Turbo Manifold - Size

[oldcorollas]

are you sure that is relevant to 4 or 6 cylinder petrol engines?
do petrol engines usually have "pulse convertors"? ie venturi type restrictions in the exhaust before the turbine??

so for their bodgy, barely referenced study (which is primarily just simulation),
pulse turbocharging is 4-1 type manifold to each turbine
Pulse convertor has 4-2-1 type manifold to each turbine
modular pulse convertor = log manifold..

and their new mixed pulse convertor... is simply half the cylinders in a 4-2-1 arrangement, then going into a log manifold?

did you read the paper before linking it?

no seriously, what does this have to do with pipe diameter?

(not to mention that this looks like a masters student type paper presented at a conference called the "International Symposium on Heavy Vehicle Weights and Dimensions", with 5 references which are all about 20 years old...hardly inspiring stuff)
http://www.mne.psu.edu/ifrtt/Confere...006/OpenMe.htm
http://www.mne.psu.edu/ifrtt/Confere...s/session2.htm


find something from SAE to back up your claims

[1JZ-Rolla]

I was wondering the same thing oldcorollas, but just figured it must be too complicated for me & I was missing the point or something......

[abently]

I'll quote the relevant sections some time tomorrow if you haven't found it by then.

[oldcorollas]

please do.
part of my job is to peer review papers for conferences and journals
i think (hope) i am reading the paper correctly.

while it mentions better scavenging, adn lower temps, the diesel and petrol engines are rather different, adn having a mixed "tri-Y" and log manifold is a far cry from "having shorter manifolds" or "smaller pipes are worse".

but i am happy to wait for your detailed explanation IN YOUR OWN WORDS

i will peruse the paper again tonight, but their starting point is the deliberate restriction in exhaust manifolds.. for diesels, to reduce the reflected wave...

[The Real Roadrunner]

Actually on this topic you will find I hold all the cards.

I'll link up the scientific test report disproving the theory later on tonight.

your talking about the joker cards yes?

i would love to see the relevance of diesel technology designed for long continous low rpm operation and what affect it has on high rpm petrol engines that constantly vary rpm.

Like Dan i would also like to know how many manifolds you have built aswell as some data on how they performed, i can atleast backup any information i give with results to prove them

cheers
linden

[actionDAN]

i think the 4agte that gained 25kw (approx) at the wheels from longer runners put out about 180kw's at the wheels after the gain. i made both turbo manifolds and they both had a high flow design, and same size i.d.

in reguards to rally car manifolds...the ford focus runs an extremely long manifold! but most just use the stock cast iron one.

[abently]

(not to mention that this looks like a masters student type paper presented at a conference called the "International Symposium on Heavy Vehicle Weights and Dimensions", with 5 references which are all about 20 years old...hardly inspiring stuff)
http://www.mne.psu.edu/ifrtt/Confere...006/OpenMe.htm
http://www.mne.psu.edu/ifrtt/Confere...s/session2.htm


find something from SAE to back up your claims

Lol, well the paper I linked is available for purchase from SAE.org if you want to instead ? (http://www.sae.org/technical/papers/2006-01-3390)

Anyway, just some relevant quotes >

In the pulse converter turbocharging system, there
exists nozzle’s or throat’s area reduction, which causes a larger loss of fluid available energy.

There is no throat’s or nozzle’s area reduction in exhaust
manifolds, so the pumping loss in cylinders is smaller.

Because of the lower pumping loss, the
BSFC of the diesel engine using the MIXPC turbocharging system is lower than that of the diesel engine using the MPC turbocharging system. For example, the BSFC is decreased by 4.3g/(kW×h) at 100% load and 3.9 g/(kW×h) at 56% load.

Obviously the results will vary from engine to engine, but the fundamentals remain the same. There is no sane reason to run smaller or larger CSA piping than the exhaust ports CSA in most modern Engines.

