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Megasquirt boost control install instructions!

The Aspirator

It's a girl!
Joined
Apr 7, 2003
Location
Vinemount, Ontario CANADA
Awesome-est thing in the whole wide world. Here's my parts list from Digikey.com:

IRLZ44 (IRLZ44NPBF-ND) ..... $1.89
100r resistor
10k resistor
1N4002 (1N4002DICT-ND) ..... $0.52

That's all you need for the boost controller, but I also got many other goodies for all sorts of extra MS features:
Table Switching:
2n2222a (497-2598-5-NDR)..... 1k ..... 10K ..... 2k2 (which means 2.2K, took me forever to figure that out)

Water Injection:
1k ..... 100r ..... 10k ..... 1n4002 (1N4002DICT-ND)..... 2n2222 (497-2598-5-NDR)..... IRL244 (IRLZ44NPBF-ND)

Launch Control:
2k2

PWM Idle:
TIP122 (497-2543-5-ND)
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Also need to buy a fast acting solenoid valve for the boost controller. Ovlov760 told me about this one that he's using:
GM solenoid part #1997152
gmboost5.jpg

They can be had for $11 at GMpartsdirect.com. This is the OEM solenoid for the Gm Typhoon. The connector for the solenoid is the same one found on most GM windshield washer reservoir and coolant reservoir tanks. It should look like this:
gmboost1.jpg
gmboost2.jpg

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So I bought that solenoid from GMparts direct, and also went to a junkyard and EASILY found that connector on some oldsmobile from the early '90's. That connector is $13 online and $26 at Napa..... Cost me $2 at the junkyard. To wire it, Megasquirt connects to the blue (or black) wire and grounds it out, and you have to provide a switched +12v to the red wire. I spliced into the power wire for my windshield wiper motor cause it was really close to my solenoid. You also need to wire in the "1N4002" diode between the two wires at the plug, connecting them. Boris740 suggested this to filter out voltage spikes and save some parts from 'sploding. Cathode (bar) goes to the positive:
boost-control03.jpg
boost-control03.jpg


I then mounted the solenoid to the strut tower and plumbed it up. Route the "in" hose (from the turbo or intake) to the silver barb and route the "out" hose to the barb beside the filter. I found that having the thing bolted to the body of the car caused it to make a heck of a ticking noise when it was turned on. Like a kid with a baseball card stuck in the spokes of his bike. I could hear it loudly when turning the ignition on, and a little bit at idle, not while driving though. So we decided to just zip tie it to the intake plumbing, no more ticking!
boost-control04.jpg
boost-control04.jpg

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Now to the megasquirt side of things.

A note on the FET that you use, DIFFERENT ONES CAN HAVE DIFFERENT PINOUTS! So if you buy the exact one that I bought ("IRLZ44 (IRLZ44NPBF-ND)") then you can copy my wiring.

It's pretty easy actually. The FET has 3 prongs, GDS.
Gate, Drain, Source. The particular one that I'm using, if you're looking at it from the front is GDS. Since you are using MS to ground out the solenoid, the Source is ground, the Drain goes to the solenoid, and the Gate is the signal from MS telling the FET when to ground the solenoid. A FET is like a little tiny relay.

Here is the proper wiring diagram that I've drawn up for you guys:
boost-wiring-diagram.gif


Gate (pin1) is the yellow wire, it goes to X4. I connected it to the gray wire using a 10K resistor, then after that I installed a 100ohm resistor inline, it's under the heatshrink.

Drain (pin2) is the white wire, it goes to X12 which goes to pin 27 on the DB37 connector. From there I have a wire going out the DB37 connector to the blue (or black) wire on the solenoid.

Source (pin3) is the grey wire, it goes to the ground pad of the missing D1 diode. I've confirmed that this is a common board ground.

Then mount the FET to the case somewhere and use some heatsink compound to keep it cool.
boost-control06.jpg
boost-control05.jpg
boost-control06.jpg


boost-control05.jpg
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THAT'S IT! Even with that suuuuper long post it's really not that hard, I just wanted to be clear for you guys and detail all the steps. Now for the software side of things. Go into code config and set the output for X4 to Boost Control.

