New Supercharger - Logs Showing No Boost??

[SprungtS]

Okay so... I just installed a Sprintex 210 intercooled kit over the weekend. I was hoping to find that the Openflash guys had a basemap to flash to get relevant tables scaled pretty close, but never got a response from them. So I started off from scratch.

Never tuned a BRZ for boost, but I have tuned 2 NA BRZs, and a couple turbo Miatas among other NA cars. The first couple revisions I flashed, I didn't notice anything other than a perceived lack of torque, especially in the mid-high range. It sounds great, seems faster than it was especially at low RPM, but not as fast as I was expecting. Figured it was just because it's only a ~6psi kit (no idea what kind of CFM though) and isn't adding a lot of power, in addition to dialed back ignition tables for safety. Also I have a pretty fast turbo car I drive a little more often than the BRZ, so my butt dyno is skewed. The BRZ already felt slower than a stock Miata.

On the 3rd revision I flashed I removed STFT from the log parameters to include boost. To my surprise, it didn't seem to go positive much at all, even at 3k+ RPM. So I pulled off and switched boost for MAP, thinking I wasn't understanding the readout boost was giving me. MAP was pretty clearly reading absolute pressure, and just barely getting over atmospheric. After I saw that I just came back to the house to pull the logs and verify what I thought I saw. MAP shows a max of around 15.9 psi @5000RPM where I cut, so less than 2psi? Then boost on the first log shows fluctuation around 0psi up to 5k RPM, with a couple spikes up to .5-.8psi. Fuel is starting to look close to target, but no boost? On a supercharged engine? What gives?

FYI: Car still has under 500 miles, I'm of the belief that a hard break-in period is good for an engine, so I'm not afraid of opening the throttle or introducing some boost- but I won't rev it out all the way, so some of that top end is going to have to wait another 500 miles or more.

https://datazap.me/u/sprungts/testin...=0&data=1-2-10

[DarkPira7e]

Why not tap into the vacuum line between the block and brake booster with an analog gauge to actually see your boost? Could have a huge vacuum leak

[SprungtS]

Don't think I have one around, but I think it would be really odd considering how well it runs, how well it idles, and again the fact that it's a twin-screw supercharger. It's not like there's anywhere to leak except the intake ports themselves - AFAIK.

Also, wouldn't the MAF sensor show higher output as the MAP sensor shows atmospheric while the supercharger is sucking in more and more air and then blowing it out away from the engine?

This is tuned by MAF voltage and RPM, so a vacuum leak should make it run like absolute shit right? It runs beautifully, very smooth and fuel is almost perfect in open loop.

If I'm thinking about this wrong, and a vacuum/boost leak is likely, I can find a gauge to buy or rent. Not concerned about that, I just want to make sure I'm not chasing a ghost. EDIT: Just checked the logs, I'm seeing 10-13psi of vacuum when off the throttle, that's pretty high for any kind of vacuum leak.

[SprungtS]

Do Sprintex chargers have some internal way of controlling boost? Possible for something like that to be malfunctioning?

[DarkPira7e]

Originally Posted by SprungtS

Don't think I have one around, but I think it would be really odd considering how well it runs, how well it idles, and again the fact that it's a twin-screw supercharger. It's not like there's anywhere to leak except the intake ports themselves - AFAIK.

Also, wouldn't the MAF sensor show higher output as the MAP sensor shows atmospheric while the supercharger is sucking in more and more air and then blowing it out away from the engine?

This is tuned by MAF voltage and RPM, so a vacuum leak should make it run like absolute shit right? It runs beautifully, very smooth and fuel is almost perfect in open loop.

If I'm thinking about this wrong, and a vacuum/boost leak is likely, I can find a gauge to buy or rent. Not concerned about that, I just want to make sure I'm not chasing a ghost. EDIT: Just checked the logs, I'm seeing 10-13psi of vacuum when off the throttle, that's pretty high for any kind of vacuum leak.

When your idling, you're only seeing 10-13? Should be lower than that. I do agree that it should be idling like garbage. It could be that you have a leak that's only apparent in boost.

[SprungtS]

I think it might have to do with the vacuum actuator. I just found this from some article:

"Through the action of the control arm, the spring biases the bypass valve (7) in the closed position for maximum boost. When the engine is started, the manifold vacuum at the throttle body develops and is able to move the diaphragm upwards against the action of the spring. This opens the bypass valve (7) and cuts boost. As you step on the gas, the manifold vacuum at the throttle body goes down, and the spring is able to move the diaphragm and control arm downwards in proportion to the decreasing manifold vacuum, which gradually closes the bypass valve (7) and generate boost pressure."

And then this:

"Bypass Valve:
The bypass valve is “open” during vacuum and closes under boost. An open valve will bypass most but not all of the boost at WOT (wide open throttle). For example: An open bypass valve may register 1psi on a 6psi kit but 2psi on some 9-10psi kits. Check valve operation with a handheld vacuum/pressure pump (i.e. Mity Pump). Pressurize the line to the valve diaphragm to see if it closes completely. Use the vacuum mode to check vacuum opening. Most valves on Kenne Bell kits can be operated manually by moving the diaphragm arm up and down. The cure for this problem is to check for full travel (boost and vacuum) with the hand held pump and replace the bypass valve is its not operating properly."

