MONZTER
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Posts posted by MONZTER
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A bunch of good post and questions. The purpose of my initial test was to see if I could make the intercooler I already purchased better. I think I succeeded. If I had to do it again, I would not buy the same set-up and modify it. I would go for a completely different tank design that doesn’t flow the air perpendicular across the core in the first place. Have you guys ever seen this site?
http://www.gurneyflap.com/bmwturbof1engine.html
Some of the old F-1 cars are great inspiration
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I love this video and the sound of that straight 6
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You crack me up Jeff... you create that which belongs in the Smithsonian, equally at home in the Fine Art dept. AND Science & Technology... and then install it on a old Datsun... I love it!
Thanks for sharing.Thanks Ron, Even better is that my old Datsun still has the original paint and rust. It makes it that much more fun not having to worry about some pretty paint.
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Why the asymmetrical plenums?
For just the reason stated by Zguy36 above. I thought a bigger taper in the bottom would help even out the flow in the second half of the core and eliminate any dead spots. I knew what direction the air was flowing so I figured a little more room on top would keep the velocity more consistent. I think most intercoolers are symmetrical because they are universal fit and you can then run the air in any direction you want.
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Did you do any calculations to see if you are getting flow separation on the trailing end of your divider on the inlet side? If that is the case, you are introducing a lot of turbulence into the rear section of the intercooler. I did notice that there were very few flow traces through the first few tubes. In any case, that is a ton better than the "as-purchased" design. Now, the real question is, why didn't you just buy a core and make your own stuff if you can do that good of work!
Yep I am getting some turbulence in the dead spot where the first and second halves of the core are separated. I will post a close up of that section so you can see it better soon. It’s not perfect, but as you said a lot better than what it was, and I will have to be just happy with that. I actually have plans to make my own tanks from scratch for my next build, and they will eliminate this problem, I just wanted to salvage the intercooler I already bought. I bought it in the first place because I am getting tired of my car never being finished, and I thought I would save some time by having one built. Well after getting it I couldn’t just leave well enough alone.
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Nice work, what did you use for CFD?
Very pretty welds too.
The software is Cosmos Floworks, I think it’s at its limits with the narrow fluid space in the core.
The company I work for just bought CD-Adaptco Star CCM+ and Star Pro-E for our external flow models, seems much more capable as it is the same software used by the F-1 teams. I will re-do some of these test with the new software after I get some training.
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It seems like there has been alot of talk about the pluses and minuses of the different intercooler configurations for our Z cars. Which is better? Same side inlet and outlet, or opposite side? That’s for another post that has been debated over and over.
What I wanted to show was my decision, and what I have found out, and how I have modified it to make what I think is a good solution to an efficient design.
My decision was to go with the inlet and outlet on the same side, as I really wanted the shortest possible tubing, not to mention what I believe to be a intercooler with less pressure drop.
So I ordered up a Custom sheet metal tank Spearco unit 18x6x3.5 , only to be really disappointed when it showed up, as I have seen better looking agriculture equipment. The inlet and outlet were just butt welded on with no regard to smooth airflow, and the ends were cut nearly square, again not really smooth creative work.
Here is a pictures of the stock unit as delivered from Spearco.
We have all heard talk of how this type of intercooler recycles the air inside, in a circular motion near the inlet and outlet. Also, it is known as not being very efficient to cooling, because all the air gets pushed to the end of the tank, not letting the air flow evenly through the core. So I modeled it up in Pro-E and set to work doing some CFD flow testing on it for a little look.
The test was done very simply, ambient on the inlet side and 25" on the outlet side. I wanted to test total CFM flow as well as pressure drop and distribution of the air. Please keep in mind this is only a quick test and the core is correct in dimensions, but obviously no tubulators, So look at the info for what it is, a comparison between one test and another, not between this test and a actual unit.
So you can see in this picture first off is a recirculation effect. The air enters in the bottom inlet, up through the core, out, back down the core, back up the core... click to enlarge the picture and look at the flow arrows.
Next is the pressure plot-
Finally the velocity plot.
So now on to the modifications.
First off is the inlet and outlet. I made nice square to round transitions 2.5" inlet and 3" outlet. No longer is there a sharp square edge right before the outlet, you can see the effect on the pressure plot above.
Next, I made smoother tapering sections at the end of the plenum.
Finally, I made divider plates to basically split the Plenum into two halves, hopefully improving the balance of flow, fixing the recirculation problem, increasing the heat rejection and thus efficiency.
Check out the arrows - no more recirculation
Pressure plot shows the air is being distributed more evenly through the full core, not just he ends.
The smooth inlet and outlet also show the lack of a high pressure flow reducing area right before the outlet.
Check out the velocity. The air seems to stay more consistent in speed, I assume this is why there is a little more pressure drop.
Check out the numbers. An increase of 162CFM through the same core.
So what do you think? Does it look like it all makes sense?
Jeff
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If you know someone who can weld aluminum, cut it open and go to town. It is really easy to clean them up once you can get inside.
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Dang that looks good. I'm a cnc mill guy, so obviously I want to know what kind of machine that is being done on, and if I can get the cad file
Sorry, I forgot to answer you on this one.
The machine in the picture is a Fadal VMC 4020 with Fanuc controls. He does al of his programming in MasterCam 9 This machine is about a year old.
They just got a new 6030 in the shop for larger projects. Total of about 5 vertical machines in the shop right now.
