6 replies to this topic

[podifold]

I've being doing a bit of research lately into the SPI manifold and how aspects of it's design might improve my fuel injected supercharger manifold.

 

I came across this discussion (http://mini-racing.f...dmission-de-spi) on a French forum about the half round shapes inside the inlets just before where the locating rings would be.

 

Anyone on here know what they're for?

 

[podifold]

I also found this thread from 2010 but no-one seemed to know for sure.

 

http://www.theminifo...inlet-manifold/

[minifreek1]

According to what Iv deciphered on that French site, the Coopers don't have the C shape on the inlets.. (bottom picture)

 

I would have thought its to create turbulance in the mixture before it enters the head/combustion chamber...

 

The smoother would have better flow charactristics at a guess, but can't see how it would make any improvements for performance...

[podifold]

I also found this video a while back. I know it's not exactly the same as our manifold but it does show how a small change to the incoming flow path can make a big change to what happens downstream of it.

 

Watch from 3 minutes in:

 

[podifold]

Any ideas? I found another thread that implies it's to do with evening out the mixture but I'm struggling to understand how it'd work.

 

http://www.theminifo...inlet-manifold/

 

Did Rover manage to stumble on something to lessen the effect of the siamese port charge robbing just before they moved over to the MPI system or is this something else?

 

I wonder what effect something like this would have on a standard alloy manifold running a carb?

[podifold]

I know there's only me interrested in this, but I found another thread that mentions this:

 

http://www.theminifo...be-looking-for/

 

Near the bottom someone implies the "lugs" have an effect on fuel distribution, saying:

 

 

I tried porting the SPi inlet manifold and found that removing the lugs gave fueling problems between the inner and outer cylinders.

[RooBoonix]

 

I know there's only me interrested in this, but I found another thread that mentions this:

 

http://www.theminifo...be-looking-for/

 

Near the bottom someone implies the "lugs" have an effect on fuel distribution, saying:

 

 

I tried porting the SPi inlet manifold and found that removing the lugs gave fueling problems between the inner and outer cylinders.

 

 

Unfortunately I can do little to help, but I'm currently taking my engine out my SPi and I am glad I found this thread as I was going to do some porting to my inlet but I'll leave it alone now!

 

Hope you find a colution/definitive answer and you can make another awesome product (I follow your Podifold thread, I find your work amazing). Good luck!

 

Cameron.

 

edit: quickly thinking, no idea if this would work, but could this be tested using 2 different manifolds 1 with the C-shaped bits and 1 without.. on an engine with a scatter pattern cam and one without? Because aren't scatter pattern cams designed to minimise the effect of charge robbing and in effect may help determine whether the C-shaped inserts are to help with this problem?

Edited by RooBoonix, 19 November 2016 - 03:14 PM.