Now go into General - boost control and set it to this:
boost-control02.jpg
boost-control02.jpg


I haven't played with the boost kPa targets map yet but I hear it's a bit iffy, just use the duty cycle target table and it'll work great. My wastegate is set to 6psi. When I first got it up and running I set the whole table to 40% DC and got 10psi STEADY till redline. I played around with it a bit and came up with this so far, it's just a simple map not even utilizing all the capabilities. It's basically just RPM based boost, I get 10psi till 4000rpm then at 4100rpm it jumps to 15psi. It's a great kick in the back to have it give you another 5psi instantly, and the controller does it's job like a dream.
boost-control01.jpg
boost-control01.jpg


Enjoy your new infinitely tune-able boost control!! Cause I sure am :cool:

John

Edit, here is the current hardware manual for boost control:
http://www.msextra.com/manuals/MS_Extra_Hardware_Manual.htm#boost
 
Last edited:
Hmm..

Sounds good! I will try that with my new setup..

And you don't need knock sense even with very loud pipe like mine, I desided to keep it conservative until time to play with old fashion headsets with hose to block... Offcourse I parted it out before doing that.

Then, what model Typhoon the vlv came from. If it works well I'll try to hook one up from finland.

Can you use that like closing the signal to WG and controlling it after some treshold boost to the table? Or is that hard to tune? BTW, you have very low base setting on your WG, it might cause some stability problems in higher boost levels. You maybe want to use something like 14-18 psi spring whit that Holset and let that vlv control levels above that.
 
I've heard (hearsay!) that while you can usually hear pinging, you sometimes can't hear detonation. And pinging, while not good, still usually doesn't cause severe damage in a hurry, but detonation, even detonation you can't hear, can damage pistons rather quickly.

I'm still having trouble conceptualizing how this is controlling the boost. The typical method uses the pressure in the intake system upstream of the throttle valve, but MS doesn't have that information available to it. I guess we are sort of backing into that by setting the modulator valve frequency, which will 'interffere' with that pressure signal a known degree and thus affect the WG actuation in a linear fashion.

I'd still somehow expect it to work in a reverse fashion somehow. Sense the MAP, then adjust the valve frequency to either raise or lower boost. That way would be a little more brainless to set up, you could just enter in your MAP threshold targets, and let MS figure out what percentage of duty cycle on the modulator valve is required to meet (not exceed) that threshold. I was just a bit vague about what the consequences would be for part throttle operation, when the MAP MS is seeing is lower than the actual pressure the turbo might be pumping, it might be making the turbo work to hard when you don't need it to, and making the throttle response even less linear than it is with an MBC.
 
That's true, it does need to operate onely above certain TPS near full throttle. And let normal WG hold the baseline boost until. Needs to figure it out..

Anyway it wouldn't be problem in my car, I'm driving it so little nowdays. Still I can't say if I use it as a daily next summer so I try to make it as easy as possible.
 
Hey John - glad to see you finally jumped on the bandwagon. Verily, MSnS-EBC is a grand thing.

I used it to change my car's personality - open valve (ergo boost controlled solely by WG actuator) up until about 90% throttle, then it went to 15PSI. That let me motor around town without big boost unless I really meant it. With a fast spooling turbo (15G) I previously had far more boost than I had any need for.

The EBC functions as a variable bleed valve, based on the table above. What you refer to, JohnMc, is closed loop, and it didn't work properly, at least in the code version I used.

Speaking of code - John, you might not know (or you might!) that the TPS% in the table is not the same as the TPS gauge. Leastways, it wasn't with my version of the code, which I can't recall to save my life :rofl: regardless, if you run into this problem when trying to put your boost up in the high TPS% range, it's TPSrawADC/255. You'd need to either look at your TPSfactor.inc (or whatever the file name is) or the calibrate TPS screen to see what 100% TPS gives you as the ADC. In my case, it was about 190/255 = 75%

Might save you some confusion, or it might add some.

Congrats further on starting the water injection. I wish I'd gotten that far... but then the M46-'splosion would have followed as surely as summer follows spring. :badboy:
 
Kuikka I don't know what model of Typhoon that valve came from, but the GM part number is posted above so maybe that will get you some answers in Finland. Or you could just order it from the US and have it shipped over, can't be thaaaat much.

