rotarenvy

read the first paragraph again intercoolers are always after the compressor and my throttle is before the compressor!

pic's to come.

I measure EGT just before the exhaust manifold to cat pipe junction so it does have time to cool. post turbo temps are also reduced from pre-turbo so you hotter than you think. try this thread on exhaust temps. they are opinionated as all forums but useful collection of data.

Brettus

iTrader: (2)

ah yes - didn't think that one through did I

rotarenvy

There’s not much point me going into detail about intercooler design as A.R.E has the most comprehensive discussion around even is their page is a little disorganised.

To keep it simple the tube and fin PWR (K&J) cores strengths are good flow with low restriction and are less prone to physically damage than other core designs like bar and plate. The major problem with the cores is how far the tube sticks out passed the end plates. This creates turbulence and poses a flow restriction through the core as illustrated with the diagram below (addapted from this page). while turbulence in the tubes is a good thing and will increase cooling the restriction at the inlet is unwanted and will cause additional pressure drop across the core. There are two main methods of fixing this. Cutting the tubes flush with the plate as this person did. Or using a venturi plate as A.R.E mention.




As you can see from the diagram above while cutting the tube flush helps there is still some disturbance. Cutting the very soft annealed tubing is also very difficult as you can end up with mangled tubes very easily and cleaning out the tubes is a PITA! A venturi plate should be much better and I thought it should be fairly easy to make.

rotarenvy

I had a cad design I drew ages ago when I was thinking about intercoolers. the idea is there but with any design there is some variation between idea and the finished product. I ended up just driving the mill from measurements of the core and the design in my head and didn't bother referring to my cad work



I haven't had that much experience on the milling machine but with good instruction from my friend I'm turning out reasonable parts.

the MAF bung below was my first milled parts. I made 4 of them in one go out of a large chunk of round stock. very waste full of material however it was easy to clamp and manufacture them this way. $50 for materials and a good days work! much cheeper to buy them from someone CNC milling them in large quantities. the ones I could find were for 3" maf pipe not 3.5" as the rx8 needs so they wouldn't have been ideal anyway.



the MAF bungs were cut by eye to marked lines. only some of the depth cuts were counted out on the mills feeds.

the venturi plate was the exact opposite. only the width and starting point was marked the rest of the cut locaions were located purely by referencing the milling feed screw and using some limit stops to reduce the number of axis to keep track of.

rotarenvy

2 days latter, after hundreds of cuts, 4 different cutters, one f*ck-up I turned $20 worth of 100mm alluminium bar stock into 2 vernturi plates.



the design was a compromise on what I intended. I couldn't justify buying a corner radius cutter specifically for this job when it probably only be used once and would have doubled the built cost, so I used a 45 deg cutter for the profile instead.

one thing this taught me was how correct tolerances is essential for parts like this. the core tubes are close but vary in spacing and thickness. the milling machine is very accurate but has some variation from the operator and function. there is only around .2mm variation on the core tubes and about the same on the mill. I didn't allow for this on my first attempt and so they were to tight a fit among other problems

auzoom

Damn, thats some serious work right there. Great work I might add. I am so jealous!

Have you bothered to measure IC inlet and outlet temps?

Cheers

Andrew

rotarenvy

I'm still trying to making the end tanks for this one so no data yet.

the ARE cooler was performing very well almost too good to be true. compressor outlet 88.2 Deg C intake temp 28 Deg C (as it goes into the motor) measured with T type thermocouple wire and logger.

I thought the ambient temps were about 26 but the efficiency is too good to be true so maybe the ambient was more like 22-24 deg.

auzoom

Wow, thats nice. I am running a PWR as part of the ProMaz kit. I dont have any data yet but I am pretty sure that its running to hot. I am electrically challenged so not sure what I need to take measurements

rotarenvy

if I were you I would just look at inlet temps as it goes in the motor. knowing what it is dropping from is nice to see but in the end you just want to know the air going in the motor is cool or how high above ambient it gets.

your using a microtech? if so it should have a air temp sensor. hooking up a pc or hand controller would be the easiest way and directly read that sensor.

auzoom

lol I just spat water all over me. Isnt it funny how you can over complicate things. You just gave me a little more incentive to find my Microtech dongle (like MM on my case wasn't enough ).

