Cooling!

[Silvia_Drift]

Hey guys.

I own a 1991 Nissan Silvia and I really enjoy lapping. The only problem is that my water temp gets way too high within 2 laps of going full throttle (around 105 celcius). This was after I removed the front bumper for better cooling.

The car is running the stock rad, all the factory shrouding and clutch fan. The car also has A/C and a large FMIC in front of the rad.

I want to do some cooling upgrades but I'm not sure what I should do.

I think the first logical step would be getting a new rad. I saw that Mishimoto released a new line of triple core rads. Just wondering if anyone has any experience with these. Will the stock shrouding and stuff fit? I know on the website it says no modification is neccessary, but it also says that the rad is 6 inches thick. I don't see how a rad that thick would fit without any mods.

In addition, the vendor I asked about the rad says that my stock water pump would not be able to flow enough for such a big rad, and my cooling issues will worsen.

Also, should I invest in an oil cooler before I upgrade the rad or will I see a bigger difference with doing the rad first?

I am only asking this because I had a Koyo twin core on my last car. That car had a smaller FMIC and no A/C and would only last about 3 laps. Not much of an improvement.

I'd really appreciate your advice, thanks.

[e1_griego]

I have a griffin radiator (single core, I think) with Nismo thermostat (not necessarily needed) and a stock clutch fan.

I have never seen higher than 88 or 89c (as measured by powerfc on the inlet to the motor).

[juggernaut]

I'm thinking:

Oil cooler;
Rad upgrade;
T-stat - Nismo or Billion - Billion slightly higher opening temp compared to Nismo;
Vented bonnet.

Whether oil cooler or rad first would really depend on your oil temps vs your water temps. If oil is in check then obviously the rad upgrade is the better option.

I understood the stock water pump cavitated at high rpm - Ross Engineering in Aus make an underdrive water pump pulley to cure this "issue".

[WorkInProgressK]

I should upgrade the rad after getting a baffled pan. 1 or two quarts more of oil keeps things cool too, and it will save your motor when you will be doing tons of G forces!

[Matt93SE]

1. Put the bumper back on. it helps to duct air into the radiator. without it, the air just flows around the front of the car.

2. play with some sheet metal (or cardboard at first) to create some better ducting from the openings in the bumper straight through to the IC and the radiator.

3. consider a more efficient, smaller IC that blocks less of the airflow to the rad.

crap.. late for work meeting...

[Silvia_Drift]

I'm definatly gonna try some better ducting since it's low cost.

I do want to buy a better rad though. The water pump cavitation issue will still apply whether I get the twin core or triple core correct?

[Matt93SE]

Yes, that's a limitation of the stamped steel impeller on the pump.. they work fine at lower rpm, but after they get so fast, they just whip the coolant into a froth. slow the pump down and it will actually pump more water.

A bigger radiator will also help, but as others have said, consider a side mount oil cooler as well. mounting it in front of the radiator may not help cooling since you're still cooling the same equipment with the same airflow. side mounting the oil cooler will use different airflow and should help lower the temps. read up on some of the other oil cooler/ engine temp threads for some of the other recent solutions going on. there was a thread from a week or two ago about oil cooler issues.

[Def]

Get an oil cooler. The problem is your oil temps are sky high and pulling the water temps up. I'd still recommend a decent radiator, no reason to go with a 6" thick one. Just get a decent one that's a little thicker than stock, add some ducting(very important), and add an oil cooler(air to oil). Done and done.

[VIDAL BABBOON]

Just my 10c worth

There are so many different opinions on cooling over here in the UK but i decided not to listen to all the Internet chuff and make my own mind up.

Ditched the following that were not adequate.

Stock rad
Stock fan surround
Stock clutch fan
Nismo stat (what a waste of time that was)
Standard oil/water heat exchanger

Then fitted the following over a period of months while monitoring the effectiveness of the modification.

Oversize alloy twin core radiator (approx 4 times thicker than stock so 2 1/2 inches)
Custom fan shroud with twin 12" fans (revotek controlled)
Tapped block for oil cooler fittings (at position where stock heat exchanger is located)
Wing mounted oil cooler
Greddy Baffled/oversize sump
Nismo rad cap (any higher pressure cap would do though)
New Nissan thermostat
New Nissan S15 water pump
Silicone coolant hoses and good clamps

Also don't forget that turbo (size) and boost will alter your temps

I can now tailor my temperatures to my needs by regulating air flow over the rad and oil cooler, and have never had issues with over temp even in extreme circumstances (prolonged period of 150MPH+ driving on the German Autobahn then stuck in traffic in Belgium for 45 minutes immediately after)

I did look at going oversize on the water pump pulley but it would not make my setup any better than it already is so see no need.

[WorkInProgressK]

Tapped block for oil cooler fittings (at position where stock heat exchanger is located)

where could that be?

I must say silicone hoses are overkill. With good motor-mounts (which you can get at the price of silicone hoses) and a good rad, the temp will not get hot enough nor the engine will move enough to destroy the OEM hoses. which are pretty strong since I run very hot any I just have epoxied mounts .

[Your Mom]

Get an oil cooler. The problem is your oil temps are sky high and pulling the water temps up. I'd still recommend a decent radiator, no reason to go with a 6" thick one. Just get a decent one that's a little thicker than stock, add some ducting(very important), and add an oil cooler(air to oil). Done and done.

what i did that helped the most. ditching the electric fans and going stock shroud and clutch.

http://nissanroadracing.com/showthread.php?t=1068

as for def's jab, yeah don't do this.

http://nissanroadracing.com/showthread.php?t=1907

[Def]

No jab intended.

In fact, I think it's a good thing you actually tested out the water to oil cooler. At least now we know for sure it's not a good route to go for our cars.

[McCoy]

Just got back from the track. With a DET and a 50trim T3 turbo at 14psi, I was hitting 280F for oil temps in a matter of 5 laps (no traffic). Water temps help 195-205 the whole time... so I know that my radiator setup is fine, I NEED an oil cooler, and like yesterday!!!

For cooling, I run the standard large Koyo, Z32 radiator cap, stock T-stat, stock fan shroud and clutch fan, ducting below the IC to radiator, and an 80/20 mix (water/antifreeze).

[WorkInProgressK]

Just asking, whats not good with the nismo T-stat?

[Matt93SE]

Why bother running a $50 t-stat that opens at 160 when the car is running at higher temps than that the whole time? even a $5 180* autozone t-stat will be open all the time.