V8 induction elbow - Is 90 degrees the best solution?

[keith2.2]

Admittedly, the initial thought behind this is that I'm surprised there is apparently only one option for intake pipe, and particularly 90 degree elbow for the RV8 engines, and the fact that it seems quite a lot of money for a 90 degree bit of silicone pipe!

Should point out - ABSOLUTELY nothing against ACT, and in all likelihood I'll be buying one of their kits..

But in the mean time, Is a radiussed 90 degree bend the fastest / highest capacity way to transfer air from the afm to the plenum?

My first thought was a very slightly radiussed direct join (not quite 45 degrees but you get the idea) and my second was a development of that but allowing for a chamber of air to aid initial throttle pickup - a similar idea is used on the Honda S2000 standard intake, and in a manner similar to the below on a frighteningly expensive piece of kit from a company called J's Racing.

Can anyone with any actual idea about thermo fluid dynamics suggest why the standard 90 degree bend is the best way to do it?

Quick illustration to make my point;

[blitzracing]

I suspect its of little odds on the RV8, considering the size metal lip the air hits where the pipe meets the plenum casting. Anything that causes turbulance in the air intake is bad, and any bent pipe will have different flow rates and some turbulance between the longer side of the pipe on the outside of the bend and the inside as the distance travelled by the air is different. As to if you could measure the affect in power output I doubt considering how crude the rest of the intake system is. There is a guy on Ebay called Mr Silicone who does pipes at a reasonable rate.

http://www.ebay.co.uk/bhp/silicone-hose

There is no point in an air reservoir on the wrong side of the AFM, you wont have the extra fuel to go with it without the AFM metering.

Edited by blitzracing on Tuesday 13th August 13:59

[keith2.2]

And of course there would be little point in trying to reduce turbulence in the 90 degree transfer - even to the point of having an identical sized pipe sleeved onto the AFM / Plenum to remove the step - because it then rushes into the plenum where it meets the trumpets...I'd LOVE to see that modelled on cfd...

[jfjfjf2]

With regard to resistance 2x45deg = 1x90. The more swept the 90deg the better. Do not use pigs bladders.

Julian

[V8Bart]

It was my thought that it could be done on the cheap, 76mm silicone 90 deg elbow off eBay 17 quid, sorted. :-)

[SILICONEKID343HP]

V8Bart said:

It was my thought that it could be done on the cheap, 76mm silicone 90 deg elbow off eBay 17 quid, sorted. :-)

Silicone does not like heat ,the thick rubber one`s from ACT are more resistant to heat.

[blitzracing]

Not sure where that comes from, even crap Silcone hose is supposed to be good for 150'C, whilst good stuff is nearer 500'c. I never managed to do any damage to them when using it for inlet manifolds on the air cooled Fiat engines I used to mess about with, and they ran a load hotter than any water cooled V8.