added OEM dual oil coolers to touring FD
 

Just thought I would tell everyone about my experience with adding OEM dual oil coolers to my touring (single oil cooler equipped) FD. I have been monitoring oil temps from my oil pan for the last year or so and have plenty of reasons to improve the oil cooling on my car.

Goals: to maintain OEM fit, finish with USDM front end, while maximizing oil cooling capability and not spending more than $500 for everything. Improve durability of system (by protecting from bent fins). Improve ducting by copious use of DUCT tape :)

Method: get OEM dual setup used. Clean up coolers & lines, get new mounting hardware as needed, ensure solid ducting.

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OLD SETUP:
Single stock oil cooler with bad ducting, bent fins, etc. (my old duct was trashed, the plastic piece that's pop riveted to the duct was totally missing, I had to duct tape that part to maintain any kind of "ducting"). Running 10-13 psi boost, stock non-sequential turbos. Ambient temps 60-100*F.

Oil: 20W-50 dino

Oil temps (depend on many factors, esp. ambient temp and engine load)
Street cruising -- 200-220*F
"Spirited" driving -- 200-240*F
Autocross: 220-240*F
Road course: 220-260*F

Oil pressure (OEM gauge): 60+ psi cold, ~40 psi warm

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NEW SETUP:
Dual stock oil coolers with new ducting, straightened fins, new gaskets/washers. Coolers and lines were professionally cleaned by OILCOOLERS.COM Duct taped the sh*t out of the plastic ducts, no way in hell air can get around these puppies, they have to go thru them!! Running 10-13 psi boost, stock non-sequential turbos. Ambient temps 60-70*F (look forward to getting more data on hotter days)

Oil: 20W-50 dino

Oil temps (depend on many factors, esp. ambient temp and engine load)
Street cruising -- 160-200*F
"Spirited" driving -- 180-210*F
Autocross: TBD
Road course: TBD

Oil pressure (OEM gauge): 60+ psi cold, ~60 psi warm

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BOTTOM LINE: 1st thing I noticed.. my oil pressure was higher than before, by at least 5-10 psi. My old cooler must have been restricting the system somewhat (clogged?). In spirited driving and cruising modes, my oil temps as measured at the pan run about 20-40*F COOLER than before the mod. The temps appear to cool more rapidly as compared to before as well when the car gets moving (ex: would take a few minutes to cool off 10-20*F before now it takes a minute or two). Water seems to run a bit cooler too (about 10*F when in motion). I will be attempting to track the car more in the next year or two at stockish boost levels (10-12 psi)... hope to keep it cool on the track too :cool: Sometimes I wonder why Mazda didn't put dualies on EVERY FD.

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SOME PICS

Used coolers before cleaning:
http://michael-david-palmer.com/gall...serialNumber=1

Coolers after cleaning (rear)
http://michael-david-palmer.com/gall...serialNumber=2

Cooler connectors & mounting bushings
http://michael-david-palmer.com/gall...serialNumber=2

Pass side cooler + duct & stainless steel wire mesh
http://michael-david-palmer.com/gall...serialNumber=2

Driver side cooler + 2 lbs. duct tape
http://michael-david-palmer.com/gall...serialNumber=2

Side view of pass cooler
http://michael-david-palmer.com/gall...serialNumber=2

Driver side as installed
http://michael-david-palmer.com/gall...serialNumber=2

Looking good!
 

Mike,

Looking good! I may be picking your brain about the install. How long did it take to swap the dual oil coolers in?

I am still trying to find a local place to clean my coolers...

Happy New Year!

Hey Charlie, happy NY to you too buddy. No prob, just give me a call. The most PITA part was getting the hardlines in (the ones that connect the two coolers). I had to take out

-airbox
-acces belt (A/C, P/S)
-I/C, duct
-battery & tray
-undertray
-bumper
-bumper rebar
-headlight bezels
-crossmember

to get good access to everything. After that, it's a matter of getting the lines in... I went from the pass side, push the lines thru the hole that sits between the radiator shroud and what I think is the front swaybar bracket. You have to be patient with that part... all in all it took me about 4-6 hours just to get the hard lines in and mounted (AFTER I had full access). And another 6-8 to cut up the mesh, bolt up the coolers, install fittings, clips, and then resinstall everything to get the car back on the ground... Other thing is that you need a 23 mm crescent/box end wrench to undo the bajo bolt on the front cover so you can install the new dual o/c line that goes to the pass cooler (you could probably use a big adjustable crescent wrench.. but I couldn't get mine off with it).

