Big radiator in an FC3S
 

I have a FMIC and I wanted a really good radiator but did want to go with the $350 R1144N koyo. Currently run a regular koyo and if the autocross course is long I start to heat up. Also on the street on a hot day in traffic I heat up. My car hates stop and go. I'm hoping I can fix this with a better radiator and more ducting.
So I am trying this radiator (30033)
https://www.rx7club.com/attachment.p...1&d=1281060523

I get allot of parts from my local speed shop that does mostly dirt track and drag cars. They have talked up the all star radiators for awhile so I took the dive and bought one. If 15-30% of your power is going into radiator, one that keeps a 500-800 hp V8 cool on a mud covered oval should do fine for a 350 hp 13bt.

I will post the work need to install and the results. It should arrive next Tuesday.

Nice, I like the Allstar stuff. What kind of pricing did you get?

Price
 

It was $190 for the radiator, $15 for the fitting (may need two), and $50 to get brackets welded on. I plan on adding tabs to mount my old fan shroud so it will be 20-50 more. So I estimate between $255 - $300 to get it ready to run in an RX7.

I'll post the final cost once I'm done.

I ran an AFCO Rad. 26x19 dual pass. Works exceptionally well. Try to get a little clean air into the rad, as the intercooler is dumping the heat into the air you are pushing into the Rad.

-Trent

Do you have an underdrive pulley? Running high revs can overspeed the pump with the stock pulleys and cause cavitation and hurt the flow. Also how hot is it getting?

This is the biggest radiator I could find. Running it now, no issues but havent tracked it yet.

http://shookmotorsports.com/FCProducts

Was direct fit, just needed aftermarket oil lines since it almost touches the frame it's so big.

I have a weird pulley set, I ran a Camden supercharger and I keep the pulley (surpentine vs V) when I switch to turbo. I run two stock honda civic belts :)

The pulleys are almost the exact size as stock.

Most of my heat issues are going from highway to stop and go. Gets up to 195 in a hurry. I've hit 200 a couple times. Car runs like crap at 200F, with good afrs. Takes awhile to cool down, 5-10 minutes of idling with hood up.

The funny thing is it does better racing, gets hot during a run but will cool down after a few minutes easy driving.

I have ducted the bumper to prevent spillage, and added ugly swiss cheese bumper which help cooling at low speed. You can not see but there are panels running and each side of the bumper from the hood to the undertray.

https://www.rx7club.com/attachment.p...1&d=1281394176

https://www.rx7club.com/attachment.p...1&d=1281394176

Here's an old data log... I'll find a better one

https://www.rx7club.com/attachment.p...1&d=1281394882

It might help to arrange things so that the IC and radiator have their own air sources instead of having the IC spill its hot air onto the rad. Dunno why it would run like crap at 200, mine runs at 200 all day no problem though sometimes the oil gets too hot. It's a fairly conservative setup with street port, stock IC and turbo and lower than stock boost (but more power! hah)

It's arranged like all FMIC, I will do some more ducting, but it's a very common to have the IC in front of a radiator. If the cooling system is correct it should not be an issue.

I have a custom intake that doesn't work well when it gets hot. (Jtech style 4 barrel intake and an auto-nomics TB) It's a trade off of performance and driveablity. I could kick the idle up to 1300 but I would rather keep my idle at 800 and fix the heating issue at low speeds. Also I need a new IAC and I'm sure I could tune out some of the issue. I have a project car and I do not expect it to like a stock car.

First mock up
 

I mocked it up today, I need to trim for the oil lines on the driver side and the wiring harness on the passernger side. It will sit much lower after trimming.

https://www.rx7club.com/attachment.p...1&d=1281804145

https://www.rx7club.com/attachment.p...1&d=1281804145

https://www.rx7club.com/attachment.p...1&d=1281804145

Sitting on IC pipe for picture

https://www.rx7club.com/attachment.p...1&d=1281804145

https://www.rx7club.com/attachment.p...1&d=1281804145

https://www.rx7club.com/attachment.p...1&d=1281804145

I just re-mounted my Afco rad. I also cut the top outlet off and welded it on the top of the rad.
I also managed to drop a spinning grinder on the rad and tear some nice holes in it. Took my four hours with the TIG to patch those little passages. :-<

here's my car blog:
www.rxracing.com

-Trent

I learned from your mistake, I taped cardboard over the fins on both sides.

I have the radiator mounted, just waiting for my turbine housing so I can mock up my turbo. Then I can cut all of the ducting and hoses.

I will post picture soon.

mocked and mounted
 

So I mocked up my turbo with my current turbine housing because I cann't seem to pick up a .96 P-trim quickly.

