|
Intercooler Rating
KW / CFM ?
Why the change from horse power that we used.
There has been a major change in the market
place in the past 12 months & it has accelerated at warp speed in the
past three months. What am I talking about ?
-- CHINESE COMPLETE INTERCOOLERS
!!!
Three years ago we started importing our
own bar-plate cores. As I stated at the time (& still on our site), we
had a sample sent out, tested it & had changes made - tube size & both
fin pitch & type. We then tested this second core & had some more small
changes made. We tested these & that became our own core that we
imported - a third generation. Please Note - that each batch of
change to specifications cost us extra money, which we had to pass on,
but was definitely worth it with the extra performance gain.
Now most people think all Chinese intercoolers are the same, in fact I
was almost sick when I read in one of the recent adds that stated their
intercoolers were made in the same factory as Hybrid-like, that's a
selling point ! Give me a break
I must also state that they are not that bad, in fact even
though I don't sell them, in certain cases I recommend in Emails & to
customers that they are the best option for them. BUT PLEASE PUT THEM
INTO PERSPECTIVE IN THE MARKET PLACE & REALIZE THAT THE COMPANIES
ADVERTISING THE 75MM CORE @ 600HP AND THE 90MM CORE @ 900HP, ARE TOTALLY
MISLEADING YOU. An engine may produce that power with one of
those cores, but because they are grossly overrated, the same engine
would produce approx. 30 - 50% more power with a properly sized core.
The fin pitch is very wide, which gives a low pressure drop, but also a
low heat dissipation rate. We have also had to repair more tube leaks
than is satisfactory & have noticed the internal fin to plate bond is
not 100% in some cores. BUT THEY ARE TOP VALUE IF YOU ARE ON A BUDGET &
THE CORE SIZE HAPPENS TO SUIT YOUR COMBINATION !
What gets under my skin is that most ' shops'
selling these Chinese intercoolers know bugger all about them, can't
give accurate advice & are just after the money. This is the worst of
spending over a thousand hours on Research & Development on our
intercoolers & developing a comprehensive intercooler sizing
computer programme (& this is
just part of one of 5 basic programmes we have developed). Sorry, but I
know most of exactly how our intercoolers work - things like pressure
drop of each100mm tube length, heat dissipation of each 100mm tube
length - (ofcourse you know that it varies for every section through the
tube length) -, pressure drop, charge distribution & cfm rating for our
Evo Hot Chilli range, & I could go on & on.
|
So what is
KW / CFM ?
| Five years ago when an Engineer (Danny Irvine) started an
affillition with ARE, he convinced me to work in
killowatts of heat dissipation (kw) per cubic feet of charge air flow
per minute (cfm)
- kw/cfm. I'm so glad he did as it really is the basis of
intercooling, & speeded our learning (R&D) process no end.
Kilowatts of Heat is NOT to be confused with kilowatts of an
increase/decrease of that engines power output - it is not a one for one
deal. When our computer programme says we are removing 50 kw heat, that
is not increasing the engine output by 50kw. That is another formula.
But it is a real world figure that people can relate to & understand
instead of degrees Kelvin, which our programme gives as well.
CFM is the volume of air output of the supercharger/ turbocharger. It
is the basic result of the cubic capacity of the engine x rpm. x
boost pressure. Things like pipe, intercooler & plennum design
along with camshaft profile, valve, port sizes etc., all have a small
bearing on cfm.
Another cfm figure that has a big impact on an intercoolers efficiency
is Ambient cfm. This is the volume of air (&, of course, it's
temperature) that is travelling through the core. This is not part of
our core rating equation, as it varies through such wide parameters, it
has to be factored in on an individual basis, & even then as an average
of conditions. It will be more specific in a race car situation that
races local events. |
So how do I get
an exact KW/CFM
rating for my application ?
| By coming to our workshop & paying to have a core mounted
in the front of your car & then data logging the air flow through the
core at different speeds. We know all the other data. Worthwhile ? NOT
at all - a waste of time & money, unless you have some way out combo!
There is absolutely no need to go to these extremes, as we have
collected enough data & experience to be able to accurately guess the
relative ambient cfm figures to compute a size that will be 98%
accurate. That is probably15% better than a couple & 30% better than
most firms selling out there. |
|
