Category: Turbo Services

IHI is the main supplier of OEM turbocharger to Subaru auto company. Although there are abundance of different turbo models across Subaru, they are mostly same turbochargers with slight variations. Today we will look at similarities and difference of the IHI RHF5H VF40 and IHI RHF5H VF46 turbochargers.

IHI VF40 is a turbocharger most commonly found in a Subaru Legacy GT, Forester 2.5XT, and Outback for the 2005-2007 model years.

IHI VF46 is a direct replacement for the VF40 on the 2008-2009 model year vehicles.

Similarities:

• All internal components are the same. Both turbocharger use the same RHF5H rebuild kit: (journal bearings, clips, oil seals, retainers, fasteners, and thrust components)
• Turbine housings are the same
• Bearing housings are the same

• Compressor housings are different– Subaru claims to use a “new” 5 arc design which greatly improves flow and turbo response. Upon measurement of both housing the A/R ratio and internal volume seems to be very similar, thus this claim by Subaru seems to be more of an advertising gimmick than an actual engineering improvement.
• Compressor wheels are different– inducer and exducer diameters are the same, total blade height and count is the same as well. Difference is in the height of the exducer blade tips. VF46 blades are slightly shorter, about 2mm. This prevent purchase of a VF40 CHRA and mating it with a VF46 compressor housing.
• Wastegate actuator mounting is different– VF40 uses 3 of the 6 retaining bolts to clamp the actuator, while the VF46 uses only 2 of the 5 bolts to perform the same task. There is no advantage or disadvantage to either design. just noting a change.
• Compressor seal plate is different– VF40 utilizes a smaller compressor seal plate than the VF46. VF40=119.36mm, VF46=130.07mm

Below you will find pictures of components compared:

This is another typical turbo project at shop. Customer sent in a TD04HL-16T turbocharger off a Volvo 850R. The turbo was in fairly good shape. Customer was in need for a standard rebuild service and upgrade of the compressor wheel from the 16T to 19T.

This type of rebuild and upgrade service costs $500. This includes cost of parts and labor. Please call or email with questions and inquiries.

Project goals:

• Rebuild turbocharger
• Upgrade to 19T compressor wheel

• Disassembly, cleaning, and inspection of all components
• Replacement of all consumables (journal bearings, oil rings, gaskets, retainers, fasteners, thrust bearing components)
• Media blasting of the bearing housing, turbine rotor blades, turbine housing, and compressor housing
• Micropolishing turbine shaft, check runout, and inspect for microfractures at the blades
• Machine bearing housing to accept larger exducer of the compressor wheel
• Machine compressor housing to accept larger inducer of the compressor wheel
• Rebalance rotating assembly
• Inspect blow-off valve and wastegate for proper operation.

Below are the pictures of the work. Click the picture for description.

This is a Mitsubishi Heavy Industries(MHI) TD06-17C turbocharger off a GMC Typhoon. This turbo was sent in by a customer for our “Basic Rebuild Service”. This turbo just started showing signs of bearing wear and oil consumption. Turbocharger completely disassembled, all components cleaned, and inspected. Bearings, housings, rotors, and turbine shaft measured with precision micrometers and bore gauges. All clearances verified and turbo rotating assembly rebalanced. Turbine housing media blasted by hand and compressor housing polished. Turbocharger reassembled using all new component and Clevite assembly lubricant. This prevents dry starts and premature turbo failure.

Application:

• 1992-1993 GMC Typhoon
• 1991 GMC Syclone
• 1992 GMC Sonoma GT

Story:

This is another custom project we did for a local customer. We modified an Eaton MP90 supercharger designed to fit a Toyota Tundra and machined it to fit a Lexus LS430 3UZ-FE V8 engine. The supercharger snout was too long for proper alignment of the belt drive system. The original TRD pulley was 2.3 inch diameter and too small for the boost pressure desired by customer. Customer wanted a boost threshold of 6psi. Using factory LS430 crankshaft pulley dimensions it was calculated that a 2.9 inch supercharger pulley will provide 5.9psi boost pressure. We chose to install a quick change supercharger pulley. This eliminated the need for custom pulley puller and allows for fast changes in boost pressure with a simple pulley replacement.

Supercharger was disassembled and all components inspected for wear and evaluated for replacement. Supercharger snout was welded to fill in an indent in the casting. This casting indent/dimple is not present on most Eaton M90 or MP90 superchargers. Great care was taken to ensure proper welding penetration as well as heat dissipation to ensure minimal component warping. Coaxial alignment of the bearing seating area is critical for supercharger performance. All component machining operations were performed using a lathe. Special fixture was made to ensure snout alignment during machining. Input shaft was shortened in the lathe ensuring all critical bearing and pulley seating areas remained accurate size and coaxial.

Goals:

1. Shorten supercharger snout
2. Determine proper pulley size requirement for 6psi boost  pressure threshold

1. Supercharger disassembly, component cleaning, and inspection. Bearings, seals, input shaft, and drive coupler inspected for wear and component replacement determined
2. Supercharger snout and input shaft precisely measured and blueprints compiled
3. Supercharger snout welded to remove casting indent
4. Machining fixture made to mount snout
5. Supercharger shout shortened as per instruction
6. Supercharger input shaft shorted
7. Dimensions verified after machining
8. Snout reassembled
9. New, low drag, supercharger seal installed
10. Quick change pulley hub pressed onto the input shaft
11. Supercharger reassembled and filled with fluid

Compilation of pictures before, during, and after machining modifications:

We have been extremely busy with turbo rebuilds and finally have pictures of a turbo rebuild we did for a customer in Anchorage, Alaska. This is an IHI VF40 turbocharger that came off a 2005 Subaru Forester. The turbo was in very bad shape when we received it for the overhaul. Customer complained of major oil consumption and smoking from the exhaust pipe. Inspection revealed a broken turbine rotor shaft and major damage to all components. . Complete rebuild was chosen as a solution. After final cost analysis we decided a whole new cartridge, CHRA, was the most cost effective solution for the customer. We replaced the CHRA to make this turbo 100% new. We disassembled the turbo, cleaned compressor housing and media blasted the turbine housing.

APPLICATION:

2005-2007 Subaru Legacy GT
2005-2007 Subaru Outback
2005-2007 Subaru Baja
2003-2008 Subaru Forester XT… EJ25 engine

Pictures of the finished product:

Pavel’s Racing Engines is proud to offer turbine housing porting and blending services for your turbochargers. This is a purposeful modification and not just another thing to add to your “modifications list”. Main purpose of turbine housing porting is to reshape the inlet and remove airflow restriction to the internal wastegate. Restrictive wastegate castings can lead to boost creep and boost spike conditions at different engine operating conditions. We blend and reshape the turbine housing to increase flow to the wastegate valve and improve boost pressure control. Porting of the turbine housing, as typically done by tuner shops, can actually be detrimental to performance and durability of the turbocharger. OEM manufacturers spend millions of dollars on research and development of the optimal housing size and shape. Porting and removing of material will increase housing inner dimensions and can lead to premature cracking. We blend casting marks of the turbine housing and polish it. Only material removal we do benefits wastegate exhaust gas flow characteristics.

Pictures of a blended and modified wastegate opening on a Subaru Impreza WRX IHI VF39 turbo: