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If you know it's possible for it to get to 190+ degrees in a real world situation........why would you not pressure test it at 190+ degrees?
And you never said if you took any Delta data....how do you know if your new IC design will work better than a stock one?
I think it's cool that you are experimenting with stuff (I wish more Mini owners would do stuff like this)....but if you don't have any data to prove you made an improvement in the design....what's the point?
No need to get bent out of shape....just asking some honest questions. I'm looking forward to seeing how it works.
From what I can tell from looking at RealOEM, MINI did not modify the hood scoop or the inner hood duct for the GP IC. It appears from pictures that other than being larger the only other thing different is the top slotted area that is a cupped diverter on the GP. The raised area between the cupped diverter is also increased. I need to do some measuring on where the duct foam band contacts the cover. I can always clip the slotted area and pivot it up. Would use some plastic from my lap top to blank off the slots. The safety straps I noted above will also be used to elevate the back/top portion of the cover so that air can reach the added 2-tube section similar to the increased raised area. I am also thinking about adding some weather stripping between the cover and IC to force the air through the fins.
It is logical to me that between the two additional tubes and then spraying heat dissipation coating on the intercooler it will perform as well as the factory GP IC.
Yes....but remember, when talking about containing pressure (boost), you need to worry about tensile strength...not compression. The Aluminum that the IC is made out of (5052 Alloy) has around 30,000+ PSI tensile strength....JB weld has around 3,690 psi.
Also, remember to heat the IC up before you pressure testing it.....as epoxy's get hotter, they get much weaker in tensile (and compression) strength. Your IC can get up to 190+ degrees if you are just sitting around in traffic.....so I would pressure test the IC at 200 just to be safe.
I'm all about innovation (I'm a mechanical engineer) , and coming out with new cool ideas of how to build/design stuff.....just make sure that you don't set yourself up for failure and test everything correctly before you road test it.
Good luck...looking forward to seeing the results...and the temp Delta's to see if the added rows of IC fins made a difference in cooling or not.
Originally Posted by ThumpR52
First, I am not going to heat the thing to 200 degrees before I pressure test it and I am not going to worry about what type of aluminum is involved. Sorry I dealt with enough architects and engineers during my working years.
1.) I was under the impression that tensile strength was a elongation element ie stretching.
2.) Using an average coefficient of expansion for aluminum a tube/pipe 11" long heated to 200 degrees would elongate to approximately 11.03 inches.
3.) The horizontal joint that I would be joining is approximately 1.5 x .375 inches x 0,5 mm. This joint is sandwiched between aluminum on two of the four sides. The boost pressure will be present on only one side of the seam, the 0,5 mm.
4.) This same pressure would be present on the top and bottom side of the joint via the aluminum tubes being joined together. This would squeeze the joint together more.
5.) In my feeble head the issue is not tensile strength but rather the compression strength of the JB weld to withstand the squeezing noted in # 4 and the adhesion strength of the product to the aluminum and whether this adhesion is strong enough to withstand the boost pressure that is trying to push/elongate noted in # 3.
So, if this was a 1000 wg spiral duct system what sealant would I use?
Oh and another question that confounded most of the ME's that I ever dealt with, at what temperature does water start to expand in the freezing cycle?
Thumper - You are right that tensile is a strength measurement in tension. In something that contains pressure, tensile strength is what you would use to assess the ability to withstand blow off pressures in, say, a simple cylinder.. But, in the IC work you are doing things are clearly more complicated than a simple pressure vessel and for other reasons (such as mounting and general handling) the IC might be well over designed for the presssure that it is containing. So the strength of the JB may be a mute point. It would probably take a complex analysis to say much more than that.
The other thing is that pressure tests are run cold before they are run hot. But, that cold test is done at a pressure set (raised) to mimic the reduction in strength of the materials being test at the higher temperature of actual operation. In this case JB cites only a bit of a loss in strength at 500 deg. So I might suggest that you test it at a bit higher pressure than you expect it to be operating at; similar to what the Project Binky guys did.
If you look at the picture of the two tube unit you will see that I coped the fins back about 1/2" from each end. If there is a gap when the two-tube unit fin meets the 11-tube frame I have some 1/2" wide aluminum stock flat stock that is just over 1 mm thick. I would make shims from that stock that would be brazed in place. With some filing I should be able to get a joint tight enough that I can then braze from either end where I cut the fins back. The aluminum brazing rod melts at 750 while aluminum melts around 1200. You do some heating and keep testing to see if the rod melts when you rub it across the infill area.
When everything is brazed up I will pressure test the unit with about 30 PSI. If I have any leaks I would then use the JB weld in the tight spot.
ThumpR52 - Totally missed this earlier post. That had the answers to my earlier questions and my comment about the pressure test.
I also went back over your earlier posts. It was interesting to see how well that brazing rod flows.
One of the big factors in this instance for brazing over JB-Weld is actually surface prep.
JB-Weld works great with a properly cleaned and prepped surface, being that aluminum is actually fairly porous and these parts are used and had oil misted air running through them, the heat from brazing will just be added insurance for bonding.
Now, back to our regularly scheduled programming...
I dealt with some very smart folks through years and sometimes they would get so fixated on something that they would overlook something that was very obvious to those from SOHK University.
Tomorrow working on some stilts with my grandson. No JB Weld, just some wood screws . . . . . .
After making some stilts this morning with my grandson I put the two parts of the intercooler together in the afternoon.
I spread heat sink paste on the two sections.
