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For some background on plans for the car. For my 1980 SA I am planning on drifting the car not high level by any means, but at my local track and other places in the state and surrounding. How my local track is run you do "hot laps" for about 20 minutes of constant driving around the track, so cooling is a big concern for me to be able to have an enjoyable time driving without having to take a break after every other lap to cool down the car.
My question to anyone that would like to post what they or others have done or any suggestions/ideas would be much appreciated(since drifting these cars isn't the most popular thing to do to them). I'm currently trying to figure out my radiator setup and oil cooling. I have seen multiple posts on people running an FB and FC coolers in their first gens in a parallel setup to minimize oil pressure drop. I'm wondering for the people that have done this where they mounted both of them to fit in the front end of the car without blocking too much direct air to the radiator. I'm leaning more towards FB/FC dual cooling since I already have an SA, FB, and FC oil coolers, but that being said I'm not against going aftermarket dual coolers if that would result in similar or better cooling than the dual stock coolers.
Also open to suggestions on radiator setups as well. Since I have an SA I sadly have the stock 16" rad and from what I have found there doesn't seem to be many options for stock size drop in that cools better than the stock unit. I was trying to fit up solely for sizing purposes the rad from my GSL, and orienting it with a slant seemed to fit and clear the motor when e fans are installed on top of it(will post picture of mock up for reference). Since it seemed to fit I had the idea of possibly running the koyorad unit for the 83-85 cars, but it's still up in the air. I really just need something that will provide adequate cooling for the situations that car will be put through for a sustained period of time. I am open to going a completely different route with the radiator if anyone has found success with it. For example I've heard that mishimoto sells "race" rads that have 20 AN outlets. I haven't checked if any of theirs would fit in the space where the radiator is supposed to go in our cars. I can do tig aluminum and what not so making brackets for it wouldn't be a problem, I'm just trying to find something that will cool my car with the abuse of constant high revs. Or if a radiator from a different car with a little fab work would fit well and provide that cooling I need for my motor.
Motor wise I'm running a carbed full bridge ported 12a. I'm also running no condenser and ac so I won't need to work around that.
Any pictures of setups would be greatly appreciated, even if you aren't familiar with the setup pictures are still very useful. Anything would help even if it is something I am blatantly doing or thinking about wrong I won't be offended if things I'm saying are completely incorrect and you correct me. I am still new to custom setups and tracking rotaries. This is also for future proofing that car because I know it is probably overkill, but i値l be REW/TII single turbo swapping it in the future.
(Don't pay attention to the engine bay, I'm still building the car so the engine bay is still dirty and blank, and this is just the spare keg that came in this car solely for mock up purposes and is supported from the bottom to not mess up the motor mounts if anyone was concerned about that)
All you really need is a good aluminum radiator with a thermostatically controlled electric fan and the stock oil cooler.
The oil cooler can throw near anything you can handle at it. The relief valve can be replaced to operate at a different temperature if you desire a different operating range from stock.
Cooling a rotary depends on air flow and surface area. The RPM that the engine is going to spend its time at is also important because the faster you turn a rotary engine the hotter it will get.
In my race car I use a 26x19 Afco 2 core dual pass aluminum radiator (use the style that puts the inlet/outlet on the passenger side of the car) and two OE style oil coolers plumbed in parallel. I have an electric pusher fan on the front side of the radiator that I run all of the time. I also have the Racing Beat pulleys that under drive the water pump. I can get 200-210F water and oil with this setup on a summer day.
If was doing a drift car where RPMs will be high while ground speed will tends to be low I would use a bigger radiator (what ever you can get between the frame rails) with 2 RX8 coolers plumbed in parallel and moved to the front corners of the car. I would use an electric fan and I would look into an electric water pump set up. Maybe add electric fans to the oil coolers if they can't keep up. Finally, duct your hood to let the hot air out.
No mater what you do, ducting is key. You want every bit of the air coming through the grill opening to go through the coolers. So the grill open has to be sealed completely to the face of the radiator.
Pictures:
This set up includes a 21x19 dual pass aluminum radiator (that was not big enough) and two OE oil coolers in parallel. Everything is sealed to a grill opening that is approx 30-35% of the radiator core surface area. This promotes air movements because it creates a low pressure area on the radiator side of the grill.
OE Oil Coolers mounted in a stair step arrangement. Mount attached to the round cross member Top of the duct removed Top of the duct attached. Making this panel a bolt in allows me to service the fittings Completed radiator duct with a removable bottom All the cooling air goes through the grill opening in the air dam
Cooling a rotary depends on air flow and surface area.
