I have my turboed 355 in my camaro. MY motor used to never get above 180 before the turbo build. Now it gets to 220 and looks like it wants to keep creeping up and i have to get off the highway. just driving around town i can stay about 215.

Things that changed from last setup to the turbo one:
crossover pipe runs right next to the bottom of radiator
Intercooler in front of radiator

So after this started happening i added a proform aluminum highflow water pump. said to have 30% more flow. I added two more cooling fans( i have 2 pushers and 1 puller) also i have the little air deflector thing on the bottom.

Im thinking i need a new radiator like a aluminum 3 core. or maybe its just my coolant temp sensor.

Any ideas would help, want to get to the track before the end of the season

 

I had the same problem with my twin turbo street car. In my case the fix was adding a bigger radiator fan and one pusher fan. The intercooler in front of the radiator blocks cool air and heats whatever air the radiator does get. Also make sure your coolant level is up. Lastly i dont run a thermostat.

 

yea maybe the thermostat is restricting flow or something. ill take it out and see what happens

 

If you're intercooled I would suggest temporarily running without the intercooler and see how things go. I know my car runs warmer a bit easier than it did before my intercooler install. I routinely see 195 to 205 if I'm abusing it. I'm running a 185 thermostat I believe. Something else that really increased my coolant temp was when I went to my 2800 stall. If I thrash on it around town a bunch it will jump the temp up after a while. Also cruising on the highway won't cool it down unless you lockup the converter! Soon as I hit the lockup on the highway the car will cool off.

Before the intercooler and stall converter I noticed no temp increases. Oh one more thing, I cut the crash bar in the center and took out the fog lights and fog light trim/tag mount. It's open in the front and putting the trim back in with the tag bracket made a significant difference in the manifold air temp at the track. So for now it's open.

 

where is your coolant temp sensor located?

 

also whats the specs on that carb your running....ive got mine running and it hasnt seen 220 before i turn my fans on

 

Are you running less timing now? What is your timing at cruise?

 

im runnin 32* atm but i also have a boost reference fuel pressure regulator......just things you might want to consider

 

im at 30* locked timing but pull timing under boost. I have a 750hp carb. Im going to take out the thermostat and see if that helps.

 

intake manifold crossover near the thermostat.

 

what degree thermostat are you running? any mods done to the carb? what size jets, what size power valve? notched rear floats, nitropyl floats front and back? choke tower still attatched?..

im running 32* locked with no msd boost timing master unit installed and with my fans on im runnin at 160* at the moment for coolant temp

 

everything on the carb was done to hanger 18 specs. so yea i have all of that, i have a 160 thermostat also. i dont get it

 

try some water wetter . just a temp fix but could help.

 

odd ive done the hangar 18 mods too with a 700 carb......works quite well, how much compression you running? how much boost are you runnin? when do your fans turn on also do you still have the air dam underneath?

 

9.5:1 ish my fans are keyed hot! yea just put the air dam back on didnt help too much

 

tried didnt work

 

i run the same compression ratio too with 9 lbs boost from my turbo at the moment

what are you runnign for a radiator? stock water pump? did you drill 2 1/8" holes in your thermostat?

 

30% highflow aluminum water pump. stock radiator tho. what are you talking about holes in the thermostat. never heard of that

 

sometime people will drill out a hole or 2 in the thermostar(on the sheet metal ring) nto aid in cooling and coolant flow.........it allows coolant to pass thru at a quicker rate without the thermostat having to be open yet....i dont see the point in no thermostat unless your in a humid climate all the time.

 

if you are overheating on the highway you either have too little coolnig capacity or there's not enough airflow with the fans off. You shouldn't have to rely on fans continuously running to be able to keep the coolant temp in check

 

have u taken a look at ur coolant lately? whens the last time its been flushed and cleaned? may have missed this but do u have AC? is it on or off when this is happening if you do have it?

 

This is what is happening. Not enough cooling capacity and/or not enough air flow.

For my situation, i have a big griffen radiator using stock L98 fans at first. I was overheating with 170 thermostat and fans on, but I never did before even with stock radiator when I was all motor 383.

So I tried water wetter, took out the thermostat, played with air fuel ratios and timing but nothing helped when it was hot outside. It quickly climbs to 200+ and I wont run it anymore above 220.

So i decided to try LS1 fans with factory built in shroud. They did the trick. Car ran mid 180's now with 1 fan on whole time in 80 deg weather, cycling the other fan on and off during stops or slow traffic.

