Manual Boost Controller questions? [Archive] - SaabCentral Forums

: Manual Boost Controller questions?


Pontius DIO
5th February 2012, 08:15 PM
I have a 99' 9-3 SE (200hp) that's basically stock except the air filter box is heavily modified and the exhaust is a little more free-flowing as well. I'm making my own MBC and have several questions:


With regards to placement, being a T-5 car, should I run the MBC in series, or would I benefit more from using it as a stand alone? I've seen these run 2 ways, one way is run where it sits between the "turbo" vacuum line and BPC, and another way is the "turbo" line and "waste gate" vacuum line are in a loop on the BPC, and the MBC is upstream somewhere.

So the 1st way would only allow faster spooling, but no increase in MAX boost?

The 2nd way would actually increase MAX boost as well as spooling?

Also, I'm doing a brass "T" with 2 nipples, ball bearing on spring, that's common online. The bleeder hole you drill, would a 1/16th in hole suffice, or do I need to jump up a size?

grkguy89
5th February 2012, 11:25 PM
take a look at this site, it may have your answers
http://www.smartperformance.net/

BobSaabit
6th February 2012, 12:30 AM
I have a 99' 9-3 SE (200hp) that's basically stock except the air filter box is heavily modified and the exhaust is a little more free-flowing as well. I'm making my own MBC and have several questions:


With regards to placement, being a T-5 car, should I run the MBC in series, or would I benefit more from using it as a stand alone? I've seen these run 2 ways, one way is run where it sits between the "turbo" vacuum line and BPC, and another way is the "turbo" line and "waste gate" vacuum line are in a loop on the BPC, and the MBC is upstream somewhere.

So the 1st way would only allow faster spooling, but no increase in MAX boost?

The 2nd way would actually increase MAX boost as well as spooling?

Also, I'm doing a brass "T" with 2 nipples, ball bearing on spring, that's common online. The bleeder hole you drill, would a 1/16th in hole suffice, or do I need to jump up a size?

1/16" is fine, maybe even too large. You don't need much of a hole there.

I'll look at mine when it's light outside, but off the top of my head it's the second way. I get fast spooling (instantaneous) as well as an increase up to fuel cut.

Pontius DIO
6th February 2012, 03:05 AM
take a look at this site, it may have your answers
http://www.smartperformance.net/

That was the site that made me question which way to run it. I just wanted to make sure 100% before I fiddle with anything.

So, the MBC will just kind of hijack the lines taking the place of "T" and "W"; the factory BPC will get a hose from "T" going right back into "W". Can that cause premature failure on a BPC?



Bob, 1/16th inch was the smallest I could find at Lowes. Online vids either say some absurd size in thousands or say nothing at all. I was trying to pirate a 1/4in ball bearing from a failed breaker bar but got a little eager with the Dremel and scored the surface. Where are you guys getting your ball bearings from as well as the spring being used? Any idea what a proper spring's weight or how much "weight" is needed to compress it? I have some springs from a Smith and Wesson J frame that are used for lighter hammer action. But it might be too stiff to allow any real adjustments.

BobSaabit
6th February 2012, 11:39 AM
Pontius:

See Gus Mahon's page, he invented these things and everyone copied his work. He has a McMaster Carr part # for a valve complete with spring and ball (stop for a short moment of silence for Gus, he was killed while riding his motorcycle a few years ago).

http://www.gusmahon.org/html/boostcontrol.htm

Check an Ace or True Value hardware store for the drill bit, most have them in a large display that goes down very small. See Gus' tip for drilling that tiny hole.

I changed the design just a little: since the Saab has large OD hoses, I bought a fitting with two 1/4" nipples, cut one off, and soldered it to the end of the bleed valve instead of using the 1/8 fitting most designs lead you to. The other end comes with a 1/4" fitting.

If you really want to build your own, you can get a 1/4" ball bearing at any bicycle shop. The rest of the stuff can be sourced at Lowes, Depot, or the plumbing dept at the hardware store.

I'll look at mine a little later today and post some notes on installation.

Pontius DIO
6th February 2012, 06:33 PM
++++1 on the bike shop Bob! I have one around the corner that has some for 15 cents each. Never thought about them! Seems like I can use the 1/16" bit to start the hole, then a tiny .020 for the actual bleeder. Too bad the nearest Ace is 10 miles away :(

What exactly did you solder? Are you saying that you put a nipple over the bleeder hole? If so, what is at the other end? A filter?