Kuikka said:
Can you use that like closing the signal to WG and controlling it after some treshold boost to the table? Or is that hard to tune?
I think what you're trying to ask is can you lock off the signal to the WG, giving you unlimited boost and/or SUPER fast spoolup, then open the valve to control max boost? If that's the question then the answer is yes, of course. You set the lower bins to 100% to keep the valve locked shut. I have not tried this yet but Ovlov760 has and says it rocks.

I do have a very low base boost setting, but at the moment I'm just running the stock turbo and it's already blowing alot of oil out the compressor wheel at 15psi so I'm not going to go crazy on boost with this sucker. Although I'll take your advice when I do run my Holset, higher base boost it is.

Kyle, the way you had yours setup is how I'm going to tune mine today. I've got a loooooong road trip coming up so I need it to be exactly like that. 6-10psi all the time unless I'm REALLY asking for it. With the new code you can just put in TPS %, no need to futz with the rawADC anymore.

As you can all tell a 6x6 map is HUGE for boost control, in my map I'm really only using 4 bins....
 
I think what you're trying to ask is can you lock off the signal to the WG, giving you unlimited boost and/or SUPER fast spoolup, then open the valve to control max boost? If that's the question then the answer is yes, of course. You set the lower bins to 100% to keep the valve locked shut. I have not tried this yet but Ovlov760 has and says it rocks.
I did that too... whatcha gotta be careful of is those odd MS "moments" where for whatever reason you get more boost at lower TPS or RPM or phase of the moon or whatever, you can get some nasty spiking. It might depend on the turbo, but with the 15G I eventually just set the base bins to 0.

I also fooled around with RPM-based boost levels, and found it to be kinda silly. Kinda neat, but mostly just silly - you can modulate boost so easily with the throttle, and control what boost you can live with via the tune. I suppose if you had a nasty cam/turbo/head combo that pinged like hell at a certain boost and RPM you could dial around it? Dunno, with my setup, I could tell the snail wasn't real happy above 15-17, so I just left it at that across the RPM range.
Kyle, the way you had yours setup is how I'm going to tune mine today. I've got a loooooong road trip coming up so I need it to be exactly like that. 6-10psi all the time unless I'm REALLY asking for it. With the new code you can just put in TPS %, no need to futz with the rawADC anymore.

As you can all tell a 6x6 map is HUGE for boost control, in my map I'm really only using 4 bins....

Yeah, I didn't much care for it - too much to dial in when tuning. I wound up making the % 0, 65 (mid throttle), and 75 (WOT) and the RPM 3000-4000-5000-6000, and really didn't even use the RPM bins at all. They can be handy in keeping boost stable, I suppose, but I didn't really run into that too much.

When experimenting DC% and boost level, I used just one cell, IIRC I set the TPS bins to 94-5-6-7-8-9 and the RPM bins to 6500-600-700-800-900-7000 or something. That left the bottom left bin (94%/6500RPM) the only one that made any difference.

Your setup might be different, so don't take my word for it, but I thought 6x6 was stupid overkill.

What I was driving at with the TPS% is the % you enter in the grid (for my code version) was NOT what the TPS gauge reflected. 75% according to the boost control = 100% actual. Like I said, they may have fixed that, but if you find you can't reach the top TPS in your grid, that'd be why. You can use the tuning window to see what's happening.

Man, sometimes I miss my turbo. My four year old asked, "daddy, where's your turbo? The grey car?" :please: I said, "It went to a new owner". Says he "did you get a new car?" I said, "yep, that's how it goes, son, you can't keep 'em all." "What'd you get, the starwars car?"

He calls the BMW the starwars car on account of it's robotic folding top. Kids rule. Threadjack over. :-D
 
John you may wish to arrange your boost control map such that when on your trip it makes enough boost at X Rpm's to pull hills and such with 1/2 throttle so that you do not have it building lots of pressure behind the throttle plate, wasting that energy and making you control speed via boost coming up, cut throttle, speed drops, add throttle, repeat.... as was the case with the OEM system that Volvo used.
I recall driving an 88 or so 760 turbo with cruise control. Set speed to 70MPH....... listen to and feel the car surge forward, throttle is cut, surge forward, repeat.

Nice work in posting this John...... More TurboBrickstas need to control boost this way.
 
woooot

what a coincidence, school's got me distracted away from tbricks but i managed to order a solenoid and fet last week then i stumble onto this thread!!
Thanks for the up-to-date thread, i'm really looking forward to the parts coming in so i can get a break from the books : ) hopefully not to result in a break of my tranny :badboy:
 
242Fast you've run a real EBC in the past, right? It'll be really interesting to hear your comparision between MS-EBC and an aftermarket one.

Just got back from an hour long boost tuning run, had some fun, learned a lot. So it turns out that megasquirt DOES interpolate between the different values of the boost map, I figured that out by running this one below. It was REALLY weird to drive, very much like an N/A car! The amount of boost varied exactly by how much throttle you gave it. More gas, more power. I could only get the full 15psi by flooring it to 100% throttle. I'd get my base boost of 6psi at everything under 40%, but above that the boost level was exactly in relation to throttle position. Sooooo different from what a turbo usually feels like at 15psi, where you can easily get full boost at 10% gas.
boost-control07.jpg

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Below is the next map that I tried. I set the bottom bins to 100% to lock the valve shut, basically giving me infinite boost. While driving I couldn't really tell if it was spooling quicker or not, didn't try it long enough I guess. But it would overboost a little bit then hit 4100rpm and drop back down to the 10psi (40% DC) that I was asking from it. This testing was only done in 2nd and 3rd gears, I could imagine that in 5th it would overboost a LOT for a long time before reaching 4100rpm. So I don't know how well this sort of setup would work all around, I only played with it for a few minutes. Ovlov760 does yours work the same in all gears? Here's mine:
boost-control08.jpg

____________

This is the last map that I created, the one I'll be using for my road trip. After my first test and finding out the interpolation thing I decided that I really like different boost levels, as opposed to a gradual increase which made the car feel boring-ish and N/A-like. This map has 3 levels.

6psi, 0% DC which just leaves the valve open and lets the wastegate do it's base boost. I get this from 0-19% throttle. I found that on the freeway cruising normally up and down small hills, I never really top 17% throttle, so this will give me low boost most of the time.

Level 2 is 10psi, 40% DC, from 20-59% throttle. All daily driving for me happens below 60% throttle, so this is great. A little more oomph than level 1.

Level 3 is 15psi, 60% DC, above 60% throttle. When I REALLY want to go fast, it's there.
boost-control09.jpg


This stuff is SOOOOOO awesome guys! It really takes a while to get used to TPS-based boost levels, espeically when you're just plain used to the turbo spooling to full boost and having to back off again. But after a bit it becomes natural. I remember back when Kyle did his boost controller last year he said something like "it makes this monster feel much more normal, the stupid fast spooling 15g is now very managable on the street, I'm not getting full boost all the time". (I'm sure I hacked that quote, but that's what I remember). Kyle I totally agree! I've never really run 15psi for any extended period of time before, but now that my car is ready for it it makes daily driving a different experience. Gotta be much more careful about how long you keep your foot in it before you're doubling the speed limit. Like you said, this boost controller makes the car much more "normal" for daily driver mode.

And I'm sure if someone were setting up a race car they could tailor the map to have all kinds of naughty fun. *cough* John Lane *cough* Does Electromotive have boost control?

John
 
I just thought of a disadvantage that I will encounter sometime soon. Utilizing the welded diff to its full potential.... When sliding around I LIKE having a whole bunch of power with little throttle input, so this map might throw my game off a bit. Ohh well, I'm sure it'll be easy to adjust.
 
John Electromotive has user defined outputs for doing just what you are having sooooo much fun with right now. When I updated the software and the chip it got 'new exciting' functions to go with. I just have to set it up. I'm as excited as can be to do so. I have long wished for the ability to regulate boost when going up a hill on gravel so that the program is not managing all the pressure behind the throttle plate and listening to the turbo hiss as it builds pressure and then the blast as all the pressurized air comes back out of the air filter.
John I'll wager that your boost controller will just make it possible for you to drive more smoothly and consistently....... This makes you faster with practice. The welded rear won't mind a bit and I'm betting that you do every bit as badly with rear tire wear with those fresh tires as you did with that last pair. Hmmmmmmmm........

Guys it seems to me that we should be taking up a betting pool for how long John's M-47 lives.

JL
 
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