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Like we weren't going to make a new intercooler for the X. For one, the stock one is pretty restrictive, and two, in order for the EVO to compete with the STI in our EVO vs. STI project it really needed one! Besides the gains we saw there is one very important thing we found, which will be a Huge concern to all X owners after they find this same thing out. Before we get too deep, lets look the hard data on both cores. First off the old EVO and the new EVO have the same exact core, just different tanks. When designing the new core, the new bumper opening is much smaller, but has much better routing to the core. So more air is pushed directly through it. Stock EVO 9 19.50" x 11.5" x 2.5625" 566.5 cu-in 25 (.167"tall charge tubes) .268" tall ambient fins Stock EVO X 19.50" x 11.5" x 2.5625" 566.5 cu-in 25 (.167"tall charge tubes) .268" tall ambient fins PERRIN EVO 9 25.00" x 11.625" x 3.5" 1017.2cu-in 14 (.375"tall charge tubes) .375" tall ambient fins PERRIN EVO X 20.75" x 12.375" x 3.625" 930.8 cu-in 15 (.375"tall charge tubes) .375" tall ambient fins tech_intercooler_evoxhangingcore This is just our prototype core we had built. This was built using a few basic things like make it as big as possible while still fitting easily. One interesting thing we found was the core wasn't centered to start with. It actually is off center by about .75" or so. Not very noticeable unless you start measuring things. So besides fixing that, we went as reasonably deep as we could, and as tall as the ambient air would still flow through it. It looks like Mitsubishi (using the same size core) got smart about making the bumper match the IC size. THe downfall is it eliminates a few inches on each side for us to make the core wider! tech_intercooler_evoxprotodriver You can see by the pics that there isn't lots of room to go too much wider. But we push the limits of the core and bumper to ensure all the air goes through the core. This leaves virtually no welds showing from the outside of the car. Other than that we use the OEM type of hanger system to secure the core. This teamed with the lower brackets makes the core rock solid.

Test Time

Onto the test! For this test we had just finished tuning Stage 1 with the Unichip and bolted on our Turboback exhaust. We left the bumper off for the test in order to be able to swap the cores quickly. The bumper beam was left on also. This may put both cores at a slight disadvantage with loosing some of the plastic diverters on the bumper, but still it makes them both equal. Another thing is our tanks we were using some prototype tanks we built not production cast aluminum tanks. Then one more thing to keep in mind (important when comparing other IC tests out there) our car is tuned! This isn't the stock ECU tuning! Or stock boost! tech_intercooler_evotempprobes Like some of our other tests we have show on the net, we are using the Innovate logging hardware to log temps and other important data. Our (3) temp probes are mounted as follows. One in the aluminum boost tube right after the turbo, one in the lower charge pipe after the intercooler, and the final one is right in front of the IC for ambient temps. Along with we do have boost, EGT and a few other things hooked up. The only other thing we would be measuring is EGT's. Normally the IC's don't effect this too much, but we noticed a huge difference in some instances.


After a few runs, the IC outlet temps seemed to keep getting worse. We did about 4 runs with about 30 seconds between them. The peak IC outlets temps started at 140 and by the last run, 149 degrees! This is what we seen on small IC's mounted in crappy places (STI), not on an EVO! So why is the question?? The EGT's caught my eyes as they seemed a bit high. The first run peaked at 1678F, hot for sure, and something too keep an eye on. By the final run 1701F was the highest. These are pretty toasty! So why?? The Pre-IC temps were astronomically high! Normally we see 250-300 on a turbo that is really working or being pushed beyond its normal efficiency range. But we were seeing 400F! You could bake cookies at that temp!! This was only on the first run! The second run was 418F which it stabilized out from there. Still this is nuts! So again WHY?? We will answer that later. tech_intercooler_evoxmounted So with some scary data behind us we thought, our IC must be able to do much better! It does and it deals with that extreme Pre-IC temps pretty well. The Pre-IC temps were still hot but about 20F cooler. First runs peaked at 380F, and the last run peaked at 400F. Well that is a good start. This drop in temp could be from the IC being less restrictive than the OEM core. We saw about .9psi vs 1.5psi drop. So the turbo has to work less to make the same boost, more efficient! Now the data that really matters. The Post-IC temps were much more inline, but still about 20F higher than we normally see. The first run showed a peak of 114F and the last run hit 120F. This was huge improvement. With a good tuning tool this could be worth a little extra timing and more power! Or, if nothing else a safer setup. EGT's also improved peaking from 1616F in the first run and 1636F. So overall the PERRIN FMIC ran more than 30F cooler on the IC oulet temps, and almost 80F cooler! All that means a happier safer engine. Worst case scenario runs are shown below and temps taken at 7300RPM and the temps for the day were 67-71 degress.

