Topic: Over heating /blowing off turbo tubes on race track

[Graywolf]

Ran my car at Black Hawk Farms Raceway Saturday Track Day and on Monday for a High Speed driving event. Place 4th out 9 cars in A modified. Missed a 3rd place trophy by 0.5 sec on 1.5mile road racing course. Beaten by Z28 camaro and two corvettes,beat a 911 turbo Porsche Carrera, three corvettes and a nissan 350z all cars highly modified for the track. Screwed up on one run because I forgot to press buttom to go to competitive mode. Another run screwed up because I blew off a turbo tube. So I had only two good runs out of 4,  On track day I was troubled with the engine over heating after running 4 hard laps each time out. Running the heater on at full blast helped some but once I hit 230 degrees I would exit the track. I ordered a Ron Davis Racing radiator today $832.00 3 wk delivery. Overall I had a blast!!!Running 100 octane

[kennysabarese]

You need a bigger turbo man! Your engine is ready for it!

[Gentleman Jack]

GrayHawk,

Sounds like you had a great time.  I don't know how much it would help, but what about vented fenders and some type of hood "scoop" that would allow more heat out of the engine compartment? or a way to get more air to the radiator? Would involve some cutting and visual compromise I would guess...

Just throwing out some ideas.  Also, before Kelu can get to you... any pics?

GJ

[kennysabarese]

SCCA racing sol's used a racing radiator as well as a rear diff cooler.

Also DDM and i think Werks has a turbo heat shield that'll keep your cabin temps down. I have one on the way from DDM

[Graywolf]

I ordered a Ron Davis racing radiator which is about a inch thicker than stock etc. and is the recommended radiator for scca road racing in the solstice performance book.  A bigger turbo may be nice but I am afraid of loosing low end torque and cannot afford it this year[about $4000]

[DeepBlueGXP]

GW, you may just have trapped air as the LNF is known for this problem.  There is a GM fix which installs check valves in the system.  Also, the car must be raised in the front when servicing the radiator as it is lower than the engine.

[kennysabarese]

How hot is too hot? My temps have gone high but come right back down.

[Graywolf]

Hit 235 degrees and yes it would come down when I slowed down but I'm can't be slowing down. I'm running on a road racing course with other drivers. I also had a frabricated intercooler protector that got bent and partially obstructed airflow. I cut it out @ the track which helped some but would still overheat. The bigger Ron Davis  racing radiator should do the trick if not I will modify the rubber dam that directs air up toward the radiator.

[perris]

Running the heater on at full blast helped some but once I hit 230 degrees I would exit the track.

interesting thing about our engine, I don't know about your rebuild though and it could be differant then the stock cooling phenominon;

turning the heater full on, counter intuitively, in our car raises the engine temerature it does not lower it

flash said something like the engine coolant is drawn into the the heater core  and out of the radiator so does not lower engine temperature like it does in other cars

[NormSky]

Perris, your not making any sense. If the heater is used to in a high temperature situation it is acting like another radiator, just a very small one compared to the main one.

Your correct the thermostat opens on the engine and continues to the heater core but goes to the front of the engine to water pump and exits to the radiator at the top of the engine. Graywolf's are to turn on the fans early as a run may last 20 minutes, thicker radiator, or a lower temperature thermostat.

[perris]

Perris, your not making any sense. If the heater is used to in a high temperature situation it is acting like another radiator, just a very small one compared to the main one.

Your correct the thermostat opens on the engine and continues to the heater core but goes to the front of the engine to water pump and exits to the radiator at the top of the engine. Graywolf's are to turn on the fans early as a run may last 20 minutes, thicker radiator, or a lower temperature thermostat.

I'm sure I mistated the reasons for the phenominon on our car but never the less, full on heater does at times cause our engine to get hotter

 it's been discussed a number of times on the other board, this is from info2x, one of the engineers on our engine;

I've heard that if your heater is on high enough (No I don't know what high enough is) you can pull enough heat out of the coolant to partially close the thermostat which can then cause temp spikes.

according to that theory, the thermostat sees colder collant then the engine temp sensor, being mechanical, the antifreeze is cool enough to close the thermostat even though the engine is  reporting a differant temerature,  if that's so, I suppose some thermosts are more prone then others

try it, go out and get your car to cruising, turn your heater full on, if your car is like both of mine and a number of others who've noticed, youll watch your temperature climb not decline

[NormSky]

At 230F when he shut it down and return to the pits it would only take a few more degrees before reduced engine or limp home mode would be enabled.  Turning on the heater at that point is not going to bring the temps down almost 40F to fool the thermostat.  Most 195F thermostats start to open around 190 so if your seeing more than 200F your not getting enough air flow. 

When in a pack of Kappas on an almost 90F humid day this past week I was seeing 205F for most of the hour highway drive.  Which is about when my low speed fans have been programmed to come on.  Riding in the pack along with heavy, non-circulating air I know there was not enough air flow over the radiator.  I have turned the heater on full and never have seen a spike but a couple of degree decrease in temperatures.  Works great awaiting staging lanes at auto crosses. 

[perris]

At 230F when he shut it down and return to the pits it would only take a few more degrees before reduced engine or limp home mode would be enabled.  Turning on the heater at that point is not going to bring the temps down almost 40F to fool the thermostat.  Most 195F thermostats start to open around 190 so if your seeing more than 200F your not getting enough air flow. 

When in a pack of Kappas on an almost 90F humid day this past week I was seeing 205F for most of the hour highway drive.  Which is about when my low speed fans have been programmed to come on.  Riding in the pack along with heavy, non-circulating air I know there was not enough air flow over the radiator.  I have turned the heater on full and never have seen a spike but a couple of degree decrease in temperatures.  Works great awaiting staging lanes at auto crosses. 

that's a good point

however I'm not so sure the theory is correct for why the engine gets hotter at times with the heater on;

just recently my secondary fan started to go and my car was getting hotter then usual, up to 225, this was not the common issue with air it was the secondary fan

again, I tried turning the heater on and it didn't lower the temp, it's hard to tell if it slowed the increase in heat or not since I shut the engine down as soon as I saw the heater trick wasn't helping

anyway you're probably right I am just not certain

[kennysabarese]

graywolf, how much is the racing radiator? I know Werks has one for about 600 bucks.

[NormSky]

Going up hill on the highway I was able to see 205F and then turned on the heat full. I ran out of up hill but the temps were still dropping at 194F. I probably still have some air. In the system after opening it up to add coolant lines to turbo, which also adds heat. This is straight coolant with no Water Wetter or anything else.

[kennysabarese]

How high can it go before I really get worried. Older cars used to have a range and have red if the heat was out of spec.

[NormSky]

Upper 230's to 240 and you'll slow down to an idle until it cools off.

[Graywolf]

Once I knew I had a over heating issue,i had the heater on full blast from the start. This helped me get a extra couple of laps. The Ron Davis racing radiator I ordered costs $832 and that is the one Gm racing recommends. So far every recommendation that I have followed from them has worked out great. The werks radiator may be a excellent choice,certainly the price.