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Turbo Intake Plenum


MONZTER

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Hey Guys:

 

Here's a Plenum Model we are trying to work out the details on, and before the daggers start to fly, we have been talking with and getting Jeff's input on this behind the scenes in hopes to bring it forth into Production.

 

The approach we are trying to take is from a "CAST" Perspective, and not a custom solution this will help keep Cost's in check and affordable!

 

Our Main Goal is 2 fold, a Balanced Normally Aspirated Engine being fed COLD air and Forced induction, from a cost stand point!

 

Stay tuned as I am trying to get the Files to Jeff so he can run a FLOW/Distribution analysis on it!

 

This is a 3 Part Plenum based on our Plenum Plates and a Cover like we have produced in the past on a Custom basis! The Difuser is an Extrusion and just welded/bolted to the inside of the Cover!

 

Again we are coming from the point of building a plenum that #1 Works to evenily Balance/Distribute Air flow and Cost, so some parts/looks will not be optimal!

 

Now the Input! :)

 

Thanks!

 

Kevinl_4b21cf629e74d741a3f580f6e2d57ba9.jpg

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Jeff, if the HKS Type 2 was to have a series of holes bored in the wall separating the upper plenum from the lower plenum, what kind of flow icrease/improvement would there be?

Reason I'm asking is the Type 2 will be going on those HKS ITB's, and I really have no need for the restriction in the upper plenum...but would like a better flowing 'period correct' looking piece when I install it on my 73.

 

I'm thinking I can access the wall with a drill bit through the carb openings, and then enlarge the holes by hand with a right angle die grinder.

 

Yes, I could use the Type 1 in the application, but the Type 2 is what HKS was hawking for the ITB's when they came out.

 

Thanks!

 

Hi Tony, I did the mods you requested, and it appears as I thought, the restriction is not between the upper and lower plenum and not really the problem. Here is what I did -

 

1.) Standard HKS Type 2 - flowed 442CFM at 25"

 

2.) Standard HKS Type 2 - Same test but without the bolt on inlet, just straight into the two openings on the plenum - 640CFM at 25"

 

3.) Standard HKS Type 2 - same test but opened up the outlet from the bolt on inlet as big as possible between it and the plenum - 582CFm at 25"

 

4.) I also tested it with the same as above, but with 1 inch holes in 4 places between the upper and lower plenum like you suggested - no real difference, just the flow into the runners did not seem as even. Pictures below are of this test. As a side note - with the above changes the pressure drop went way down as well.

 

My opinion would be to leave the plenum alone and work on the bolt on inlet. Currently the inlet is only 60mm inlet where the others I have been testing are at 70mm. (Rons flowed a huge 844CFM and mine is at 650CFM both at 25â€) There is a lot of thick walls in the inlet and some serious porting really seems like it would help without messing up the nice even flow.

 

I hope this helps :icon42:

 

Jeff

 

 

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tony_d_mod1.JPG

 

tony_d_mod3.JPG

 

tony_d_mod4.JPG

 

As usual, click the pics to enlarge

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First and Foremost! Don't thank me, thank Jeff, Tony and Super Dan! They have help us more than you can imagine!!!!!!!!!!!!!!!!!!!!

 

Prox we have a ton of stuff going on here, and we are trying to get something out there for the 6 cylinders, as we are working diligently on it!

 

We are also working on Flathead's, Rotory's, Nissan's, OEM projects! LOL! :) Please bare with us guys!

 

Our CAD system is different than Jeff's so I am hoping he can take our CAD files and do a simulation on it!

 

Kevin

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First and Foremost! Don't thank me, thank Jeff, Tony and Super Dan! They have help us more than you can imagine!!!!!!!!!!!!!!!!!!!!

 

Kevin

 

I also don’t want anyone to forget Mike (TurboBlueStreak)

 

He is the computer genius who started this hole CFD testing process. He taught me how to do it and I thank him. He was also responsible for all of the first test, as well as Ron’s test. He is currently working on some really good stuff.

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Here are some shots of a standard 4x4x24 box with a 70mm inlet. Same 20psi boost at 793 cfm. Just as expected runner #1 not looking so good.

