Turbo Manifold - Size

[actionDAN]

lol this wont end! everyone wants their 5 cents now.

[abently]

Everyone is chipping in their 2 cents because changing runner length is such a band-aid solution most Engineer's wouldn't accept.

This is one of the most technical IC engined vehicle Forums online that I feel sorry for anyone who reads this and goes out trying different lengths looking for more power when infact they are looking in the wrong area.

Here is a properly Engineered Turbo Engine >

http://www.themotorreport.com.au/372...lcon-revealed/

An all-new exhaust manifold has been tuned to minimise exhaust gas flow restriction into the turbocharger and optimise the flow balance from cylinder to cylinder.

More turbine power has been extracted out of the exhaust gas, resulting in enhanced turbo responsiveness and further minimisation of turbo lag.

The reduced internal surface area of the new exhaust manifold maximises heat transfer to the catalyst, improving engine emissions by heating the catalytic converter faster after cold start-up.

Overall, the new exhaust manifold has delivered:

• a 14 per cent reduction in flow restriction

• a 10 per cent improvement in flow balance

• a 42 per cent reduction in internal surface area

• a 36 per cent reduction in weight

The net result of all the turbo system improvements is a significant increase to peak power and torque outputs on the new I6 Turbo engine, along with new levels of engine responsiveness and considerable gains in terms of fuel economy and efficiency.

Maximum power is up by 25 kW to 270 kW at 5250 rpm, while peak torque has increased by 53 Nm – or more than 11 per cent – to 533 Nm, which is available across a wide rev range from 2000 rpm – 4750 rpm.

Remember you don't see Nizpro or the others offering longer exhaust manifolds as a power upgrade for these setups....

[RONA]

Remember you don't see Nizpro or the others offering longer exhaust manifolds as a power upgrade for these setups....

They offer a tuned length manifold which has longer runners then the factory log style manifold. Nizpro Offers this as a further step after all other areas which offer cheaper gains have been exhausted. (I think its like stage 4 of their setups)

The power & torque gains are more from the fact it runs more boost then anything else. BA/BF ran 5.5-6.5psi stock, from what I have seen FG are running closer to 8-9psi which is what the BA/BF Typhoons ran and low & behold they made 270kw & 550Nm of Torque.

So Ablenty can we see some pics of your manifolds.





(ETM Manifold Test Vs Standard BA, same boost only difference was slightly more timing added as it could be without pinging.) I also wonder how much of the gains were associated to the new larger dump pipe as well .

[actionDAN]

so why do the fastest cars on earth have super long runners? isnt it funny how many experts there are on all these forums. you guys should be working for an f1 engineering team instead of wasting your time on these forums. how many of us on this thread are 5'4" and have a 3" penis? i cant be the only one. i'll just post up a few more links and quotes...thats sure to give me atleast another inch

[oldcorollas]

what your quote of the Ford marketing blurb doesn't mention is...
the new cylinder head and plastic 1-2-6 intake manifold...
that boost has almost doubled, from 0.4 to 0.7Bar...
that they use higher efficiency garrett turbo...
they used a new higher efficiency intercooler with less restriction...
and also slightly increased compresison ratio of 8.8:1 (this is a highly developed engine? )

and yet after all this... their 4L turbo engine with 0.7Bar boost only produces 533Nm?
if this was an efficient turbo motor, then they SHOULD be getting 680Nm of torque. (or at least 650)
it means the engine is only running about 78% efficient compared to a WELL DEVELOPED motor


abently, the problem is that you link reports and papers to back up your claims, BUT they don't...at all..?

you said larger runner diameter is better.
to prove that, you link a bodgy conference paper which talks about REMOVING an intended restriction for high boost DIESEL motors (the pulse convertor, in use since 1974 and well developed now) and SIMULATED improvements by having half of the manifold as 4-2-1 style, and half the manifold as a log style....
but that paper doesnt support your claim at all? even disregarding how bodgy the paper is, there is nothing in it regarding runner size......
you COMPLETELY missed the point of the paper..... (i still cannot fathom how)

many people can be right for the wrong reasons, but that doesn't excuse that you use strange and non-supporting data to "prove" your points when you are pretending to be scientific about it......

