PTP is selling a bunch of turbo chargers for the RX8.
I would like to see you do one. They get big bucks and about 360 HP.
The trick is to use a stand alone anti detonation fluid
injector controlled by a piggy back or add on micro processor
that monitors intake manifold temperature and injects
anti detonation fluid when the temp rises above 140 F or so.
I think HKS is making it.
This neatly by passes the need for RX8 low compression rotors.
It also should get about the same low speed MPG due to
the 10:1 rotors. This is right out of the Reno air racers SOP book.
http://ptp.tuningmotorsports.com/home.php
http://www.rotaryeng.net/Turbo-RX8a.jpg
Paul Lamar ...No rotor no motor.
----------------------------------------------------
Hi Paul,
You may be aware of serious overheating problems on the RX8.
Putting a turbo on exacerbates this. We did one for Mazda and, although
it can work if you are VERY careful, there are systemic weaknesses that
a larger radiator does not address. I have no problem with turboing
the engine, but until someone figures out a way to cool it (I have tried
several aero devices without enough success), It is a poor idea in
my mind.
Jim
----------------------------------------------------------
I was unaware of any cooling problems on the RX8. My 2003 stick has
30,000 miles on it and I have never ever experienced the slightest
over heating. Under what conditions does it occur? Idle? City
driving? Or high speed? In my previous five rotary powered
cars that I have owned, starting with my new RX2 in 1973, I
occasionally experienced cooling problems. So far no cooling problems
at all with the RX8. No other problems either since they fixed
the flooding on start problem up with a flash to the PCM.
I see some mistakes in the RX8 cooling system design but no
more so than some other new cars. I also see some improvements
over the RX7. The frontal area of the rad core is larger
and the core thinner. That is an improvement. The rad is laid
over about 30 degrees I would guess. This allowed the larger
core frontal area. I see some improvements in the RX8 water pump
compared to the 3rd gen water pumps as well. Less restriction
in the water flow coming out of the block.
IMHO cooling mistakes are as follows: The duct feeding air to the
rad is not sealed. The duct shape is not of the Kuchemann and
Weber streamlined diffuser design. Namely trumpet shaped.
The back of the rad air path is restricted by the battery box and
the air filter. It could use an air vent in the hood placed
directly over the battery box and air filter if those objects
were not placed there. Getting free flowing air out of the
back of a rad is as important as getting air in the front.
Scott and Harley, have you guys had any cooling problems with
your RX8s?
The bottom line is the metal temperature within 1 mm
of the combustion chamber just below the lower spark plug.
Sort of cylinder head temp.
I have written a small book on the subject of cooling
rotary powered airplanes. Here it is in html format.
http://www.rotaryeng.net/how-to-cool12.html
We have been through hell cooling the rotary
in airplanes for the last seven years but we are asking
for (and getting) a continuous 150 to 200 HP hour in and hour out.
The aircraft cooling system must be designed and done right.
Paul Lamar ...No rotor no motor.
Hi Paul,
I don't know how you monitor the eng cool temp but you cannot use
the stock panel gage - it stops moving about 165 F and doesn't start
again until 205~210 F. If you see any movement above the "normal"
range, your engine is seriously overheated. Mazda has bought back a
number of RX8's in Vegas for engine failures. We did a considerable
amount of testing and on a 93 F OAT day it is easy to see 215 F Eng Cool
Temp. After a lot of testing, I am convinced at one large obstacle is
the lack of an engine driven fan - noisy, but powerful. The FD was much
the same. The FC never had a serious problem. We have tried turning
vanes, lip spoilers and closing the underside vents with minimal
effect. In our RX8 flash, we move the electric cooling fan on temps
from 98/101C to about 8 C lower. This helps avoid heat build-up but
does not cure the problem.
Jim
-------------------------------------------------------
A thicker rad is harder to blow air through. Only helps
if you are doing 200 MPH.
Sounds like the gage is defective. Is Mazda fixing that?
I have never seen mine move beyond the half way point.
Do I need to install an aux temp gage? Do you sell anything
that will work? If not do you have any recommendations for
parts that will work and installation instructions?
I think I have a DVM around with a temp function.
I'll see if I can hook it up to my RX8. I know I have a tire
temp gage but the cable is not long enough to reach into
the cockpit.
You are right about elect rad fans in general. They are wimpy.
Time to check the volume flow of those fans. Also check the
amp drain on the stock fans. A 20 amp fan is only .36 HP electrical
HP in. Net mechanical HP is only about .3.
Here are some specs on the Spal fans that Ferrari uses I think.
First attachement.
Sounds like the electric water pump thing all over again.
Paul Lamar ...No rotor no motor.
Jim, I just thought of something. If the CAN turns on the RX8
fan without a relay, putting more powerful (higher current drain)
fans in there might blow the FETs (transistors) or the relay.
In that case it seems like the simplest thing to do is use a temp
switch many elect fan kits come with. Have you checked the current
drain on the stock RX8 fans? If ten amps or so a twice as powerful
(20 amp) Spal fan is going to help.
Paul Lamar ...No rotor no motor.
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