FAQ

Q. Does Honeywell provide hoses, connectors, or manifolds for the two turbos?

A. No. Honeywell will provide either the GT12 or the GTV15 and the associated paper documentation. It is the team's job to design the turbo into its engine. (Note: teams can potentially receive design points based on the design they use.)

Q. How close to the restrictor should the turbo be placed?

A. That is up to the team. The location of the turbo with respect to the restrictor has no bearing on the performance of the turbo. Check the Formula SAE rules for exact restrictor-location requirements.

Q. What happens when running a high compression ratio with a turbo?

A. There are many considerations that might be overlooked when turbocharging an engine that was not originally designed for one. The turbo is generally robust to higher engine compression ratios. However, peak cylinder pressures are more easily reached with forced induction, and the risk of blowing a head gasket, or even fatiguing the head bolts increases. If compression ratios are too high for the turbocharged application, teams might also encounter temperature related issues. These include: an overheated engine, overheated turbine housing, coking of oil, an incomplete combustion process, poor exhaust performance, and other heat-induced engine problems.

Q. What precautions should be taken when using the variable nozzle turbo?

A. Safety first. VNTs are designed to broaden the usable range of a particular turbocharger. With vanes closed, the unit acts like a small turbo, and can generate the appropriate amount of air flow very quickly. With vanes open, the unit acts like a much larger turbo, and can generate a higher amount of flow. Honeywell’s Garrett VNT™ turbos are designed with a vacuum actuator such that, if the vane actuation system were to fail, the vanes would fail to open. This prevents the turbo from overspeeding, and helps to protect the engine from any damage. If you alter the actuation system, be sure to allow for the vanes to go "full-open" in the event of a failure. The second consideration is temperature. Most VNT™ turbos are designed for diesel applications, and thus, are not capable of handling gasoline exhaust temperatures for the long term. If your team decides to use a VNT™, and you desire to move the vanes during engine operation, be advised that the vanes may become sluggish above 825°C. For any other VNT specific issues, please contact your team's Honeywell support engineer.

Q. How is the team supposed to actuate the wastegate assembly?

The drawings provided in the care packet include notes about the amount of air pressure necessary for actuating the turbos. Please read all the notes on the drawings, since they contain valuable instructions about how to mount the turbo, how much air and oil pressure to provide, and other helpful details.

Q. What oil flow rate and pressure must be provided to the turbo?

A. The drawings provided in the care packet include notes about the amount of oil pressure and flow rate necessary for operating the turbos. In the design process of placing the turbo on your engine, you should place the turbo so that it is above your oil sump. For more information, read the notes on the drawings. They contain valuable instructions about how to mount the turbo, how much air and oil pressure to provide, and other helpful details.

Q. What water flow rates are acceptable for turbo operation?

A. Water-cooling of turbocharger bearing housings has been widely used to enhance bearing durability. It is designed to remove heat from the center housing after the engine is shut down. This is accomplished because a thermal siphon is set up in the center housing. As heat from the turbine housing and exhaust manifold soaks into the center housing, the water is vaporized and rises, drawing in cooler water. This continues until there is insufficient heat to cause the process to continue.

Installation

In order for the water-cooling to function properly, the center housing needs to be installed below the water level in the engine. The water inlet to the turbocharger needs to come from a lower point in the cooling system up to the center housing. The water outlet needs to go from the turbocharger up to a higher point in the system and cannot have any high spots or "traps" in the line. 

The center housing has four water fitting locations. Two of these should be selected such that they are on opposite sides of the housing and the water inlet is lower than the water outlet. The other two locations should be sealed off. These items help ensure that the water-cooling will function properly and the necessary thermal siphoning will take place. Please note the inlet and outlet connections for the water hoses on the drawings provided. If the turbocharger were installed without the water lines being connected, the unit will operate at temperatures similar to, or slightly higher than, the current non-water-cooled unit. However, the water-cooled center housings could be run on engine tests without the water lines connected with no adverse effects, provided the engine is cooled down adequately prior to shut down.

Flow Requirements

There are no set flow requirements for the cooling water, since the majority of cooling in the center housing is done by the lubricating oil while the engine is operating. The most important water-cooling takes place after engine shutdown, at which time the flow of water is a function of the thermal siphon and the flow rate is low. Therefore, the water lines to and from the turbocharger can be sized conveniently. The flow restriction through the center housing is negligible and so would not be of concern for the cooling system capacity.

Sealing

The water and oil passages are separate cast passages, so there are no seals to worry about. The passages are pressure checked on the assembly line to ensure casting integrity.

Q. What do I do if I break the provided turbo and need a replacement?

A. Honeywell will provide one replacement turbo per year and we request that you send the failed component back to us for analysis purposes. Upon receiving the broken turbo, we will promptly mail your replacement.