matt167 Posted March 24, 2016 Share Posted March 24, 2016 (edited) I've decided to start collecting parts for my NA-T conversion for my 2001 Forester.. Long story short, calcs in my head is that it will cost less than $1k extra if that in fueling and timing components to go from 5 PSI to about 12 PSI without any issues and I won't have to re buy anything to get more like I would with the simple setup.. So it will make closer to the 300hp mark... Which might break the 220+k MI N/A 5spd. It just might JDM WRX transmissions with the rear differential included, go for about $900 shipped and I can get one here any day of the week for that, and are 4.44:1 ratio. Should give me a little bit of a punch over stock 4.11:1, but I deffinetly do not want to go to a USDM trans which would cost about the same anyway, and the 3.54 ratio would be 'ho hum' to me. When going to the Turbo trans, is there any other gotcha's than the clutch setup that is different? will my CV's fit? how about drive shaft?. I know the rear diff should fit as long as it's an R160.. I don't know how to tell the R160/R180 apart since I don't know of any USDM models that are R180 except the STI? With a connection to someone in Aus who has stuff shipped to and from the US quite a bit, I could probably get a dual range trans and all the bits like center console ect... for just a little more than that. probably couple grand at most. But not sure that an N/A trans designed to take 2.0L HP will live long. Edited March 24, 2016 by matt167 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 24, 2016 Share Posted March 24, 2016 (edited) you could put dogtooth gears in at 1 and 2 I think there are sometimes labels on TOP (convenient huh?) of the diffs that help differentiate them. might be some good info for you over at NASIOC too. Edited March 24, 2016 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
matt167 Posted March 24, 2016 Author Share Posted March 24, 2016 dogtooth gears? I havn't heard of them. Not opposed to doing it tho, if it will work.. Probably grab a lower mile trans from a wrecker just in case... I wonder tho, if that .33:1 is a noticible improvement.. A bit of reading shows that 4.44:1 WRX transmission could be many transmissions, depending on RA/ non R/A, STI V6,V7. that they all had different gear sets and that some are shorter than others.. I'm only interested in the cheaper ones, that list as replacement for '02-'07 USDM WRX Also, does my Forester have hill holder/ Hill assist? I only ask because I was told it may have it.. It's a 2001 S model. Quote Link to comment Share on other sites More sharing options...
wtdash Posted March 24, 2016 Share Posted March 24, 2016 (edited) Hi, I can't help much other than to warn you that if you drive this on the highway, the 4.44 may get old - if it's going to be a DD. I've read- somewhere>Legacy Central?< that the RPM's were near 4K @ 60 MPH - in 5th. Seems too high, but might want to do more research. Also, be aware that Subaru changed the bolt pattern of the rear pinion flange of the rear diff in the mid-90's, which hopefully you're getting one newer, but I don't know if that's the only time it changed. I'd guess (!) the drive shaft will work, as Subaru's 5-speeds and matching rear diffs are the same size - end-to-end. And most of the pre-2006 (?) Subaru turbos had a PULL clutch vs. the PUSH used on NA versions....so you'll need a matching FW, etc. 300HP from 12 psi...seems ambitious....what's your setup? TD Edited March 24, 2016 by wtdash Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 24, 2016 Share Posted March 24, 2016 some discussion of modified gearsets; http://ppgearbox.com.au/page.asp?parentid=2&parent2id=14&parent3id=26 Quote Link to comment Share on other sites More sharing options...
matt167 Posted March 24, 2016 Author Share Posted March 24, 2016 I pull 3k RPM's at like 65mph now with the 4.11's, so at a .33:1 gearing, it shouldn't be more than a 200 RPM difference, give or take. Seems like 4k at 60 would be a slipping clutch.. I'll have to find charts for the gearing tho, and I'll calculate it to see. I don't drive highways much at all. Main road cruising for me at 55-60 MPH. I knew about the clutch differences and the clutch/ flywheel was on the list anyway. I'll just have to add the correct slave cylinder and possibly new starter to the mix As for the HP, I said closer to 300hp It will be an EJ22E with rebuilt EJ251 heads. I'll probably hone and re ring the engine to make it fresh. probably split the case and do new bearings too. just make it fresh, but a low mile engine I can see an odo on I won't worry about.. Comp ratio should be 8.9:1 Probably a new or rebuilt TD04, possibly something bigger.. Stock 2006 WRX intercooler... Between 8-12 PSI at least. The engine should have wiggle room for more Fuel will be Walboro 255 LPH pump Microsquirt will control a second set of injectors, undetermined size just yet, but they will be in the ports above the stock injectors. Diyautotune sells the weld in injector bungs to make it work. Wideband setup going to Microsquirt to make tuning easier The secondary injectors will only come on when the engine reaches 0 VAC or a slight positive pressure.. MAP will be voltage clamped too, so the stock ECU won't know anything and no codes will trip Timing will be controlled by an MSD DIS-2 ( discontinued but still obtainable ), trigger the timing retard function with a pressure switch... I could run the ignition system off the Microsquirt also, but the stock ECU may not like it, and theres no reason not to use stock timing control with a retard under boost. Hood will be modified to use a WRX or possibly Outback Sport/ RS scoop. whatever I find that looks good. I have a MIG welder and those parts won't be hard to find, even if I had to cut a hood section All in all, it should idle like stock, drive like stock out of boost, but once boost kicks in.. run like no other Forester in this area.. I've always read 7-10hp per PSI of boost, but the reports of just running 6 PSI and RRFPR's give a 50hp boost on the dyno.. Realistically, the EJ22E/251 hybrid will probably start around 130hp and not the stock 165hp. So it may end up at only being 200hp or so, going by the 7hp per PSI... However, with the 8.9:1 compression, it's not as limited so I could likely make a little more boosting to 15 PSI or so Good to know about the dog gears. Kinda makes sense to do it that way.. I've never opened a Subaru manual trans but have others, and it's not a big deal to me Quote Link to comment Share on other sites More sharing options...
matt167 Posted March 25, 2016 Author Share Posted March 25, 2016 Other way to do this would be the 4.44 JDM WRX trans but then use the rear diff from an A/T USDM Forester which is 4.44, It would be a little cheaper and guarenteed bolt in.. But some JDM WRX trans are VSLD front and Suretrac rear Quote Link to comment Share on other sites More sharing options...
ccrinc Posted March 25, 2016 Share Posted March 25, 2016 As long as you understand that those transmissions are considered to be made out of glass... They never did handle the torque from the EJ20 engines very well to begin with. I've heard of people who are on their 3rd or 4th transmission before they understand that high revs and "sport" shifting are gonna be the death of it. Emily Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 25, 2016 Share Posted March 25, 2016 starting in 06, the 5 spds in the WRX had a little shorter shifter, and a better 1st gear synchro - maybe other improvements? that might be a good trans to put straight-cut gears in. consider lighter flywheel and lightweight crank pulley too - 4lbs of rotating mass = ~1hp. anyway - sounds like a fun project! way above my skills Quote Link to comment Share on other sites More sharing options...
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