Cheers

Andrew

rotarenvy

just make sure they have a aftermarket sensor tapped into the pipe work after the intercooler and don't just use the std air temp sensor which is in the MAF?

auzoom

Well the good news is that I found (well the wife did ) the dongle. Problem is that the Air temp isnt registering Going to have to get my hands dirty now eek!

rotarenvy

do you have a aftermarket air-temp sensor screwed into the pipe work near the throttle?

rotarenvy

I decided to make the intercooler end-tanks by a triangulated transition from the 2" pipe to the rectangular intercooler end.

I thought the triangulated transitions would give a nice flow pattern similar to this picture taken from ARE web site




After a few test runs my first triangulated tanks are turning out better than I thought they would



they need to go back to weld some pipe to the ends so I can clean up the transition: then they will be welded on with the venturi plates.

ORX-800

Great work Jarl!!!

Richard (ARE) would be very, very impressed with your efforts in managing the intake air flow.

Cheers,
Danny

rotarenvy

it really hurts to have to shelve the big ARE intercooler I'm running at the moment. it is so well made and gives super low inlet temps.

it got me thinking I should try a turbo next to make use of it. I have the pipe work, cooler and engine management covered. the manifold and turbo is about all I'd need

ORX-800

Why not go the compound charging route...have the supercharger feed a turbo?!

Cheers,
Danny

Brettus

iTrader: (2)

auzoom : Just did this DIY for an IAT - could be usefull

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-iat-sensor-turbo-164751/

rotarenvy

I just finished installing a new MAF pipe. no more than 4 " long and with a 90deg bend right after the MAF. seems to work fine. it shows what can work as I didn't feel this one was perfect since there was a little misalignment (turbulence) where the filter attached. sill not running a MAF screen




the intercooler is almost there the venturi plates have been welded on and now the tanks just have to be welded on. I will play with mounting it this weekend so I can see if the pipes are better opposite each other or diagonally opposed.

rotarenvy

finally the intercooler is all welded up and I had planed to mount it on sat and do some of the pipe work on Sunday.

nothing went right it was one of those weekends...

I measured out some mounting points and designed a mount. the mount was going to be bent out of some aluminum so I marked it out and annealed the metal. started to bend it up and the aluminum snapped so I wasted 1hr and had to redo it.

second time round the annealing worked and I bet it up. drilled the holes and everything lined up perfectly. I went to bolt it on and realised the bolts I chose weren't long enough. no worries I thought I'll just replace them with longer bolts. they were studs and couldn't be replaced easy.

so I thought what could I o to salvage the mount. I know I'll make up some sex bolts. I was very happy with how they turned out and they worked... but the location was too tight to mauve to tighten them since I'm mounting the cooler under the radiator

I gave up ...

Kane

iTrader: (1)

Sounds like beer:30 to me man.

Rule of three.... if three things go wrong in quick sucession, time to just call it a day.

rotarenvy

that sounds like the cure to me

I have realised that being NA sucks after disconnecting the blower for a week.

I couldn't stand the feel of the car NA an not being able to complete the pipework motivated me to hook the supercharger back up without an intercooler

it's a good test since to see if the front mount intercooler is the cause of the problems.
I should have tried it before changing the intercooler. good thing it looks like my suspicions were correct it's going to be painful staying out of boost but way better than NA

rotarenvy

well I couldn't stay out of boost long lol

it works great without a front mounted intercooler! my local shop told me front mount intercoolers didn't work well with superchargers and I should have listened to them!

the current tune must be very conservative so hopefully there is lots of power waiting in the tune!

I'm still hoping the smaller intercooler comes close to the non-intercooled feeling.

rotarenvy

I finally finished the new intercooler install and went for a drive. I don't have any air temp data yet however the new intercooler is a 98% improvement over the 600x300 size cooler. the smaller pipe work did the trick and returned the throttle response. I can't tell the difference in throttle response with this cooler and no intercooler.

time for more boost and a proper tune

rotarenvy

it has taken awhile but I finally have a new pulley combo on for more boost. after 3 attempts with incorrect belt lengths, I ended up buying an AP underdrive pulley and with a custom supercharger pulley it all went smoothly.

it is a small ratio increase over what I was using and I don't think it will change much since I was getting belt slip with the larger pulley. I can no move ahead and solve the belt slip with some custom pulleys.

I can't wait to test the car but I think I'm tempting fate since my A/F mixtures seem quite random. there's another issue to solve