Schramm

Well I just bought a 1987 Corvette the car had a 100% turn key 383 stroker engine in it. Below are the specs from Golen Racing engines (engine has less then 5K on it). This also in the same engine compartment has UNWRAPPED Hooker long tube headers so you can imagine in that compartment there is a lot of heat. Today it was 89 degrees and driving down the road it runs at about 185-195 degrees which is very normal. But stop and go is taking it to 235-240 which is scaring me as there is $9,000 wrapped up in the motor. My question is: Is there a way (without modifying the hood with a larger scoop) "as that is not me" to get more air or help the car run cooler in stop and go traffic? Any help would be great and appreciated!



Existing 350 motor blueprinted and built by Golen Engine Service to 383ci 450hp/470lb/torque stroked, engine built to handle Nitrous Oxide kit for 700hp.

· Bottom End, 4 bolt main, ARP main studs, Thermally cleaned and stainless-steel shot, bored, honed w/torque plates, Clevite H-series cam bearings and pioneer freeze plugs, Eagle 4340 forged steel crankshaft (Dynamically Balanced), Scat 4340 forged steel I-beam rods (6” length, full floating) pistons, Mahle plasma moly rings (1.5mm, 3mm), Comp Camps roller hydraulic lifters, Cloyest true roller timing set, Melling high Volume oil pump, Fel-Pro performance gaskets. All head and misc. bolts by ARP performance:

· Top End, Dart Pro 1 aluminum bowl ported and runner matched heads, Manley stainless 2.02” intake valves, Manley stainless 1.60” exhaust valves, Pro Magnum 1.6 roller rocker arms, Comp Cams double valve springs with hardened retainers and locks, High flow water pump, BBK performance 58 mm throttle body, 30 LB Hi-IMPE Fuel Injectors, Adjustable fuel pressure regulator, SLP Long tube intake runners, Edelbrock high flow intake manifold, Super coil ignition, with 8.5 mm wires, Denso iridium plugs, PCM custom tuned chip for blueprinted motor.

John A. Marker

The first thing I would do is check behind the radiator to see if you have collected leaves and other s**t that might be blocking the radiator.

Next, consider the purchase of a high flow water pump. I have a Flowkooler and it keeps the engine about 10-15 degrees cooler than the stock pump (160 stat also).

You could remove the rubber dam in front of the windshield to get more air OUT. It will work better if you are moving.....if you are standing still, you will not exit enough hot air to really cool things down.

mike100

Are your fans programmed to turn on at a lower temp? like both on at 205 and maybe turning off at 200 deg F?

I don't see headers dissipating so much heat that it causes a significant increase to your coolant temps. Standard manifolds get just as hot, they just have more mass. maybe if your tune is running lean and or a little low/retarded timing at idle speeds, the engine will run hotter.

Schramm

I think that the relay went out on my front fan. I have the Z52 package on the car which has a fan in front of the radiator as well as behind and I noticed that the front fan is not running. Normally the car runs around 175-185 degrees tops on a 90 degree day and this just happened today. I ran the car up to 200 degrees to check this and the manual tells how to bypass the front fan and when I did what it said it ran fine so that means that the fix is like 10 minutes and $19.99 for the part. I am going to check out and probably change out the water pump to the best highest flow pump I can get.
Thank you very much for answering me, I love this car and don't want to do damage to the engine so I think the high flo pump will be great.

Rob

rodj

Time for a bigger radiator
http://forums.corvetteforum.com/c4-t...e-be-cool.html
http://forums.corvetteforum.com/c4-t...0-hp-lt1s.html
http://forums.corvetteforum.com/c4-t...omparison.html

Aux fan is designed to turn on at 238 F and when it does it does little except make a noise
http://forums.corvetteforum.com/1574822290-post12.html
Do not rely on it for additional engine cooling

Fit a bigger main fan to move more air through radiator instead
http://www.dewitts.com/pages/product...asp?ProdID=428
http://forums.corvetteforum.com/1574823689-post15.html
http://forums.corvetteforum.com/1574814326-post9.html

corvetteronw

DeWitts radiator.

Schramm

Already has an high end radiator and water pump, I just asked my mechanic. Thanks but it is the relay for the front fan. I am going to look into a better water pump once I talk to Golen who built the engine.

rodj

Which doesn''t turn on until 238F

Churchkey

If cutting the cowl seal suggest leaving some on in front of the driver area. A blown coolant hose will spray the windshield with anti freeze. Its difficult to see through & the wipers will smear it. Big pucker factor! Been there.

Just my opinion: Vette E-fans could be better. Here's a fan mod that works & works well even with blowers, turbo's or on spray. Just general info not a how to.
http://www.go.jeep-xj.info/HowtoTaurusFanInstall1.htm

Muffin

May not be the final solution but it is the best starting point.

CREWZIN

The auxiliary fan in front of the radiator, as pointed out, doesn't come on till about 240 degrees. On the drivers side of the engine between plugs #3 and #5, there's a sensor that regulates when that fan comes on. All it does is ground that sensor when the temperature reaches the 240 degrees. It has a red and black wire. I took the black wire, ran it to a switch under the dash and grounded the other end. When I activate the switch, the aux fan comes on at my command. Hot here in Florida and I keep that aux fan on all the time. Whoever on this forum said that fan doesn't do anything is wrong. In the "winter" (if Florida has a winter) I usually don't have the aux fan on but if I'm in line at a bank or something and see that the temperature is raising, I can flip the switch and watch the temperature digital gauge start to drop.

