Do I really need to fit all that air intake hose?

[alzmoore]

So, a hose goes from the grill by the filler pipe to the top of the wheelarch, the air the reappears through the side of the wheelarch and is piped to the inlet to the filter.  Surely all that isn't necessary for a standard road car? The real reason I'm asking is that its like trying to fi a big ship into a small bottle, there is barely room for one hose, let alone two.......

Any thoughts?

Alan

 

[CarBuff]

You are not the only one to think about this...

http://www.lotusespritworld.com/EGuides/EModifications/RamAir_conversion.html

 

FWIW, the Bosch FI Esprits sold in North America and Australia had a direct pipe to the airbox.

 

[alzmoore]

Brilliant..cheers Atwell

 

a

[Qavion]

Just be aware that you get more intake noise in the cabin with that modification. It may not be pleasing to everyone.

[Jacques]

Like who?     I think that a good intake sound is almost better than a good exhaust sound. If I'd wanted a silent car, I might have gone for an Electric one. But each to his own, of course

I think I'll try it out this coming Winter. But I did read something long time ago, about the ram air mod, not being so great in heavy rain. Just saying.

Kind regards,

Jacques.

 

[MrDangerUS]

This large vacuum hose could/should be converted to the smooth bore pipe to prevent negative pressure gradient at the compressor inlet port.

 

See pictures and discussion here:

Comparing corrugated (dryer) hose to the smooth duct of the same diameter, the latter creates less flow restriction.
See results of the test here: www.autospeed
(Scroll down to the heading title "Phase 3" and you see the results).

Edited October 1, 2016 by MrDangerUS

[MrDangerUS]

Here is a diagram for the above modification, see attachment.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~***~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Additional performance improvement can be achieved by introduction of the whirl generator in the turbo trunking duct (close to the compressor inlet).

Air ow coming into the compressor can be rotated in order to in enhance compressor performance. So called positive pre-whirl is when intake air flow is rotated in the same direction as compressor wheel rotation, and negative pre-whirl is opposite. At low engine speeds, the compressor impeller speed is too high in relation to the air ow velocity, so the incidence angle of the blade tip is away from the design point.

Adding pre-whirl in the rotational direction of the impeller (positive pre-whirl) can help to improve the incidence angle and the inlet Mach number is reduced. Since the flow already has a rotational component before entering the compressor wheel, the relative velocity, critical mainly at the wheel tip, is reduced. Inlet Mach numbers can be in the range of 1.5. This speed is associated with energy losses, reducing the surge margin. The lower the inlet Mach number is, the smaller the energy loss can be. If the incidence angle is optimized and therefore the energy loss resulting from ow separation can be avoided again the surge margin is increased. Hence the compressor wheel is able to speed up.The flow already includes a whirl component, so the work done by the impeller on the flow can be reduced, which leaves more energy to speed up the impeller wheel. This can help to improve transient response and increases the pressure ratio for a given amount of the turbine energy. Taking into account information found in the literature,that swirl of greater than +40 of vane angle is negative and that swirl up to +20 can give positive efficiency effects. Comparison of compressor maps with no swirl and 0.11 swirl clearly shows efficiency improvement  and the trend for efficeciency "islands" to move towards lower mass flow (evident in lower pressure ratio area).  For more, see:

D. Guentert, D. Todd, W. Simmons, Flow tests of an naca-designed supercharger inlet elbow and the effects of various components on the flow characteristics at the elbow outlet, Tech. rep., National Advisory Committee for Aeronautic (1946).

http://naca.central.cranfield.ac.uk/reports/1946/naca-tn-1148.pdf

https://www.google.com/patents/US3922108?dq=3,922,108&hl=en&sa=X&ved=0ahUKEwjA1pylk7jQAhVmq1QKHSYHAyIQ6AEIHTAA