BTW, what can these cars handle safely (daily driving + spirited, carbon deposit removing spurts around town) as far as boost? I'd be OK with a 1-3 psi MAX boost as well as the faster spooling (especially in 1st gear).

Off to collect my bearings for a bit :lol: you've been a big help.

Pontius DIO
6th February 2012, 06:37 PM
The *old school* way I remember reading about was getting a "jet" from a Holley carb and inserting it in a vacuum hose on a "T" LOL. Anyone ever hear about? It'd was a super simple bleed off, albeit non-adjustable, just have to find a proper jet. A tiny orifice in a vacuum line would be similar as well.

BobSaabit
6th February 2012, 08:56 PM
POntius:

I ordered my "bleeder valve" complete with bakk and spring from McMaster-Carr. The pre-built model comes with a 1/4" hose barb on one end but a flat cap on the other with a hole in the center. I drilled out the hole and installed a 1/4 barb at that end too.

The usual method for setting up the MBC without a boost gauge is to set it midway and take it out for a 3rd gear WOT run on the highway. If you hit fuel cut (it will happen within 10 or so seconds), you back off a little and try again. If you don't hit fuel cut, you dial it up a little and try again. The goal is to get it where you can go WOT and never hit fuel cut (15.5 psi AFAIR).

If you set it up in the cold weather it will be fine year round, although you could dial it up a notch in the Summer since hot ambient air gives less boost than cool air.

Pontius DIO
7th February 2012, 12:34 AM
Good tuning tip Bob. I just finished assembly of my home made MBC and getting ready to install and take for a quick run and see how it does. :cheesy:

Pontius DIO
7th February 2012, 02:16 AM
OK, took it for a run. It felt less laggy and more responsive (torque felt consistent) but max boost (as per the factory gauge) was never reached. I could get out of the "GREEN" zone, but only as far as 1/4 of the way into the "YELLOW" zone. Normally it'd go 3/4 of the way into "YELLOW", almost at the "ORANGE/RED" section. Anyone have any ideas? Maybe I didn't tighten enough? I didn't get too bold with tightening, and was doing 1/4 to 1/3 of a turn, test, repeat.

Pontius DIO
7th February 2012, 12:47 PM
Anyone? I made a basic brass "T" with 2 barbed 1/4" with a custom stop and adjustment bolt with stop nut. I'm using a 1/4 in ball bearing and a 7/32" OD spring with 16 wire. I cut the spring little by little until I had zero resistance blowing into the end where it receives it's source vacuum/boost with the nut backed off. I then adjusted while blowing into it until I couldn't blow into it anymore. I'm confident the valve works, just unsure if tightening more will hurt anything?

BobSaabit
7th February 2012, 02:51 PM
Pontius:

Did you hit fuel cut? If not, increase the boost until you do, then back off. Your conditions (faster boost) are consistent with proper operation, but it should head to the red zone almost immediately even under moderate throttle.

Pontius DIO
7th February 2012, 05:19 PM
Hmm. I just tried a full turn further and the needle never went past the 1/4 way mark in the "YELLOW" or middle zone on the gauge like before. Oddly enough, punching it in 2nd the gauge went to the 1/4 mark, but the torque felt like it was less, even though it was clearly boosting the same. :( Never anywhere near the "RED". The car never jerked.

I have the inlet nipple on my valve (end with ball bearing) attached to the intake hose that gets pressurized. The outlet is attached to the waste gate. The BPC has the "T" and "W" looped together. What am I missing?

losacker
7th February 2012, 05:43 PM
keep tightening it. i had the same problem when i installed my smart performance mbc. if it isnt tight enough you will get less than stock boost. i bought mine from a member for about 30$ and it has an atmospheric pressure regulator so my boost doesnt change with temperature. honestly it would have been easier to just buy youre mbc from smart performance. once i got mine adjusted it has worked perfectly since. good luck!

Pontius DIO
7th February 2012, 05:53 PM
keep tightening it. i had the same problem when i installed my smart performance mbc. if it isnt tight enough you will get less than stock boost. i bought mine from a member for about 30$ and it has an atmospheric pressure regulator so my boost doesnt change with temperature. honestly it would have been easier to just buy youre mbc from smart performance. once i got mine adjusted it has worked perfectly since. good luck!

