For me, one of the most important aspects of modifying a track car is to make it run cool. So therefore my FD has the following:

-Custom V-mount (pretty much identical to the monster Rotary Extreme) w/ Koyo rad fabbed to be just like the rad you get from rotary extremes kit.

-Re-Medly water pump
-Brand new OEM thermostat (FD thermostat)
-Brand new 70/30 water coolant. (70% distilled water) nothing else added
-PFC fans kick in at 84c but at the track I have the fans on full blast

I believed this should be more than adequate to maintain my FD which on track days runs 10psi on stock twins. Today I had a track day at Willow Springs and realized after 2-3 hot laps, my temps began to reach 105c!! Of course I began to do cool down laps but I dont understand why its beginning to overheat. This happened repetitively.

Today the track temp was about 95 degrees Fahrenheit; so it was pretty hot. But on the way to track, while stuck in traffic, cruising, redlights, etc. My temps NEVER went about 86C. After I begin to do cool down laps on the track, my temps steadily decline, especially if I cruise in 4th or 5th gears or neutral. So it seems the temps rise on load or high rpm range


What Im asking you guys is what else can be the culprit for my overheating? I couldnt even get close to pushing my car at the track because it just begins to heat up. This exact same problem happened before I had a V-mount and new thermostat. The only other possibilites I can think of are either ducting issues (but do I really need to duct my V-mount?) and maybe my ebay pullies is slipping?? (i dot have an airpump)

Id really appreciate some input guys. Thanks

 

no guru but my .02

ducting isnt neccessary but helps a lot. it forces the air to the IC and RAD instead of letting the air escape.

if you really want cooling id also add duel oil coolers and an AI kit...
also ive been told switching to evans engine coolant also helps lowers temps

 

thanks for input.
I have two oil coolers already----sry should of mentioned it earlier.
AI is in the future but as a car running on stock boost, It should run cooler than the way it is now.

As for ducting, I dont feel very assured that ducting the already minimal air gaps will reduce my temps so much. I will def still look into it.

 

Are you running one stock oil cooler?

 

No, I have fresh dual r1 oil coolers perfectly ducted.

 

post pics of the vmount set up?

 

105 is not that bad, dont worry about it. Ducting will help tremendously especially for the oil coolers.

 

My oil coolers are ducted fully.....

This is my set-up. Its the monster rotary extreme core which i picked off a wrecked FD and the rest is just custom fabbed up work. There is no gap between the radiator and I/C. Its nicely seeled.

 

I see HUGE gaps around the rad/IC. Bring your car to a fab shop and have them make proper ducting.

You will notice major drops in temp.

 

Do you have your undertray on?

 

With that setup and intake, I'd get a greddy headlight cover to help bring air to the filters since you do have a large gap on the filter side that air can go around and not through the IC/Rad v-mount. Not sure about the driver side but it there isn't anything sealing that IC to the frame with foam or something, then air can slide right around that side too. The other thing to consider is the temp of 95 out...that's pretty hot to begin with which makes cooling the radiator a alittle slower since the air coming through is hot as well. I actually re-watched one of my best motoring videos where they have the FD along with the skyline, wrx, nsx, s15 and a couple of other cars. They also hooked up coolant and oil temp guages to measure those while doing a 15 lap battle with a thresh hold of 130c for coolant and 110c for oil. The FD"s coolant temp got to 129 ( I think all the other cars passed that mark except the skyline) and the oil temp got to like 112, which was the highest of the cars since the rotary uses oil moreso compared to piston engine to cool the engine as well. You've got dual stockers so that's covered other than upgrading them.

Tim

 

Ducting is pretty crucial. But you should not be using an undertray or you should have a custom splitter that allows the radiator to vent like this... I just took these at night right now lol.



thewird

 

Contrary to what others may say ducting is absolutely key IMHO for a solid trackable car Anything less is just being lazy. Ducting is cheap and effective. You can "get-by" with less but any tried and true track veteran and car will tell you seal EVERY nook and cranny and force every cc of air through the radiator primarily and then the IC. The V-mount is an excellent setup if properly ducted. I'd submit yours is not. Those huge gaps on the side are pumping cool air right around that $2000 setup rendering it only partially effective.

Set the fans to run on high at a lower temp. they will come on anyway but no need on waiting until the higher temp is reached..get them to switch to high early.

GOOD OIL COOLERS... dual oil coolers. Push a car hard and even the OEM duals will get stressed. Oil accounts for a substantial amount of engine cooling in a rotary...more than in a piston engine. I've seen numbers as high as 30-50% of the cooling in a rotary is done by the oil. Big oil coolers is a must...sorry no bling factor but they work. Install an oil temp gauge and watch the oil temps as closely as you watch your coolant temp and you will see what I mean. Duct and seal the coolers just like you do the radiator. Absolutely run all the stock undertrays (as modified for the v mount of course)

Drill the t-stat - it's a flow restriction and adding a few holes aids coolant flow. Run the 70/30 mix as you are doing.

Box off the intake elements so they recieve dedicated cool intake air and not air heated by an IC or radiator. Cooler air in = cooler air entering the engine. Note we are talking about cumulative effects where every little bit helps.

Open up the nose of the car to make the radiator opening as large as possible. Even with a stock nose there was something called a shark-mouth mod before the '99 nose became available to open the opening up and get the maximum amount of cooling into the car. There is a reason the '99 bumper has larger openings.

