EFR 6255 Discontinued.. 6258 Here I Come!

I was initially at a dilemma on whether to go for the smaller snail in the BorgWarner EFR (Engineered For Racing) range or to settle for something slightly larger such as 6258 since Stage 2 of my engine mods entails significant cylinder head and camshaft profile mods. You know me la... Being an NA Bagus kaki since I started modding cars I like my forced induction engine to behave like a large capacity NA engine without having to rev to kingdom come for some decent power. To illustrate my dilemma the specs of the 6255 and 6258 (single scroll T25 flanged version. The twin scroll version uses a T4 inlet flange with a larger 0.92 A/R) is as follows:

• 6255 and 6258 A/R: 0.64
• 6255 and 6258 Compressor Wheel Exducer Diameter: 61.47mm
• 6255 and 6258 Compressor Wheel Inducer Diameter: 49.6mm
• 6255 Turbine Exducer Diameter: 55mm
• 6258 Turbine Exducer Diameter: 58mm

(Dunno what I'm talking about? Read more about turbo terminology and details in Garrett's excellent faq)

The only difference is a 3mm larger diameter exducer for the 6258's turbine. More details can be found in BorgWarner's turbo website TurboDriven.com. The website includes an excellent match bot program that will assist in turbo matching. The decision by BorgWarner to discontinue the 6255 once current stocks run out has really made the decision for me. Apparently the decision to discontinue was because in many customer cars the 6258 has proven to spool as early and as well as the 6255 yet has more top end! The 6258 is rated from 225 to 400hp while the 6255 is rated from 200 to 350hp.

 To summarize on why EFR:

• Gamma-Ti turbine wheel that has about half the mass of an inconel version found in majority turbos
• Dual Ceramic Ball Bearing Assembly with Metal Cage.
• Forged Milled Extended Tip Compressor Wheel ala Garrett GTX
• Stainless Steel Turbine Housing. Bye bye rust!
• Water Cooled Bearing Housing. Bye bye ricer spec turbo timers!
• Large Internal Wastegate. The EFR can be configured for external wastegate operation if you so wish.
• Compressor Recirculation Valve aka BOV. No need to purchase a separate BOV.
• Boost Controller Solenoid Valve allowing ECUs to control your boost strategy if your ECU has this feature.

Graphical view of the EFR's features

More details can also be found in my earlier post. Picture of the 6258 provided by BorgWarner

6258's Compressor Map

Technical Drawings provided by Borg Warner



 The order is now out and hopefully the snail will arrive by end January. Patience is virtue.

Happy New Year 2011 Everyone!!!