16v integrale - Custom Inlet manifold project (lots of pics)

Competition engines and ancillaries - general discussion
WhizzMan
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by WhizzMan »

Very nice to see all this, very informative. Where do we order? ;)

As promised, (with Guy's previous permission): A paper about intake trumpet shapes.
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Guy Croft
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by Guy Croft »

I speed-read that article (as many members will know I do, missing things!!), one of many produced by the magazine in collaboration with the late Professor Blair. I went (as one does..) straight to the conclusions. I think the assertion that ...

"on the other hand, in racing, where the last few hp per 100 hp is the difference between winning and losing, the design exemplars discussed above are not to be lightly ignored"

could be slightly misleading, in that, whilst they may be simply comparing various advanced designs and stating (rightly?) that the difference between one good design and another is modest, there is (from my direct personal dyno exp) a huge difference in torque and power between none - mediocre - roll-back, and as most here will know (or at least those who have read my new book) the length of the intake system (from valve to rampipe exit) on atmo engines is a major factor in the exhaust-intake pressure-wave interaction. Not so on turbo units, mind..

G
tricky
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by tricky »

Thanks for the link Whizzman, I think Iv'e seen the paper before (or at least one very similar). Like Guy I only skipped through, but I'll read it properly later on.

Guy, In an ideal world I think I'd prefer the runners to have a 5- 7 deg included angle tapering into the head like the SOHC project in virtual workshop, a little dificult to acheive with this type of design and indeed the 16v head in fabrication terms because of the oval entrance.
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Guy Croft
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by Guy Croft »

I don't think you could better your setup and it certainly gets my approval.

I think in this game (which after all is NOT F1) it is important to retain a balance of form & function vs time and cost. You can drive yourself mad trying for utter perfection in every particular.

G
arguti
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by arguti »

What a work of art and craftsmanship....are you going to make some more for us to buy?

Stephen
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tricky
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by tricky »

Stephen, Iv'e had a few emails asking the same thing.

With the greatest respect I'm not really in it to make a buisiness, it's just for fun as I enjoy tuning as a hobby or should I say obsession ? The labour time that goes into making it is huge that I can't really spare outside my trade. If I can help at all with anything in particular, drop me an email.

Richard
Twice as many valves
LanciaNut69
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by LanciaNut69 »

Hi Richard,

Completely understand the concept of obsession making what you do economically unviable - I have a car like that, which I will post up details about in the not too distant future.

I do have a question however, that I would be grateful for your input/response. You mentioned earlier in this topic the calculations required to tune the length of the inlet runners. Could you point me in that direction or give me the calculations please? I am in the process of looking into changing from individual throttle body injection to plenum, and have the same choice as far as adapting a stock unit over fabricating my own.

Thanks and look forward to hearing from you, and the next update!

thank you

Darren
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Guy Croft
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by Guy Croft »

Without in any way wishing to undermine Richard's work - and readers will know my advice was sought and given on this item - calculations of inlet tract length (where there is pressure above atmos in the plenum) are completely pointless because unlike an atmo engine the (lower) pressure wave in the cylinder sees higher pressure immediately at the inlet valve not the rampipe end so you can't 'tune for length' because there is no length to tune.

Off-boost there may be a case but there the calcs (such as you will be able to perform in a VERY limited way) will invariably tell you that with the rather short primary lengths turbo units have, in order to trigger charge momentum via a wave reflected from a higher pressure zone the inlet has to be, er, longer which is only going to increase the viscous loss under boost.

If anyone doesn't believe me ask the Technical Director of Piper Cams and he will tell you. Better still readmy new book (AGAIN?) because I took time to set this down probably for the first time.

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LanciaNut69
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by LanciaNut69 »

Thanks Guy, and in my case the engine is not forced induction so I am guessing that these calculations are more relevant to me?

Darren
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tricky
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by tricky »

Darren, It sounds like an N/A project with the mention of throttle bodies ? There are calculations to determine a rough outline for runner length but all the maths in the world can't predict the exact effects, software simulation and dyno's are needed to pin point it.

Because it's such a 'can of worms' I can only explian what I meant by longhand, but it won't make sense if you don't understand the principals of acoustics.

On it's own it's a massive topic and very subjective, for that reason I'd rather not publish any more detail in this thread.

Rich
Twice as many valves
LanciaNut69
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Re: 16v integrale - Custom Inlet manifold project (lots of p

Post by LanciaNut69 »

Hi Rich,

Thanks for coming back to me. Yes, the project is normally aspirated - fuel injection ITBs at the moment, but looking to change to a single throttle body with a plenum. I have no broad (or in all honesty even narrow) knowledge of accoustics so will work with what I have and experimentation I guess.

First thing is to maybe source some ready made plenums (HF Turbo ie/Argenta, etc) and see what room I have to play with in a Montecarlo. After that, then perhaps the scratchbuilt option is a better way to go.

Thanks for your time and good luck with the rest of the project.

Darren
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