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Turbo Intake Plenum

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Hey Braap,

Thanks for your comments, Unfortunately I don't know the answer, I'm just working from what just looks and feels like it would work properly. Helix posted a link above from somebody else doing the same type of design for a 4 cylinder. He had the slot facing the runners forcing the air down them. He determined this to cause turbulence in the runner and moved it to the middle like I have shown. I guess the best answer is lots of R&D to find out.

 

Jeff

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Curiously, the last drawing Braap put up looks a lot like the inside of the old HKS Type-1 Turbo Surge Tank. The smaller upper plenum was what was vented to the float bowl, and there were two metered orifices that bled pressure into the larger plenum between the ITB Pairs at 3&4, and 5&6.

 

I haven't looked at the Type 2 Plenum closely, I got it and shelved it due to other jobs in progress (24 Hours of Lemons, anyone?) so I can check it in a couple of weeks to see how it compares. I know it has a similar plenum division, but is done differently than their Type 1 Plenums.

 

Jeff, would you want to take a look at those old 80's Tech HKS Plenums in person? I could probably make my way your direction if you're interested in taking some dimensions. It would be interesting to see the CFD comparisons for 80's technology...

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Your modeling of the air flow looks neat, but at your highest velocity in the intake you are over sonic velocity, choked flow! At 6000 rpms a z flows about 8550 cubic inches per second in a perfect world, half of you model. It seam that boundry layers, the higher the velocity the thicker they are, were missed in the model. This might have been picked up and not shown in the computer model.

 

I still think the design is great and is a whole lot better than my 4x4 box with a hole in the end!

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Jeff, would you want to take a look at those old 80's Tech HKS Plenums in person? I could probably make my way your direction if you're interested in taking some dimensions. It would be interesting to see the CFD comparisons for 80's technology...

 

Hi Tony,

Ya I would like to look at those plenums. I could reverse engineer it in Pro-Engineer so that it could be run on CFD software, but I can't speak for TurboBlueStreak if he will run the simulation or not:icon43:. Maybe after the new year we can get together and check it out. Thanks for the offer.

 

Jeff

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Your modeling of the air flow looks neat, but at your highest velocity in the intake you are over sonic velocity, choked flow! At 6000 rpms a z flows about 8550 cubic inches per second in a perfect world, half of you model. It seam that boundry layers, the higher the velocity the thicker they are, were missed in the model. This might have been picked up and not shown in the computer model.

 

I still think the design is great and is a whole lot better than my 4x4 box with a hole in the end!

 

Not sure how the analysis was run, and if this was accounted for or not. This time I have to base the runner size on experience. Dave Rebello ported the head and was very specific about asking what engine size, cam, boost and HP goals. The end of the runners match to what he ported the head to. Actually not much bigger than stock. Interestingly the head flowed good numbers with the small ports @212cfm at 25" Dave said big ports doesn't necessarily mean good flow, but small ports help with velocity which will help with off boost performance. I guess well see

Thanks for the comments, maybe TurboBlueStreak has some comments on how the test was run.

 

Best Regards

Jeff

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So, I have pretty much finished the design for the turbo plenum. You can see in the pictures below the complete assembly. I have integrated the AIC system as well as the vacuum reservoirs into the backside of the plenum. Should make for some clean hose routing to the throttle bodies and all necessary systems MAP, FPR, gauges, BOV, AIC, EGR.

In this new version I have smoothed out the entrance into the main plenum from the entry slot where it looked to be a problem.

Turbobluestreak ran some new CFD plots of this rev. Check it out and let me know your comments.

 

I have the stock on order and this thing will be in the machining center next week.

 

Click on the pics for a bigger view

 

57.jpg

 

125.jpg

 

216.jpg

 

311.jpg

 

49.jpg

 

cfd_rev3_velocity_1.jpg

 

cfd_rev3_velocity_2.jpg

 

cfd_rev3_velocity_cut_1.jpg

 

cfd_rev3_velocity_cut_2.jpg

 

cfd_rev3_pressure_1.jpg

 

cfd_rev3_pressure_2.jpg

 

cfd_rev3_pressure_cut_1.jpg

 

cfd_rev3_pressure_cut_2.jpg

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this looks great. but why make it so you weld it together?? why not make the 2 sides bolt together with an o-ring to seal it?? like just have half an o-ring grove on each side and then just add tabs around the outside to bolt it together. to me that would look way better and maybe even allow for different size plenum chambers to suit different taste's/preference

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this looks great. but why make it so you weld it together?? why not make the 2 sides bolt together with an o-ring to seal it?? like just have half an o-ring grove on each side and then just add tabs around the outside to bolt it together. to me that would look way better and maybe even allow for different size plenum chambers to suit different taste's/preference

 

Good idea being able to get back inside it for testing and tuning. I looked into it but the part wall thickness would have to go way up which would add a lot of weight. Also, the plenum is really big, and I just have clearance around it for the booster, my header, wastgate and such. Welding it is simple and easy, and personally I like nice TIG welds in moderation. I guess I could always cut it back open if I had to. I also think I would have to have a wideband sensor in each exhaust runner to find variations, I am not ready for that yet.

