.

I think the question would be... what kind driving is this car for?
for normal driving.. i would say a large plenum volume.. would make u stall at corners.. and so on.. but one a straight quarter mile u might get some solid peak power..

i dont know much.. i am sitll leanring.. but just my little input.

[absolutepressure]

I got a question.
I know our engines "suck" the air in. However, I think it would be more correct to say the the atmosphere forces air into our engines. So you could say that our engines don't exactly suck air in as much as they create a vacuum that the atmosphere eventually fills.
So seeing as the air is forced through the restrictor instead of being sucked through it shouldn't we be able to achieve > mach speed through the restrictor? Is the only reason we don't have that condition because the atmosphere doesn't have enough power to push the air in at that speed? Does the turbo provide that extra power to push it through faster?
Am I getting at something here, or am I just out in left field? Set me straight if necessary.
Thanks

[Bill Kunst]

I think your right. The question should be, "what sucks more(vaccum), turbo or engine?"

I think, and maybe I am wrong, that a turbo not only can create a larger vacuum(pressure differential) in most cases, it also creates it at a lower rpm, maintaining that throughout the rpm range. I would guess that if you timed the cams correctly (and created a proper profile) that you could produce a very similar vacuum strength from the engine, but not across the rpm range that a turbo can.

[Joy Pathak]

Well...

hmm...

achievieing a hihg mach number in the restrictor... i was thinking the exact thing while reading my my compressible flow book.
WHAT I THINK.. and htis just an opinion... is that... we should try to increase the inlet pressure...... but try to lower the backpressure..

so the flow that comes in... say.. 1atm or whateer.. say we put in that turbo.. and increase the nozzle speed ... get the converging nozzle to hit Mach 1 at throat... and then lower the back pressure.. so that we can actually get the speed to increase in the diverging part. usually our backpressure isnt low enough so the speed starts to decrease in the part after the throat.

i unno how that wud work... or nething.. just thorowin something out htere.. for ppl to talk abt.. i might be wrong tho..

like i said.. still learning!

[Wesley]

Of course, you know the only thing that affects speed of sound in an ideal gas is temperature. So from a theoretical standpoint, if you could avoid that pesky detonation, intaking several thousand degree air could actually let you exceed the speed of sound relative to atmospheric temperature, while the gas would still be flowing below Mach, relative to its own temperature. Just like a rocket engine right?

The following link makes a good general explanation of nozzles and the physics behind them. No equations, but a good starting point, addressing flow situations in nozzles. It has a fun applet to play around with too!

http://www.engapplets.vt.edu/fluids/CDnozzle/cdinfo.html

[VFR750R]

The mach speed doesn't overcome the density change. Rockets get the mass flow back up with entrance pressure...which we can't change.

[Homemade WRX]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
The mach speed doesn't overcome the density change. Rockets get the mass flow back up with entrance pressure...which we can't change. </div></BLOCKQUOTE>

well.....

lol

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Homemade WRX:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
The mach speed doesn't overcome the density change. Rockets get the mass flow back up with entrance pressure...which we can't change. </div></BLOCKQUOTE>

well.....

lol </div></BLOCKQUOTE>

I know; I get the random comment of the week award. How come someone hasn't recommended ram air again yet?...

[Wesley]

Oh, sure, rain on my parade.
Would putting an icepack on the throttle body be against the rules? I know intercooling is prohibited... but what if it doubles as a drink holder?

[CornellGixxer]

Id rather have a heated cup holder sitting right over the restrictor... http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Bill Kunst]

intercooling is not prohited, just everything besides air to air.

[absolutepressure]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CornellGixxer:
Id rather have a heated cup holder sitting right over the restrictor... http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

Maybe an electrical current running through an aluminum restrictor?...

[Bill Kunst]

so, has it not been resolved as to what temperature of air we want going throught the restrictor?

[Superfast Matt McCoy]

Assuming choke flow velocity changes proportianally with the speed of sound: the colder the air the greater the mass flow.

[Joy Pathak]

c=sqrt(mRT)

yup as temperature increases... velocity of sound increases... lower the temp.. lower the speed..

so choked flow velocity would reduce.

I am all for the Icebag around the throttle body idea. http://fsae.com/groupee_common/emoticons/icon_wink.gifhaha