Guess I'll try to muster up the courage and tighten some more. I actually didn't mind making the unit myself, as it gave me something constructive to do :cheesy: Thanks for the tip!!

losacker
7th February 2012, 06:02 PM
Guess I'll try to muster up the courage and tighten some more. I actually didn't mind making the unit myself, as it gave me something constructive to do :cheesy: Thanks for the tip!!

hahah, if you have the time then thats awesome! but yeah keep tightening. fuel cut will keep you from over boosting so dont worry about that. :cheesy:

BobSaabit
7th February 2012, 06:44 PM
Yeah, keep going. Without a boost gauge there is no way to know until you hit fuel cut.

Don't be shocked when it feels like you hit a brick wall... just go with it and keep adjusting.

Pontius DIO
7th February 2012, 08:12 PM
Thanks for the help guys! I turned another 4 turns and finally got the needle to touch in between "YELLOW" and "RED". Right on the the gap between the colors. Never hit fuel cut-off though, so there's probably more in it, but until I get a proper boost gauge and do some maintenance I'm happy where it's at.

There's a steep winding hill nearby that would bog 3rd gear from a 25mph roll and now I almost have to lift as it's hitting 50mph+ and still pulling. That's about a 10mph+ improvement.

So, all in all very happy!!

BobSaabit
7th February 2012, 08:53 PM
You can go a bit more... about 1/8" into the red is OK and won't hit fuel cut. Don't be shy! Everyone should feel fuel cut at least once!

Pontius DIO
8th February 2012, 08:41 PM
LOL Bob. The way I designed my MBC was the end with the adjustment bolt goes into a plastic section (was a 90 degree 1/4" Nylon hose barb and 1/4 pipe thread; cut nipple off flush and used remaining section; ran adjustment bolt through the center; less chance of leaks and movement, gives extra adjustment as well). I'm afraid that if I tighten more, the bolt will protrude past the inside of the center of the hole (think of it as a guide to keep the spring centered) that houses the spring, and the spring might slide sideways. I also put a small rivet in the spring's end that the bolt comes in contact with to prevent any spring binding during adjustment and stop the bolt from threading into the spring ;)

I seriously need a new tranny mount under the battery box and the P/S motor mount before I go any further. Not to mention the fuel pump is on borrowed time >:|

The car is definitely much much more responsive and the torque starts much lower than it used to. 3rd and 4th gear are a blast too!

2.3LiterCivicBeater
8th February 2012, 09:06 PM
so what happens when the ecu senses knock and tries to lower boost but cant and you melt your pistons

jakejm79
8th February 2012, 10:25 PM
so what happens when the ecu senses knock and tries to lower boost but cant and you melt your pistons

The ECU also adds fuel and retards timing, and since you cant (or shouldn't, since it can be done) pass the stock 15.4PSI fuel cut limit I haven't heard of any pistons melting at stock or below boost levels, keep in mind the manual BPC is only useful on a T5 engine with the stronger internals.

2.3LiterCivicBeater
8th February 2012, 11:20 PM
so if youre at wot and 15psi with a mbc and stock tune wouldnt your fuel trims already be in the upper limits. So if you get knock and ecu cant lower boost so it tries to add more fuel wouldnt the STFT go through the roof and set CEL

jakejm79
8th February 2012, 11:42 PM
There is enough overhead in the stock tune and the additional fuel is so minimal that I don't think it makes a huge difference.
Like I said before you still get the retarded ignition timing and you are running relatively low boost levels (aren't talking Stage 3+ levels) maybe you don't have the same level of protection, but what you still have is more than adequate. Also knocking should be of less concern since you should be running 93+ if you are pursuing any kind of performance.

BobSaabit
9th February 2012, 12:04 AM
^ this

If you run an MBC you need to use 93 octane. It's also only appropriate on a (stronger) T5 motor. You also don't run boost past the stock 15.5 by definition.

Is it a little risky? Yes. So is running WOT at any point for that matter. I've run mine for 100K miles and never heard the engine knock, even once (and it's a 'vert, so I have a better chance than most to hear it).

jakejm79
9th February 2012, 12:10 AM
You will/can run past 15.4PSI with a diode, then I'll agree you do run the risk of serious damage, more so from running lean than from the ECU not being able to control boost tho.
If you are that paranoid, you could always install a knock sensor light.