Just give me a call. When are you getting deployed? You gonna make the cruise in a couple of days, would love to have you :D

where did you get the connectors and bushings and extra duct? malloy mazda?

connectors, mounting rubber/bushings, duct
 

-connectors should come with your coolers if you get them used... I don't think I've ever seen any which were sold w/o them

-my connectors were removed when the coolers were cleaned

-the bushings/mounting rubber was also part of the used coolers/brackets I bought... if you don't get them w/ the coolers/brackets just try to find them from someone in the F/S section OR Mazda Malloy :)

-duct from Malloy. cooler connector gaskets also. I wouldn't go to anyone else for OEM FD Mazda parts :icon_tup:

How much did it cost to have the coolers cleaned? I know that at some point in my car's life it had an engine pop and I would like to reuse the oil cooler...but am afraid of what could be lurking inside. Pacific oil coolers is only 30 minutes away from me... :)

Those coolers look amazing after they were freshened up.

Also, more restriction in the oiling system will create higher oil pressure. It probably takes more effort to pump the oil through a second cooler. Also, oil pressure gauges aren't that accurate for getting the actual value. Often times they aren't linear or even close to what the gauge is labeled.

Looks like it was well worth it!

oil cooler/line cleaning price, etc.
 

They were $150/cooler + $50 to straighten the fins. They also cleaned up my oil lines (three of them: one that goes from oil filter pedestal to driver's cooler, another that goes from front cover to pass cooler, and also the one that goes from cooler to cooler). They did a good job, but their service was less than what I would consider good, and I know there is another place in Texas (AMERICAN COOLER) that does similar work for about the same price. All in all, my grand total was $350 for cleaning my lines and coolers. I have more pics in my gallery. PICS TO CLEANED OIL COOLERS

In general, I agree, but since the OP for the OEM gauge is taken from the rear iron, which is DOWNSTREAM of any restriction offered by the oil cooler system, I think it would be less susceptible to an oil pressure increase.

Also agree, should connect a mechanical gauge to get real readings. I did notice a "trend", however, from before to now, and that is not exactly hard data, but still "noteworthy" :)

I think so, I should have done this long ago. I think every FD driven reasonably hard, ESP IN HOT WEATHER, should have two oil coolers.

That is a great write-up!

Is there an 'ideal' temperature for the oil in the FD? It is interesting to see the temperature readings you got, for comparison, years ago in my old Triumph TR7 I routinely saw temps of 280 to 300 degrees (the car had no oil cooler).

I guess my point is...the cost-to-benefit ratio?

Mike,

congrats on a 5 star thread. dual oil coolers should be on any modded FD. as we know the rotary rejects more heat thru oil than a piston engine and you have shown a material advantage to going w 2 coolers.

you have gained oil pressure because you dropped oil temp. the two are inversly related.

interested parties might read my related thread, "Dual oil coolers cheap."
https://www.rx7club.com/showthread.p...+coolers+cheap
the thread ended up around 5 pages. pics of my installation on page 3. the key is adapting an inexpensive (off the classifieds) driver's side OEM cooler to the pass side.

it is a simple matter to straighten the fins on your cooler. should you wish to monitor oil temps i recommend removing the oil level sensor on the driver's side of the oilpan and brazing a bung to it. i love the FJO temp sensor and digital gauge.

nice work Mike showing us the temps.

howard

:)

I would say the cost is minimal for the benefits of increased cooling offered by the duals... Ideal oil temp... according to Racing Beat, oil going into the motor (not measured at the pan) should never go over 205*F. That's pretty darn chilly. Here's from their website: RACING BEAT

Oil temperature is critical in rotary engines. Oil temperature entering the engine should never be allowed to exceed 205°F. While many factors affect oil temperature, oil cooler size and location are very important to consider. Roughly one-third of all engine heat rejected via the water and oil cooling systems goes out through the oil cooler. The oil cooler should get about one-third of the total cooling air flow.