US6129511	Oct 27, 1998	Oct 10, 2000	Carrier Corporation	Method and apparatus for controlling interaction between variable guide vanes and variable diffuser of a centrifugal compressor
US6554568	Jun 15, 2001	Apr 29, 2003	Daimlerchrysler Ag	Exhaust turbocharger for an internal combustion engine
US6796296 *	Dec 9, 2002	Sep 28, 2004	Jay S. Kim	Fluid swirling device for an internal combustion engine
US7322191 *	Dec 28, 2005	Jan 29, 2008	C.R.F. Societa Consortile Per Azioni	Device for imparting a whirling motion on the flow of air for supplying a turbo-supercharged internal-combustion engine
US7412830 *	Dec 22, 2005	Aug 19, 2008	Daimler Ag	Compressor in the induction tract of an internal combustion engine
DE2060271A1	Dec 8, 1970	Jun 29, 1972	Kuehnle Kopp Kausch Ag	Verfahren zur selbsttaetigen Einstellung des Eintrittsdralles bei Verdichten der Abgasturbolader und Leitapparat dazu
EP1416123A2	Oct 10, 2003	May 6, 2004	Bayerische Motoren Werke Aktiengesellschaft	Vortex inlet vanes

[MrDangerUS]

This  whirl generator seems to  have a  very low pressure drop. Location: trunking duct/pipe, within 6" from the compressor inlet.

[MrDangerUS]

FYI: Optimal angle of the vein is 38-40 degrees

[MrDangerUS]

Oooops, sorry for the typo

It should be:

Optimal angle of the fins/ vanes should be 38-40 degrees

[MrDangerUS]

Here is a study/dissertation on this subject and a couple of pictures of my CAI pipe swirl insert.

https://hal.archives-ouvertes.fr/hal-01884250/document

[MrDangerUS]

Finally, I have replaced the "dryer" air inlet hose with 3" aluminum tube and silicone elbows/couplers.       My upgraded flow turbo spools much faster, now.  Expected/estimated 20% flow improvement.  Car feels much more responsive.

All parts are from the eBay.  Parts used:

-30 deg bend 3" dia tube, cut to suit

-75deg bend 3" dia tube, cut to suit

-3" to 2.25" (2.5"?) straight reducer from CAI tube to turbo inlet mouth

- 3" to 3.25" ( measure your air box outlet dia) to 3" tube, straight silicone reducer for air box to CAI tube transition.  And, misc. worm clamps

IMO, rear trunk floor has to be removed to fit/clamp everything easily, unless... you are a magician.

[Jacques]

Would there be any merit in giving this tubing a layer of exhaust wrap to prevent hot air from the engine compartment heating up this piping from the outside?

Kind regards,

Jacques

[MrDangerUS]

Jacques,

Yes, excellent idea!

[Jacques]

John,

Regarding the worm clips for the tubing, would there be any gain in securing these by using another type of clamps, like for example the ones that VW use on their cars' drive axle universal joints rubber boots? I have seen the worm clamps turn loose over time, and while not needing to undo them all the time, one might consider this other type of clamp, where one end is pulled through a clamp hole, and then tightened and bent. I've never seen these come loose. Stainless metal as well, so no probs regarding temp.

I don't know about the edges of them , as they are not slightly bent, so they could in theory cut into material of the silicone tubing. But outside on the exhaust wrap on this intake tubing, they would not have that sort of potential issue, I believe. See pic.

Btw. using the worm clamps, I usually give them a bit of sanding with a 80 grit on the inside, so they are a little less prone to go walkabout. Similarly with these clamps.

Using worm clamps on the tubing and exhaust wrap on top of that, I would consider wrapping it in such a way, that the worms on the silicone tubing would be free (very little area), so I could check and eventually tighten them when inspecting the car. Would make it easy peasy. Yes, it could or will lead to heat suck, but I think that would be quite little in comparison. I did that on my old Golf many moons ago. Just my two P.

Kind regards,

Jacques

[MrDangerUS]

Constant Tension Clamps made by Norma or Torro, stainless, FOR Silicone Hoses- they never come loose.

May look for couple of these.