Stock FMIC Tuned Stage 2 PERRIN FMIC Tuned Stage 2

3000RPM Inlet 245F/ Outlet 104F Inlet 238F/ Outlet 101F \ 7300RPM Inlet 412F/ Outlet 144F Inlet 398F/ Outlet 120F IC Efficiency 80%-78% at redline 82%-85% at redline. PEAK EGT's 1678-1701F 1616-1636F The lower RPM IC efficiency numbers are a little scewed as the temps just started to climb at this RPM. Which one made the most power? Again to be clear, this started as a stage 1 car with just FMIC's swaped from one set of runs to the next. Of course our core made more power. Now it wasn't tons but there are a few reasons for that. The super high turbo outlet temps, turbo is pushed to the max as far as flow, and we didn't turn the boost up from where it was or do any ECU tuning to really show the benefits. What was most important was consistency! The car would loose HP every run, and by the 5th run it was down 15WHP. With the PERRIN FMIC installed it only lost about 5WHP and it leveled off. dyno_intercooler_evoxfmictest


So where is our core?? Well we learned very quickly that sheetmetal tanks is huge labor sucker-upper, and cast endtanks work and look much better. So the downfall is this adds a bit of time (and cost) to get our FMIC out, but it will pay off to those who wait. Some may wonder what is involved with making endtanks? There are many steps, but I bet none of you expected to see wood involved in one of the steps! Step one is make a prototype set to use, and another to build a pattern from. We used a couple of our other cast tanks as a starting point, then started to cut an weld until the tanks were done. From there the part goes to the pattern maker who will create our part from one of many different materials, and most commonly use is wood! I know something you might find in your Benz on the dash! Maple and other dense woods are used to create both the inside cavity and the outside of the part. With a pattern finished, sand can be poured around the pattern, pattern can then be removed. The 2 halves are stuck together in a box, and molten aluminum is poored in. After cooling, out comes our end tanks! tech_intercooler_protoevoxtanks Basic prototypes of tanks with notes for the pattern maker tech_intercooler_evoxpattern2 After some back and forth, and test fitting, pattern for the casting process are created This makes it sound like its a long ways away, but actually our FMIC i just around the corner. This info may sound new to those reading it, but actually we have been sitting on this waiting to release it closer to when we can start shipping the FMIC's. In roughly 3 weeks parts will start showing up in customers hands!


In conclusion, Our intercooler works great! Wait, so, why does the EVO have such high Pre-IC temps?? If the turbo was really pumping out those temps without something else effecting it, the turbo would have to be running about 45% efficient. This can't be as we have Compressor maps showing air flow and we know that base on the HP we see it can't be that, then what? Wait until your car cools off one day, run your hand above the compressor of the turbo under the exhaust manifold and heat shield. What do you find? I find nothing, yes almost no room between the turbo and the exhaust manifold! There is roughly .250" between the turbo compressor housing and the exhaust manifold. What happens with exhaust manifold glows red hot under normal conditions? The extreme radiant heat heats up the entire aluminum compressor housing and in turn heats up the air going through the turbo. Normally when air gets compressed in this situation it heats up to 250F-ish, and the fact its getting heated up to 400F is a little scary! Ok so besides the extreme heat coming out of the turbo, I wonder how this is going to effect the longevity of the turbo. If the turbo outlet temps are 400, the compressor housing must be significantly above this. While the CHRA of the turbo is cooled by coolant, and there is oil running through it, this is much hotter than a normal turbo runs. I see a potential for future issues. So what are WE going to do about this? We have 2 things in the works, just wait and see! The fact the turbo is latterly a quarter of an inch from the glowing red hot exhaust manifold is a major design flaw. Its amazing the Stock FMIC does an OK job of cooling it down, but still the IC out temps were much hotter than we typically see on the Subies and on other cars. With that said, I am very happy that our PERRIN FMIC did make a difference in all aspects. If we can solve the Turbo out temps, I think the FMIC can be fully utilized and be worth at least twice as much as it showed on the dyno. Now its time to do some further tuning!

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