anyway, this is "peer review"
if you can find anything at all to support your claims, i am happy to check for you

[oldcorollas]

so why do the fastest cars on earth have super long runners? isnt it funny how many experts there are on all these forums. you guys should be working for an f1 engineering team instead of wasting your time on these forums. how many of us on this thread are 5'4" and have a 3" penis? i cant be the only one. i'll just post up a few more links and quotes...thats sure to give me atleast another inch

Dan, which are the fastest turbo cars on earth with long runners?
drag cars (Titan?), salt lake racers? indy/champ cars?
which ones are you referring to?

(btw, toymods is a hobby AWAY from work )

[TA22 1MZ]

so why do the fastest cars on earth have super long runners? isnt it funny how many experts there are on all these forums. you guys should be working for an f1 engineering team instead of wasting your time on these forums. how many of us on this thread are 5'4" and have a 3" penis? i cant be the only one. i'll just post up a few more links and quotes...thats sure to give me atleast another inch

its all good mate, dont get worked up about it.
These forums are an awesome tool because you get to dicsuss so many options/ideas and generally get quality feedback on the matter. However, some times there are people who also post info which is bulls*&t and not proven.
Thats why there are a few 'moderators' (like oldcorollas, the real roadrunner, etc... who have been playing with cars for years and have a very good handle on whats right and wrong) as such who do like to ensure what is written as factual info is indeed based on real life testing/experience.
This needs to happen otherwise alot of newbies could come on and be lead down the garden path following someones info which is completely wrong. As already mentioned in this thread, show us some pics of your manifolds and results gained vs a control manifold. If your results prove a theory wrong, awesome, everyone gets to learn something new

[abently]

OC, yes but there are noise and emission restrictions that Ford have to adhere to.... and then space constraints, Warranty/longevity issues etc etc.

If you want to see some real scientific testing on different exhaust manifolds and its effects, feel free to buy this > http://www.sae.org/technical/papers/2005-01-3812

It clearly confirms what I and others here have said about exhaust manifold volume and its effects.

[ed]

i love these threads

[oldcorollas]

OC, yes but there are noise and emission restrictions that Ford have to adhere to.... and then space constraints, Warranty/longevity issues etc etc.

If you want to see some real scientific testing on different exhaust manifolds and its effects, feel free to buy this > http://www.sae.org/technical/papers/2005-01-3812

It clearly confirms what I and others here have said about exhaust manifold volume and its effects.

do you actually have a copy? or are you just linking and pretending it agrees with you? i'm checking my sources now

in what way does it clearly confirm what you are saying? please state how and why.

I am intrigued by this statement from the abstract

The GT-Power models of all nine setups were calibrated against the measured data. The need for efficiency and massflow multipliers is described. The efficiency multiplier depended on mass flow through the turbine, with a distinct minimum value (0.7-0.8) around 0.03 kg/s and higher around that. The efficiency multiplier could not be shown to depend on pulsation amplitude of the turbine inlet flow.

that means..
the model they used did not match the experiment.
They had to use a "fudge factor" (efficiency multiplier) to make the data match.
The fudge factor didn't have any correlation to the size of the pulses...

and yet the paper is titled
"Calculation accuracy of pulsating flow through the turbine of Si-engine turbochargers - Part 2 Measurements, simulation correlations and conclusions"

so that means their simulations didn't work?

checking back on Westins thesis from 2002...which was on "Accuracy of turbocharged SI-engine simulations"