You have to remember the exhaust manifold is just one part of the whole system and that you have to keep that in mind when you see unexplainable gains otherwise your just walking blind.

[oldcorollas]

you seem to miss the point of the paper..

in petrol car engines they do NOT use a pulse convertor nozzle.

this paper is VERY simplistic...
all they are really saying is that by removing the pulse convertor nozzle, they reduce pumping losses, and therefore increase output. But they completely disregard the thermodynamic reasons for having the pulse convertor in the first place.

how abotu you look at why the pulse convertor nozzle is there in the first place
the paper is.. not very good quality at all, and certainly no justification for claiming that smaller pipe diameter is worse. it looks like an undergrads ticket to a conference

in fact the paper has nothing to do with pipe diameter, and is only talking about removing the pulse convertor nozzle...
strangely enough, exhaust were used without the pulse convertor nozzle before....


edit: here let me help you with the patent for the pulse convertor.. which was from 1974
http://www.freepatentsonline.com/3786630.html


Actiondan, unless restricted to using stock manifolds, you migth find the WRC ones are cast out of Inconel nickel based alloy. thinner, lighter, stronger... much more expensive (but they look like stockers from the outside)

[actionDAN]

oh i didnt mean the wrc cars. ive never really been around them. the ford focus wrc car defenatly uses hand fabricated inconel tubular extractors. sux how many restrictions they have on them cars

how many ppl on here have actually made any of this stuff they are quoting? seams like everyones an expert on the internet! hello ego?

[abently]

I and some of the others here I assume have also.

I haven't had any trouble with the extremely short manifolds maxing Turbo flow which is why I'm inclined to say, if you do find substaintial gains from changing lengths then you have an issue somewhere else.

Most of the cast looking WRC manifolds I believe contain high levels of nickel and whatever else they can use to minimise thermal conductivity. Obviously the header designs are made from Inconel (625 I think).

[abently]

actionDan, Ok, I (and I'm sure the others will chime in) will try and go through why you got the result you did.

You stated, the power increase it made was on 1psi less Boost. That doesn't help much unless the test was done back to back on the same day ?

Assuming that Boost was equal and power increased, then you could speculate that inertia tuning is what occured here with the longer manifold. But this also raises the question of what EMP was like and what the cam timing/overlap was if FI alone could not emtpy and/or fill the cylinder or prevent reversion ?

Like I said before, I don't like to walk around blindly and I'm sure you don't either. Overlap/reversion is a real and power zapping issue in Turbo setups with an extremely small Turbine housing at the top-end but you did essentially more than double the manifold volume... and on a 400cc cylinder, that would effect pressures.

[actionDAN]

this debate is getting old! im going to make some toast. cya

[abently]

I know you've personally made probably over 100 manifolds and would of done many back to back testing of them and I know that on many occasions gains are made with the longer runners, but on a properly designed/Engineered setup, you should not gain more average power with a such a large runner length change. I'll let this thread be.

[actionDAN]

yeah i defenatly dont disagree with you, im just lazy to carry on

[The Real Roadrunner]

how many ppl on here have actually made any of this stuff they are quoting? seams like everyones an expert on the internet! hello ego?

over 300 manifolds so far, 2 in the last 2 days.

Abently, just because you on holidays from primary school doesn't mean you should come into the tech section talking total and utter crap. unless you actually post some pics of manifolds you have built and techniques you have used i doubt you would even know where to start.

Dan, why would you use CAD software to design a manifold? seems like you would waste more time designing than you would if you built the same mani 3 times.

32nb pipe on a 4a to only achieve 180rwkw after it gained 25kw, why bother? 25nb will happily do 50wkw+ per runner and give less lag and make more power than the same manifold built in 32nb, been there proved that.
Btw 760mm is way to long for a small capacity engine, you would lose a shitload of heat and reduce the exhaust pulse to next to nothing by the time it got to the turbine.

cheers
linden