SO its a combination of not enough air flow and not enough cooling capacity.


With turbos you are heating the oil temps up alot and the extra underhood temp further decreases the motors ability to stay cool. You need a large cooling system.

 

ill try that hole trick with the thermostat.

Coolant was repaced when i did the build, like a month ago.

No ac

 

onther thing are you running a serpentine belt setup with the correct belt routing? mine with the fans on stays at 160*

 

v belts so yea its all fine. The hole trick seemed to have worked but i was just running it in the drive way so the real test will be when i drive it.

 

I would check how it works during boost.
In general, 1/3 HP goes to the crank, 1/3 HP goes to the exhaust, 1/3 goes into heating the block & coolant.

The cooling system needs time and/or mass to expel that HP / heat.

 

if you do pull out the thermostat make sure you replace it with a plate restrictor. Its not good to not have any sort of restriction or else it will overheat due to water passing through too fast.
Do you have an engine oil cooler? that could help too

 

you do not need a restrictor.

 

I was told if I didn't have a restrictor water would flow through the radiator/engine too fast without giving it time to cool it down. Am I missinformed?

 

so in other words your saying its of if the coolant continuously passes through the system without cooling off 1st?

thermo stats or restrictors will allow the coolant to at least cool down to a certain temp in the radiator while the coolant is heating up in the engine.once it reaches a certain temp then the thermostat opens allowing the cooler coolant into the engine and the hotter coolant into the radiator. then the thermostat closes and repeats the cycle again once the engine coolant has heated up again.

to be honest i think his issue is something other than a thermostat

 

no, you are correct

 

Its a heat transfer issue. The time it takes to pass thru the rad changes the amount of cooling medium flow is needed to cool the water and/or the size of the cooler.

I dont have the heat transfer equations and theory to properly explain it and maybe I am wrong but this is my understanding...its been along time since I had that class.

Restrictors or thermostats just slow the amout of flow that goes thru the radiator so that the temperature differential between water coming out of the motor and water coming out of the radiator is greater than unrestricted flow. Both systems should equal out to a equilibrium temperature in the end, its just that the thermostat will keep water in the motor hotter for a given cooling system.

Example, my 89 camaro was factory set to well over 200 deg F. It used to run that hot. Cooling system (rad and fans) is designed to handle those kind of conditions plus extra capacity for factor of safety. If you took out the T-stat and ran the fans all the time, it should run much much cooler. The ECM and Tstat are controlling the temp but do not set the limit of cooling capability. Cooling system is capable of more it just is "restricted". Case in point, I swapped to 170 stat and changed the fan turn on temps to around 165 off, 175 on and it hovered around 170-180 all the time, no other changes made to the system.

The T-stat system has a larger differential due to more time being spent in the rad to cool down. But it also spends more time in the motor so it gets hotter in the first place. The mix just equals out to a set temp.

With no restrictor the water will flow til it hits max temp set by your cooling systems capability. If your cooling system is sized to only provide 180 deg operating temps for a set ambient air condition, it will arrive at that temp. Water out the motor may be 190 but water out the rad will be 170 lets say since its unrestricted in flow and doesnt have the time to cool down like it did with a thermostat. So, the differential is smaller but still reaches an equilibrium.

 

FWIW - I have a 1986 IROC Z with the stock radiator in it, it had a 91 L98 engine put in it when I got it but I know the history off the car and the radiator was not changed, I added AFR heads and a D1SC 88-92 set up with the same stock radiator but I put a 160* thermostat in it. Because of poor installation of the Procharger bracket I had noise problems with the head unit before I really got a chance to drive it, with no forced induction the car ran very cool. However, when I got the head unit back and put it on, the engine ran very close to the red like and the water temp, according to my BS3 set up read around 250*. I'm guessing the old radiator couldn't take the heat and pressure and gave out. I've been using the same radiator guy for about 9 years and I ordered a stock replacement. so far, with the radiator it doesn't run hot. I'm only suggesting this in case you too have an original radiator, with the boost and the eventual restriction of the older radiator it might just not be free flowing enough any more. Also, the coolant in the radiator was very clean.

Is it possible that combination of pusher and puller fans could actually be a restriction at highway speeds? I have two pushers, by the way.

 

So i bought a EMP/ stewart thermostat. it seemed to fix everything. It was said to be built for a high flow water pump which is why i thought i would try it.