MONZTER

now thats looking better, and the pressure drop is much lower than the HKS. getting closer

So I took Monday and Tuesday off and took the family to Palm Springs. We stopped at the WWII airplane museum. Some really beautiful stuff in there. Anyway, I was checking out all of the intakes and air scoops on the planes. One thing they all had in common was the inlets for the radiators. All of them had a deep honeycomb "grill" that acted as flow straightners to the turbulent air. Hmm this gives me an idea. Jeff

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:

I was looking at the analysis of the pressure on the HKS and realized the pressure range on the chart was pretty wide. So I revised the scale and now look at it.. 20psi was put in, but there is more than that in the inlet neck and a big pressure spike at the inlet bends. Looks to me like this intake cannot flow this much air at this much pressure without backing up. Tony D - I think I remember hearing you say the high HP cars would port or cut away some part of the plenum??

I ran the test at lower boost on the HKS Plenum. Looks the same, same equal flow distrabusion, so I wont be posting the pics. Can anybody see anything negative about the results above?, If there was room for improvement, what would it be, and how would that be acomplished. I would still like to see less swirling and less bends in the airflow.

So once again, Thanks Tony D for the loan of his HKS Type 2 intake for testing. I was really interested in seeing how this plenum would flow given the success of it over the years. My plenum I have been working on has been plagued with a couple of vortices that have been causing the front two cylinders to run with less airflow. I wanted to see how consistent the HKS would be. So wouldn’t you know it? the HKS plenum looks pretty good. There is still swirling, but this doesn’t seem to be affecting the flow down the runners like my design is doing. The pressure looks to be even down the runners as well as the velocity. So check out the pictures below and let me know your comments, I know now I have more work to do on my design to even out the runner flow more. I have posted pictures of cut away views so everybody can see the internal baffling at work. I went as far as to model the plenum very accurately, down to the internal casting bumps for threads, to the shape of the runner inlet. It’s as close to the real thing as I could get. The test was run at 20psi boost 793CFM the inlet ID was 62mm so a inlet velocity of 4880in/sec was used. I will be running less boost on the next analysis and post the results soon. One more thanks to TurboBlueStreak for the lessons in the Floworks software by the use of his models from previous test. Click on the picture for a bigger view in my gallery Jeff

I was actually going to look into the opening of the valves in relationship to the cam I will be using. I don’t think only 1 valve is open 100% at one time. There may be 1 valve open at 100% and 1 or 2 more partially open. I will look into it. I have most of the HKS type 2 modeled and have run a quick analysis on it. Looking really very good and even flowing so far. I will post the results soon. MonZter

On the V-8 engines they use a carb before the intake so the manifold is wet. On this intake the plenum it is dry because of the injector placement. Getting the air to start to swirl once it enters the runners and into the cylinder is a good thing for what you say, but having it swirl in the plenum will just make heat and reduce flow.

Just so you guys understand, I have a day job, actually one I quite enjoy. Z cars are my hobby and will stay that way. I have no plans to make, reproduce, sell, devalue or profit from any Z plenums out there. I will have spent way more time and money on my design than if I just went and paid top dollar for an HKS. This is purely a fun learning experience that I am going through to build myself a plenum for my project. My purpose to this thread is to show all what we learn so that everybody may better have a idea of what to do when they make their own. This is what I thought this forum is about and why I like it so much. A group of intelligent creative people who love to build and fabricate their own z parts to make their z-cars into what they always dreamed about. I am seeing more and more post of people trying to sell stuff on this forum, I hope this site doesn’t become that, you won’t see this from me. So seriously don’t you think that if somebody really wanted to copy and rip off the old HKS plenums they would have by now? MonZter

Tony, Thanks again for letting me borrow these. Much appreciated Jeff

That sounds great Tony. I'll get with you to check them out. It will be good to see if there is any magic in those old HKS intakes. BTW my computer fried the other day, so I have been recovering all of my files (nothing lost) and my new computer will be in soon. This is why there have been no updates lately. Back on real soon. Jeff