Maybe my search-fu is off, but I can't find much info on using RX-8 oil coolers in FCs.

In short, the car is a bridge-ported, T-70 monster that will be 400-500 RWHP when on the track. I plan on doing time attack and HPDE and I need better oil cooling, plus there's no good way to fit the OEM cooler with my new custom v-mount setup.

After much experimentation, I've settled on dual side oil coolers. The problem is that I already spent way more than my budget so I'm looking for cheap ways to use junkyard parts without sacrificing functionality. I've got access to multiple oil coolers from RX-8s at the local junkyard ($25-30 each).

My question is this: will 2 RX-8 oil coolers be good for cooling ? They will be fully ducted with a dedicated clean air source. The way I've got it set up, I could probably even work in a 3rd RX-8 cooler if necessary.

Thoughts?

 

i've seen people run FD coolers, and the Rx8 coolers are bigger, so it should work. you do need to find out why the Rx8's engine failed, lots of Rx8 coolers full of bearing shavings

 

Good to know about them being larger than the fd's; I wouldn't have guessed that.

Also, they were totaled in car wrecks so they should be ok, but I'll probably have the flushed just to be safe. There's 6+ in local junkyards, so I've got a lot to pick from.

 

i think you havent seen it much b/c of the lack of problems with the stock Fc cooler. though i would think they would be popular with v mount guys..

 

Honestly, I was never super happy with my oil temps with the stock cooler when I ran it hard. I think some of it may have been the fact that the flow is restricted some from it being sandwiched on the rad, though.

I have all sorts of crazy plans in my head, but I think to start I'm just going to get the 2 coolers, stick them under the headlights, then try to figure out the best way to duct and plumb everything. Hopefully it will stop raining so I can actually pull them from the cars....

 

I agree the dual oil coolers are a major bonus I've v mounted my setup and gone with dual 30 row oil coolers and they work a treat what bumper are you going to run that will determine where would be the best place to fit the coolers in regards to ducts etc

 

I've got a stock bumper at the moment, but I'm hoping to get the Type-1 bumper from Shine either for Christmas or with my tax return. That one has much larger openings I can use for the oil coolers, then find a new place to duct air to the brakes.

 

Here's my setup



Stock FC oil cooler moved foward, passenger side FD oil cooler mounted on driverside.

 

I ran dual FD oil coolers for a couple of years. The only reason why I did it was because of high oil temps (which at some points affects water temp) with a FMIC and the stock FC oil cooler.

I then switched from a FMIC to a water cooled intercooler, and recently went back to a single oil cooler (sebtrap 72 row) on the near stock OEM oil cooler location. At this point, I don't have much data, and wont have any until the weather cools warms up.

I prefer the simplicity of the single cooler. Less lines, less fittings, less possible leaks; besides, if dual oem oil coolers is barely adequate for a high HP FD, why are we using them as an upgrade?

 

even the FD duals are not an upgrade to an FC single cooler, not sure why anyone would think that, it's been discussed and disproved many years ago.

the reason most would want to do it is to lower coolant temps, since the main downside to the FC single cooler is that it raises water temps as a side effect. when running a FMIC then you have 2 heaters before the coolant even gets its share. proper V- mount and dual RX8 coolers however might be a good alternative and if not for the oil filter pedestal banjo could have possibly been nearly plug and play(with the exception of mounting).

 

I picked up my pair of RX-8 coolers (with mounts) today for a grand total of $35. I'm going to give them a good flush to make sure they aren't clogged, but I didn't see anything suspect in the oil that drained out of them so I think I'm safe.

Not sure why I didn't think about it, but BOTH coolers have a bypass thermostat. Upon researching it, these open at 90C (194 F) which is more than I would like. That and the failure mode of the thermostat is in the bypass position, so I'm not overly happy with them.

When I inspected them, I discovered that there is a hole between the inlet and outlet location. The thermostat extends outward to plug that hole closed, forcing the oil through the cooler. I can actually tap that hole and plug it, remove the thermostat, and run a normal external oil thermostat.

 

I should also mention that I already have fairly extensive mods to the oil system so I already going to be making custom oil lines regardless of what I do for the oil cooler. If you search for 13B-RX3, he has a thread detailing his upgrades and I have done most/all of them.

I've got the oil hose connecting up to the front iron instead of the front cover, have a remote filter/oil pressure regulator with a HP4/Corvette oil filter, and have external oil lines running straight to the stat gears instead of using the internal dowel passage.

The reason for the dual oil coolers is purely for airflow reasons. I am going to a lot of trouble making this v-mount setup so that I have better airflow through the radiator, and I don't want to spoil it by slapping the oil cooler back in front of it.

Part of the reason for bypassing the OEM thermostat isn't purely to get rid of it - I plan on upgrading to a pair of larger and better oil coolers as soon as I can afford it. By already having the aftermarket thermostat in place, it keeps me from having to re-do my oil lines again. I'll post up some pics of the coolers later.

 

i'd just leave the thermostat in one, and remove the other. if you're just cruising the oil can be too cold

 

i'd ditch all the thermostats, you guys are wussies.

not like you are worried about emissions or anything. keep it simple has always been my motto.

 

I'm not eliminating the thermostat entirely, just the OEM one. I'm going to run one similar to this:'

Remote Oil Thermostat - -10AN Mocal Remote Oil Thermostat

More reliable and opens 15 degrees sooner. I do like the "keep it simple" thing, but it will still be driven on the street some.

 

Are you running a VMount or FMIC? I am having the same issues but have a FMIC. The in/out pipers of the intercooler take up all the available space in the fog light openings.

 

ahem..maybe it is just me but this is my question.(sorry if it gets a little off topic)
do those coolers,in that location, not inhibit air flow through the brake ducts to the front braking system?
Cool engine.lousy brakes..?

 

I'm going to run v-mount.
As for the brakes, that is definitely a good question. I'm going to move the brake ducts to a new location. I'm getting the AWR brake duct mounts and will add NACA ducts somewhere. Or get a different bumper, not really sure yet.
This whole thing got put on the sideline (buying a new house) so its likely going to be Summer before I make much more progress on it. I'll update as things happen.

 

If you remove all of the ducting to the front wheel area, then yes you will be directing less cool air to the brakes. Depending on your car setup that and power level, that may not even matter.