So you want the file? Hmm I'll have to think about that one:icon42:
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The first CNC pictures from before were of the roughing operation The final pass has been finished on the inside and it is ready for the back details. I had him spend a little extra time with a smaller step-over on the diverter section, but leave the entry into the runners a little more rough. I figured I would have to do some smoothing on the runner entries after welding on the Wiggins flanges anyway. He has already roughed out the inside of the front half. Should be only a couple more days to have it all finished machined. After machining I will pin it together for alignment, add a little tape to seal it off and bring it to be flow tested before welding it together for good.
It seems like you guys like seeing the progress of the CNC work so I guess I'll keep posting pictures
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So, picked up some finished components from the CNC shop today.
Here is what’s new- click on the picture for a bigger view
The cover plates for the integrated vacuum and AIC rails.
As you can see in the model I have designed rails in the back of the plenum. The cover plates will go over the slots and be welded close to form a rail. The top one is for the AIC solenoid and PCV valve. The bottom one will be for the MAP, blow off, fuel pressure, and boost gauge. Since I am using ITB I wanted a signal from each runner to collect into the rails.
I also got the weld-on connectors for the Wiggins clamps. One side of the adapter will weld onto the plenum, and one side will weld to the ITB. The Wiggins clamp holds them together with no tools, so it will be easy to pull off the plenum to sync the ITB’s (thanks Tim for the idea)
The bad news is the other day my friend at the machine shop called and said “hey your flanges are finished� What I said, and he sent me a picture. By mistake, he ran my old files of the bolt on adapters I was going to use to connect the plenum to the ITB's OOps. So he pulled up the correct files and finished the Wiggins adapters above.
So, anybody need some beautifully machined adapters? They are standard Webber spacing and 45mm ID 6061. PM me and I can send you prints of them. 6pcs total. Since they are 1 off custom parts there not cheap, but I am just looking to help out my friend get some of his cost back.
Jeff
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Dang Jeff!
That is a hunk of metal!
Albiet soon to be inredible looking!
Ya and 90% of it will be chips for the scrap man.
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I think making a plastic model and testing it would be a great idea, as I do believe in taking the CFD results for what they are, just first results. For me aluminum is easier, faster, and cheaper than rapid prototyping.
The CNC proto is being cut right now, check it
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Hi Jon,
You’re bringing back memories of my install. I use the camber plates that Eric and John make with the 5/8 ball. I think I remember the top threads on the stut being smaller than 5/8 by a little bit, and I also remember the large diameter of the strut, up next to the ball would limit the amount of articulation that the camber plate could achieve. What I did is turn out a "top hat" pc that installed into the ball from the bottom. This top hat reduced the id for the strut threads and then spaced the shaft away from the ball, allowing more articulation. Wow does any of this make sense? I could draw you some pictures if it will help. These struts are not plug and play, but I like em.
Jeff
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The runners are actually TWM ITB's that I merged together with a TWM intake manifolds. Basically, a bunch of cutting and welding to get the shape, angle, and new flanges. I will use staged injectors as well. And yes the Plenum will be CNC machined in two halves and then welded together. No casting right now. Check out my gallery for more pictures
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I mountain bike on a 2.1 lb carbon fiber frame. Rocks hit it all the time, Not big rocks obviously. My carbon driveshaft from ACPT is about 10x thicker. Now, I would not put it on a rock crawler, but a road car, no problem
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Does anybody know anything about this cars engine? I was told it was a straight 6 BMW. Oh the sound. Do you think a Z could ever rev and sound like this?
Great video BTW. Watch it full screen with the volume UP
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The carbon driveshaft has been great. I had an aluminum one before, and I kept breaking the staps on the clutch pressure plate during autocross runs (3X) I switched to the carbon driveshaft and it felt noticable smoother and less jarring when on and off the gas My car is all solid mounts for the diff, and suspension, and urethane for the trans, engine. I also changed clutch styles at the same time, so dont know if it fixed the problem, but have had no clutch issued since. The Yokes were the really nice heavy duty spicers and joints good for 500hp. Its not cheap, but I always believe it is all the little things that add up. As I first mod to your car? dont know if youll see the value, but when getting close to the ragged edge, I think its money well spent.
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This is the one I have been using for almost 2 years now http://www.acpt.com/article2.html
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I took an old one apart just to look inside, I could not get it back together, bearings went everywhere. OOPS
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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.
Now here is the same plenum, with the flow diverters added. Big difference huh.
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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I Just for the sake of argument, couldn't the strut housing be sectioned shorter and the nut left at its regular length? The nut is a lot thicker than the strut housing, so presumably there would be no loss of strength there.
I dont see why not, except that it would be too easy;)
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All of the photos are of the A1 and will only fit the 240 strut after being cut down. The ones Jon had Q1 are for the 280 and should would with no mods
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Sorry Jon, I don’t mean to confuse the issue. I thought you were saying you were going to order the same part number that you already have but with the A1 at the end instead of the Q1. I thought you meant the A1 designated the thread size.
The part number I ordered (B4-B30-U232A1 M48x1.5 OST) It did have to be cut down.
Every time I talked to the guys at Bilstein it was a real pain in the butt. I think they have so many different options, that they cant keep track of them.
Thanks for sharing.
Intercooler CFD Testing
in Nissan L6 Forum
Posted
Me too, Thats where I got the idea from. Good book. most of my parts I have been building are based on the "ideal" concepts from that book