Hello all, thank you for taking the time to read this post. I was wondering if anyone has experienced anything similar or can shed some light on this issue...
Background context:
The car is a 2006 Subaru Legacy GT which started out life as a 5EAT auto, subsequently swapped with a 6MT manual from a UK spec 3.0 legacy...
Engine (in short) is a forged EJ207 with a Spec C VF36 Hybrid turbo with forge actuator (0.9bar spring), 850cc injectors, parallel rails, FPR, 340lph pump etc... In theory, the engine which was freshly built by a very reputable engineer should be good for about 350-380bhp on the current setup.
When the car had the 6MT swap completed, it was mapped on the road, and (despite no dyno graph), using MAF g/s as a rough guide on how much power it was making, it was doing (comfortably) 350+ bhp at 1.6bar boost at 70% WGDC.
However... it wasn't all good news... there was a persistent misfire at 4500rpm which was investigated very thoroughly by the garage who did the 6MT swap, to no avail.
Fast forward 6 months, the car ended up at another garage who specialise in supplying/fitting/tuning standalone ECUs. The decision was made to just jump in at the deep end and do this in order to completely control all engine function with a separate ECU and remove any of the remaining 5EAT auto trickery hidden in the wiring (which we felt may be the root cause of the misfire issue).
Ecumasters EMU Pro 8 fitted and mapped - absolutely no misfire. Car runs well, smooth, now MAF-less but very much drivable like OEM day-to-day.
EXCEPT... it's not all good news. The car only made 300bhp and 295ft lbs at 1.35 bar!
When I spoke with the tuners, they said that the turbo was tailing off to 1.0 bar at redline and was evidently at the limit of its potential, therefore it stayed at 1.35 bar and the map was considered done...
When the car was mapped on the standalone ECU (by the garage who fitted it), they had no base-map for a 2006 JDM Legacy to build on, so it had to be written from scratch. This included the AVCS settings for the legacy quad (dual) AVCS. They told me that due to the engine being high compression (it is pretty high, higher than a standard twinscroll which is already on the high-side), they had very limited ignition timing to play with when trying to make extra power. They also appear to run AVCS straight through the rev range whereas the first tuner explained that it needs to turn off at some point the higher up the rev range you go.
Having taken this info back to the tuner who road-mapped the car initially, he was confident that there was something in the new map limiting the car being exploited to it's full potential. Both the first and second garage have spent considerable time with the car and any genuine mechanical faults would have been picked up by now, particularly when fitting and mapping the standalone ECU. He explained that that due to the fact the AVCS works slightly differently when tuning Subaru engines vs say a conventional ICE car, this could well be the problem.
Now I'm at a bit of a crossroads. Does anyone have any similar experiences or knowledge which they'd be kind enough to impart? Both garages are very experienced in tuning various cars, the first tuner moreso in the Subaru world. What I don't want to do, is have to have about 4 maps done before it finally makes the power it should have in the first place! Do we think it's worth having the first garage look at it, again?! I've spent so much money I didn't intend on spending on this car, the fun levels are dropping at a rapid rate of knots haha...
I'm also conscious that (despite me meaning absolutely nothing negative by it at all), I don't want to give the impression to either garage that I don't trust their work and am taking my business elsewhere (they're both very experienced and I've no real issue with either of them). In essence, If the second garage fitted and mapped the ECU at great effort (took an age to optimise all the base-map, weekend overtime etc), I don't want to cut my nose to spite my face and look like I'm untrusting of their work, taking it to the first tuner (who also happens to work closely with the second garage on occasion!)...
It's a bit of a tricky one. I've spent so long fighting with the car that I'm so relieved it works and drives eventually, but at the same time It feels even more frustrating that I've been disappointed by the final outcome, as it is way less than it should have made in theory!
Sorry for the long-winded post, really just looking for some second opinions and a bit of advice really. Bonus points if you're clued up on the technical tuning side of things and have any ideas why the car made so little power!
Thank you,
Legacy1997