 

Jeff

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That's just plain beautiful - nice work, Jeff!

 

On the vacuum ports integrated into the backside - I'd suggest leaving yourself a couple of spare ports - there always seems to be one more thing that you need to connect. You could just plug them with a nice anodized hex plug in the meantime.

 

Also, do you already have a solution for a compressor bypass? If you so desired you could integrate a flange for the bypass of your choice, or even design your own, integrated right into the plenum with a properly sized valve...

 

I always like to complicate things... :mrgreen:

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On the vacuum ports integrated into the backside - I'd suggest leaving yourself a couple of spare ports - there always seems to be one more thing that you need to connect. You could just plug them with a nice anodized hex plug in the meantime.

 

Also, do you already have a solution for a compressor bypass? If you so desired you could integrate a flange for the bypass of your choice, or even design your own, integrated right into the plenum with a properly sized valve...

 

Hi Tim,

Thanks for the comments, good Idea of making a couple extra ports in the vacuum log. I currently have provided for in rail #1 the Air Idle Control, and the EGR. In rail #2 I have provided for the MAP, Boost gauge, Fuel pressure regulator, and the Compressor bypass BOV. Can you think of anything I am missing?, or some suggestion for future needs?

 

I really wanted to integrate the BOV into the back corner of the plenum tank (I have a Tial) but there is no room. I have pushed the engine back an inch and the plenum is close to the brake booster. My plan was to run it in the intercooler outlet tube in front of the core support, Do you have any suggestions or comments if this will be a good place to put it? Is there an advantage to putting on the plenum?

 

Thanks Jeff

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I really wanted to integrate the BOV into the back corner of the plenum tank (I have a Tial) but there is no room. I have pushed the engine back an inch and the plenum is close to the brake booster. My plan was to run it in the intercooler outlet tube in front of the core support, Do you have any suggestions or comments if this will be a good place to put it? Is there an advantage to putting on the plenum?

 

Thanks Jeff

 

by back corner you mean that area of very high pressure near the rear cylinder, right? That looks like the perfect place.

 

how far away from the exhaust manifold would this plenum be situated? perhaps you can modify the back corner so there is a flange on the underside?

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Hi Tim,

Thanks for the comments, good Idea of making a couple extra ports in the vacuum log. I currently have provided for in rail #1 the Air Idle Control, and the EGR. In rail #2 I have provided for the MAP, Boost gauge, Fuel pressure regulator, and the Compressor bypass BOV. Can you think of anything I am missing?, or some suggestion for future needs?

I kinda thought you might have already had that covered, just couldn't tell from the pics. Do you have an external boost controller, or do you plan on using the TEC3? Maybe leave yourself room to add one if you don't like the GPO control?

I really wanted to integrate the BOV into the back corner of the plenum tank (I have a Tial) but there is no room. I have pushed the engine back an inch and the plenum is close to the brake booster. My plan was to run it in the intercooler outlet tube in front of the core support, Do you have any suggestions or comments if this will be a good place to put it? Is there an advantage to putting on the plenum?

 

There are those that will contend that it's better to be in the plenum, so that the airflow doesn't have to change directions. I don't know how big of a deal this is, or if it really ends up working this way, especially when the throttle is still partially open. This does seem "directionally correct", though. Seems like TonyD is the bypass valve expert (among other things) - so I will defer to him if he disagrees.

 

Since I seem to be in the business of making your life more complicated tonight, what if you just used the diaphragm assembly from your TiAl and integrated the valve body part of it into the plenum? This might allow a bit more clearance (and would be slick as hell :flamedevi )

 

I put mine more towards the front of the plenum, like this:

almost2.jpg

 

Oh - and have you considered either V-band or Wiggins clamps (stupidly expensive) for connecting the plenum to the throttle bodies instead of the bolt-on flanges? This is one thing I wish I could have done with mine - the bolts on the bottom side are a huge pain to get to. A nice quick release setup would have made the setup much more serviceable.

 

If you stay with the flanges, I had o-ring grooves cut in the throttle bodies so I wouldn't have to mess with gaskets...

Engine_109.jpg

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