I’ve had a couple of EFR 8374’s on order since late last year, and understand the general frustration expressed by a few in this thread. I finally managed to get my hands on one a week before WTAC to run on my otherwise tarmac-rally spec IX. After reading through all the dire innuendo expressed in this thread, I have to say, we approached tuning the car with some serious reservations. In fact, if time had permitted, I am pretty sure we would have probably reverted to running either my HKS T04z or TS GTX3582 instead.
Tuning the car for a few hours the night before the event, it made an easy 424kw atw at 2.0 bar, despite the fact it was tied down with 6 straps and running soft R’s on the rollers. For reference, the same car, on the same rollers, with the same target boost made 417kw atw running the T04z. Although peak power was comparable, what really surprised me was the relative power down low. At 4500rpm the 8374 was making ~70kw atw more power than the T04z, despite the car now running a 0.2ltr less displacement with the new bottom end.
We took the car to WTAC and flogged it for three days, and the turbo didn’t miss a beat. Ignoring the numbers, trackside the real benefit from the EFR is throttle response. With the T04z, in some short corners I used to left foot brake and get on the gas early to try and get the turbo spooling and get drive off the apex. Now, with the EFR’s responsiveness, not only is the “left foot spool” redundant, there are a couple of corners where I am short shifting and driving out on the much more lineal torque.
We will get back on the rollers later next week and refine the cam timing and balance of tune and then see how it performs at 2.5 bar. My view for what it is worth; product introduction and packaging issues aside, I can’t see why you would run anything else based on what I have seen to date.
SK