Pontius DIO
10th February 2012, 06:19 AM
Technically I'm probably right at or 1/2 to 1psi above stock at full boost. But instead of bypassing boost with an open waste gate, boost starts early and stays strong. Max HP is about the same, but the HP/TQ numbers in the lower to mid rev ranges definitely feel higher. (Reminds me of installing an awesome camshaft with a broad torque curve) Opening up on familiar roads the car used to feel like an NA car with secondary butterflies opening around 4k RPM. Now it just goes. I think it'd keep up with my 96' Mark VIII now, maybe even pass it up. But acceleration was the biggest improvement.

Seeing as how the ECM has the ability to adjust and monitor air/fuel ratios to compensate lean or rich conditions, I don't see the problem. And the timing getting retarded by the ECM is another preventative measure. If I added a bigger turbo, dialed in 30psi boost, bypassed fuel cut, kept a stock fuel pump and injectors, ran a factory intercooler; then I'd be asking for trouble. I run premium grade fuel in all my cars too.

I'm actually so happy with the performance now that I'll pass on a 230hp Stg1 from GS. Might add a better intercooler though and run a small fan on it to keep constant temps (during summertime). Ideally 290-300hp would make this a really fun car, but that simple little MBC will keep me content until/if that happens.

Pontius DIO
11th February 2012, 04:21 AM
If anyone is wanting to make an MBC and getting confused along the way, feel free to PM me and I might be able to help with your design. Here's what I used to make mine with part #'s and where I purchased the stuff:


Bought from Lowes:

(1) 1/4" brass "T" junction all female ends [no part number avail]
(2) 1/4" barb X 1/4" MIP threads [Part No. A-192]
(1) 1/4" X 1/4" Nylon Hose Barb [Part No. A-199]
(1) 1/16" drill bit to start the bleeder hole
Optional:
(2) 1/4"-20 x 1-3/4" Combo Round bolt with Nut (Zinc Plated)
ACE actually sells bolts with a knob attached that could work too.

Bought from Ace Hardware:

(1) 1-3/4"lgth, 7/32" OD Compression Spring [Part No. #9U]

Bought from local Bike Shop:

(1) 1/4" ball bearing - can possibly substitute a 5/16" bearing

You'll have to find a place selling one of these:

(1) .020 - .022 thousandths drill bit for bleeder
-----------------------------------

I never found a local place selling a .020 bit. BUT, I had purchased a "T" junction for 1/8" vacuum line from Auto Zone. In the end of the "T" was a tiny brass orifice restricter with a .020's hole in the center :) I removed it, drilled a 1/16" hole in the brass "T" junction which was very close to the orifice restricter's OD on one end. I used solder and a small butane torch and soldered the orifice restricter in.

The 1/4" Nylon barb was a 90 degree barb. I cut the barb end off with a small hand saw flush; resulted in a nylon "plug" that threaded into the brass "T" junction, with a hole in the center that the adjustment bolt goes into, preventing unwanted turns and making the adjustment bolt snug. I used a drill bit slightly smaller than the adjustment bolt to open the hole. Then, I tightened the bolt into the "plug" from the other end to "thread" the center hole in the plug. Removed the bolt, and installed it correctly.

I used 2 of the "nuts" and ran them all the way up the adjust bolt (came with the packet) Then tightened them against the top of the bolt's head. This way when I needed to make adjustments, I just grabbed my 1/4" wrench, and could adjust easily.

Right where the APC/ BPC is (you'll be disconnecting the "T" and "W" vacuum lines from it), look above it on the core support. There should be a small section of metal that makes a great spot to mount the MBC. I mounted mine with the adjustment nut facing "upwards" toward the underside of the hood. Use zip ties or whatever to fasten it in place. While making adjustments, it's a super convenient spot and isn't in the way.

The spring will need to be trimmed a bit as it is longer than needed. I suggest buying 2 or 3 of them in case you cut too much off. I mocked up the end with the adjustment nut, installed the spring and bearing, then from the top looked to see how much spring binding there was. Then removed the spring and trimmed, repeat until correct length. I also installed a tiny rivet in the end of the spring that I shaved it's head down to the OD of the adjustment screw. This prevents binding while turning the adjustment bolt as well as stops the bolt from actually threading into the spring itself which you don't want. Also, only cut from one end of the spring. And make sure that end is facing the ball bearing. The other end that is NOT cut, will still be coiled tightly which makes it hold up better to the adjustment nut (and rivet if one is used)


I'll try and get pics up and hopefully it'll help someone as I had to source videos that weren't the greatest while making mine, as well as confusing and vague sites that aren't the greatest.