Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

Hey HT. So I'm running a TiAL Q BoV and a TiAL MVS 38mm wastegate. Two questions here:

1) Is it ideal to have the blow-off valve open on idle? Apparently for MAP cars this is whereas for MAF cars the valve should be closed. I just wanted to be certain if it's okay that the valve is open on idle
2) I am seeing up to 10 pounds at full boost but I'm only suppose to push 5 pounds max based on the wg spring. My TiAL MVS wastegate has a 5 psi green spring in there. What's going on here?



Some extra context for my setup (and you can check my thread here for some pictures https://honda-tech.com/forums/forced...ter-3322947/):

• B18C5 Stock block
• Go-Auto XS500 Turbo kit w/ GTX 2867R turbo
• TiAL MVS WG (5 pound spring)
• TiAL Q BoV / HKS Racing SQV (just installed and have my TiAL sitting now)

re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

You're in vacuum at idle, and the BoV is before the MAP sensor so having it cracked open is fine. It should close once the intake is pressurized.

Don't know what to tell you about the springs, you can find color charts for Tial springs and their corresponding "weight" online. The colors have changed over the years (I think only once or twice) so make sure you know how old your WG/springs are.

re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

Yes, the spring floating at idle is fine, and IMO ideal on a MAP car for response.

Are you getting the MAP reading from the log or from a gauge? Where is the gate vac signal coming from?

BOV random ,,,

Tial chart
http://www.tialsport.com/documents/MVSspc.png

re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

do you have the top port[s] on the wg open to atmosphere?
do you have the other two AIR ports in the bottom of the wg plugged with the caps that came with it?
If your answer is no to either of the above questions, that would be why you're running roughly double what the spring is rated for.

re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

I have the latest spring with the green color which is rated for roughly 4.35 pounds

I am getting my vacuum source from the intake manifold read through a PLX vacuum sensor as well as data logging


All air ports are plugged and I have my vacuum lines hooked up to a boost controller / vaccuum source per Hondata's instructions (Hondata s300 Programmable ECU Guide). So it sounds like I should open up the top wg airport then?
https://cimg0.ibsrv.net/gimg/honda-t...ed7ddb24b2.png

re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

that is all correct for when using a boost controller. Keep it as is.
I assume you have the top hose to port 2 on the solenoid, and the bottom hose is T'ed into the boost source hose that is connected to port 1 on the solenoid?
What are your settings in Smanager for the boost control tab?
Where is the boost source hose connected on the engine?

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

That is correct, top wastegate is to port 2 and bottom wastegate is to port 1 with a tee to a vacuum manifold. Here are some pictures
https://cimg7.ibsrv.net/gimg/honda-t...dbd43db255.png
https://cimg1.ibsrv.net/gimg/honda-t...08fb3226b3.jpg
Middle port feeds solenoid, left feeds purge valve, right is boost source and the far right is for catch can



https://cimg3.ibsrv.net/gimg/honda-t...166b1b9b5a.png
Hondata Boost Control tab

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

That's your answer right there. Everything mechanically is working perfectly. You have the settings set up to run almost double what the wastegate spring is rated for by having the boost control set at 85% duty cycle everywhere in the gear based table. If you change that whole table to 5% you should see around 5.0-5.5psi at all times. Or alternatively, where it says "control method" click "fixed duty cycle" and change it to 5%

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

First, click that variable frequency box. Turn that shit down to 20-31hz lol. Second, click the fixed duty cycle box. Input lower numbers like 10 percent, and see whats you boost to, increase from there. After that table is setup off of what duty cycle is reached from whatever certain psi. Then you can go down the the boost by gear by rpm table. Or you can just chage duty cycle inputs in fixed, write them down, or remember what is what. Then input into the cells for bbg.

85 percent is always gona over shoot it. Although, you "CAN" leave the 85 percent in lower rpm cells to help ramp the boost up. It kinda like a broken down quick spool setup. But, you want to taper that down fast.

3 port solenoid correct? Or 4port?

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

Yes, that too. Though I usually suggest 45hz. Mac solenoids are designed for 30hz-60hz, and 45 works perfectly in most setups

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

yes it's a 3 port solenoid

Thanks for the input guys. Next time I take her out I'll be sure to update these settings as you guys have stated. It's odd that my tuner was confused when he saw 7- 9 pounds on the dyno.... he's been tuning turbo Honda's for awhile now I figured he should have known this? So couple of questions here:

1) If I change those settings do I need to re-tune for the reduced max boost?
2) If it's set at 85% of maximum boost, isn't the maximum boost dictated by the wastegate spring pressure? Sorry for the noob question I'm still learning here.

Re: Troubleshooting: TiAL Q BoV and 38mmMVS WG issues
 

Yeah I would think your tuner would know this.

1) if your tuner did their job properly, no you should not have to re-tune for lower boost. When tuned properly, usually you only have to re-tune if you RAISE the boost. But, if your tuner couldn't figure out the boost level issue, I don't know how much I'd trust their tune to begin with
2) wastegate spring pressure is minimum boost, not maximum boost. The duty cycle percentage is just a percentage of the ON signal to the solenoid compared to the OFF signal to the solenoid, and it does not correlate to any specific level of boost in relation to all vehicles as a general whole. Different setups can vary a LOT. Typically, with small and mid sized turbos, 100% duty cycle is roughly double what the wg spring rating is. But with larger turbos, or any setup that is very efficient, 100% duty cycle can be as much as triple what the wg spring rating is for. It's different with every vehicle and every setup. The only thing that is always true is that wg spring rating is always the minimum boost, which occurs when you don't use boost control, or when the boost control solenoid is at 0%