Thanks HC. I was initially planning on adapting the driver's cooler per your ingenious thread, but just got lazy and decided I would just pick up a set of OE duals when I could get the right price :) You were my inspiration for the wire mesh, BTW, great idea to protect the fins. The first time I got really concerned with oil temperatures was when I was on a track a year or so ago... temps got to 260*F at the pan! Not good. Having that data, how could I not put duals on my car? I think for a 100% street car you could get by fine, but anyone who really pushes really should have the xtra cooling IMO.

Another awesome thread with impeccable timing for my own use :D
I will be acquiring dual coolers next week to do the same thing. If you don't mind a PM or two if i have a question I would really appreciate it. This will probably be my biggest project on the FD thus far (suspension, Diff brace, twin power etc were all super easy).

Did you do this by yourself by chance? Just curious if two or three ppl would make this an easier project.

From the FAQ thread, Damian and other have used

The companies info:
American Cooler Service, Inc
921 W. Mayfield RD. Suite 136
Arlington, TX 76015
817.419.8008
http://www.airsport.com/mrknklrv.htm


https://www.rx7club.com/3rd-generation-specific-1993-2002-16/oil-cooler-fixing-cleaning-pics-info-382612/

Just a little note:
When I did this mod to my Touring, the seller didn't include the oil return hard line, the one that goes from the 2nd cooler back to the engine. I notice that a lot of people selling their R1/2 oil coolers don't have that line included.

Make sure you get that line! It cost over 100 bucks from the dealer.

Nice and timely thread (as this is my next mod)!

That's even better when people provide data.

Wow those oil coolers look clean!

Great thread! Reading this makes me wonder if oil pressure/temperature played a roll in my engine going.

After I had my engine rebuilt in Dec I drove it home. I noticed my stock oil gauge was reading higher than previous. I didn't make the connection that lower oil temps equal more pressure.

Obviously its much cooler outside now than in the summer time! Duh

I have an R1 with dual oil coolers already but now that I've read this thread I will check the ducts, and fins along with getting proper gauges!

Great thread Mike! The stock dual oil coolers are much more capable than most people on here realize I think(ie you see alot of people with street cars with ridiculously huge aftermarket oil coolers... most of the time with no ducting). I know you said you wanted to keep the USDM look, but if you ever need some additional cooling, I've had the 99spec bumper drop temps an additional 10-20F. That'll prob. be overkill for you, but thought I'd put that here just in case.

Even more cooling?
 

Good thread. I also added new dual OEM coolers during my rebuild (at a cost *never* to be repeated). During one of my first test-n-tune track days my new wheels rubbed through the plastic fender well liners right behind the oil coolers. My initial reaction was "Huh, that sucks", but then I realized it might help the flow through the coolers even more, so I cleaned up the edges and put mesh in the holes to keep out debris. I don't have any hard evidence that this actually helps, but it sure seems like it should. My local track is in the high desert, so cooling is paramount to my build decisions. Probably not worth trashing your fender liners to see if it helps, but if you still see temps too high...

Dave...

Wow, good info Mike. I need to get the R magic ducts for the 99 spec bumper now. :)

No prob, just PM me. Yeah, did it alone, but it would have been nice to have one other person help to pull the lines thru the rad shroud/swaybar bracket hole I mentioned earlier, but that's about it. Everything else is pretty much a solo job for the rest of the stuff.

Thank you for posting that. Damian and GooRoo and I think Rich (GoodfellaFD3S) had them do their OEM coolers. Look up a thread by Goodfella called "spent some time in the garage" or something like that.

Absolutely critical part. Most of the setups I see f/s don't include all the stuff you need.

Yeah, having had the single cooler and looking at temps for the last year+, I am so happy I added the 2nd one. Every degree counts with these motors, and when you can remove 20-40*F with STOCK equipment, I'd say that's pretty good!

Thanks to you. Appreciate the parts, they were in pretty good shape to start.

Good to hear. I get the feeling a lot of people who drive these cars underestimate how much heat these motors make as compared to a piston engine of comparable power. Keep oil, water, fuel, and air cool and you are golden!

