- Turbocharged or supercharged engines and intercoolers obviously go hand in hand but
there's a little bit to consider when it comes to choosing an intercooler and we're here
with Shannon from Plazmaman to talk a little bit about the different options.
Now one of the age old debates in the world of intercooler selection is the debate between tube
and fin vs bar and plate.
Before we get into the pros and cons of each, could you just talk to us a little bit about what
those terms actually mean in terms of the construction of the intercooler core?
- OK so tube and fin construction is basically going to consist of a hollow tube which the air
will pass through.
Bare and plates will use a solid bar to exchange the heat.
- So now we know what the actual premise of those two cores is or what goes into making them up,
what are the differences in terms of their performance?
- OK so they both have pros and cons, depending on your application and what
you're doing.
Tube and fins are very very efficient, quite light and they're very very consistent
so they're very good at doing repeatable back to back exchanges.
Bar and plate, very very good at holding off heat soak for an initial period but once they
have heat soak in them, it's quite hard to recover.
- OK so I think probably most people consider the intercooler's usefulness in terms of its
ability to take the heat out of the intake charge and then dissipate it to the atmospheric air.
Now the tube and fin, you're talking about, it's quite thin and it does a good job of that
whereas the bar and plate's got a little bit more thermal mass to it, it's a little bit more
material in there so that actually absorbs the heat initially into the aluminium material itself
correct?
- Yes that's correct, they're also fused internally as opposed to externally so
you actually lose flow path with them so that's why you'll see a lot of very very
thick bar and plate cores so you're getting more material to absorb but you're also taking
back or gaining back that flow path that you need.
- Talk to us about the weight of the bar and plate versus tube and fin,
significant difference there?
- Yeah definitely a significant difference.
Say a 600 x 300 common size intercooler you would probably see nearly 4 kg of
difference.
- OK that is a significant difference but then it comes down to that thermal mass with
the bar and plate, so the advantage there.
OK so obviously pros and cons both ways though.
How would you choose a particular style of core for an application?
- So we do usually ask the customer what the vehicle's aimed to be doing.
Street driving, we prefer the tube and fin, we just find that you don't quite get enough
airflow across the core to get the exchange back or be consistent and repeatable with
the bar and plates in normal street driving.
- Look for the bar and plate you really need high airflow, once it's thermally heat soaked,
that ambient airflow across the core in order to get the heat back out of the core?
- Yeah that's correct so I'd say a drag racing situation would be probably ideal for most
bar and plate situations.
But any street car, circuit car I'd definitely say to go tube and fin.
- OK so interesting, I was going to just talk about circuit or road racing, so even in that
application where typically you're going to have relatively high airflow and high
consistent speeds, still a better solution there going tube and fin.
So yes you are getting some air speed across the core but it is on boost a lot
so it is, you're asking it to absorb constantly so yeah it still just doesn't
quite get enough time to recover.
- Let's talk about sizing as well and I'm guessing there's a bit that goes into
choosing an intercooler for an application.
You mentioned the 600 x 300 x 76 or 80 mm core, it's a very popular core for a lot of
applications.
When it comes to the ability to fit a bigger core, is bigger always better in terms of an
intercooler?
Not necessarily, we find, again packaging is one thing.
I mean, it's physics, you're going to need a certain sized core to do a certain sized job.
You just have to do it that way but we find, you're filling more volume for no
reason, you slow down your air speed which means that the vehicle's going to have less
throttle response.
I personally, I just try and size them right from the start but yeah 600 x 300
seems to be a very good number that works in a lot of vehicles as you said.
- Now the other aspect I wanted to talk about is some of the intercoolers that we see come
out of China, and obviously they're being produced at a price point, the price point's
being driven down and down and down so there's a massive difference between
what Plazmaman would charge for a quality intercooler and some of the cheaper
brands out of China however I've dyno tested a lot of these myself and what we've found in
some applications is that the air temperature's through the roof and they're
really almost there for show and doing almost nothing.
What I found though, once I dug into that a little bit deeper was some of the Chinese cores,
definitely not all of them, the flow path through the internal structure of the intercooler
has essentially no fins at all so can you talk to us about that, what's that actually
mean, why are those fins internally important?
- Yeah so you need to scrub the air in order to cool it so you have to have a certain amount
of fins per inch or a ratio that you need in order to slow that air down and give it time
to actually change and cool before it can hit the intake.
So typically a lot of these ones, they don't have a lot of internal finning as you
mentioned so they're simply just passing air through, doing a very minimal exchange.
- So I just want to point that out because I know a lot of people purchasing products
for their car rightly are concerned about the price and it's just so important to make sure
you understand what you're buying because last thing I want is to see people going out there,
spending good money on a product that actually doesn't work and I mean personally on a couple
of the cars I've tested, just simply changing to the same size intercooler with that proper
internal fin structure, we've seen differences of 40, 50 kW or more so it's really significant.
Now those internal fins that we're just talking about though, I'm guessing there is a sweet
spot for that because having those is obviously going to cause some flow restriction as well
so with a well designed intercooler, what sort of pressure difference can we expect to
see between the compressor outlet side and the inlet manifold side of the core?
- So that is a bit of a hard question to answer, it does have a lot of variables to it.
We actually have supercharged specific cores as well for the reason that you were saying.
They usually require about 30% more airflow than what a turbocharged car would.
So if you put a turbocharged core on say like a Vortex side mount supercharger,
you're going to get a tremendous pressure drop across the core.
Because simply there's too much internal finning, you are slowing the air path down
so much that it's putting back pressure on the supercharger, the supercharger
then can't get the air out, it's then asking the engine to work harder to do that and
you get quite a large parasitic loss.
So we've actually seen 100 to 150 horsepower before in a couple of LS pro charged style
vehicles where we've simply just switched to a supercharged specific core.
So it is very very important that if someone does want to buy an intercooler, they choose
the right one for the application with the right amount of internal finning.
- Last element I wanted to talk about is the end tanks and there's different options from
fabricated sheet metal through to cast and more recently we've seen that billet has
become an option.
What's the requirement around going to a billet end tank, is this only for those running
massive boost pressure?
- Yeah so usually it's to do with a very very high boost pressure.
Also it's looks as well.
I mean people do want to have a look and say look I've got a billet end tank but we
do try and do a little bit of CFD in those as well just to improve the airflow distribution
to the top of the core and just make it a little bit more efficient.
But yeah certainly it's a structural integrity thing as well.
- Alright great to get a little bit more insight into the options that are available
and of course if people do want to find out more about the Plazmaman intercooler range,
where can they do so?
- So they can check us out at plazmaman.com on our website, our Facebook page and of
course our Instagram.
- Perfect, thanks for the chat.
- No worries, thank you very much.
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