I'm going to check my connections there, came inside to get a light and write this comment. If the connections are good I might have to figure out how to do the test they're talking about with a handheld pump. I really doubt the valve is bad on a new kit, I probably just have a leaky hose or something.

[SprungtS]

Found something.. I think? The plastic line going to the bypass valve was connected fine. I removed it to check that it had a good vacuum source. It did, so I hooked it back up. I noticed, however, that the valve's actuator looked a little crooked... Almost raised off the back of the manifold. I gently pressed downward on it and it popped into the 6-7 o'clock ish position like it wanted to be there. I thought it was solved, and the actuator rod was just bound up, but the test drive showed the same condition. When I checked under the hood, the rod was back in the same position, looking bound up at 4 o'clock. I took a bunch of pictures and two looked like they showed it best.

[For clarity, the black plastic rod in the pictures is the actuator rod. To the right of that rod is the bypass valve/actuator itself.]

[SprungtS]

In case anyone's interested or has this problem in the future:

I found a picture in the install guide that clued me in to what's going on. Page 31 of this manual shows the pictures. The actuator rod is supposed to be around the 2:00 position when at idle. It's supposed to be around the 11:00-12:00 position when under load, to close the valve. Mine seemed to want to be on the bottom, not on the top. I realized that when they put this manifold/supercharger setup together, they bolted the vacuum actuator on backwards, which looks like it just put the hose connection in a harder to reach location. However, for some reason, the metal "stop" that bolts in with the actuator was either bent out of the way or never quite made it where it was supposed to. The stop is supposed to keep the actuator rod from hitting that 3:00-4:00 position mine kept getting stuck in.

I just bent the stop tab back where it would do its job, and took it for a very short test. Definitely building a few pounds of boost (didn't need the MAP output to tell that..), so I came back to continue tuning. I wanted to post this update in case anyone else has this problem and finds this.

[Kodename47]

Just an FYI but the OEM MAP sensor reads up to around 1.37 Bar so you should see the output flatline at maximum around 3-4k RPM.

[kev0]

Originally Posted by SprungtS

In case anyone's interested or has this problem in the future:

I found a picture in the install guide that clued me in to what's going on. Page 31 of this manual shows the pictures. The actuator rod is supposed to be around the 2:00 position when at idle. It's supposed to be around the 11:00-12:00 position when under load, to close the valve. Mine seemed to want to be on the bottom, not on the top. I realized that when they put this manifold/supercharger setup together, they bolted the vacuum actuator on backwards, which looks like it just put the hose connection in a harder to reach location. However, for some reason, the metal "stop" that bolts in with the actuator was either bent out of the way or never quite made it where it was supposed to. The stop is supposed to keep the actuator rod from hitting that 3:00-4:00 position mine kept getting stuck in.

I just bent the stop tab back where it would do its job, and took it for a very short test. Definitely building a few pounds of boost (didn't need the MAP output to tell that..), so I came back to continue tuning. I wanted to post this update in case anyone else has this problem and finds this.

Apologies..but can you somehow circle the actuator rod that is supposed to be at 11:00-12:00 position on idle? I'm having a hard time seeing it for some reason..Thanks!

[SprungtS]

Originally Posted by kev0

Apologies..but can you somehow circle the actuator rod that is supposed to be at 11:00-12:00 position on idle? I'm having a hard time seeing it for some reason..Thanks!

So sorry! Haven't logged on in a couple weeks and just saw this. I attempted to circle it to show what I mean. The circled part is the end of the black plastic actuator rod, which connects to that valve (the metal part). I drew a quick MS paint arrow to show kind of where it should be pointed. The actuator rod isn't what is in a 12:00 orientation at times, it's the metal part that the rod connects to that rotates into those positions.

[kev0]

Originally Posted by SprungtS

So sorry! Haven't logged on in a couple weeks and just saw this. I attempted to circle it to show what I mean. The circled part is the end of the black plastic actuator rod, which connects to that valve (the metal part). I drew a quick MS paint arrow to show kind of where it should be pointed. The actuator rod isn't what is in a 12:00 orientation at times, it's the metal part that the rod connects to that rotates into those positions.

Ohh I see now. Thanks! It also seems as if you've gotten the updated version. My actuator arm looks nothing like yours. Interesting! (Ignore the red outline)

[SprungtS]

Yeah, your style is what the instructions showed when I was going through the install. I think that's part of why I didn't notice anything was wrong, it just looked like a new version. I wonder why they changed it.

Also, your vacuum line that goes to the diaphragm is on the opposite side as mine. It looks like mine was bolted on backward, but I'm not sure. It may just be how they're doing them now, but I think it makes it harder to get to the vacuum line when it's installed.

[kev0]

Originally Posted by SprungtS

Yeah, your style is what the instructions showed when I was going through the install. I think that's part of why I didn't notice anything was wrong, it just looked like a new version. I wonder why they changed it.

Also, your vacuum line that goes to the diaphragm is on the opposite side as mine. It looks like mine was bolted on backward, but I'm not sure. It may just be how they're doing them now, but I think it makes it harder to get to the vacuum line when it's installed.

Can you draw how your vacuum line is positioned? I'm struggling with my setup because I've been dealing with a vacuum leak since day 1 of install haha. I suspect it's the actuator as well.

Do you mean yours is setup like this?