LM boost control v. boost spike problem

[tryingbe]

Swirl 782 head with 2.5L running LM V12.5 cal. Using 87 TII vacuum map setup to the, vacuum line from source, to the solenoid, to the actuator is less than 1 ft. Not using any orifice

Boost is set at 13psi via boostvspeed I'm experiencing boost spike to 17psi at initial spool up, rpm is less than 3000rpm when it happens. Boost would settle down quickly and it would go to the predefine setting all the way to redline.



Only setting I've change so far is lower than MinimumRpmToTrackBoostCreep to 1220rpm, doesn't seems to help.


Any idea which table I need to change to try the reduce my boost spike?

[Aries_Turbo]

BoostWotDutyCycle and BoostWotDutyCycleAdj

since you dont have the exact same setup as stock (ie no restrictor) BoostWotDutyCycle is going to have to be retuned to the new setup.

whatever your BoostAllowed tables are set to, you have to adjust the values in BoostWotDutyCycle so that you dont get spikes or lagginess.

i think there are adaptive values for the boost control too so you can see how far off you are. Unfortunately, ive never datalogged them so i dont know exactly what to do to determine what they are. Rob would know though.

Brian

[tryingbe]

Are FullThrottleWastegateDuryCycle C8is100Percent FromMap and FullThrottleWastegateDutyCycleAdjustment FromRpm the same values as the one you're talking about?

[ShelGame]

Yes, those are the 2 main DC tables. It's a tough call without the restrictor, but my guess is that you'll want to increase the slope of the line (ie move it toward horizantal, not vertical) going up to your max boost. Also, make sure that the last point goes out at least to your max boost setting. I would probably go a couple psi higher. Since your close to stock boost and still getting spikes, I would probably increase the DC near your max boost. That should slow it down.

[Aries_Turbo]

rob, are there adaptives in the LM stuff for the boost control like i see on your MPScan SMEC setup file?

i loaded a list file and the premade LM MPScan setup file and i didnt see anything like the SMEC has for boost control adaptives.

Brian

[ShelGame]

rob, are there adaptives in the LM stuff for the boost control like i see on your MPScan SMEC setup file?

i loaded a list file and the premade LM MPScan setup file and i didnt see anything like the SMEC has for boost control adaptives.

Brian

I'm pretty sure there are, but I never really looked to be honest. The pre-made MP Scan files don't have everything in them. Just the basics...

[Aries_Turbo]

yeah i knew the premade ones didnt include everything, but i figured the list file would.

Brian

[tryingbe]

Yes, those are the 2 main DC tables. It's a tough call without the restrictor, but my guess is that you'll want to increase the slope of the line (ie move it toward horizantal, not vertical) going up to your max boost. Also, make sure that the last point goes out at least to your max boost setting. I would probably go a couple psi higher. Since your close to stock boost and still getting spikes, I would probably increase the DC near your max boost. That should slow it down.

I thought without the restrictor will give me LESS spike? I can't imagine having the restrictor on now, it'll probably want to go to 25psi on the spike.

But I'm not having trouble with my max boost. I'm having trouble with boost control at my initial spool up. Currently I have it set as 12psi to 16psi depends on my speed. When I get on it on 2nd gear, turbo will spool to 20psi, then come down to 14psi to then go back up to 15psi at the end of 2nd gear. What do I need to do to so I will not have to boost spike at the initial spool up on the turbo?




I tried to adjust to this, no difference.


Any picture of how I should adjust the line? I'm not good trying to convert your words into graph. Thanks.

[Force Fed Mopar]

Here's what I have mine set at in my T-LM cal for my 2.2 Daytona w/ a heavily shimmed small can wga. I have my target boost set at 17 psi, it spikes to 19 on initial spoolup, then drops down to 17 as the engine revs back towards redline.

FYI the boost control did not work right at all until I made the last point drop to near 29 psi (3-bar)

[tryingbe]

Force Fed Mopar,

Would you make the SHOW HEX tables on the right side a little bigger so I can see your X and Y point numbers? Thanks.

[Force Fed Mopar]

Should be able to click the pic twice and make it larger? I'll see what I can do...

[Force Fed Mopar]

Try this, you should be able to read the names if you mouse over them but the first is the FullThrottleWastegateDutyCycleAdjustmentFromRPM, the second is the FullthrottleWastegateDutyCycle.

[tryingbe]

Your settings didn't help me. I'm gonna try something else and report back.

[Force Fed Mopar]

Are you running a Garrett or Mitsu?

[tryingbe]

Custom T04E/T3 Garrett.

[tryingbe]

Alright, this didn't do anything. Trying something else.

[tryingbe]

This seems to do the trick.

[Force Fed Mopar]

Hmm, odd...

[tryingbe]

Still spikes, but it spike to 14psi and kept at 12psi instead of spiking to 20psi.

[ShelGame]

Alright, this didn't do anything. Trying something else.

What does the table immediately above this one look like?

---------- Post added at 10:06 AM ---------- Previous post was at 10:05 AM ----------

This seems to do the trick.

Well, since your boost target below ~40mph is actually only about 8psi, I'd say you're still spiking if you hit 14 on spool up...