Aftermarket intercoolers. Why the hell are they so expensive? I've been chasing off-the-shelf 'coolers for an up-coming buyers' guide and I've been horrified by the RRPs on some of these things. By the time you pick up the core and have end-tanks welded on you're often looking down the barrel of a cool $3000. For what is nothing more than a glorified radiator for your induction air! Certainly, an intercooler is no mystical device - as some retailers would have you believe...The themes that aftermarket suppliers pump their products up with are the ooh-aah bar-and-plate core, high quality welding and - when supplied in a kit - how well the intercooler fits to the vehicle. Now while it is very nice to see a high quality intercooler kit under the bonnet of any car, its main justification must be (1) - its heat exchange capabilities and (2) - its flow rating. In other words, the intercooler needs to cool down the turbo'd air as much as possible while not posing too much of an airflow restriction. A larger intercooler is the preferred thing. They have the most surface area to cool the charge-air and they usually have the most flow.
Now if I were chasing a mega-efficient intercooler for my streeter, I'd be looking at all of my options before I handed over my 3k. One option that no one seems to be interested in is twin intercoolers. Just take a trip down to a Japanese import wrecker and you'll see their collection of air-to-air intercoolers proudly on display. Now they might not all be huge, but imagine their flow and heat dissipation capacities doubled. That makes their use a lot more feasible. Depending on their size, you might pay up to around $350 for, say, a Toyota 2JZ-GTE twin-turbo Supra intercooler (as factory used on a 206kW engine). While on its own this is no match for a big Trust intercooler, what if we bought two 2JZ intercoolers and parallel plumbed them into the engine bay as a pair? Hmm, now we're talking a much closer match!
If Toyota ran any given intercooler on their 206kW six, you can bet that it won't have any more than about 1½ psi pressure drop across it (in its standard engine configuration). Knowing the power output of the engine that an intercooler came from is a big help. In the case of our twined Supra intercoolers, we now know that they can potentially flow a massive 412kW - with acceptable pressure drop and heat dissipation (depending on how compressed the intake charge is). A set-up such as this should provide a highly cost-effective upgrade for any mildly modified WRX, GSR, VL turbo or whatever. On a smaller scale, a Nissan Pulsar ET turbo would have an awesome intercooling arrangement if you twinned a couple ex-R32 GTS-t Skyline intercoolers. These things are slagged for being a little on the small side, but - factory rated at 158kW - you can see how much power you could put through a pair of them!
Whet it comes to installing a twinned pair of intercoolers, one possibility would be to mount one in each inner wheel arch. You can then route airflow to each core from cut-outs in the front bar and have air pass out into the low-pressure wheel arch (as Nissan do in cars such as the aforementioned GTS-t). By having the intercooler system split in two, it can also actually be easier to cram more intercooling under your bonnet. Instead of looking for one single massive cavity to locate the core, you can make the most of other smaller areas that would be otherwise wasted. Don't forget, a single large spot for a monster air-to-air intercooler might not even exist on some cars.
Plumbing the twinned intercoolers may be a little difficult, however. If you've got twin turbos, it would just be a matter of connecting each compressor outlet to an individual intercooler and gradually merging the two post-intercooler pipes prior to the throttle body. But for those cars with just a single turbocharger, you'll also have to split the compressor outlet pipe into two to take air to each of the cores. As far as I can see, the plumbing on a single turbocharged car is the only area where things may get a little messy - and airflow may be compromised. But by paying extra attention to the 1>2 and 2>1 pipe junctions, you should be able to keep airflow up (perhaps by using an extractor collector for the 2>1 merging).
It's a set-up you should definitely look into when you're looking for some serous intercooling!
In this job o' mine, my ears take in all sorts of tales of woe and mechanical explosion. Probably the most alarming I've heard of late is in regard to one of our past WRX feature cars - Wonder White. I bumped into Gary - the proud owner - while he was running the car at a recent Adelaide drag street-meet. In case you've forgotten, his weapon of choice is an immaculate WRX wagon with Drummond suspension, front-mount intercooler and - now - a VF/STi turbo charger to replace the 400hp AVO unit. This guy had it made - or, at least, so I thought...
I asked him if he'd had any mechanical problems with the car. I was fully expecting him to have chewed a clutch plate (which he had done), but I was gob-smacked to hear there was also a major engine let-go. After all, my experiences with a boosted EJ20 turbo engine had been one of 100% reliability. Gary says that - with less than 20,000 kilometres on the clock - his mighty Rex cracked one piston in fairly spectacular fashion. A cracked piston, eh? I then wondered if he'd been running too much boost for the stock injectors, running it on crap fuel, or if the fuel pump had died momentarily? Nope - it was none of the above. It turns out that the innocent looking pod filter had deposited its cotton oil onto the airflow meter hot-wire and wreaked havoc with what the ECU thought the engine was doing. Eeek. This was only identified as the cause after the engine had expired. Too late...
Now there's a whole lot of people out there running around with an oiled filter on their tuned-to-the-limit mad machines - I wonder if they're aware of the possibility of such a destructive event? Probably not. Perhaps - in Gary's case - over-oiling of the re-useable element might have caused engine failure. In any event, it's something we should all be very much aware of....
Oh and - of course - Subaru Australia didn't want anything to do with chipping in on Gary's engine re-build, coz the car was modified. Boy, for such a lucky bastard, Gary sure had to do it tough!
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