Inlet manifolds - shape and length!

[bmboy]

I am looking at twin dellortos for my current project (all will be revealed in the coming months) but am unsure about what sort of manifold you give most benefit.
I am going to be making one from stainless (unless you suggest otherwise) and will be using a pair of DHLA-E 's but I have seen them fitted in two different ways. Maybe someone with some deeper knowledge than myself could shed some light of this. Here are some examples;
my.opera.com/PTKdesign/albums/showpic.dml?album=662086&picture=9012830

Short and sweet! That is what I would imagine would be best as the distance travelled by the fuel/air mixture will be lowest and there are no tight bends.

www.rally24.com/res/img/products/skoda-130rs-replica-32770_2.jpg

And that's how Skoda did it back in the 80's. Obviously they must have done plenty of research but no harm in trying to improve on it! Its away from the exhaust which is a good thing from the point of A; safety and B; heat.

Any thoughts?
Thanks.

[lewist123]

Can't offer much help mate, but interested to see what you are cooking up!

In my mind, a straight intake system appears to be the most efficient at allow air into the engine, but other factors like heat soak, carb orientation and other things must play a very important role.

In addition, intake length is also important. So perhaps the bannana manifold was a good compromise between intake length, heat soak and other elements?

[Bozwell]

link i posted a while back

iv'e done loads of research on this and there is a lot of information out there but a lot can be very misleading. diameter and length are very important but unless you make a few manifolds different lengths and diameters you'll never know which works best on your engine. (or purchase some adjustable trumpets like the ones in the link above)

short does not automatically mean more power at high rpm. going longer can increase power through the whole range even at high rpm. there are plenty of free calculators on the web so all you can do is pick a length and diameter as a starting point and fingers crossed it'll work.

[bmboy]

Wow that's great! Thanks, and Lewis I think your last comment seems to hit the nail on the head. The plot thickens......