Apex blowing coolant...please help

[RWH]

My sled has been running perfectly at 17 lbs of boost and then last saturday it started blowing coolant out the overflow. I have about 200 miles on it since the boondocker kit was put on. It had a bender on before that. Coolant system was pressure checked today at 10lbs and didn't drop a bit in 4 hours. Could it still be a head gasket or is there a chance it could have had an air lock.

 

[KnappAttack]

Deto lifts the head blowing coolant out when running. What octane you running?

 

[ProstockBenji]

was the head retorqued to proper specs before runinng 17lbs of Boost , if not you blew your head gasket .

 

[RWH]

I am running at least 50/50 110 to 92 and usually it is closer to 60/40. This has wiseco pistons in it. I didn't do the motor work myself. It was done at a shop that has done a ton of these sleds.

 

[Ted Jannetty]

I am running at least 50/50 110 to 92 and usually it is closer to 60/40. This has wiseco pistons in it. I didn't do the motor work myself. It was done at a shop that has done a ton of these sleds.

There are a few possibilities that caused the head gasket failure, first and most common is not enough octane, your playing chemist and estimating your octane (too risky at that boost level), 2nd the head was not torqued as per my instructions to 38 lbs. or 3rd, the turbo is too small for the boost level your running and holds too much heat in the motor, or 4th your cooling system is not up to the power output of the motor at that level.

Hope this info is useful.

Ted.

 

[dirkdiggler]

I'd say you didn't run enough octane. With 17 pounds of boost you should be running strait race fuel not a mix.

 

[RWH]

So I should definately do the head gasket and start running better fuel. I was told I didn't need to go straight race gas until over 20lbs of boost with the pistons. Is there anything else I should do while it is down?

 

[dirkdiggler]

So I should definately do the head gasket and start running better fuel. I was told I didn't need to go straight race gas until over 20lbs of boost with the pistons. Is there anything else I should do while it is down?

Who told you that????? 17.5 pounds on a 10 to 1 motor requires 98 octane fuel according to the Calculator.

 

[77srxdude]

So I should definately do the head gasket and start running better fuel. I was told I didn't need to go straight race gas until over 20lbs of boost with the pistons. Is there anything else I should do while it is down?

Who told you that????? 17.5 pounds on a 10 to 1 motor requires 98 octane fuel according to the Calculator.

According to that then 17.5 lbs should be safe - 50/50 of 110race/92pump gets you over 100 octane - correct? I assume you can avg the two octane levels - or does averaging not work correctly with octanes.

The calc puts 22 lbs at 104.5 oct for the RX - at that point it makes sense to run straight race.

This is the same setup I am running now - so please correct me if my thinking is wrong. I plan on running 10 lbs on 92-93 and 15 lbs on 50/50.