Julian's '91 200 20vt

[loxxrider]

Nice score on the Treadstone.

As far as the boost control is concerned, the more info you have about it's dynamics the better. The "losing control" part is due to the valve's physical limitations. It can only open and close to fast due to mass. If you try to make it open and close too fast (higher frequency with either low or high duty cycle (either way it has to open or close fast compared to moderate duty cycles), it simply wont. So you'd want to operate that MAC valve at fairly low frequencies to maintain the most control over boost pressure. However, that will come at the sacrifice of response time of the system.

Remind me again why you went with a MAC valve instead of just using an N75?

I think if you want to solve this issue you need to simplify things. Get back on the stock wastegate configuration with either the MAC or an N75 (better IMO). Just run it open loop by setting P, I, and D all to zero. Then fill in your boost refDC table with values of something reasonable like 30-50%. Adjust them and see what happens. Then you can start playing with PID and multiple WG port setups. There are just too many variables right now to tell what's going on!

[88a5tq]

Ya I agree Chris. I do believe that the 2.2 bar spring will solve this though. I hadn't even thought about going back to the n75. I don't know what rate the spring is stock but I'm guessing it's less than 10 lbs which means anything over 20 lbs will have minimal control to it. I believe that is correct

I'll be running some pretty conservative DC values after the new spring for sure

[loxxrider]

Interestingly, VEMS has a lot more fancy boost control methods now. You can do all kinds of stuff! I haven't seen the latest until today. Whatever you do, just put P, I, and D all to zero and play with your reference DC whether based on RPM or based on boost target (those are the two methods you can choose from now). Go out and put your valve on the 10 hz it was designed for and try it at various values of ref DC. You should be able to peg the boost or have nothing as well as everything in-between, but it wont be very controllable


I really don't think the new spring is the problem. It may be a bandaid fix, but I ran the stock wastegate from 5 to 25+ psi with no control issues. Try it though and see what you get.

[88a5tq]

real quick just wanted to say anything worth noting that during this boost creep and drop in the noticeable dental drill sound seems to lower in loudness as if the WG simply isn't asking for as much work from the turbo.

[88a5tq]

Thanks Chris I'll check the spring out in a half hour. Got this awesome treadstone today. Included ecu for size comparison incredible quality for sure. No I have to wait on the piping to build the prototype.

PS the spring fit without any issues!

[PRY4SNO]

I was pretty happy with the construction of my Treadstone. Especially for the price.

[pilihp2]

That's pretty wide. Is that the one you ordered? or did they send you the bigger one on accident? i thought you were going with the smaller one?

confuse


EDIT: I guess going of ecu size that does look like the right size. Looks large for some reason

[88a5tq]

Ya it's the 9 inch long core not the 6 inch. It's smaller than the oem one I believe. When I opened it was like "wait this is big enough for 500 hp?" Lol its so pretty

[88a5tq]

Ever find yourself letting people know that they have a signal bulb out when they don't use it?

Car feels great at 25 psi. I have been using the same DC # across the entire rpm range for each MAP value. Looks like my 30% choice for 274 kpa (25 psi) is just right for achieving the goal when the engine first hits that MAP. It understandably tapers down to 23 as I move towards redline though. Gonna check out my log with PID=0 today to tune the rest of the boost/rpm table. I'm seeing what I like lol

[88a5tq]

Remind me again why you went with a MAC valve instead of just using an N75?

I figured that changing to the huge cobra head turbo inlet boot as well as continuing to use my massive K&N Tahoe filter was cutting down on the amount of vacuum in the intake, which the n75 needs to "pull" the wastegate shut via the bottom vacuum port, making it VERY difficult to reach the 25 psi level. I wanted to change to a top and bottom port control system because I thought it would be easier for the ECU to regulate to 274 kpa by using the abundance of MAP to "push" down on the top WG port instead. I forgot I had the restrictor in the bottom port but that resulted in using way less DC % with the MAC valve. I suppose it will stay there now. I went to 25 hz on the valve since it will react quicker to changes in required DC.

I think I will buy the universal ebay IC piping kits in 2.5" dia so I can make the route all at once. Any insight on the quality? Im sure it wont be aluminum lol

[88a5tq]

Sorry to pick on you Chris I don't suppose you would be fine with sharing what values you're using on the CLT/MAP table as well as the IAT ignition retard table? I don't really have anything but the zeros for the first and the base tune figures for the latter table. I'm clueless basically haha

[loxxrider]

Yeah I can share them, just need to get to a computer.

The cx racing piping kits are great. I have nothing to complain about with them don't hesitate ordering one.

[DE80q]

I have a CXracing piping kit on mine as sell, good stuff there.

[88a5tq]

That's good to hear thanks I will order a 2.5" kit soon

[88a5tq]

Right so yesterday with 25 hz and 45 max %DC and PID = 0, I managed 264 kpa. It's in the zone! Nearly...

I did order the piping kit yesterday so that's about 8 days out.

[loxxrider]

Nice, so you can start messing with pid whenever you're getting close to having it tuned in the boost range you want. Just follow my guide!

[88a5tq]

[88a5tq]

Question:

Does the pre-throttle body intake tract (after the BPV and IC) get subjected to a heavy vacuum backwards through the IC towards the BPV/BOV port? I have my w/m nozzle installed in the beginning of the charge pipe just inches after the michelin man hose and near the (Al!) IC and I'm wandering if more than oil can settle in the IC and it's stock crosspipe.

The thing is I'm considering putting my unmolested charge pipe in and using one of those sandwich type w/m injector bungs to install the nozzle in the silicone 90° elbow that will be connected directly to the treadstone IC's exit. Ya or nay? I don't want the meth getting sucked backwwards into my beautiful new IC work-of-art where it will puddle... Thanks all

[loxxrider]

I don't see any chance of meth going backwards until you close the throttle.

[88a5tq]

Not sure if nay lol

Small chance of yay?

[88a5tq]

Was getting a 3 psi oscillation at WOT causing some weird sounding runs lol. Yep, runs IN the car
I tried messing with the I and D figures and couldn't lose it so I just went with P only. Gonna try that for a while until I can get my % DC vs MAP table completely tweaked. I was using very minor numbers for the PID values too which just made it even more frustrating. I and D were only 6 and 15 or something

[loxxrider]

Yeah, you may need bigger values than that. Try p and d without I. That should kill the oscillations with enough d. Don't be afraid to give it the d.

[pilihp2]

Don't be afraid to give it the d.

[88a5tq]

no going back now. Commencing project brain thrust mastery. Maybe a little d is all it needs hah

[loxxrider]

Maybe a little d is all YOU need



Things just got 100% awk


But i thought maybe in spirit of all the recent news...