crashnscar

What do you guys do about heat?
02 z06, built 416 with DeWitts radiator and an engine oil cooler. At the track, I am hitting 220* oil temps after the first lap, and 280-290* after a few more laps before I pull it off track (about 10 min into a session). Coolant temps are getting between 245 and 270... How do I keep this motor cool? A second oil cooler? Big *** hole in the front bumper?

Rob Burgoon

What do you guys think? maybe a tigershark nose?

Make sure you are using 100% water and water wetter for the track, and be sure to put some antifreeze back in after.

Look into sealing off the sides of the radiator so air coming in has to go through it.

If the EOC is internal, then getting coolant temps down will help bring oil temps down. If the EOC is external, lower coolant temps will still help some, but make sure it is getting fed air and consider ducting to force air through it.

A functional extractor hood might help too.

Other than that, you blew it adding power to a track car. That makes everything harder.

jpobrien

I have the same type of problem with my C4 track car. I'm at Putnam Park this weekend, and I can't seem to fix the thing. Mine is a 383 LT1. I've been chasing this for a year now.

I think I'll try the pure water idea tomorrow. To me, it seems like the thermostat is not pushing enough flow to the radiator (and I've changed that thermostat 2 or 3 times now). I changed to an electric water pump, changed the head gaskets - nothing seems to work.

If anyone has some LT1 advise, I'd love to hear it.

gkmccready

Have to ask the dumb question... you've blown all the leaves and dirt and crap out where the radiator, etc, is, right?

Is it a DeWitts with a built-in EOC? Or an external EOC?

FWIW, at Thunderhill in the hot days of summer my C6 Z51 with a stock motor will stabilize the oil temps in the 290-300f range by mid-session (say 10 minutes in to 20-25 minutes). Begging for more cooling, but the T1 guys all say 300f is fine, just don't go any higher.

crashnscar

WOAH, 300*F is fine?!??? Definitely have never heard that before. I'd ideally like it to stay around 230*F or less and coolant about the same....

Radiator has a built in heat exchanger, but it is not in use.... the oil cooler is external and right where the radiator is.
I bought the car how it is, so I will look into what ducting is there and what I can do.

Are there bumpers that make the car a front breather and very open in front? I think that combined with a vented hood will do the trick.

sperkins

300* is way up there. Some would say that's not a problem, but most of us would say otherwise.

You'll never keep your oil temps around 230*. If you can keep it around 270* you'll be fine. FWIW, my stock C5Z would hit 300* oil temp on a hot day in no time at the track. I added a large cooler at the condensor and I haven't seen 270* since.

sperkins

A Dewitts and an EOC should be fine for a naturally aspirated LSX. Your problem may be in the tune. Also, are you sure the fans are working properly?

crashnscar

What would be wrong with the tune? Too much timing? Not enough fuel?

The fans work fine.

BTW, I am hard on cars.... Porsche PCCB (ceramic brakes) are not supposed to fade and not supposed to wear. Rotors and pads were done after 3 track days, 6000 miles. I'm pretty fast and harder on cars than the majority of people.

AU N EGL

Three days? , what took you so long? the PCCBs are to last a life time under normal street use, not on the track. Just like normal brake pads, there are different levels of CCB rotors and pads.

Know a few P-guys who opted NOT to get the PCCB and put on the normal Brembo Porsche brakes so they could stop their cars in the first place.

The higher the oil temp and coolant the less HP you have. Keeping those temps down is essential.

Did you get a big enough radiator for your engine build and use? Or just a replacement radiator with EOC ?

I am not fond of EOC radiators. I think that separate oil coolers and a big 4 core racing radiator is needed for any racing and or track days.

along with at least a accu-sump if not a dry sump for a larger engine build. Personally when I build a new engine, it will have a dry sump system.

What oil and wt are you using? If your not using at least a 40wt racing oil your going to run into heat issues.

Redline 40wt
M1 5-w50
RP 40wt

Finally, when did you last change your oil?

Bill Dearborn

I would check a few things in the installation before making major changes. Are the seals between the A/C condenser and the shroud in place or are they loose and allowing cooling air to bypass the condenser and radiator? Have you taped the center spoiler so it will not deflect at high speed. Once you are into triple digit speeds the spoiler has a tendency to blow back on its springs. Using some duct tape to tape it to the radiator support brackets will keep it from deflecting. A little more scraping and damage when driving on the street but it is made to be replaced.

My Z runs somewhere between 220 and 230 coolant temps and 265 oil temp with a Ron Davis Racing radiator with built in EOC. The setup has a remote oil filter so I run 9 qts of oil when I am on the track. Temps were about 15 degrees cooler for each before I installed a thermostatic bypass to keep temps during winter driving as the oil temp wouldn't go above 100 degrees when driving on the highway in 35 degree ambient temps.

Also check to make sure you have a full coolant load in the system. If there is an air bubble that will reduce cooling capacity.

With the built engine you are making more HP than my stock Z so the engine will run hotter. One thing one of my old engine builders told me a long time ago was the difference in high HP engines was the ability of the builder to get more HP while keeping the engine cool. It is easy to make the HP but it isn't easy to make it efficiently. He told me he could build an 800 HP NASCAR engine and it would be competitive for a few laps but his inability to match the top engine builders engine efficiency meant the engine would soon overheat.

Bill

tmak26b

Have you looked at the gauge lately? Car operates around 210F. 230F, dream on. The Corvette is built for higher oil temp, nothing you can do about it. It's just the way it is.

bowtiguy

I know this isn't an apples to apples comparo.... but my Ron Davis radiator w/o EOC kept coolant temps below 230 at Road America during the NCM event in my 08 C6Z. Oil temps, however, crept up to 248 at one point while pounding on my 454 LS7 for 20 minutes straight ( 10W-30 Joe gibbs synthetic oil nothing less than 45 Psi at idle).

Its amazing to watch the oil pressure drop with increses in temp.

I'll be adding a larger external cooler and Mocal 180 degree Oil thermostat as the stock C6Z oil cooler doesn't get me above 130 by the time I get to work 13 miles from my house driving on the bypass/toll road. I figure this will be the best of both worlds and will allow me to hammer it in the AM w/o warming the car up for my neighbors to hear.

0Vector Vette

I ran a C4 383 LT4 for years, 465 RWHP. Blocked off the quick warmup bypass in the waterpump. Tore all the guts out of the thermostat. Also ran a Mezierre electric water pump. Aluminum racing radiator. Heat extractor hood. Car would then run 210 degrees all day.

crashnscar

Alright, so it turns out my center factory air dam had been bent all out of place. Do you think that could have been the entire issue?


and here is a picture of my massive 12" x 10.5" oil cooler

AU N EGL

Yes - no air getting up into the radiator.

rbl

Air dam does not contribute to cooling. It creates a high pressure area for front end stability. Car will cool the same with or without it.

I doubt you are really seeing 240-270* coolant temps. That is approaching 25 Psi on the cooling system.

I would start by checking your gauges.

Rob's 73

I'll partially buy that on a C6 but on a C5 you will get minimal air flow without it.

sothpaw2

Can you let us know if the pure water+ wetter helps you and by how much? I tried the wetter but with normal Dexcool mix and couldn't see a real difference on my '02 Z. Saw 270's on oil and so I backed off and stayed in 4th instead of using power in 3rd; this allowed me to manage the temp.

Sidney004

What are the water and oil temps?

crashnscar

I would guess that it would contribute to cooling on the c5, because it creates a high pressure zone directly under the nose of the car which is where the radiator gets its air..... if the car was a front breather rather than a bottom breather I would completely agree.

How would you suggest I check my gauges?