What temps are you guys seeing? and where do
you have the temp gauge sending unit installed?
I have the sending unit in the 20b stock stat cover
its a autometer and I am seeing 210F +
I Just finished installing a BIG custom made rad
which I thought would be lots to keep this thing cool
but it's starting to look like its not enough either

I ran a stock rx7 rad with a GOOD fan, it was
fair if not better than the new rad.
the new rad is much thicker so I had to use 2 small fans,
instead of the one big one, but it looks like the temps at
highway speed are still getting kind of high.

I checked the temps around the motor from many
different areas, with a no touch temp reader, and the
hottest spot on the motor is at the stat cover.
the oil temp seems to be about 210 on the hot side of
the oil cooler, and 165 on the cold side so I think the oil
is cool enough.

so, is it running hot or am I taking the temp from the
wrong area on the motor?

matt

 

highest temp seen so far on the autometer, is the mark
between the 210 and the 250 mark,,, so I would assume
that would = 230F while it was at that temp I did some
more no touch readings and the rear housing (cast steel)
was 202F and the front housing was about 209F
and the stat cover was reading about 220F I think the
problem is just not enough air flow through the rad

matt

 

As long as I can run at 40+ mph, the temperature will stay in the 190 - 195 range, even with the air conditioner on.

Stop-and-go traffic will push that higher. At 225 (slow traffic), I follow the example of some of the 3rd gen guys and turn on the A/C compressor (forces fans on) with the temperature setting on the Logicon set on "Hot". That will hold the temperature to about 230, if I don't have to stay there more than about 15 minutes.

 

I agree--air flow is the key. On the 3rd gens, Peter Farrell and some of his customers have found that the solution to high temps on the track was as simple as a block of wood to force the plastic nose opening a little wider.

 

my fd runs at a high of 104 cel when I am on the boost on the highway....will drop to 96 when out of the boost. I believe that is right around 200. I am re-designing the air flow to the rad now. I put in the big greddy front mount intercooler and have also put in a huge rad. The problem is getting the airflow through the intercooler and through the rad. One of the things we did on the other race car was to force the air through the i/c and rad by using duct work so that there was no other place for the air to go. Putting the duct work in is time consuming but very effective as you control the amount of air going in the front of the car.

At higher speeds (190+) this is critical as too much air going under the car makes for a very unstable front end.

 

I am going to duct tape up around the rad and try to
seal things up,,
what do you guys think of moving the auto trani
cooler to the back side of the rad? The way I see it
in most cars the trani is cooled by the coolant in the
rad so is it that much worse to have the oil to air
cooler for the trani behind the rad?

matt

 

George,,, so you have the sending unit for the temp
gauge at the stat housing?
you have a different nose on your car as well,, which
might be helping keep it cool on the highway.

matt

 

This is a good thread. I haven't thought of where I'd put my temp sender. Hmm, maybe the Tstat housing really is the hottest part, and therefore the best place to put a sender? Or maybe on one of the threaded holes on the back of the water pump?

now, it should be ok to mount the tranny cooler behind the rad basically for the exact reason(s) you stated. I will need to do that too if I ditch the stock rad.

 

(blush) I don't know. One of the joys of having Peter Farrell do the conversion is that the only location I had to worry about was where to sign the check. I'll try to take a look at it, this evening, and get back to you.

And, yes, the nose helps. That's why I got it. Both the nose and the fender flares were motivated by engineering issues, not appearance.

 

i have the temp gauge in the stock location, and i was seeing the same as george. above 35-40mph it would stay at about 90c and below 40mph it would get up to about 100c. i have put bigger fans on it, and winter is coming. i still have the stock front end, and a front mount with no under cover (it's in the works) and a k2rd radiator.

mike

 

I have the under cover made and it didn't
really help, thinking of making it bigger
and covering farther back, it seems to be not back
on the hiway as long as I don't get on it for to long,
around town it starts to get warm, I think I am going to
work on the larger under cover and remove the stock
nose and see how much of a difference it makes, then I
will know if there is any hope to make it better.

matt

 

i was thinking about putting a flap on the bottom of the radiator like an american car, i may not need it though. i need to drive it with the new fans.

mike

 

Can you tell me what radiators you are using?? Copper or Aluminium - what sized tubes? How many rows? I was looking at getting a custom alloy radiator - 2 core with 1" tubes - just thinking now - will this be big enough???

 

surface area of the core is 22" x 20" with really big end
tanks for vol. it just fits between the frame boxes, and
is touching the hood on top, and hangs as low at the
bottom, as the bottom of the nose.
its a custom made aluminium 2 core with 1" tubes,
I think it will be big enough if I can get air flow through it.
I have to do the silicone hose and tie wrap thing,
2nd turbo stopped working and I assume vac hoses are
the problem, once that's done, I will pull the nose back
off and see if it will run cool with the nose off ,
if it does then I know its just a matter of making more
holes in the nose for air.

matt

 

http://www.k2rd.com/Online_Catalog/FC3S/FC3S-index.htm
i'm running the k2rd radiator, its 19x22 and its double pass.
i got my flanges so i get to drive the beast soon

mike

 

OK. I looked. Between the radiator and the water pump, there is a metal fitting with the filler cap. The sender is plumbed into the side of the fitting.

 

Attila the Fun,, your sensor is in the same area as on
my engine and we are seeing close to the same numbers,
not sure if this makes me any happier, I just
hate to see that high of temps in
traffic,,, you said that you see as high as 230 F
I would think in the long term that would do damage
/ cause oil leaks etc?

matt

 

Attila the Fun, for got to ask what was done for a sway
bar on your car?

matt

 

i put a temp gauge in my 1st gen, in that spot. on a hot day with the ac on it was between 85-90c just cruising. i got on it coming up the hill and it got up to about 95c. so thats what a normal healthy (it wont die) 13b with no turbo runs.

mike

 

I agree. If my potential buyer doesn't take the car, I will change the ducting to the radiator and add a higher capacity fan to address that.

According to Peter Farrell, it will be ok as long as I keep it under 240 degrees.

 

Mitch Piper, who wa working for Peter Farrell at that time, fabricated a custom anti-way bar for the car.

 

ok i drove the 20b today. without the fans it wants to run at 95c, with the fans it stays at 85-90c

mike