I buttered both the sections that were mated together with JB Weld, put the 2-tube section into the 11-tube and clamped them together. I taped the two areas where the heat sink paste was so that when I clamped the pieces together what oozed out would get on the other parts. After I undo the clamps and clean the area I will seal the joint area with something like gutter caulk.
I made some aluminium strips that would span the joint area of the main frames while at the same time also extend out over the tubes/fins.
You might able to see that I formed the strips to go over the small flare out of the main frame area.
I had the straps on without any epoxy and pre-drilled the frames where I had installed the backing plates that I had brazed in previously. I buttered both the frame and the straps, installed them and then placed the pop rivets. You can see the "flare out" section where the tube/fins slip into the main frame.
My thought is that these straps will support the JB Weld from the inner pressure. On the frames the backer plates covered 90% of the joint area so the straps address the small sections that did have some 1/16" gap and also would hold the 3/8" joint that is between the 2nd and 3 tube you see above.
I used the long-set JB Weld that will harden to almost 4,000 PSI. I am thinking that between the backing plates, the pop rivets, the JB Weld and the cover straps I should pass my pressure test. With the clamps I was able to get the two 1 1/2" fin joints very tight and buttered both sides there as well.
Going to wait a full 24 hours before I remove the clamps.
What was your thought on using the heat sink paste between the two tube section instead of JB welding them? Not sure it makes any difference, just curious.
The kind of stilts that you use your arms with are difficult to master so after making a pair we decided to go another route. Going to create some wooden "drywall" type stilts that have a footprint similar to a shoe. Will have a vertical that will stop at the knee and be taped to the leg. Looking for an old pair of sneakers to screw down to the elevated shelf.
What was your thought on using the heat sink paste between the two tube section instead of JB welding them? Not sure it makes any difference, just curious.
A typical fin has about 194 sq inches of surface area and in the end I wanted a good heat transfer between the two pieces. IMO the fins do not hold the cooler section together as that is for the much thicker rail material to do.
The kind of stilts that you use your arms with are difficult to master so after making a pair we decided to go another route. Going to create some wooden "drywall" type stilts that have a footprint similar to a shoe. Will have a vertical that will stop at the knee and be taped to the leg. Looking for an old pair of sneakers to screw down to the elevated shelf.
I remember stilts that were just a pair of 2x2s, 8’ long and a wood wedge piece screwed or nailed in about a foot or 2 up. They were kind-of ugly and hard to use. The “drywall” type look like they would be more fun. There is always Salvation Army for sneakers. Or in my case, Gramp’s closet...
Well, the biggest thing I found after all the discussion on tensile strength, temperature logging and deltas was that all those that have a Gen1 S and any of the other two configurations of that ie JCW or GP, should check to see how tight the duct seal of the hood scoop is.
I worked on the IC cover this afternoon and instead of trying to stick a ruler into the hood scoop to measure where the duct seal hits the cover I taped some paper towel on the cover, wet the foam duct seal with some water and closed the hood. Surprise, Surprise!! The seal was not really contacting the cover on the back left side of the cover. I only had good contact on the back right side and right side corner. Just think about the air that was not going into the intercooler but rather just going out the back into the engine compartment.
I am going to do a similar test with the GP cover and would think it will be a little better as I am lifting the back of the cover up about 1/8" to mimic the OEM GP cover that does have an extended higher section over the fins.
I cut some of laptop cover into strips and epoxied them onto the bottom of the cover. This will lift the back section up so air can get to the two added tubes. I used some cabinet barb nuts on the strap and will use some screws from the top side to lock everything in place.
A better shot of the strip/straps that were epoxied.
From the wet towel test I can verify that the duct seal is not on the slotted back section of the cover. I don't know why the factory has those slots instead of just cutting the section out.
I removed the clamps from the IC and will work on a pressure test tomorrow after the building some more stilts. I got thinking about the Project Binky thing and they cut down an intercooler to fit in their project car. What I am doing is just a little different as I cut a unit down but then merged it with another. Yes welding would be the way to go but I am trying to visualize whether there would be enough room to get to the tube connection point. Possibly you could cut the entire tube/fin section from the rail, add the two tube section cut in a similar fashion, weld the rail sections together and then weld the extended rails to the larger tube/fin section but the tubes are really really thing and I don't know if a welder could manage it.
I had 30 psi on the unit with no leaks where I had worked. All my seams held tight. I put water in both of the intercoolers when I first got them but did not pump them up at all. With 20 PSI of air I found a very small hole in one tube. I used soapy water to test things and the leak was small enough that I only got larger bubbles. Usually a larger leak will have allot more smaller bubbles.
So I removed a couple of the fins, used a very small file to roughen the area up and then rinsed the area with lacquer thinner. I took a very small screwdriver and coated the area with JB Weld. Will do another test in the morning.
Finished up the cover and now will start fabricating some extension straps for the top mounts. I did cut out the slotted section of the cover and put a length of PVC pipe that I cut into a 1/4 circle. Used epoxy to attach it but will follow up with some small screws into the aluminum angle that I also epoxy in placed to help hold this "diverter". You can see the two screws that I have holding the strapa that I epoxied in place.
I attached this modified cover to the OEM IC as I wanted to see how it looked. I used silver paint as there is another new thread where a member used some heat dissipating coating on his intercooler that was black. I really like the contrast of the black IC to the silver cover. I will not transfer my JCW plate over to this modified cover until I have had it out and put some miles on. The good thing about the extension brackets is that the original upper brackets will remain in place and this will still support 11 of the tubes. The relocated top bolts that will connect to the extensions is more for keeping everything lined up
12-28-2018, 07:11 AM
