Hello,
I am new to the site but have already gained so much useful information from here. It's great!
I have been working on a 1993 Legacy turbo wagon as a project for the last few weeks. It is a high mileage car but runs great.
My mods so far include
Snorkus Mod
K&N panel filter
Electronic boost gauge
'06 wrx TMIC
Ebay BOV
stainless up pipe
3" turbo back free flow stainless exhaust
18x7.5 wheels
Yesterday I installed an MXS manual boost controller with plans of boosting to 12psi
I did a few high power runs while incrementally increasing the boost each time. When I got around 10-12psi my turbo (or so it seems to be) started to shudder and lose power. I reduced the boost to 7psi and the problem was still there. I removed the MBC and reconnected my boost solenoid. Now the problem exists at 5+ psi. The engine makes lots of power and runs really strong up to 5psi and then it shudders and doesn't make much power. There is also the occasional single "tick" or knock during acceleration which can be felt in the gas pedal.
I haven't ever heard of this problem before and am hoping that some of you more experienced guys would have some ideas. Anything would help.
Thanks!
Last edited by JRHolt on Mon Dec 20, 2010 6:33 am, edited 3 times in total.
Yes I did go to about 13psi, I have heard lots about fuel cut defenders and may install one. I didn't know if I would really need one for my application.
I thought the ecu could be in limp mode so I disconnected the battery for a few minutes to reset it. The problem still exists. Is it possible that I am experiencing turbo compressor stall/surge? What could be causing it?
JRHolt wrote:Yes I did go to about 13psi, I have heard lots about fuel cut defenders and may install one. I didn't know if I would really need one for my application.
I thought the ecu could be in limp mode so I disconnected the battery for a few minutes to reset it. The problem still exists. Is it possible that I am experiencing turbo compressor stall/surge? What could be causing it?
Thanks!
Pulling the battery terminals wont reset the ecu, if you want to reset the ecu follow Josh's directions on this site.
Also if you wanna run more than 12lbs you're gonna want an fcd. They're pretty easy to make. I have made several and sold them here. Just don't have time to do it anymore.
Materials at radioshack are like 8-10 bucks. But it's well worth it. Also whos to say you're not going to go higher than 12-13 in the future? Might as well just go ahead and install one.
91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
I haven't had a CEL which is strange. I will follow the ecu reset instructions today and hopefully that will help. The FCD sounds like a great idea. Like you said cj91legss, I may want to go higher than 12-13 in the future. Do you have a wiring diagram to make an FCD or a link to the appropriate thread?
Thanks again guys!
It's good to get input from people who know and love these cars.
I took the entire intake plumbing apart to look for any problems cracks or leaks, cleaned my MAF with alcohol. Checked all electrical connections and put a fresh set of NGK plugs in (just because it was easy to do with everything apart).
I didn't find any issues but at least I know everything is good.
I checked the ecu for code and there were some old logs but no current faults. So I ran it through the whole process and finished by clearing all the old faults.
Once that was all done I went for a little cruise to see if anything changed. The motor runs a lot smoother with the new plugs (the old ones were very eroded). At the end of the drive I got my foot into the pedal and there was no shudder noises or hesitations at all! It is running really strong... I am VERY happy.
Thanks so much for posting and lending me a hand! It was much appreciated!
I will be putting a fuel cut defender in before I bump the boost up again, just to avoid this problem.
Any additional info on the FCD would be great.
I think there was a leak between my turbo outlet and my intercooler y-pipe. The silicone coupler had slipped a bit. I have the stock '06 wrx y-pipe and it seems to be quite restrictive and a bit flimsy. I will order a cast aluminum/silicone coupler y-pipe to replace it.
The old plug weren't terrible but they had worn quite a large gap. I wanted to put some NGK iridium plugs in anyway. I have them in my forester and they are really smooth. I plan to put in a set of MSD coils soon and some better wires.
Thanks for all the help!
Here is a photo of my old/new plugs for comparison
JRHolt wrote:
I will be putting a fuel cut defender in before I bump the boost up again, just to avoid this problem.
Any additional info on the FCD would be great.
Maybe we'll do a Vancouver meet since you are somewhat close to me ( Maple Ridge ) Im going through the same mods right now. I don't have mine on the road just yet, gonna switch the interior, do some body work and get it painted first. Hopefully soon
Where did you scoop the 3" downpipe ? I think I should definitely get one of those if im running around 13 PSI as well.
Build Thread :HERE 92 SS 5MT. Project Daily 84 Jetta Coupe. Real Project 99 A4 Avant. Wife's Daily
Hey CFK
Glad to hear you have a similar project so close. I would love to see some pics of your legacy.
I will have to bring mine over to the mainland some time.
I bought the 3" exhaust on ebay. It is designed for a 2002-2005 WRX but we have the same turbo flange on the down pipe and very similar geometry. I had access to a hoist, welder, air tools, etc because I am an aircraft mechanic. However there were minimal mods required to install the system. The kit cost me $350 CAD shipped to my door. Crazy cheap and the system is actually really well built. I believe it is copied off a Borla kit. I remounted a few hangers and added aprox 6" of pipe to get my tailpipe just tucked under my bumper.
I documented the install. I should post it over the holidays. The difference in flow is HUGE! The engine has way better throttle response and the turbo spools up a lot faster. Oh and the kit also comes with a 2.5" stainless up pipe with bolts right in.
The exhaust note is awesome! It really brings out the boxer rumble but is still quite enough for a daily driver. I will do some videos so you guys can hear what it sounds like and will post the links with my install thread.
Here is a link to a Youtube video for an exhaust sound clip. You may need to turn your speakers up, the sound is quiet on the video. It is available in 720p as well. http://www.youtube.com/watch?v=lGA4HnAq_1o
The exhaust sounds awesome! It has a really deep "boxer" rumble. I noticed a significant increase in power with the new exhaust. Also my turbo spools up quicker with the free flowing system.
