Uncontrollable Boost - M20 w/ 6262

[Evan_VRM]

Well the problem is solved. Got the flange welded on there and it holds 9psi all day now. I plan on recirculating the dump pipe tomorrow though...

Aside from that the boost control solenoid is all wired up and she’s getting a proper dyno tune on Wednesday!

[mikey.antonakakis]

Nice!

[Evan_VRM]

Yeahhh... not so nice results on the dyno. First pull is at 10psi, second one was at 17. Tuner thinks the comp turbo is garbage. I’m scratching my head trying to figure out what else it could be. No boost leaks as far as I can tell, timing is dead on, AFR’s are good, exhaust is free flowing. It runs smooth it just doesn’t make any power.

[Evan_VRM]

I wish I knew why these always upload sideways

[varg]

Mind posting your ignition timing table and ignition trigger settings?

[nomansland92]

Ya that's not right you should be closer to 350+ at 17psi. Have your down a leak down or compression test. I had a good compression test but failed a leak down one time, was a inlet valve leaking around the seat slightly. If you don't have a boost leak and your timing is reasonable and base timing is set correctly that air has to be going somewhere. Do you have a adjustable cam gear that's off, or cam/crank is off a tooth? Good to hear you got the boost control figured out though! Sent from my SM-G892A using Tapatalk

[Evan_VRM]

I did a compression test in March before really getting to work on this project, and since then have driven realistically less than 10 miles. I have not done a leakdown but the thing runs so dang good I am fairly certain it is healthy. I also have zero blow by. I know that doesn't replace the test, but my logic is that even if leakdown was at 30%+ adding boost would still add more power than we're seeing here.

Ignition settings are attached below. I also posted this on Bimmerforums and am being told my crank wheel setting (currently at 97*) may be off, which would be awesome. I watched the tuner verify it but looking back I am not confident at what he was looking at...

As for cam: non-adjustable stock gear. Definitely was correct before turbo'ing, although I suppose it is possible it jumped a tooth though I've never had that happen on an M20. Worth checking though.

[varg]

It’s way off, 84 is the correct number.

[ForcedFirebird]

Those numbers are all wrong. You need to use the diag function in TunerStudio to lock the timing and use a timing light. Should be around 84° offset and that's why your timing numbers look so low. Stock timing is in the upper 20's at 100kpa, -1° is already excessive.

[McGyver]

Dumb question: Would having the crank setting and timing completely off contribute to OP's boost control problem using the unmodified WG location?

[mikey.antonakakis]

Regarding timing checks: unless you *know* that your adjustable timing light works flawlessly (assuming you or your tuner are using one), set it to zero or use a non-adjustable light. I spent $100 for a decent one when I got my car back together, set Megasquirt to fixed 10deg advance and set the timing light to match, and the thing was jumping around like +/-5deg between 1000-2000rpm. Once I set the light to zero, set MS fixed timing to zero, I was finally able to dial it in, and my trigger offset ended up exactly at 84deg.

Maybe there are better adjustable lights out there, but I've yet to use one that does what it's supposed to reliably.

[Evan_VRM]

Well this is all certainly an interesting plot twist... I literally watched him "verify" the timing with a light but obviously there was some confusion as to what he was looking at. Not real confidence inspiring. I will make absolutely damn certain it is dialed in correctly with a light tonight then my tuner and I are going to have a serious discussion.

As for the boost control, AFAIK overly retarded timing will absolutely cause boost control issues. That being said I know creep is an issue with this manifold anyway so I'm not too upset about my configuration now, IF i can get it to make reasonable power.

[Evan_VRM]

Regarding timing checks: unless you *know* that your adjustable timing light works flawlessly (assuming you or your tuner are using one), set it to zero or use a non-adjustable light. I spent $100 for a decent one when I got my car back together, set Megasquirt to fixed 10deg advance and set the timing light to match, and the thing was jumping around like +/-5deg between 1000-2000rpm. Once I set the light to zero, set MS fixed timing to zero, I was finally able to dial it in, and my trigger offset ended up exactly at 84deg.

Maybe there are better adjustable lights out there, but I've yet to use one that does what it's supposed to reliably.

I have a non-adjustable timing light, but was going to borrow a programmable one. This may be a stupid question, but will the car run with timing fixed at 0*?

[ForcedFirebird]

Dumb question: Would having the crank setting and timing completely off contribute to OP's boost control problem using the unmodified WG location?

Sure. If you are dumping expanding gasses in the manifold while the WG is trying to control said pressure. Now you are creating a situation where intake manifold pressure has less effect since the exhaust pressure is so high. OP should put a boost gauge on his exhaust manifold between the tubro/engine and see what kind of ratio exhaust:intake. Most decent systems will be around 1.5:1, but a poorly setup system will do 2:1 (or improper ignition timing - or ant-lag etc can also cause this), 1:1 is ideal but not easily reached.

You can use a fixed light. Just have to mark the crank pulley. OR The reluctor is 60 teeth, so each tooth is 6°, each rise/fall is 3°. Set MS to 12° and see how may teeth away from TDC you are.

[mikey.antonakakis]

I have a non-adjustable timing light, but was going to borrow a programmable one. This may be a stupid question, but will the car run with timing fixed at 0*?

It should idle, mine did with 60lb injectors, a little rough but it was good enough to set the timing. I probably had to bump up the throttle stop (or idle valve setting if you're using one).