Thank you so much for the reply this was miles more helpful than I was expecting to get! With the oil coolers I was leaning more towards FC/FB coolers since I already have them, but for the sake of weighing all my options I値l consider it. When you talk about pushing them to the corners of the front do you mean like in the bumper like essentially in front of the wheels? With I assume some venting cut into the front bumper to account for them or am I understanding this wrong.
Also I was already leaning towards a pusher fan due to space and what not, and I was wondering how you liked the pusher setup over a puller?
Also with the electric water pump setup how would this improve the cooling would it help the cavitation or?(I知 not very familiar with electric water pump setups but if it would be beneficial I don稚 mind learning about them and installing one)
Yeah, locate the oil coolers the way they are on an RX8 - on the front corners of the car in front of the tires. This gets them out of the air path for the radiator.
The pusher fan was a necessity because installing a larger radiator means moving the radiator back towards the engine. Even with a smaller radiator in the the stock location I ran out of real estate when I installed a 13B in my car. So I had to reverse the wiring and mount the fan on the front side of the radiator.
To me the benefit to the electric water pump would be consistent movement of water regardless of engine speed. Also for drifting you would be able to circulate water between runs with the engine turned off. Some club racers are looking at using a Davis Craig water pump for their application. On a rotary it allows you to ditch the water pump and water pump housing so there is some potential for weight savings.
Yeah, locate the oil coolers the way they are on an RX8 - on the front corners of the car in front of the tires. This gets them out of the air path for the radiator.
The pusher fan was a necessity because installing a larger radiator means moving the radiator back towards the engine. Even with a smaller radiator in the the stock location I ran out of real estate when I installed a 13B in my car. So I had to reverse the wiring and mount the fan on the front side of the radiator.
To me the benefit to the electric water pump would be consistent movement of water regardless of engine speed. Also for drifting you would be able to circulate water between runs with the engine turned off. Some club racers are looking at using a Davis Craig water pump for their application. On a rotary it allows you to ditch the water pump and water pump housing so there is some potential for weight savings.
Do you think fully making a new bottom piece for the front bumper(like I see you've done) would be the most beneficial thing to make for the radiator ducting and oil cooler ducting. Also I'm guessing for the cooler ducting it would be similar to the rad ducting with ducting straight to them with probably something to keep anything big from possibly going in there. Don't the RX8 coolers already have a built in thermostat so you wouldn't have to run one to bypass the coolers or am I wrong?
That electric water pump does sound pretty good since there isn't really a good place for me to do cooldown laps at my local track after the runs. Would his website be the best place to grab information about them? And is there any one in specific that they were looking at installing? Also would it still be smart to run a external thermostat/in-line bypass or not really?
Well the idea is to get the air to go where you want it to go and not where it will want to go. The air dam (with a splitter that I am working on) is way more aerodynamic than the OE fascia with the air duct sticking out. At least that is what it seems to me. I have a screen in the grill opening to keep out debris. I would study how the oil coolers are ducted on an RX8.
We have always removed the T-stats from the OE oil coolers and installed a machined dowel in its place so that oil can't bypass the core. The logic is that a T-stat is a failure point and we have no problem getting our engines up to temperature in a race. The OE style replacement coolers that I am using do not have T-stats so nothing to do there. Its up to you whether or not you keep them in the coolers you use.
I would reach out to the Davis Craig people with your questions regarding electric water pumps. SakeBomb offers an electric water pump kit that seems to be fairly comprehensive. https://www.sakebombgarage.com/sbg-c...kit-fd3s-rx-7/ The SakeBomb kit retains the water pump housing.
On my cooling system, I do not use a water T-stat (for the same reliability reasons listed above) but instead have a 3/4" restrictor to slow water flow. If you don't run a T-stat you also have to tap and plug the water pump housing. https://www.rx7club.com/build-thread...-992966/page7/ Post #156
Well the idea is to get the air to go where you want it to go and not where it will want to go.
So what you池e running at least is the mostly flat faced front with the new splitter you are working on is that correct? And what seems to be a grill opening for your radiator/oil coolers and then another for what i assume is your intake. If you don稚 mind me asking what kinda of design were you thinking about going for with you splitter on that style front end?
The aero/body work rules applied to the class I am racing in dictate the design of the air dam and splitter. RX7s duct air to the radiator under the bumper and the grill open in the air dam is approximately the same size. The rules allow for brake ducting which explains the two round holes on either side of the grill. Finally the rules allow me to duct intake air through head light or T/S light openings so the carb breaths air through the T/S openings in the bumper.
