legacycentral bbs

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!

Did you go any higher than 12 lbs accidentally? If so you could have caused fuel cut which means your ecu can be in limp mode.

If you're going for 12 lbs, i'd seriously think about a fuel cut defender.

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!

Any CEL? Are you sure all your lines are hooked up properly, including your MAP sensor?

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.

http://legacycentral.org/library/literature/codes.htm

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.

Thanks for the ideas guys.

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.

Success!!!

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.

Thanks again!

A late welcome to the BBS.

I would suspect your problem was either a leak in the intak plumbing or spark plugs. These cars seem to be rather fussy about spark plugs.

How did the old plugs look when you removed them?

Hey thanks for the welcome.

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

It sounds like it may have been a combination of both, plugs and intake leak, which caused you to go too rich under boost.

Well now I know. Thanks again!

Merry Christmas

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.

Thanks again!

http://bbs.legacycentral.org/viewtopic.php?f=2&t=14620

This is the shematic i use for making the fuel cut defenders.

Excellent!

Thanks.

those plugs were ridiculously fubar, good that you got it back to prime.

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.

3" DP is definately a good buy.

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.

If you are interested in more info regarding the exhaust kit here is a link to the ebay page.
http://cgi.ebay.com/ebaymotors/3-4PCS-S ... 572wt_1165

Here is a photo of the exhaust system installed on my 93 wagon

Cheers!

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

thats sick!

i am looking into doing the same to my car.

Ive got a white 93 wagon ej22t as well!!

how does the ebay exhaust sound? do you notice alot more power?

-Clay

Hey Clay,

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.

Good luck with your wagon!