Thanks Brent, I should have clarified: I much prefer the 99+ bumpers, I think they are dead sexy infact :cool: Speaking of overkill, only problem for the near term (and foreseeable future I suppose) is that money is a concern... a proper conversion to 99 spec plus all the other crap I would want to do is out of the question. SO, I was set on making my USDM body work do the job. The 99+ ducts are huge, no question they are better for moving more air thru the coolers. Just look at the 93-95 o/c openings compared to the 99+ ones and you'll realize right away... the 93-95 ones are undersized by comparison.

Thanks for posting the pic. Just be careful that the rear of the coolers don't get messed up by debris (sounds like you put something over it). I think you would need something like 3-5 inches behind the cooler of free space to provide good flow thru the fins... but I'm not a fluid mechanics guy. If it makes you feel any better my driver's fender liner has been chewed up since I got the car, just got a new one the other day to replace it. The high desert... where at? You talking about Buttonwillow, etc.?

Hey Gene! Still haven't seen your new wheels yet! Yeah, ducting does wonders for any of these heat transfer devices that work with a cooling fin type setup (most radiators, intercoolers, oil coolers, etc.). One of these days I will be 99 spec like you :D Hope to see you and your car soon.

Awesome thread Mike, thanks for posting the before/after temperature data.

Memorial Day weekend track day update
 

Hey guys, been a while since I posted about this, but wanted to update results from my recent track day on 2010 Memorial Day weekend :cool:

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My impression for oil temp limits, as measured from the oil pan (hot oil before coolers):
dino oil < 260*F sustained
synthetic < 300*F sustained

To remind everyone, couple of notes on my rotary setup:

-stock non-sequential turbos
-93 USDM front bumper cover and OEM ducts
-20W-50 dino oil
-OEM FD dual oil coolers dropped my oil temps, in every condition (traffic, street driving, track) by 20-40*F, as opposed to stock single.
-W/ the single cooler, I used to see 260*F on a slower road course, Cal Speedway infield, May 2008 (see pic of track & vid below).
-Top speeds for me were around 100-110 mph.
-On track I was running lower boost than I do on the street (track, stockish level = 10-11 psi; street = 12-14 psi), probably making 250-270 whp on track.
-That was a cool day too, probably 60-70*F.
-When I hit 260*F oil @ the pan, I had to back off almost every other lap.
-Here's a vid of a portion of that day, skip to 1:16, and yes I suck, I'm a regular Joe who loves FD's, not a race car pro :)
The following pics are not quite to scale. But scale is printed on the track maps. Here is a pic of the infield shown in the video above, running clockwise.

https://upload.wikimedia.org/wikiped...ircuit.svg.png

-A lot less stress on motor in that configuration, as compared to a recent track day (Memorial Day weekend 2010) which was a lot higher speed/load.
-Was hitting over 130-135 mph on the oval/nascar bank every lap, pretty much topping out my 4th gear on my rotary powered/geared car.
-Oil hit 240*F tops, that was with mostly WOT conditions, same boost level and rest of the car setup was basically the same, AND it was hotter that day, about 80-90*F.
-Limiting factor that day was water temp, on last 5 minutes of 25 minute sessions (tops was approaching 230*F @ water filler neck), NOT oil temp! (opposite of last track day in 2008, where oil kept me cooling down every other lap).
-Car ran great that day. Running counter clock wise. Memorial day weekend, 2010.

https://upload.wikimedia.org/wikiped...ts_Car.svg.png

Finish line pic :D
http://michael-david-palmer.com/gall...serialNumber=2

Here's a vid from the Memorial Day 2010 track day:

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Bottom line: if you drive your car ON A TRACK, weather is hot, you NEED dual oil coolers. I think a pure street car, even with high hp, can get by with a OEM single. The FD OEM ones work great, after gathering the data from the track days and also street driving, I'm convinced! Nothing wrong with aftermarket bigger ones either, just make sure you have a thermostat in them :)

You may recall that I made a thread a couple weeks ago about dual oil cooler setups for a '94 PEP. I think my friend may go for the used OEM route after all (buying a proper R1/R2 setup), just like you did. It seems to have the greatest benefit per dollar with an easy installation.