The rules dictate how far the splitter protrudes beyond the body work (2" or 3" with a wt penalty), how high the splitter has to be off of the ground (4") and how far back the splitter/under tray can extend rearwards under the car (to the front axle center line). The splitter will be made of a plywood/resin laminate.
The aero/body work rules applied to the class I am racing in dictate the design of the air dam and splitter.
Thank you this will really help. I was wondering for your front bumper I know you said you池e restricted by your class requirements and specifications but that being said if you weren稚 would you change anything about it or do you like the flat faced with the holes and openings for the different vents? or would there be a different design you would have liked to do.
The aero/body work rules applied to the class I am racing in dictate the design of the air dam and splitter.
I知 also curious about the difference in cooling of the RX8 oil coolers vs like an FB/FC dual setup if you happen to know?
Regarding the thermostat deletes in both the water pump and oil coolers my only concern with that for me is that for when i go to my local track I will be driving my car from my house to the track because it痴 only a 10 minute drive and I currently don稚 have the best trailer set up. So I知 wondering if I値l just have to deal the the t stats if I want to do this.
Also with the electric water pump I feel like deleting the water pump housing like you said seems like a pretty good option. I値l have to do some more research on that, but I like the sound of it. Do you know of people that have gone this route?
Given that an RX8 makes 230+HP I would say the coolers are pretty good.
As far as the air dam.....I built what I knew. There are tons of options. Google for images of E Product Rx7s, Rally Rx7s and maybe do some searches on ebay for RX7 air dams then pick what you like.
T-stats are designed to help an engine get to operating temp faster. This improves driveability until the car warms up. Beyond that a T-stat doesn't make an engine run cooler because when it opens it stays open. On the water side, if the T-stat is removed the flow does need to be restricted. If memory serves the Mazda Water T-stat is a fail safe design. Which means if it stops working it opens and stays open. Non OE types may not work that way. We weren't sure about the Oil T-stats so we got rid of them.
I have seen electric water pump setups online. Google is your friend
Given that an RX8 makes 230+HP I would say the coolers are pretty good.
How are your lines plumbed up for the dual oil cooler setup. Do you have like the output from the motor t壇 to them both then the outputs from the coolers t壇 back into one and then to the input of the motor?
Also probably a dumb question but for the radiator how did you go about your inlet and outlet hose setup like did you cut ones from another car to fit?
Oil coolers are plumbed with -10 AN braided hoses. I have used -10 AN Pushlock hose but had one fail so only use braided now. You can get -10 to Metric adapters from Mazdatrix. On the engine I used a tee filling and ran two lines forward to top of each cooler. Then ran separate hoses to the engine from the bottom of each cooler to another tee fitting on the rear of the engine.
I have had to change this as a result of going to the wider radiator. I now run a single line out from the engine and then split to two hoses at the top of the rear cooler. I still run two lines back to the rear of the engine. This isn't tested yet and is hard to describe.
Another advantage of the RX8 coolers is that it would be easier to package the hoses.
For radiator hoses, I use some scraps to figure out the shapes I need. Then I go to an auto parts store and ask to look at what they have. This time around I ended up using the upper radiator hose from a Jeep/Dodge SUV that has a 3.6L V6.....at least I think that it what it is. I saved the part number and ordered three of them for spares. I am able to use the one hose to make both an upper and a lower hose. You won't know what you need until you settle on a radiator and get it mounted. Pay attention to size of the filler necks because really large ones can be a PITA.
You have to think outside the box because sometimes you may need to use union or an adapter(s) to get everything to fit.
Oil coolers are plumbed with -10 AN braided hoses.
Thank you that really helped a lot! So those adapters from metric to -10 tee fitting those would go into the motor on input and output and then the coolers just normal metric to -10 fittings?
I知 also picking up two RX8 coolers for pretty cheap today so I値l actually be able to start mocking up my brackets and what not and have a better idea of what I知 working with.
How you route hoses may end up being different than what I did. You will find that -10 braided hose is stiff and doesn't like sharp bends. Also where you have things like ignition coils and the size of your radiator will dictate the hose ends you have to use and where you have to run the hoses.
There are a few rules that I think you should follow:
Never attempt to use 45 degree gas fittings in place of AN fittings
Fittings that have a pipe thread on them have to be tightened periodically which means that eventually they won't be at the angle you need
If you need a 90 or 45 degree angle to connect a hose then use a angled hose end
Don't let bare braided hoses touch parts of your car, wiring, other hoses, etc.
Braided hoses are covered with stainless steel wire that will act hack saw and damage what ever it comes in contact with
If contact is unavoidable, cover the braided hose with something.
