Paul, You mentioned a radiator supplier for custom sizes
 > other than Griffin. Said there was "no epoxy used". Didn't
 > manage to save that one. Who are they? I think Lynn
 > Hanover used them as well. Bill Jepson

I use Griffin. Cheap, and no problems.

Lynn E. Hanover

Lynn, I know they are welded or brazed but don't they also use

epoxy

around the base of the tubes? I might add it was Griffin that

supplied

the oil cooler that split in at least three instances resulting in

two

in-flight fires and one seized engine resulting in a fatal crash.
I suspected it was made in China. Use only oil coolers that have

been

tested at well over 100 psi. Or just use the stock Mazda oil

cooler.

Paul Lamar

Being familiar with those cases, I will just say this: if you

don't

design the installation properly, and don't specify what you need

to

the

maker of a custom cooler, you can't blame the maker.  Griffin

makes

their own oil coolers.

I have a custom Griffin oil cooler that I'm impressed with (the

stock

Mazda not big enough for a 20B).  I specified 125 psi operating
pressure; it was tested to 150 psi.  It hasn't flown yet, but I

have

reason to be optimistic.

Al

That is different than the Griffin oil cooler I saw that failed. The

one

I saw came in
a Chinese card board box. I know Chinese card board when I see it as

I

used to sell
clone computers. :)  Yours looks pretty good. For other people
installing a three rotor what did it cost?

Paul Lamar

Al Gietzen wrote:

Cost $514.00 (Feb,'02).  The quote for 2-10 units was $441.00 ea.  I
thought the price quite reasonable compared to other quotes, and

better

than the $$597.00 for an 11.5 x 16 coolant radiator from Ron Davis
Racing that I'm not impressed with.

The oil cooler core is 5.5" x 21.5" by 3.25" thick.  Internal

turbulator

tubes, 14 fins/in.  I know you think it's too thick, but Griffin

quotes

1.48" h20 airside drop at 1600 cfm (about 40 fps [27 MPH] air flow

velocity.  I

did my own measurements and got 1.25", so I believe it.  Oil side PD

[pressure drop]

quoted as 27 psi at 18 gpm.  No double check on that.

Al

Interesting data Al thanks. The RX8 200 HP has one rectangular oil

cooler

about 8 or 10 inches square mounted just ahead of the left front tire
and just behind a large scoop. The 250 HP version has two. One on each

side.

There are no stone gards in front of them so new ones will be a

popluar

item in the parts department for a few years not to mention ruined

engines

that have been run with no oil pressure as a result of FOD :)
First think I am going to do is make a screen to fit in the scoop

hole.

Hint hint... Jim.

Paul Lamar

For those of you who are new on the list the stock oil cooler seems to

work pretty well;

circumstantial evidence indicates that the stock cooler will cool well

over 200 HP in

an ideal (whatever that is???) duct.  Tracy and Ed are both cooling

175 - 185 HP

with the stock cooler.
The stock cooler (not including tanks) is 19.625" * 4.5" * 2.0" for a

total

of 176.625 cubic inches.  Note that Al's cooler has 384.3125 cubic

inches.

Ken Powell

I would definitely recommend against (with a high level of confidence)
expecting the stock cooler to cool a sustained 200 hp power level on a
90 degree day no matter how ideal the duct.

Al

Nobody with the possible exception of Tom Parkes 3 rotor is cruising at 200 HP.

Paul Lamar
 
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