My car has been having an erratic idle for about 4 months. It started when my maf went bad and I had a couple of instances of hitting 20+ lbs of boost and an afr of 17:1. After a day at the track running slower than I expected to, I decided to do a compression check. 1:180, 3:182, 2:90, 4:180. Damn. I had a sinking feeling that my compression was bad now I know. The good news is I still managed to pull a 12.48 and on one run I trapped 114.92 with 3.5 pistons and a slipping clutch. The bad news is I have to pull my motor again. I severly doubt that this was from running the nitro. I am sure it didn't help but I have only been running that in the last month. This has been going on for 4. What would you do if you were in my shoes? Replace all four with better pistons or replace the one with another stock sti?
Did you get retuned after you swapped out MAFs? My tune was so screwy from tuning on a barely working MAF that I needed a completely new tune once I switched in a new MAF. Are the STI pistons comparable in strength to some of the more expensive built pistons? I'd probably keep OEM, aftermarket pistons are more likely to exhibit piston slap, burn oil, etc.
im with jason stick with oem. i hope you dont have block damage. funny story to show how strong the boxer is. i was at 1:80 3:40 2:120 4:20 . so running on less than one cyl i ran a 14.3 with only a boost controler to beat a 95 cobra. man was i dumb in those days. but even with that amout of damage it was still very stong! why was my car in such failure? inexperenced shops in fla working on my car did a boostguage and boost controler install and had it all kind of messed up.
I would stick with OEM Mike. I'd pull the block, maybe break it down and double check everything before it goes back in. If you go for new pistons, would it be advantageous to simply go for a full new block? Perhaps when its broken down, you can go about replacing bits and pieces of the internals with forged ones. However, in light of what we've seen recently from Crawford (and rumors from Axiss), I would be hesitant to try anything other than OEM. Perhaps you should go JDM with a fully forged STi 2.0L sti block
Yeah man, sorry to hear, car still moving good tho. Lemme know if ya need a hand. Thankfully I located a pair of r180 axles for 100. <sigh of relief>
I just found 4 brand new take out pistons for $50 from Axis. Not a bad deal. The damn rings are going to cost more (120.00) because they won't split a set. 30 for the headgasket, 48 for the head bolts another 25 for cam seals and intake gaskets and I am back in business. If only I could find a way to just get one set of rings I could do this all for under 200. That's less than the MAF sensor cost me. I'll probably have an install day at my house if anyone wants to come by and help out.
post up when you are doing this. i am definitely interested in helping and getting to know more about our engines!
If schedule permits, I'd love to help. I guess at least, if you damage another piston you'll have spare rings
Engine pulling is easy on the Subies. I can have one yanked in 45 minutes. Now putting one back in is a different story.
I would like to help out with this also. PM me if you need a hand. I would definitely like to learn more about this... Mark
I need to get my hands on an engine again. I don't plan on modding my sti too hard until the warenty runs out. I'm used to being under the hood of my GSR every weekend . An install day would be awesome, plus i'd love to learn more with hands on experience about this new beast under my hood!