Don't put a hose end/fitting in a a bind by running the hose in a tight radius bend.
Follow the assembly instruction provided by the hose/hose end manufacturer. Buy the tools and use light wt synthetic motor oil or the assembly lube that is recommended
I bet there are numerous YouTube videos that demonstrate how to assemble an AN Hose end
For Hose and Hose ends don't mix brands.
If you buy Aeroquip hose, use Aeroquip hose ends for example
I find that Aeroquip ends are easier to use than the cheap stuff anyway
On the front of the engine, I used -10 tee fittings with swivel ends like this one.
Wow thank you so much. I never expected to get all of this information I appreciate it more than you know.
For my e fan setup is there a certain cfm I should try and make sure it has?
Also I致e been looking at venting for my hood and saw that most of the hoods seem to be for air in rather than venting out. So in turn I assume I値l probably have to make something myself. And I was wondering is your hood an entirely new molded hood or did you make the cut outs and side platings underneath?
On the front of the engine, I used -10 tee fittings with swivel ends like this one.
Just thought I might ask since you seem to know a pretty good amount about our cars and have race experience with them. I was wondering while my motor is getting balanced and bridgeported and I have some time before I get it back to order all my seals for it. Am I fine to run oem apex seals in my motor or would I need to look at a stronger one?
On the front of the engine, I used -10 tee fittings with swivel ends like this one.
Apologies for the spam I知 just making sure I ask some of the things and don稚 forget them. But while I知 on the topic of motor stuff I知 definitely going to get with a lightened flywheel(probably as light as I can get) since I知 getting my motor balanced to a counterweight. I知 trying to figure out what clutch/flywheel setup I should be looking at for my car. My setup is 12a full bridgeport with a weber 48 ida. And I was looking on mazdatrix and saw the I think it was 4.5, 5.5, 7.25 inch clutches that some were 2 disc some 4 disc. I assume I値l just need a two or maybe even just run a single disc I知 not sure, but do you have any suggestions or comments on these?
You're welcome. Just passing on what OG racers have passed on to me
On the fan I think you want one that fits, moves as much air as possible at the lowest amp draw. I don't know what the CFM of my fan is. It came with the car when I bought it in 02.
My hood is made of carbon fiber. It was laid up by a guy in the race shop I work out of. He also added the vents in the hood for me last year. Racing hood vents are readily available as allot of sanctioning bodies like the SCCA and NASA now allow them. https://www.summitracing.com/parts/t...iABEgJeuvD_BwE
Regarding engine seals - work with the people that are doing the balance and port work for you. Allot of engine builders use OE seals but again what you use should be guided by the people porting/balancing your engine
For the clutch, I have the Mazdatrix 5.5" flywheel with a Quarter Master 2 disk rally clutch. It is all extremely light. Note that multi-plate racing clutches are not at all like street clutches. They do not like to be slipped and can be hard to deal with at low speeds. I think the clutch you buy will be determined by the HP you will have and the transmission you are going to use. I have no idea what is needed in drifting. You'll need tor research that. Don't be surprised to find that your flywheel/clutch/transmission costs as much or more as your engine.
You're welcome. Just passing on what OG racers have passed on to me
I didn稚 think about just buying the vents and just cutting and installing it into the existing one That would probably be pretty easy and straight forward.
A friend of mine runs a single disc spring 6 puck clutch that he really likes in his drift car so I値l probably go with something like that. I知 also running for right now the 5 speed trans from a gsl but am trying to find a cheaper TII trans to install. Would I need to change my clutch/flywheel setup when I switch to the TII trans or would I be able to keep it the same?
Regarding the alternator are you running like an s5 or fd alt or are you running something different? Because I知 not sure how much the e fan and electric water pump and stuff would pull from the alt.
I am running a stock FB alternator and an small AGM motorcycle battery. Don't know the year of the alternator. You can determine what you need by adding up all the amps from all of the electrical stuff you could ever have to run on your car. Obviously you won't run some things at the same time but that is how you determine amp requirements for an alternator.
A T2 trans requires a larger flywheel (240mm clutch surface), it will have a different bell housing and will require a different starter. I also think the drive shaft is different so search around for that on this site. If you search around on Mazdatrix, Atkins Rotary or even eBay you will see that the flywheel/clutch/pressure plate is different for a turbo RX7.
I am running a stock FB alternator and an small AGM motorcycle battery
For your radiator do you have it setup with a separate expansion tank to fill/bleed the system or do you have it ran with a cap and just an overflow? I知 trying to figure out which would be more advantageous to do.
02-10-21, 12:39 AM
