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1998 2.5rs build up

1.8K views 14 replies 7 participants last post by  Brilliant25  
#1 ·
Hey guys this is my first post to this forum and I'm also new to the scooby world but plunged right in and purchased a 98 2.5RS. My last car was a s13 with a rb25det but sold it as I was tired of nissan, and am wanting to try something new. So after searching and reading and reading some more I have a few questions... I believe the way I want to go is a USDM sti short block, and use my stock dohc heads. With a good head gasket and studs will the stock heads take boost well? If not what needs to be changed? My next question is what to do about fuel management? How well will the stock ecu react to positive manifold pressure? Can I get away with some larger injectors and a SAFC2? Thanks to all for the time and hopefully I will have some pics up by the end of the week of the car.
 
#3 ·
Actually the hard part about the 98s were the fact that they were MAF engines... The DOHC heads were alright but not for high boost... I would go with a SOHC head setup only because 1 its one of the best flowing heads and 2 it runs a MAP and its easier to tune... The STi shortblock is the way to go so other than that it should be a nice strong engine...
 
#4 ·
Well I'm trying to avoid a lengthy rewiring stage as I hate to chop into pristine factory wiring. Switching to the sohc head would involve switching harnesses correct? If I have to switch harnesses I would rather just move to a jdm STI setup.
 
#7 ·
Also I have never had any problems with my MAF. I believe 99 was the year that had the weak MAF. Also the 98s ecu doesnt learn as well as newer cars so you can get away with a SAFC without it relearning all the time, I would say that 98s are one of the better years to try and turbo.
 
#11 ·
While the 98 motors aren't techically as good as later EJ25s in most repsects, they're by far the easiest to turbocharge without going to standalone management or lengthy wiring changes. With that shortblock and completely stock heads, you can make 250-300 whp all day long with careful tuning, using just an RRFPR, AFC, and bigger injectors. A timing controller would also be a great thing to have, but they are hard to find as they are discontinued.
 
#12 ·
ok so I just happened to run across an ej20 short block out of a wrx for 100 bucks, one of the cylinder walls has some light scratching from a cracked piston thats in it. Everything else is good. Would it be worth my time to fix the ej20 short block and use it or stay with locating a sti or legacy short block
 
#14 ·
ok after a visit to a local machine shop I found out it needs .025 over... So 'm going to buy it. Its not a sti short block but I feel like it can get to my horsepower goals. I was thinking about JE pistons... anyone like/dislike these?? One of my friends has my digital camera causing a delay on pics, but as soon as possible I will take some of the car and the shortblock and post.

Brandon