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What are the Vee temps I need to be aware of?
Assume a hot, sunny day in August, what is the max temp I should avoid while idling in grid and awaiting the signal to go?
What is the reasonable operating temp I should look for at speed- as in, if I start to creep over it I know something is amiss?
My old man always said that if oil temps gets above 300F on track, it's time to start getting worried
You should never see the temp gauge rise while on grid. These are aircooled engines and the oil temp should not get high enough to move your temp gauge if the oil is cool from sitting otherwise you will cooking your heads.
Never idle your car sitting in one place for more then 5 minutes. I typically don't idle my car for more then 2-3 minutes because during the pace lap the engine is going to get all the heat it needs.
Cylinder head temps should never exceed 350 F. Oil is happy at 200F to 220F.
I have had FVs that I did not use an oil cooler with because I had the cylinder head cooling was good enough.
EGT should be under 1300 on long straights. The EGT number is from air cooled FSV days. The issue with EGT is that to get the engine to come off corners well, it needs to be on the lean side. But on straights, lean meant a lot of cylinder temperature and the engine lost power at high temps. I never played with an EGT on a FV. For a FSV, getting the EGT numbers just right could be several mph on top end.
This year I saw 237 max on a very hot day. I wouldn't want to go much above that. I've been told 260 is the time to worry but I've heard guys tell of 300, but their gauges could have been off.
I agree with mikehinkle, limit the idling and slow speeds to the minimum necessary to get to the false grid. I start the car at the one-minute signal.
If you have to run the car static in the pit or at home for more than a few minutes, use a couple of good box fans to dissipate the heat.
Not knowing what type of vee you have (how tight the cockpit / dash area are) it would be immensely helpful to run a head temp gauge.
I do.
Glenn
With a beltless FV, don't let it idle
If vintage with a belt, let it idle all day long
With todays oils (most with reduced ZDDP), I'd start hitting the panic button at 260. Good chance that if you make it to 300, you'll just have confirmation of a smoked engine.
If you have a vintage car with a fan, make sure the fan inlet is getting fresh air. Once fresh air gets to the fan inlet, that system has more than enough head and oil cooling. If a current era car with scoops, head temp is really the critical issue. Hot heads will drive oil temp up.
Good gauges (CHT and Oil Temp) are always a smart idea if your not sure where the numbers are at.
Thanks for all the info. I have digital gauges and want to set the temps for the warning lights. These numbers will help me. The data logger is nice, but I have a real hard time seeing the LCD numbers on the track. Having shift lights and warning lights is very helpful.
Bill is right about the oil will work fine at 300 degrees. My question would be where is all that head coming from. If you are seeing 400 degrees or more at the cylinder head, you got a problems. And you are loosing a lot of HP because things are too hot.
The key is to keep the heads cool and the oil warm
Steve,Quote:
Originally Posted by S Lathrop
Where are you measuring your head temp? Under the plug or on a head stud?
That would be a probe in the head. The 350 number is actually for air cooled airplane engines. With a sensor under a plug, you will see higher numbers. If I were racing FV, I would be looking at cylinder head and EGT numbers both.Quote:
Originally Posted by Diamond Formula Cars
But I think is a very good number because above that you reduce the strength of aluminum and above 450F you will start changing the heat treated characteristics of aluminum.
I've been struggling to reduce temps to 350 under the plug - am I doing it wrong?What does a probe in the head look like and what is the degree difference to the plug or a head stud? Thanks
I don't believe anybody's cylinder head temp numbers. It is much like comparing hp numbers between dynos. I have seen cars with "uncompetitive" head cooling scoops that win dozens of races and Runoffs. 30 places back on the grid will be cars that replaced those "uncompetitive" scoops with highly developed parts that lowered head temps by 300 degrees. Thermocouple sensors are consumable items when installed on FV cylinder heads, and sensor location is critical and very subjective. The temperature is critical at very specific locations in the engine, none of which are measurable, although the plug may be closest. So depending on where you measure the temp, and the design of your cooling airflow, you can have very low readings on a cylinder temp sensor and have horrific numbers where it matters.Quote:
Originally Posted by Bob Posner
I believe each application needs a custom interpretation of that application based on a relationship between oil temperature and head temperature as measured on that application.
No, I don't think the same brand cars with the same brand sensors are necessarily comparable. You would really need to move the same engine between the cars.
I always measure my temps under the plug. Bob, If you are seeing 350 under the plug then rejoice because I have never seen temps, in that location, under that.Quote:
Originally Posted by Bob Posner
So what temps are you seeing?Quote:
Originally Posted by Diamond Formula Cars
Thanks. J
400-500 depending on the type of cooling scoops.
Quote:
Originally Posted by Diamond Formula Cars
I measure under the plug and see 375-390 depending on elevation. At homestead I saw 375. Ambient was about 75-80 degrees. Elevation was a couple feet over sea level. Car is a Vortech.