4 FOX SNAKES - Ross' 20vt 4kq

[Toph]

WOOHOO, nice work!

[chaloux]

no coolant leaks
no fuel leaks
no oil leaks
no boost leaks
no electrical bullshit (anymore)


2nd gear, 10psi. Party time. Temporary ugly boost gauge in the vent falls out. whoops
[youtube]http://www.youtube.com/watch?v=hx9NjMXLHv4[/youtube]

THANK YOU FOR THE HELP MARC

And some pix:

[chaloux]

So now it's time for boost tuning and fuel tuning. Marc's base map comes with boost essentially "off", correct? So I need to up the refdc vs rpm values, and change my target MAP values. Right now PID is also 0-0-0. Any good starting points for a 30r?

[85oceanic]

DUUUUDE That thing MOOOVES! Congrats! MORE VIDS ASAP!!!

[Hank]

Looks quick for the boost you are running. That thing is going to rip on 24-25psi pump tune. Dibs on a ride!

[loxxrider]

PID being 000 will give you wastegate pressure... I'd tell you some decent values, but I'm not with the right computer at the moment. If you are using closed loop (PID) then the ref DC dont really matter. If you are using open loop though, then those are what you change. Using PID, you change the boost target.

[Marc]

PID being 000 will give you wastegate pressure... I'd tell you some decent values, but I'm not with the right computer at the moment. If you are using closed loop (PID) then the ref DC dont really matter.

not true actually. in closed loop mode the refdc table is used as the "pre-fill" for the PID control.

what I do is start in open loop, figure out what refdc produces my desired boost, and then I back off by about 5 or so in the refdc table and tune my PID settings.

[loxxrider]

PID being 000 will give you wastegate pressure... I'd tell you some decent values, but I'm not with the right computer at the moment. If you are using closed loop (PID) then the ref DC dont really matter.

not true actually. in closed loop mode the refdc table is used as the "pre-fill" for the PID control.

what I do is start in open loop, figure out what refdc produces my desired boost, and then I back off by about 5 or so in the refdc table and tune my PID settings.

I should have said that having the PID at 0-0-0 *should* give wg pressure as long as your ref DC is set up right, otherwise you won't have any control to lower boost.

Good info there. I thought they might be linked somehow, but couldn't really figure out how. I always wondered!

[chaloux]

Fuel pump - on while cranking or off? Right now it's off and hard as fuck to start, as in it pretty much doesn't. But it seems to food when the pump is on. So Wtf

[chaloux]

I think it should be on. I'm going to tie it into my ignition switch today.

Also gave her a bit if a treat last night, new wipers and rain x

[EDIGREG]

I should have said that having the PID at 0-0-0 *should* give wg pressure as long as your ref DC is set up right, otherwise you won't have any control to lower boost.

PID 0-0-0 means closed loop is off. The only way to get spring pressure is if all refDC values are 0.

[EDIGREG]

Here is the process I follow:

-Tune open loop control to produce near but slightly below your boost target
-Tune closed loop MAP/RPM table to reflect your actual targets
-Tune P/I/D settings
-Start with 'P', leave 'I' and 'D' = 0
-Increase 'P' until your boost climbs up to your target
-Tune 'I' so that overshoot is minimized and boost is stable across rpm
-I leave 'D' = 0. It can help reduce overshoot, but in some cases will cause ripple.
-If you are still overshooting your targets, easy solution is to just set them slightly lower so that the overshoot gets you to your target

[loxxrider]

I should have said that having the PID at 0-0-0 *should* give wg pressure as long as your ref DC is set up right, otherwise you won't have any control to lower boost.

PID 0-0-0 means closed loop is off. The only way to get spring pressure is if all refDC values are 0.

Yes, that is certainly what it means. You will of course get whatever pressure your refDC gives you if PID are all zero. What I was confused about (which I've figured out now) is that the final DC value can be subtracted from via PID (which makes sense) so you should indeed set your refDC close to your target boost level rather than setting it at spring pressure as I was thinking for some reason before (was pretty busy at work). Glad the version of VEMStune I have now has the formulas for boost DC and such available in it right in the closed loop settings

[chaloux]

Hmm so when I up my dc I'm still stuck at about 170kpa. Gotta check my n75. Can be done with engine off by upping the dc and I should feel a click in the n75 right?

Oh and my target is 200kpa.

[loxxrider]

Hmm so when I up my dc I'm still stuck at about 170kpa. Gotta check my n75. Can be done with engine off by upping the dc and I should feel a click in the n75 right?

Oh and my target is 200kpa.

It wont do anything unless you change the "Boost valve off below this pressure:" setting under "Boost control" > "Boost PID settings" to something under 101.325 kPa

That thing will start buzzing like a mother****** when it turns on. Can't miss it!

[chaloux]

Okay so I get nothing. RefDC is 100% for the first few values. I tried two n75s, one of which was known good. Put the "boost valve off" setting to like 30kpa, well below atmosphere. So what's the deal? I'm assuming it's wiring or a setting somewhere that is just not right.

Hmm. Video coming.

[chaloux]

Crap, shoulda made it a bit darker. Oh well, you get the idea. 5 minutes of fun, only had fender rub once... if I take it to a track it's going to need to be raised up a little!


If you can, wait a bit before watching and it should be a bit darker.
[youtube]http://www.youtube.com/watch?v=X6IhwAys0YA[/youtube]

[85oceanic]

Car sounds and looks great man!!!

[chaloux]

Ugh. Couldn't take the car to work this morning because I couldn't get it started. I definitely need to tweak my starting/cranking/enrichment settings. Is not having an iac screwing me over?

[EDIGREG]

Looks fast... why don't you have an iac? Doesn't need one, but it gives you better control over the idle

[chaloux]

Okay. Well idle is pretty rock solid once it's going, even cold. It doesn't affect startup in any way though? Really it runs amazing... ONCE it starts.

[EDIGREG]

It does, it opens during cranking. But you can feather the throttle and achieve the same thing.

[chaloux]

I see. I just did some reading, apparently if I don't feather the throttle it will flood every time (according to Mattias), even when hot. But it doesn't seem to be the case, it starts hot very easy. I also just read that disabling the cam sync may fix it. It was running wasted spark on IIc and started great even in the cold with the same configuration (but now built, 7a cams, lower compression , and cps). I got some things to check out regardless.

[85oceanic]

I don't have an Iac and it starts every time. Even in freezing temps. The only thing that gets me is that my starter has a mild short going on so it draws way too much amperage so my actual crank speed is a little low.

[chaloux]

Ben could you send me a log or a config file? chaloux at gmail dot com

This morning I decided to try firing it up without cam sync. Fired up immediately but ran crappy/stalled. WTF. Halp