Inlet manifold designs - some science, inc cutting PB manifold up final cut done

recently / this afternoon, i have been investigating the differing styles of inlet for a upcoming project, which will require a custom manifold.

So Audi / Lehmann seem to favour the tapered twin plenums which can be seen here @bufkin engineering

i have also found this HPC - inlet design

i would love to build one like this


any other interesting designs out there?

 

Go on spill the beens Alan... what does it need to flow air into... strong hp 8v?

 

The guys at GS may have one of those if you want a looksie.
Also have other types too for comparison.

 

that would be good eddie, ill see if i can get a sneaky peak next time im there

i understand a little bit of the theory of the inlet design, but the one above puzzles me, why would the trumpets be tilted over at differing angles?

 

oh it will definately be an 8v!! it will always be 8v Jason.

 

a couple of links of interest courtesy of HPR thankyou

http://v-eight.com/tech_forum/viewtopic.php?t=250

http://www.audizine.com/forum/showthread.php/330469-Apikol-Big-Plenum-Intake-Manifold-Updated-w-runner-pics/page1

 

some pics courtesy of HPR again

 

So today i received a pb inlet (Thanks to MikeH) which will be cut up for my custom inlet. as i cut it up ill post some pictures.

I thought that it would be good have a quick look and see what the plenum volume is and the total volume of the plenum and runners.

the plenum holds about 1.8 litres of water, the same as the PB engine... coincidence? the runners hold about another litre of water, the total being 2.75 litres, i could maybe have squeezed a touch more in but not more than 2.8 litres, so the runners are about the .25 of a litre each. ill measure the lengths as we go.

 

the manifold differences on the 2E and AGG

 

There seems to be a clear difference with FI manifolds to NA, the FI often taper where as the NA have a flatter part to the direction of the inlet track. I would have a good look at OEM high performing NA engine manifolds such as Honda, Ferrari etc lots of pics on the net and these have proven to work. The 'after' market manifolds may not always be worth the money you pay, but then again most are FI.

Big volume plenums (1.5 x engine cc or something like that cannot quit remember the figure!) with the entrance of to one side to aid air flow seem to be a good choice, rally cars, ferrari, etc

 

I have a couple of manifoldy projects on the go soon. I will try and persuade Chris to put up some photo's for discussion purposes.
Bikes have started to use different length trumpets on each pot (fours: R1) to try and broaden the power band width. Worth trying?

 

ok, so the first part of the PB inlet manifold cutting up exercise
step one

some pics from the TB end, no cuts at this point
the furniture inside the manifold.





im sure all that crap helps!!!

 

step two - cut the TB mount flange off, i did this because i wanted to keep it for another day.

took this pic, cos my arm was feeling it at this point


never could make vertical cut!!


view down number one


incidently number one runner is 255mm from the top of the port to the floor of the plenum

the rest will be measured as we go along!

section bolted to a PB throttle body, a view you dont see very often



next step, get some metal blades for the Jigsaw!! and slice along the length of the plenum, more to follow....

 

did some more cutting tonight!!










i have now measured all the runners using the same method, they are all within 2-3mm the same length, 255mm!! nice one VW

 

If your arm gets tired, stone cutting discs for the angle grinder work a treat on cast ally from what I've heard

Are you going to add volume by building up the plenum?

 

Did anyone else get the optical illusion where that looks like a fish - head on the right, gills behind...

 

funny i was looking at the 9 inch grinder sat there from when i did the patio thinking hmmm i wonder, i may just try it, now

yes more volume is the main point for doing all this in the pic below, you can see a casting line 2/3 if the way up the runner, that i were i plan to make the next cut, the runners should be almost round by that point

 

just you mike, altho now you have said it i can see it.

 

I have 1 of the lehmann 4 cylinder inlet manifold on my 8v g60t.Ill post some pics as soon as i can.Im also in the process of building a G60 syncro with a 5 cylinder TTRS motor,the manifold on the rs motor is based on the lehmann design ill take a pic of that too.

 

cool that would great, sounds like some interesting projects!!