• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Newb: boost creep question

L

littlesnides

New member
Joined
Oct 7, 2013
Location
New Martinsville, WV
I have a 93 Volvo 940 Turbo with an Auto w/ 210,xxx. I just recently have been pecking away at completing a stage 0. The only thing I have yet to do is the Fuel Filter. Anyways, my exhaust started leaking and rattling, so instead of replacing with stock parts, I "upgraded" to a catless 3" and straight through Magnaflow muffler. A bit buzzier than I prefer, but I planned to get a 3" inch Cat when I got a new DP. I guess I hadn't researched enough before doing so, bc now I have boost creep.

I know that I probably don't have the supporting mods to be boosting over 15 psi, so when it approaches 15 I let off. After adjusting the wastegate arm 1.5 turns out, it didn't have much effect. Can I safely turn it out another .5? Should I test it with the actuator disconnected? I read a few threads that guys were getting fuel cut at a certain psi? Many guys were saying that they'd creep up so high and it would stop. I am interested in seeing where mine will stop, but wondering if that is too risky? Supposedly a rebuilt turbo, but I'm wondering if the PO messed with the actuator during the process.

Thanks for any help or suggestions.... apologies if I am beating a dead horse, I did some searching
 
If you're getting boost creep, I would recommend porting the wastegate opening. That's a huge restriction. On my 13c I enlarged it a lot, and have near zero boost creep (~1psi) with a straight exhaust.
You could get a spare exhaust housing and modify it, then swap the exhaust housing over when you're all done grinding away on it.
As far as boost goes, you should be fine at 15psi with stock everything, though a wideband is a good thing to have. On my car I hit 10.5 afr at 15psi/full load (lh2.4), stock MAF.
 
Same car, same scenario, finally figured it out last week. My 13c goes to 12-13psi, I installed an MBC so it gets there quicker. As long as it doesn't go past 15psi AFR should be fine, I haven't tested any higher than that with my wideband and stock setup.
 
Initially I had factory exhaust and MBC at 11 psi... Was getting 7.5psi before the MBC and 3" catless back (factory downpipe). So I thought my spring in my MBC was buggered, so I replaced it, but no change in creep. I took the MBC back off to see if that would eliminate my issues, but it didn't. Yeah I get to 15psi and let off. I am sure it will go higher. I don't let it.

DarkKratoz- if you locate one for ~$100 pm me so I can snag it! I've got brown tops on the way.
 
may have a bad wastegate actuator. under normal circumstances, even running open downpipe with nothing but the oem preload will not result in substantial boost increases (maybe 1-3 but certainly not 7-10).

I'd make sure the hose going to the gate isn't leaking, and consider unhooking the arm and letting it flap open & see what happens
 
I put a new hose on with same results... I did notice that I had some oil gunk buildup in my MBC nipple though. I tried cleaning both connections with them on the car, and they didn't seem to be gunked up. I'll try unhooking and see if I still get boost.

Thanks Dark! Good site.
 
Sorry I haven't given an update, I have finally got a chance to lay under my car and take it for a spin without the actuator arm hooked up.

It was very slow to build boost, but once it got around 4500 boost once again started shooting above 15 and i let off. I guess I was blessed with a small wastegate hole.
 
Seems as though this car does not have a 13c on it, but a knockoff reproduction that didnt come with any "badging" or an adjustable wastegate arm (PO advertised a "rebuilt turbo").... 15g for sure now
 
I've got a 15G that's got pretty much no shaft play and seems to be in pretty good shape. Decided against the turbo path for my car so it's just laying around.
 
You must log in or register to reply here.
Back
Top