Your pain threshold for cooling down should be more like 110degC. 105degC is fine. I've run years at 105deg C without issue but also with commensurate low oil temps as well. Do a search on safe coolant temps. Much above 115degC and you run the chance of cooking an seal. As to Tim's comment...those guys rebuild engines daily so I wouldn't use that as a data point. My norms for hard track use are no higher than 105degC coolant and aboyt 225degF oil.

Vent the hood. All that hot air is trapped under the hood until it is sucked out under the car. Vent the hood and give that V mount IC somewhere to vent to.

Add an good lip spoiler - '99 lip will fit the '93 nose. Add a splitter. Again it grabs air and shoves it into the nose intake rather than sneaking under the car.

AI will help but it is another level of complexity that can go wrong on the track. Tracks cars are simply. Systems are taken OFF the car to aid with cooling...not added. And at near stock boost levels and even as high as 14 psi you don't really need it if you take care of all the above.

Then of course there is going to a single turbo - for more efficient and cooler intake charge temps....ported motor - car works less hard for equivalent power levels

A few things to consider FWIW,
Crispy

 

Nice write up Crispy. In regards to the best motoring, it was a stock car comparison of what a stock car can do at the track and also what temps they would see so it's a good comparison showing data that goes along with what you said...the oiling system on the FD does add in cooling the engine more than piston engines since it was absorbing more heat than the rest of the stock cars (I think they had a slow intergra with some mods on it to be competitive but it also ran the hotest on the coolant side with a 142c).
But to the OP, follow the advice given out and you should be fine given the fact everything is in good working order.

Tim

 

You need to look at your pic again because you have holes all over the place. Remember air will always take the path of least resistance. Just because you have the latest hottest thing going on in your engine bay with the V-mount, doesn't mean that it is miracuously going to perform wonders all by itself. You have a lot of ducting to do. Also, you need to separate the intake from the rad and IC area. During WOT, the turbos are pulling all the air away from your IC and rad.

 

thnx for the replies guys. I already started to check out some carbing ducts and will prob try to fab up duct shiled/plates for the sides of the v-mount. Just got to find mounting points. I need to hurry because Im going out again in july.

Im sure if I kept on it, my temps would of sucseeded 110 given the rate the temps was risisng. And im pretty sure I dont want to reach 129c lol. Thats crazy and I bet Ill be changing motors by the week.

-- I also forgot to mention. I do have the undertray on and obviously its modified for the v-mount.

 

it's good that you are planning to do ducting but as I said, at 105, it's not big deal and iam pretty sure if you kept going at it, it'll stay at 105 with the mods you have. Never can have enough cooling though.

btw, i rarely see any FDs on the track anymore so it's refreshing to see that a fellow socal FD owner is trying to beat the crap out of an old car I usually do all the buttonwillow events and occassionally Streets...I am sure i'll see you at some point!

 

Yea I finally got time this summer to beat on my car alittle since Im not taking summer school. Do you go with speedventure events or redline? I just started speedventures.

 

I'm thinking your water pump is slipping. Get rid of the AST or move it, and add something like a Pineapple or one of the other brand idlers. The hot air intake and large gap on the intake side of the intercooler aren't helping either.

 

You definately need to do the ducting work you have just started, but I would also add the idler pulley that Ihor suggested. At higher RPMs most of the aftermarket pullies have been known to slip at the waterpump, reducing the pumps effectiveness. I bet if you walk out to your car you can grab ahold of the puley and turn it with your hand as it will just slide against the backside of the belt. DO NOT overtighten the belt to try and compensate for this. You will end up with more problems. Just invest in the idler pulley.

 

That carbing crap won't work. I'll post some pics of some of my V-mount ducting later to get you started.

Crispy has all the right answers on this topic and Ihor's input is also spot on.


Edit - go search for a thread from Atihun in the Single Turbo section for some nice ducting pics.

 

I began to mess around with some scrap sheet metal I have at home and came up with this. I'm going to buy some more metal and make a final piece when I get a hold of my friend who has a welder.

 

^ YES!

Packing foam also work well for stuffing in holes around pipe and hose penetrations.
HTH,
Crispy

 

Doesn't drilling your T-Stat essentially keep the system from pressurizing, which raises the boiling point?

Also, from what I've seen people who run Evan's Coolant experience higher temps than others.


OP try some Water Wetter too...1 bottle will work wonders.

 

Nope. Don't confuse the thermostat with the filler neck cap. It's the cap that controls system pressure and subsequently the boiling temp of the coolant. With respect to coolant boiling it's the other way round. Higher pressure = higher boiling temp.

As for the drilled T-stat, the t-stat simply controls the flow of coolant to the radiator. When cold it merely keeps coolant circulating *in the engine* to get things up to temp quickly. When it hits a certain temp the t-stat plunger opens and sends the coolant to the radiator. For the most part the opening temp is 195F so once it hits 195F (the most common T-stat temp used) the plunger opens up and allows coolant to flow to the radiator. 195F is pretty cold relatively speaking...about 90C -note we are talking normal track operating temps of 100-110degC. The t-stat once up to temp is open *all the time*. So what's the big deal? Well the orafice of the t-stat plunger is small restricting flow to the radiator. Drilling a few holes in the t-stat flange will aid flow to the radiator. So why not just remove the t-stat altogether? As i understand it, the system needs some back pressure to ensure adequate residence time of the coolant in the engine to absorb engine heat. If flow is too quick coolant will be pumped through the engine without the time to pick up any heat!

Image of my drilled "summer" "track" t-stat:
http://www.reganrotaryracing.com/pulleys.htm (lower left of page)

Regards,
Crispy