It's tight but plenty of room for the lower hose. I will be clocking the compressor outlet veritically so there will be more space than shown. I order a stainless hose kit from summit racing. Should be easy to bend up a hose.

http://www.summitracing.com/parts/SUM-390012/
http://www.summitracing.com/parts/SUM-390024/


Here pics with the turbo
https://www.rx7club.com/attachment.p...1&d=1283107053
https://www.rx7club.com/attachment.p...1&d=1283107053

I used 1/4 plastic strips to isolate the radiator and finished mounting it. I still need to duct more, block the top, make a shroud, and fit the radiator hoses. Hope to be done next weekend. Here's the pics of it mounted.

https://www.rx7club.com/attachment.p...1&d=1283107053
https://www.rx7club.com/attachment.p...1&d=1283107053
https://www.rx7club.com/attachment.p...1&d=1283107053
https://www.rx7club.com/attachment.p...1&d=1283107053

summit hoses suck huge donkey balls
 

OMG the summit hoses suck huge donkey balls. None of the ends fit over what they say they do. I call summit racing and their only input was to soak the ends in hot water, which did not work at all. I had to use a pipe spreader to get the ends mounted. The pipe does not make tight bends.


Away the hoses are in, I do not know if they will hold water.... My turbine housing is one it's way, and I hope to have the fan shroud done this weekend.

Update:
 

I got busy and never rapped up this thread:

The top hose radiator hose I paid too much for keep blowing off, so I picked up a regular one from the parts store and it works like a champ.

https://www.rx7club.com/attachment.p...1&d=1307881670
https://www.rx7club.com/attachment.p...1&d=1307881670

The next issue was too many radiator caps. The coolant system would never recirculate right, so I deleted the one on the coolant neck. I cut the top of an aluminum cap and ran a 1/2 NPT tap through the flange. It's not enough thread to seal, but holds it in place for poxy (JBweld industrial). I used a standard 1/2 to 1/4 npt adapter to put in a coolant system air bleeder screw. (part number 641-3377 from napa, comes with 2 for $10.81) This seems to be working well and makes bleeding the air out of the system easy.

https://www.rx7club.com/attachment.p...1&d=1307882327

https://www.rx7club.com/attachment.p...1&d=1307882327


Here is final system without the cooling panel. My fan seems to be running much less with this configuration. I'll have to wait for a race or a really hot day to test it out.

https://www.rx7club.com/attachment.p...1&d=1307882327

https://www.rx7club.com/attachment.p...1&d=1307882327

Made a new cap delete
 

I was not happy with my cap delete so I made a nicer one.

https://www.rx7club.com/attachment.p...1&d=1308277613
https://www.rx7club.com/attachment.p...1&d=1308277613

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I am interested in this setup. Where did you relocate the heater core return tube?

i don't know where he did it, but on my 3 rotor i had the same problem, there are a couple of ways to fix it.

1. put a fitting in the radiator, this is the most stock way, but it needs to be welded/brazed which can be complex/expensive/a hassle

2. on mine i had a piece of pipe in the lower radiator hose, so i tapped that for a fitting. use pipe, like plumbing pipe, its thick enough to have a brass insert threaded in.

3. the FD water pump housing has the heater hose in it, so you could run that, or put a bung in the FC one maybe?

heater core return
 

I'm current not running a heater core. I was planning on making a hard pipe for the lower hose with a bung but I moved to SC and have no need for heat. The fans are enough to un-fog the windows so far. I have heard of small electric heat cores used on hot rods as a plan B.

AWR makes a setup just like this one. It's a bit more expensive though.

they sell a kit with a separate t-tube for the heater core:
http://www.awrracing.com/images/cooling_acclg.jpg

Radiator - 1986-91 RX-7 Crossflow Competition - 7507 - AWR Racing Store

It's arranged like all FMIC, I will do some more ducting, but it's a very common to have the IC in front of a radiator. If the cooling system is correct it should not be an issue.

I disagree that it is arranged like all FMIC, as most cars with FMIC have the heat exchanger cores stacked with no space between them. This allows incoming air to penetrate the cores as one with much less a drop in velocity.

With a large volume between the cores the velocity drops off and the flow becomes turbulent and does not penetrate the second core easily.

Look at all factory cars and you will see stacked heat exchangers (FC) or heat exchangers with separate dedicated ducts (FD).

In addition, having the IC set back in the bumper opening works much better for cooling at low speeds as air enters the smaller front opening and meets with less resistance penetrating the heat exchangers than turning around and flowing back out of the bumper opening. With a the heat exchanger far out in front with no duct air has a tendency to glance off the front and flow around it as if it was a solid bumper skin at low speeds.

I would say rather you have arranged it like almost all FMIC on FC/FD. I would also say almost all FMIC FC/FD have coolant/oil heat issues on the track after multiple laps.

If you said that all turbo rotaries will have varying degrees of heat issues with multiple lapping I would agree, though you might be amazed to monitor stock 3rd gens even with their wholly inadequate IC and radiator sizes.

I remember watching an Options Video where they monitored coolant/oil temps (on Tsukuba circuit I believe) and I seem to remember the FD was one of the coolest running while other stock cars (NA and turbo) overheated or even broke down with just 5 or so laps.