This licentiate thesis deals mainly with modelling ofturbocharged SIengines. A model of a 4-cylinder engine was runin both steady state and transient conditions and the resultswere compared to measured data. Large differences betweenmeasurements and simulations were detected and the reasons forthis discrepancy were investigated. The investigation showedthat it was the turbocharger turbine model that performed in anon-optimal way. To cope with this, the turbine model containedparameters, which could be adjusted so that the model resultsmatched measured data. However, it was absolutely necessary tohave measured data to match against. It was thus concluded thatthe predictivity of the software tool was too poor to try topredict the performance of various boosting systems. Thereforemeans of improving the modelling procedure were investigated.To enable such an investigation a technique was developed tomeasure the instantaneous power output from, and efficiency of,the turbine when the turbocharger was used on the engine. The project’s initial aim was to predict, throughsimulations, the best way to boost a downsized SI-engine with avery high boost-pressure demand. The first simulation run on astandard turbocharged engine showed that this could not be donewith any high accuracy.

he hasn't had much luck with those simulations

further to that, the SAE paper you linked was FROM his thesis... and this is what he had to say abotu the manifold part

Chapter 8, and papers 6 and 8, covers the last investigation of this work. It is a broad study where the impact of design changes of both manifold at turbines on both simulation accuracy as well as engine performance. The scientific contribution here is that the common theory that the simulation inaccuracy is proportional to the pulsation amplitude of the flow is non-valid. It was shown that the reaction was of minor importance for the efficiency of the turbine in the pulsating engine environment. Furthermore it presents a method to calculate internal flow properties in the turbine, by use of a steady-flow design software in a quasi-steady procedure. Of more direct use for the industry is important information of how to design the manifolds as well as it sheds more light on how the turbine works under unsteady flow, for instance that the throat area is the single most important property of the turbine and that the system has a far larger sensitivity to this parameter than to any other design parameters of the turbine. Furthermore it was proven that the variation among individual turbines is of minor importance, and that the simulation error was of similar magnitude for different turbine manufacturers.

throat area of TURBINE.....

[oldcorollas]

by the way, i have his doctor thesis on which the SAE paper was written.. Ed, you want a copy?

hmm, interesting..
he found that increasing the manifold volume decreased the amplitude of the pulses BUT that this correlation is not straightforward.
the main reason was the increase in diameter of the tubing of the 4-1 and the log manifold, due to the expansion of gas and loss of velocity,
to maintain high gas velocity and high pulse amplitude, the best solution is to keep the pipe the same diameter of the port, and then the length does not have so much effect.. more reading needed after work.

oh look.. here are the manifolds they used

also, did you realise they are only testing to 1800rpm?


from the (very short) conclusions..

"according to measured/calculated turbine efficiency the turbines seem to be poor at absorbing the first and most powerful part of the exhaust pulse"

which is what turbo and diesel manufacturers have known for a long time anyway
ie, setting up a manifold mainly for pulse does NOT extract the greatest efficiency.

however, he did confirm that dumping the exhaust into a 5 litre bucket before the turbine was suboptimal

[abently]

Yeah, I've got the SAE paper, but not the thesis (can you link it here ?). I know it wasn't be all end all testing esp with the fudge factors but it was as reasonable as you can expect and is inline with current OEM trends.

Garrett themselves state that longer runner Turbo manifolds is purely for inertia tuning at the disadvantage of turbine response.

There has been some development in turbine efficiency and interestingly the latest BorgWarners turbines come across as peculier.

Pulse tuning does occur at many different lengths though so a reasonable balance should be able to be struck if one desires.

[JustenGT8]

What a great thread to jump into 11th hour multiple parallel discussions going on within the thread confusing themes but as a general contribution, the manifold needs to be 'fit for purpose'.

A race car use only manifold may indeed benefit from longer runners as it's operating environment is much narrower than what most here would experience with their more general purpose cars. Other components on a race car, like the turbo, are also optimised for a more specific purpose which again may better suit a very specifically designed manifold eg those crazy FI manifolds.

For an all round performer i have found little benefit by playing around with longer tuned length manifolds, nor going to the trouble of split pulse or equal length.

The attributes i have seen work are things done to retain heat and velocity in the exhaust gas....eg ceramic coating, exhaust wrapping and generally shorter, smaller diameter runners. No change in max power, but gains in response were made for sure.

