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Custom made inlet manifold https://www.ausmini.com/forums/viewtopic.php?f=5&t=55586	Page 1 of 2

Author:	EAB [ Wed Jul 29, 2009 9:19 pm ]
Post subject:	Custom made inlet manifold
hey guys (and girls) this is a cad drawing of the inlet manifold i'm going to knock up for frog. Sits the weber carby on top of the rocker cover (and back a bit) so i dont have to move my speedo and cut the firewall up. initially was going for a 180deg u bend to get both inlet/outlet straight, but to get it bent to this diameter was going to cost me 250 bucks. so this is essentially my backup design angles down to a 1.5" bend with a radius of 76mm, height difference between intake/outlet is 190mm and it pushes the carb back 100mm would love to hear what everyone thiks about this! Matt

Author:	Harley [ Thu Jul 30, 2009 10:01 am ]
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What happens to the bonnet?

Author:	sgc [ Thu Jul 30, 2009 11:23 am ]
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Harley wrote: What happens to the bonnet? Mini shaker!

Author:	blue_deluxe [ Thu Jul 30, 2009 11:34 am ]
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Wouldnt that drop the power band down in the rev range? As its quite a bit longer than a standard manifold?

Author:	spraycanmansam [ Thu Jul 30, 2009 12:06 pm ]
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Should give it a heap of torque with those long runners... reminds me of one I've seen on here that had an 8 port and twin webers with a similar manifold design.

Author:	Mokesta [ Thu Jul 30, 2009 12:24 pm ]
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Keep it warm or you'll have shocking manifold wetting issues. That 180 deg change in flow direction will centrifuge the fuel out of the charge onto the manifold wall too. That shape of manifold works a treat on port-injected engines. Not so good with carb. M

Author:	Flute [ Thu Jul 30, 2009 12:41 pm ]
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I used a Redline 3005 inlet manifold with Ramflo 400 series filter and didnt have to cut the firewall or move anything with my 45 weber. Got it ported and then ceramic coated, came up OK.

Author:	Mokesta [ Thu Jul 30, 2009 4:53 pm ]
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Oh, and here's one I prepared earlier... It was for my EFI project that was shelved when I priced-up suitable computers, had 2nd baby, bought another car etc. etc. I have built it and still have it in a box somewhere. M

Author:	EAB [ Thu Jul 30, 2009 5:51 pm ]
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Harley and sgc: yep, fiber glass mini shaker bonnet, painted gold on the green car. blue deluxe & spraycanmansam: I'm not sure if it drops the power band down that much. The race car i'm building at the moment (Formula SAE, not a mini) has tuned runners to 5000rpm which are slightly shorter these ones will be, with the length of these ones it wont have a huge effect on the power curve (i think) its more about torque. At the moment my peak power is about 5500 rpm anyway, i usually don't use that and wouldn't mind it having a bit more grunt lower down. Yes should increse torque which will be very nice in the engine i'm running now Mokesta cant really do much about the fuel wanting to go towards the outside of the manifold, apart from getting as fine a spray as possible. and as you say keeping it warm. If it is bad i'll run two channels along the outside curve and water heat it. cold on the inside of the curve, hot on the outside... do you think that would work well enough? very impressive manifold by the way, how come you ran dual injectors? Flute: i have the big K&N filter already (2"?) and a 5" manifold thats been ported and gas flowed, which wont fit, but i also have some of the smaller filters and a shorter manifold (but would still need to move my speedo). Just having a little fun!

Author:	Mokesta [ Thu Jul 30, 2009 6:36 pm ]
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Intent of dual injectors was to be able to pulse each cylinder as required and to keep injector size down to keep them cheap! Water heating the manifold to keep wetting at bay sort of defeats the purpose because you'll lose air density. M

Author:	MG Rocket [ Sat Aug 08, 2009 2:19 pm ]
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Mokesta wrote: Keep it warm or you'll have shocking manifold wetting issues. That 180 deg change in flow direction will centrifuge the fuel out of the charge onto the manifold wall too. That shape of manifold works a treat on port-injected engines. Not so good with carb. Mokesta wrote: Water heating the manifold to keep wetting at bay sort of defeats the purpose because you'll lose air density. This is what makes engine design/modification so hard yet so interesting..all the conflicts. So much seems counter intuitive....but EAB I believe this could be a worthwhile solution to the problems that Mokesta pionted out... Powre Lynze http://www.allpar.com/fix/holler/head-porting2.html[/b] An easier solution could be..... Is to make the manifold a larger diameter than the port so the fuel is sheared off from a little pool that congregates at the join of the head and runner.

Author:	blue_deluxe [ Sat Aug 08, 2009 2:45 pm ]
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What FSAE team are you in? Im in the QUT team. Got to remember the size of the engine as well and the different characteristics they have.

Author:	MG Rocket [ Sat Aug 08, 2009 3:07 pm ]
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blue_deluxe wrote: What FSAE team are you in? Im in the QUT team. Got to remember the size of the engine as well and the different characteristics they have. I don't know what those acronyms mean....however air and fuel have no idea what size motor they are going into. A principle is a priniple Fuel will stick to the wall of an intake manifold whether its 7 litres or half a litre, an clearly EAB is going to have that concern with his design. These are just ideas to unstick it and keep the droplets fine.

Author:	blue_deluxe [ Sat Aug 08, 2009 3:45 pm ]
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FSAE is Formula: Society of Automotive engineers, its an annual competition between engineering students to make a motorbike powered open wheeler and compete in various competitions. This is the 2007 Queensland University of Technology car: Sorry about my comment, I misunderstood the topic, i was still talking about inlet manifold length, But agree with what MG Rocket said about air-fuel ratio.

Author:	MG Rocket [ Sat Aug 08, 2009 5:38 pm ]
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blue_deluxe, sounds like a fun project to be involved in. Mazda obviously don't make bike engines...are they the sponsors of that great looking machine?

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