I'm a tad concerned about water temps with the new 383 motor. During an off track lawn-mowing session last season I tore off the plastic skirting along the front fascia of the vehicle and bent down the center scoop. The stock motor never had anything close to a cooling problem, even after extended track sessions on hot days so I never fixed it, but obviously the new motor makes a lot more heat so I'm concerned. I put a bracket from the plastic nose down to the scoop under the rad to hold it in factory position, but I'm wondering of the scoop being bent lower actually forced more air in.

It's 101 degrees and humid this week, so I've been doing as much testing as possible, but the car is not streetable so I won't know for sure how it does while actually driving until I can get on track. Here's what I've discerned so far:

At idle in the garage (at least 15 degrees hotter than outside, no air movement) water temps hit 210, oil about the same. Outside, tooling around the parking lot (providing some air movement across the radiator) I stay at about 200. I really can't do much except a few hard 1st through 2nd runs, which quickly get the temps up to 210 (like at idle) but they seem to stay there.

How necessary are the fascia skirts for cooling, and anyone have thoughts about whether or not I'll get enough air flow? I know idle can be an extreme test for water temps, but racing is the worst heat generator.

Does anyone have suggestions to improve cooling? Please, no suggestions to buy a gimmick like a "big mouth air dam" or to get a new radiator. I'm hoping to avoid the latter solution, and frankly, I've read enough posts that say that doesn't help anyway.

Thanks in advance.

 

My 383 was running a little hotter than I liked it. So I built my own equivalent "Big Mouth Air Scoop", added a secondary pusher fan, upgraded the radiator to a dual core and added an oil cooler.

Now when moving, my temps stay at 167 at 75 degrees and 180 at 95 degrees.

Sitting idle at 90 degrees, It will go up as high as 190.

 

Jon, I would actually consider starting with an OIL cooler. You will find the larger, more powerful engine will want to heat up your oil substantially more than your coolant/water. Unfortunately, they are a pain in the nuts to plumb on our already cramped C4s, and about the only place to mount the cooler itself is IN FRONT OF the radiator--DAMBIT!

 

The air dam makes a big difference, especially at speed. I'd get one on there...

Be well,

SJW

 

Front air dam does make a difference once the car gets moving, and if you are expecting higher temps then maybe the BigMouth will be useful for you. Larger radiators wont fix an idle overheating issue, but when air starts moving over them the temperatures really drop compared to stock. Mine warms up as it did before in traffic, but temps steady about 10F lower than before once it gets moving (DeWitts). (20F difference on the highway).

So, at the least you need to replace anything thats broken. I'd save anything else until after the engine is in there and you'll know how much money you really have to spend.

 

HELPED MORE THAN A 2500 DOLLAR RON DAVIS RACING RATIATOR AND OIL COOLER AND 2 LARGE SPAL FANS ..MINES BIG MOUTH FROM MID AMERICA ACI I THINK VERRY NICE..

 

I have an oil cooler (of course mounted to the front of the radiator) which of course hurts the water temps.

Other than overblown performance claims, my concern with a pricey aftermarket piece like the "big mouth" is the fact that someday (hopefully a long time from now) this car will do a little 4-wheelin and I don't want to rip it off and have to buy a new one. That's why I'm asking this question in the first place

Not worried about idle temps, so maybe I'll have to get off the wallet and get a bigger radiator to protect the motor. We'll see after friday when she gets to go over 3000 RPM for the first time.

 

My temps are higher as well with my 383. I do have the big mouth air dam and that seems to help while driving. As far as idle I just turn on both my fans and that readily brings the temps down. I know its a source of frustration but I'm glad to see that I'm not the only one that has higher temps since getting the 383 in. Sorry I don't have a solution or suggestion to bring the temps down.

 

Hmmm.....just finishing up the build on my new 383 - you guys have my attention about the higher operating temps. Guess I need to start thinking about cooling options? Bigger rad....???

 

I think Your temps seem just fine for 101 deg days and tooling around in the parking lot, close to stop and go traffic. It was 100+ here in Charleston yesterday and my car was right at 210 in stop and go with the A/C on. While my car will drop to 180-190 with the A/C off even in the high heat it does have a Be-Cool Radiator and a 170 T-stat and my ECM is programed to cycle on that range. You realy need to get the front valence corrected for when you race to have proper air flow at speed but as long as you can keep it bellow 225 you are fine. BTW glad to see you finaly have all your problems sorted out and good luck.

 

Here, Here!

Once I test it and everything's a-ok I'll post the "she's back together and running great" post for some CF hi-5's. Before that I don't want to prematurely ejac...er...celebrate.

I straightened up the air dam and it looks good. I can play with it tomorrow to see what raising and lowering it does to temps.

If anyone is feeling generous, take a picture of the STOCK air dam set up and post here. I'd be thankful. Actually, if anyone is feeling REALLY generous, put a ruler in there so I can see the correct distance from the bottom of the nose to the top of the airdam.

Topload, I don't know that I have a problem yet, I'm just being over cautious. You do that when you rebuild your motor twice in 10 months. The stock cooling system (water, certainly not oil!) is pretty solid, let's see how it handles an extra few hundred HP.

 

I'm not convinced that the oil cooler is raising your coolant temps all that much. One way or another (unless you had an oil/air cooler that was not in the radiator's intake air stream), the oil is probably going to transfer most of its heat to the coolant, whether it gets there through the block & heads, or gets there via the air passing through the cooler and then the radiator.

You can get a stock air dam replacement assembly from Mid America for $40. I'd recommend you spring for it.

I can't put a ruler on there right now because my Vette and I are not in the same place, but here are a couple of photos that include the air dam on my '94:



.



Be well,

SJW

 

Thanks for the pictures, it looks like I have most of it, just not the side skirts. So as long as air flows through the oil cooler, even if it is hotter air than ambient, it should be fair.

Here's what I have, my digital camera is damaged so these are taken with a flashlight and a phone...sorry for the poor quality.

Here is the scoop, you can see the bottom of the nose and the scoop. The bracket is not in the stock configuration, but seems to do the job for now.



Here is the cooler, right in the center of the radiator.