Could you give some information about the relationship between oil temp and water temp with the single cooler and the dual coolers? In warmer weather, how close do they tend to be under various types of driving? Are oil temps usually exceeding water temps even with the dual coolers?

It's interesting, on my old non turbo FC (which has the same basic cooling system as the FC turbo models) my oil temps NEVER exceeded water temps. This was an original radiator and FC oil cooler with over 150k on them. I remember doing multiple back-to-back runs at Deal's Gap without stopping to cool down. Oil and water temps were both constant at around 100C/212F. Water temps were measured with an aftermarket gauge in thermostat housing and oil temps were measured with a sandwich plate at the oil filter. I haven't even bothered with an oil temp gauge in my turbo car because I suspected/assumed they would rarely exceed the water temp. The FC factory oil cooler (found on all models, turbo and nonturbo) is a gigantic high quality piece:

https://www.rx7club.com/attachment.p...1&d=1278862241

Too bad there's no way this would easily fit on an FD, as they are pretty much dime-a-dozen to acquire.

^^ That's a good question, something I've been paying close attention to both before and after I had the duals. I'll try to present this as clearly as I can. The overall trends are more important than the numbers themselves:

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My water cooling setup is worth mentioning:

-Koyo aluminum radiator
-80/20 water/coolant ratio
-13 psi pressure cap
-re-medy water pump
-NO AST
-no special ducting for the rad (but have factory undertray)
-180*F thermostat with small hole drilled in top
-fans come on at 84*C, high speed @ 90*C

Regarding the relationship between water/oil temps on my car, this is for ambient temps from 50-100*F. These are my recollections, not electronically logged. Uncertainty in the temperatures is about +/-5 to 10*F:

-----------------------
-----------------------

SINGLE COOLER
-steady state freeway driving
*water = 180-190*F
*oil = 160-200*F

-traffic/stop 'n go
*water = 190-220*F
*oil = 220-240*F (yikes!)

-track
*water = 200-230*F
*oil = 220-260*F

-----------------------

DUAL COOLERS
-steady state freeway driving
*water = 175-185*F
*oil = 140-180*F

-traffic/stop 'n go
*water = 185-210*F
*oil = 180-220*F

-track
*water = 200-230*F
*oil = 200-240*F

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-----------------------

Add'l observations:
-generally, oil was always hotter than water (EXCEPT steady state freeway cruise)
-oil temp very sensitive to ambient temp (ESP. on freeway cruise conditions)
-water not as much
-water temp changes lag oil temp with both single & duals
-oil cools much quicker with duals
-increase in oil temp always resulted in increase in water temp
-single cooler: oil-water delta was something like 40-60*F
-dual cooler: oil-water delta was something like 20-40*F
-with both setups: during warmer weather (say, ambient > 80*F), oil is always hotter than water (except freeway cruise); opposite is true when colder (say, ambient < 70*) (except freeway cruise)
-my water temps are now 10+*F lower in most conditions after dual install

*example: (90-100*F ambient)
-SINGLE COOLER: oil was always 200-240*F, water 190-220.
-DUAL COOLERS: oil was always < 220*F, water 180-210.

-duals appear to offer greater cooling effect as opposed to the single @ higher ambient temps & heat load

*example:
-on recent 90*F track day with lots and lots of 4th gear WOT to ~7500 RPM, did not have to take cooldown laps til very end of of 25 minute session due to high water temp
-oil topped out @ 240*F
-laying off throttle cool down oil almost immediately (after maybe 10-20 seconds, almost 10-20*F)
-took about 15 minutes to get water to 220*F, slowly creeping to 230 over next 5 minutes;

-whereas 60-70*F 2008 track day, not so much 4h gear action (short shifting 3rd-4th a little bit)
-oil was hitting 260*F every other lap (more or less)
-laying off throttle not enough to cool down car... had to drive almost full lap to bring oil from 260 down to 220
-water hit 230*F about 15 minutes in and went between 220-230*F during alternating cooldown laps (more or less)

Hope that helps...

^^ I've seen pics of that cooler before. Maybe you could fit it in front of the radiator, I have no idea what the dimensions are on that piece but it sure looks huge! Probably wouldn't work on an OEM front bumper I'd reckon.

Nice Mike!!