 

Again, click on the picture for a bigger view:

 

cartec4x4pressure.JPG

 

cartec4x4velocity.JPG

 

I was looking at the flow pattern and at the front of the box and carb #1. It looks like a diffuser plate just inside of the box would improve air to the first carb. I mocked up one out of 3/4" copper pipe that is split apart and will be silfossing back together and is about 1-1/2" across. This would cause turbulence in the front of the box and would force air to carb #1.

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Well it’s been a long time since I have posted any new test results. I have been busy working on the plenum, really trying to get it dialed the best that I think it can be. If this work really pays off, well I guess we’ll see, But for right not the difference between this final design and my last design I almost settled on is dramatic. Before I had vortices that really hurt the flow balance between each runner as well as the total flow (see the first few pages).

 

So here is what I did –

Step one was getting the pressure across the slot evenly by changing the width of the slot, the thickness of the slot, and of course the taper of the sub-plenum. Even with this pressure balance out, I was still getting vortices once the flow moved into the plenum and stated down the runners. For example it had a runner mis-balance of about 30% - that’s pretty big if all this info really translates into real world.

Step two was the idea of adding the ribs or flow diverters. By simply adding these and then adjusting their length slightly, I am now able to get the flow per runner balanced within 3% of each other. Keep in mind, there are 2 different ways I checked the runners. The first way was 1 runner at a time, but this is pretty easy with our plenums for z cars because we don’t have a bunch of odd runner shapes to deal with. When I tested this way all runners were the same within 1 cfm with a total flow of 226cfm per runner at 25”. My intake ports that were done by Rebello flow 210cfm at 25” so that should be a good match. I then went on to test the plenum flow with all 6 runners open at one time, and got the 3% difference. So what this means is if you hooked the plenum up to a flow bench with all 6 runners attached, all 6 runners would flow the same (within 3%) with a total of 671cfm. Now which test is more important, one at a time or all at one time, I don’t know, but I figure if they are both good then I have my butt covered.

 

So here are some pictures of the test with just the slot and no flow diverters. Keep in mind the range is only about .25psi from the lowest to the highest on all of the pictures.

 

cfm_1.jpg

 

cfm_2.jpg

 

cfm_3.jpg

 

Now here is the same plenum, with the flow diverters added. Big difference huh.

 

cfm_4.jpg

 

cfm_5.jpg

 

cfm_6.jpg

 

cfm_7.jpg

 

cfm_81.jpg

 

cfm_91.jpg

 

cfm_101.jpg

 

cfm_11.jpg

cfm_12.jpg

 

Ron and I have been going back and forward on how to prove these test are valid and worth all the effort, I’m not sure, except for what the dyno will say. TurboBlueStreak who started this testing is doing some great work with port design and the computer. Interestingly enough his model of a stock port flow within a few CFM of what a stock port flows on a real life flow bench. I have also tested the flow of 40mm throttle bodies and have gotten the same flow numbers that were told to me by the guys making the extrudabody ITB’S. So I am confident the numbers are pretty close.

 

I guess to sum it up – We just have to remember this testing is just a tool, and only part of the process. Call it very educated guessing and we’ll see how it ends up on the dyno.

 

I am turning over the IGES files to the machine shop, and moving forward with the CNC proto. I’ll post some pictures of the real part once they’re ready.

 

Thanks for all the input

 

Jeff (MONZTER)

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Jeff, again awesome work and ducumentation. This thread has some of the most intersting and creative ideas when it comes to induction. Im glad that everyone helping you is so will to share there thoughts with the community. Keep up the good work all of you and thanks.

 

Jeff when do you expect to have the car running and on the road?

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Sell it to the Japanese, and make sure to include the flow data...they go bonkers for diagrams like that! LOL

 

"SSS" at one time was the home of the Devil-Z in Wangan Midnight, Speed Shop Sinohara...I guess now the new MonZter-Z will come from "SSS" as well!

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Sell it to the Japanese, and make sure to include the flow data...they go bonkers for diagrams like that! LOL

 

They will!!!!

We had a rental van when we were in Japan(1992) while the Subaru was being serviced. On the side of this van there were diagrams of the engine and driveline on the OE fender/body graphics! Somewhere I have some pics. I'll have to dig them up.

If I recall correctly the van was called a "Bongo"?!? LOL?!?!

 

Sorry for the threadjack...

That intake looks great!

I hope to be able to model in CAD as well as you, Jeff, in my lifetime. :windows:

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