Schramm

Where does it say that the aux fan doesn't come on until 240 degrees? I find that no where in 3 manuals.

CREWZIN

I don't have it in writing but it's been mentioned dozens of times on this forum, I've read it in one of the Corvette magazines, and my Corvette mechanic told me when I was thinking of adding the manual switch under the dash. It might not be exactly 240 but I've heard 235 a lot.

anciano

This is one of those ongoing themes that leaves me completely baffled to see it still being discussed because the solution is so simple and cheap -- manual fan switches.

Less than $10 and an hour or so of work will end the overheating problem and its attendant anxiety forever. By flicking on both switches I can watch the temp drop like a stone down to the thermostat-controlled 185 level even while idling on the hottest day. Completely stock cooling system, BTW, which is entirely capable of doing the job if you can get some airflow through the radiator.

This mod has made a 200% difference in how I feel about driving the car in congested summer traffic. Well, more than that, really. Before: no way. Now: no worries.

Schramm

So let me see if I understand because I thought the fan between the rad and engine ran all the time and the aux fan started up (from what has been said here) at 240 (which really makes no scenes that it wouldn't come on til it is way too hot) but you guys do seem like you all agree. If that is correct then you should only need one switch to turn on the aux fan when needed, right?..... or am I missing something. I dont want to come off sounding stupid, but since Corvettes generally have so little air flow based on no open grill why don't these fans start up to keep the car at the proper 185 degrees? I have read a lot about this issue as I am very worried about my investment in this car and last night I found on Corvette Central a upgraded fan that is a perfect fit to stock and takes the cfm of airflow of the main fan from 1700 to 2350 which is an increase of 30%. These is no retiring, however I think putting a manual switch in for the aux fan is wise. I bought the upgraded fan last night and bought it but in the meantime I think that I will have Midas put in the manual switch as they are putting my new tires on tomorrow. Please let me know if the main fan doesn't always come on. Where do you get the switch or do you mean just wire a toggle switch.

Thanks to all for chiming in!
Rob

anciano

No, no fan is running until the temp reaches 228, at which time one of the fans kicks in, and the second at 235. Many will argue tha these temps are OK ("it was designed that way") but I am not the only one that thinks it's too friggin' hot.

I think the problem results from a design dictate that the hoodline be low and swoopy, which requires the radiator to tilt backward. With airflow coming up from a scoop under the hood there is only flow ACROSS, but not THROUGH the radiator at low speeds, and none at all when stopped.

At highway speed there is enough turbulence inside the shroud to push air through the radiator, so overheating at speed is very rare if the system is operating normally.

But there's plenty of fan power to draw air THROUGH the radiator and out the back of the shroud, so I see no reason not to make use of that instead of spending big buck$ for fancy radiators and high-capacity water pumps. Especially the water pump -- it can pump its little heart out, but if the liquid is not being cooled at some point in its circuit all the pump is doing is pushing overheated water around.

I know many will disagree with all this, but as long as my car is running cool and happy so am I.

Schramm

Well I just spent the last 1/2 hour out in my driveway letting my engine (with the hood open) run to see at what temp the fan kicked on as I would think if you have a 185 themastat that is the temp that the fan would start. When the car hit 185 low and behold the fan kicked right on. I took it to 203 degrees and the main was constant but the aux fan stayed off. The temp over the next 10 minutes never rose past 203 probably because the hood was open and air flow was constant. In a video put out by one of my favorite companies (Royal Purple) they say that temp can be reduced by up to 20 degrees with the use of Royal Purple Ice. Now I will say that I only use Royal Purple 20/50 motor oil in my car as recommended by Golen Engines who built the motor and all other fluids are Royal Purple. I use it in all my cars and trucks and really like it. I am going to test that therory by changing the rad fluid or draining some and adding the ICE. I will talk to Midas tomorrow about hooking up a switch on my front fan (aux) tomorrow as well.
Thanks for your info. I am new to this car so all info is taken very seriously and appreciated very much

Rob

coorslight

i turn a/c on in traffic and the fan comes on and watch temp drop.......

383vett

Back to your header wrap question. Underhood temperatures have very little to do with internal engine temperatures. Coolant temperature is determined by the efficiency of the radiator and fan, not the temperature of the air around the motor. Header wrap will help lower intake air temperature and result in more hp. You problem lies elsewhere. I have always used Water Wetter by Redline in all my motors which increases the ability of coolant to carry away heat.

Dans 85

Rob,

I'll bet your car has a performance computer chip, that's why your main fan is coming on at 185 not 228 as normal commanded via the ECM.

If that's the case I doubt a switch will do much as your main fan will be on most of the time already on a hot day.

For a max cooling setup why not just wire the front and main fan together and forget about fiddling with a switch and having to constantly monitor the temp gauge?

Doubt the Purple will do much, up to 20 degrees? Maybe a few but 20? Total B.S.! When it sounds to good to be true...