RTW DC2R

Previously, it was my understanding that you SHOULD run the coolant lines with the BB turbos, as it can help extend the life of the turbo. But I recently had a discussion that running the coolant lines can actually help to overheat the motor and that over time the coolant lines can/will eventually leak causing the turbine/compressor to rust. I also was under the impression the coolant passages were isolated from the turbine/compressor housings, but apparently they arent?

I would assume running a larger radiator (if possible) could help with cooling issues. But are there any known negative effects of NOT running the coolant lines on these BB turbos?

Just looking for some further opinion and clarification.

Soccerking3000

you should definately run the coolant lines because the ballbearing turbo's dont use oil to cool they only use it to lubricate the bearings, hence why most of the time you need to run a restrictor since they use so little oil. Older journal bearing turbo's need more oil because the lubricate AND cool. If you didnt need to run the coolant lines why would any of the companies put them on there?

Also as for the turbo heating up the coolant and causing negative effects on the motor, thats bs you wont see any difference in coolant temp if you have a good radiator.

RTW DC2R

Thats basically what I was thinking, which is why I was surprised to hear it, especially since it came from a reputable source. I dont want my setup to be half assed, and if running the coolant lines do more good than harm, then I want to do it. Maybe Ill just run them, and if I have any overheating issues, Ill remove them and see what happens.

Are the coolant passages isolated from the housings and wheels? If they arent, are there seals that should be checked or replaced, sort of like maintenance items?

Chip

The amount of additional heat put into the coolant by the turbo is so miniscule compared to the heat put in it by combustion, I wouldn't worry about it. It's my understanding that Garrett will not warranty a BB turbo that has not had the coolant lines hooked up.

80884

Run the coolant lines, they are there for a reason. If your car overheats with them on then i'd have to say the car needs a better cooling system and the overheating problem is not because of the turbo having coolant going through it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Garrett &raquo;</TD></TR><TR><TD CLASS="quote">"Garrett ball bearing turbochargers require less oil than journal bearing turbos. Therefore an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go “uphill” at any point.

Following a hot shutdown of a turbocharger, heat soak begins. This means that the heat in the head, exhaust manifold, and turbine housing finds it way to the turbo’s center housing, raising its temperature. These extreme temperatures in the center housing can result in oil coking.

To minimize the effects of heat soak-back, water-cooled center housings were introduced. These use coolant from the engine to act as a heat sink after engine shutdown, preventing the oil from coking. The water lines utilize a thermal siphon effect to reduce the peak heat soak-back temperature after key-off. The layout of the pipes should minimize peaks and troughs with the (cool) water inlet on the low side. To help this along, it is advantageous to tilt the turbocharger about 25° about the axis of shaft rotation.

Many Garrett turbos are water-cooled for enhanced durability."</TD></TR></TABLE>

Quoted by Garrett from Garrett's website onto honda-tech in quote form. ha ha

Zakar

they are there for a reason.. this has been covered a million times

your car shouldnt overheat