wtdash Posted November 27, 2017 Share Posted November 27, 2017 (edited) Came across a CL ad for '98 OB that has a LOT Of upgrades - HERE and attached. I'm not here to Dis on the owner, but he states the stock CR of these engines is 8.1:1 not the claimed 9.7:1 (Edit*): The stock 2.5 DOHC from 97-99 is billed to be 9.5:1. This is very misleading, I have measured it many times and it is a consistent 8.1:1 ratio this is why these cars are so sluggish off the line Anyone confirm this is the case? Just based on my limited info, there's no way the stock engine makes 165HP/Torque if the CR is that low. And personally, I don't think they're that 'sluggish' compared to other cars of that era. But i'd agree the DOHC requires some RPM's to get to the power curve. *I edited to be what the Owner's Manual states. The '96 EJ25D was the 9.5:1. Thanks 1998 Subaru Outback, Expedition - CL.pdf Edited November 27, 2017 by wtdash Quote Link to comment Share on other sites More sharing options...
ocei77 Posted November 27, 2017 Share Posted November 27, 2017 The FSM's for the 96-98 EJ25D lists it as 9.5. O. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 27, 2017 Share Posted November 27, 2017 The pistons in the block in the pic are not 25D pistons. Might have low compression pistons installed and just doesn't know? Not enough detail for me to tell if that's a 25D or 251 block, so can't say for sure what setup he actually has. "Sluggish off the line" is a relative term. Anyone who can read a dyno chart can see that the 25D doesn't make peak power until the 5k rpm range. Torque is also a slow rise until higher RPMs, and that's all due to the cam setup. Twin cam engines are tuned to make better power at higher RPMs, the trade-off of that is less power available at low rpm. Quote Link to comment Share on other sites More sharing options...
wtdash Posted November 27, 2017 Author Share Posted November 27, 2017 Ok...i'm going to take the CL poster @ his word that he's referring to the '97-'99* STOCK EJ25D engines he worked on as noted in the CL ad. The pics in the ad are of the upgrades he's done - Not stock. Regardless, I'm still just curious if any of you engine gurus have come across this assertion he made about the STOCK EJ25D not being 9.7:1 CR. *The '96 is listed as 9.5:1 in the Owner's Manual, the '97-'99 are 9.7:1, but the '99 is the Phase 2 block w/different pistons to work w/the Phase 1 Heads - I think. Quote Link to comment Share on other sites More sharing options...
wtdash Posted November 27, 2017 Author Share Posted November 27, 2017 (edited) The FSM's for the 96-98 EJ25D lists it as 9.5. O. Yeah...I just looked that up, too.....but I don't believe that's correct as the '97-'98 were NOT the same as either the '96 nor the '99. '96 had the HLA valve train and weird (Ok...different) combustion chambers, and the '99 EJ25D was a Phase 2 block w/different pistons than used in the EJ253 versions (from what I've read). The '99 does have the same 9.7:1 CR per the Owner's Manual. Edited November 27, 2017 by wtdash Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 28, 2017 Share Posted November 28, 2017 No way are the 25D's in the 8's. They are around 9.5 GD Quote Link to comment Share on other sites More sharing options...
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