I would love to try a decent merge collector as per what Linden and Kyle use to see what that delivers but bugger all room in my current setup to fit them.

Theories are a great place to start thinking about your application and/or look for why something isn't working but real world results are where it's at and a heap of experience here that should be considered.

[godlovesugly]

so loner runners could possibly give you a little more power and shorter runners will definitley give you better response??

im confused lol. but kudos to all for not resorting to name calling, you are stronger than i am :-p

[oldcorollas]

is publically available
http://kth.diva-portal.org/smash/rec...pid=diva2:7928

it is too easy to overthink turbo manifolds.
turbo works by absorbing energy from the exahust.
the energy is available in the form of both temperature and momentum of the gas (not inertia)

as the gas goes through the turbine, it reduces in temperature, (which also reduces the volume and pressure) and reduces in momentum (the speed energy as such).

the driving force across the turbine is the temperature differential and the pressure differential.
to make turbo work bestest, you want to maintain both those gradients as much as possible.

in reality, you improve the dump side of turbo by increasing the size. this both reduces backpressure (friction if you will) and provides an expansion chamber that will also reduce pressure..
you could try to reduce temps, but the rate of heat loss on the cold side is much slower than the hot side, the the effect is marginal.

on the hot side, for maximum turbine efficiency, you want to have gas with the highest temperature possible, with the highest momentum, and the highest pressure.
high temp is maintained by using thick walled or low conductivity metal, or by ceramic coating, or by reducing the length (for thinwalled manifolds).
reducing thermal mass is beneficial as it takes less time to reheat before turbo get eficient. thinwall also helps, but may reduce the max output of turbo.. etc (it is all a matter of degrees)

highest momentum = highest velocity. ie, don't increase the pipe diameter, except to reduce friction.
highest pressure = don't introduce restrictions/points of loss.

BUT,. that pulse converter you first linked to has the job of increasing the pressure before the turbine. it was shown thermodynamically that having the tapered entry to the log manifold had the effect of increasing velocity and pressure before the turbine, whilst reducing backflow toward the exhaust ports.
the paper you first linked, i think, is wrong in it's assumptions and simulations. too simplistic.
the manifold pressures in a high pressure diesel engine are very high, much higher than is acceptable in a petrol engine, but because they have high compression and small combustion chamber volume, the problem of residual gas is not so big, plus, the extra heat can be beneficial for compression ignition for efficiency. but for petrol engine you want low manifold pressure.

after all that, you start to think abotu the fluctuations in the pressure.. ie the pulse tuning per exhaust pop.. but as mentioned in the thesis and around the place, the initial part of the pulse is not effective at spinning the turbo. it is better to maintain a higher constant flow of higher temp, higher pressure, higher velocity gas.

the split pulse scroll does that by taking a given mass of gas, and maintaining the velocity all the way to the turbo = higher momentum and higher pressure.
ie, if you the 4-2 parts into the 2-1, that final bit you are expanding too much (pipe diameter too big ) and losing energy.

however, from engines point of view, you want to reduce manifold pressure, as that increases the amount of residual exhaust gas. that in itself is not bad for fuel efficiency (in fact it is good) but it reduces the potential power output etc etc.. so you have to only concentrate on keeping up the temperature and the velocity (momentum), whilst not restricting maximum flow (but max flow is much less of a concern then lower velocity, except for a single rpm engine, and even then you are limited by turbine speed, so proper placement of wastegates can assist with flow and pressure, while maintaining good conditions for the turbine)


ideal manifold (from the turbos point of view) =
small diameter to reduce expansion and maintain velocity, but not so small to introoduce too much wall friction or reduce total flow.
low heat capacity material for the manifold or ceramic insulating layer on the INSIDE to maintain higher temperature to the turbine
shorter length to reduce heat loss (but mostly negated by the use of proper materials/coatings), but long manifold is not really bad, and could be good from a pulse reflection point of view and aid in scavenging. long manifold can also help to maintain a more constant pressure at the turbine entry which increases efficiency..


but hey, thats just my musings.... based on many papers and the experience of good manifold builders