Intake manifold discussion

[curtis]

Trying to make this area technical again.



First Chris Plesko and Pivvay started this fiasco years ago, If you never heard of Pivvay aka shifted thinking do a search here Chris and his car Pivvay were one of the founders around these parts newbez....I found the results graph here

click me for picture

Now over a year ago Dave Buschur started it again on the evo stuff....Later he made friends again with Marco at Magnus and after just reading through the new edited thread seems like he make a really fair unbiased attempt to level the playing field.

click me

Now if you just read through that the Kanasi and Hypertune seemed to fair better I really think its something with the angled mount on the throttle body. Two I wish he would have tested is the Thailand southeast Asia angled t-body mount intake on ebay and a Hawver. The Hawver is a normal mount but plenum and runner design is about the same. I had to weld up the ebay type last summer for a local that split it racing Toretto at our local track. /ubbthreads/images/graemlins/grin.gif The plenum and the lower are both cast but cast separately then tigged together. As usual the manufacturer made pretty welds and didn't worry about penetration, I guess there married and use to it. Again another /ubbthreads/images/graemlins/grin.gif

Reason for this I've been watching for a manifold to finish everything I need for the motor. I'm still going to build a cyclone style one with long / short design but need the car done first and this will give me something I can test against. A week or so ago a local started parting out his 10 second car and I picked up the Hawver he had. Now I have more than enough t bodies in the shop to use, a bunch of 65mm ford units, 3 dual butterfly ford units, a Q-45 90mm and a stocker. Even have the idle motor area milled off of a stocker so If need be I can weld it to the bottom of the twin butterfly. I really want to use one of the Ford units its two 57mm butterflies and is progressive rate on the secondary so throttle response will be about the same at idle and just tooling around in traffic but at about 30% the second one opens to 100% when the primary does so mid range response and downshifts should be kick ass.


Now to mount this on the Hawver I would need to machine the inlet to at least 81mm's and machine 4 new holes, Planning on making the holes on the Q45 bolt center arrangement so if I ever or the next owner wants to use that it would be done.

Now the question is If I machine a flange for the twin butterfly ford and have it mount at 45 degrees + or - a little for the IC pipes then machine a flange for the original t-body mount do you think I should just go from the oval on the ford to a round 90mm or stay at the 81mm. I know it sound anals and not that much but going from 81 to 90mm is alot of surface area when your talking airflow.
Staying at the 80 is more velocity compared to the 90 but by having the throttle body angled more like the HKS or the Hypertune I'm hoping to even out / balance the runners. I really think thats the secret to those to manifolds. But maybe the loss in velocity and the air going turbulent is a good thing. I don't have a flow bench local at my disposal but I could just machine out two different sets of flanges and build two and ship them off to Chris to test.... but large ovals to round holes in a bend is a pain in the ass to bend and fabricate. Kind of hoping someone has remote mounted a t-body before and has some input. If not no big deal.

Hope you enjoyed the links above and here's the Pivvay site click me

 

[BoostedAWD91]

Thanks for starting this thread Curtis. I was trying to find this out last year when I bought one of jmf's and there wasn't any recent discussions or tests with all the new products out there.

 

[Whoodoo]

Quoting curtis:

Staying at the 80 is more velocity compared to the 90 but by having the throttle body angled more like the HKS or the Hypertune I'm hoping to even out / balance the runners. I really think thats the secret to those to manifolds. But maybe the loss in velocity and the air going turbulent is a good thing.



This is true, however with intake design, higher velocity is not always a better thing. In order to really find out what is best you will need to put it on a flow bench. For what its worth, I would think that staying larger would be better because the throttle body is a choke point in the intake system, and keeping it larger would reduce restriction.

One theory as to why the angled throttle body intakes are better is this:
Moving air has inertia just like any other moving object. By having the throttle body at an angle, the air entering the plenum has a component of velocity in the direction away from the runners. This essentially 'throws' the air towards the back of the intake allowing for a more even distribution to the runners.

 

[belize1334]

To me the most interesting part was the discrepancies between the flow rates of the different runners on any given manifold. He quotes the stock manifold at 327, 308, 300, 300 respectively. That puts two holes running 2.5% rich and one running 6% lean. I'd like to see similar numbers for the 1G and 1G-cyclone manifolds averaged over a few samples so that injectors could be more carefully sized to get consistent AFRs across the board.