Post your Synapse DV config and results
May 16, 2011, 12:39 PM
#196
For street driving, I think the valve works really well out of the box. I drove fro 2 weels of street driving, and didn't have any issues. I have said the same thing regarding my TiAL QR. IMO, street driving is still not a good way of testing to make sure a part works that way it is designed to.
May 16, 2011, 04:46 PM
#197
So i got my Synapse installed tonight. I decided to try it in push mode first with the vac line hooked up to Port B and Port A VTA. The car seems to build boost faster and pulls really good in 1st and 2nd (only hitting aobut 22 psi in these gears). But in the 3rd-5th I get a flutter sound once I hit around 25 psi. What do you guys think is making the flutter- BOV, wastegate, or compressor surge?
I know I need to retune the car because I'm quite certain now that my old BOV was leaking. I just wanted to get some input on what could be causing the flutter before I tackle the retune.
I know I need to retune the car because I'm quite certain now that my old BOV was leaking. I just wanted to get some input on what could be causing the flutter before I tackle the retune.
Well I tried it both ways and got pretty much the same result. Still getting some flutter in third and a lot in fourth. Could this be a result of running too much WGDC? Now that my BOV isn't leaking I don't need to run as much to reach full boost and perhaps it's causing compressor surge?? IDK What do you guys think.
So I went and did some tuning this morning and managed to solve the flutter issue. I pretty much found out that 95% of the drivability and tuning issues I was having were related to my old BOV. Without getting into too much detail, some of my boost settings were kinda wacked out because the old BOV didn't want to hold boost after it hit 25 psi and it also wasn't reacting and closing fast enough after I would push the clutch in. The last time I was at the track it seriously felt like my clutch was slipping because in between shifts I don't think the old BOV was closing properly and the car just wouldn't really pull after shifting gears at WOT. Now when I shift gears at WOT... It feels like I'm being punched in the chest!!! Boost comes on almost instantly once I let the clutch out and punch the gas, and the thing pulls like crazy!!!
Bottomline... The Synapse DV is awesome!!! I wish I would have bought one of these a year ago. Drivability is better than either one of the stock 9 BOVs I've used and obviously the Synapse holds boost much better as well.
So for anyone who cares, here's what I did in regards to the tune. (This is the Reader's Digest version):
- I tried lowering the WGDC to 50 from about 4000 up. This would only give me a peak boost of about 17psi and I was still getting the flutter after about 4500.
- Made some changes to the Boost Adder tables (which were out of whack because of the old, leaking BOV) and zeroed out the Boost Error Correction tables. This seemed to solve the flutter issue whenever I would hit peak boost.
- Starting raising the WGDC back up until I was hitting my previous peak target of 25psi. I ended up running almost the same WGDC in the mid RPMs (4500-6000) as before, but about 10% less WGDC after 6000 in order to hit the same boost at 7000 (about 22psi)
Last edited by Ian0611; May 16, 2011 at 08:07 PM.
May 20, 2011, 10:23 AM
#201
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Finally got to track test the Synapse diverter valve in its multiple orientations over the weekend. In both, autox and road course, I find that the valve works much better in port B only. Running both ports gave me flutter, and alittle bucking. Furthermore, I find that running push mode was the best for my setup. Mind you, I have the TiAL flange setup, and the bov is mounted directly to the uicp, and not the intake pipe like most stock configurations. During the testing, I ran into the same partial throttle issues I did with the TiAL. However, I started playing with the preload adjust, and it started working better and better. I'm right at the halfway point of the adjustment, and works really well. The car feels absolutely amazing on and off throttle.
What I've found in road racing applications is especially true in this scenario: Long straight that goes into heavy braking, with a tight exit that requires slow throttle input. If you're setup with A+B, you'll find that the vacuum is too strong and it opens the BOV/DV. So, for anyone road racing, I really recommend using Port B.
The solution by other manufacturers is more spring pre-load, which translates into the DV/BOV not working in other critical areas. Pneumatically, with only Port B the DV/BOV won't self relieve pressure until well over 60 psi anyhow, so, you'll be just fine.
May 20, 2011, 10:35 AM
#202
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BTW just as a side note, I know that we talk alot about the DV being quick to open, but the real gold mine is how fast it closes, when you open up the throttle again. It may open in 30 ms, but it also closes in 30 ms. You should see just how incredibly fast turbo shaft speed can actually pop when it is properly re-loaded during throttle transitions.
May 20, 2011, 02:48 PM
#203
BTW just as a side note, I know that we talk alot about the DV being quick to open, but the real gold mine is how fast it closes, when you open up the throttle again. It may open in 30 ms, but it also closes in 30 ms. You should see just how incredibly fast turbo shaft speed can actually pop when it is properly re-loaded during throttle transitions.
I can't believe how much different the car feels now that I have a properly functioning BOV! Yesterday, on my way home from work I did a quick shift from 1st to 2nd at WOT and I actually managed to chirp the tires going into 2nd!!! That's something that I've never done the entire time I've owned the car. I'm still having some fluttering/surging issues in 4th and 5th but I've managed to get that worked out in 1st-3rd so I'm sure I just need to lower the WGDC a little more in those gears (Thanks Tephra for gear based boost maps
) The Bottomline is that I love this thing and I'm still kicking myself for not buying one sooner! With as good as the car feels right now I think I'll hold off on making my switch to E-85 and any other mods and just enjoy what I have for a while 
May 27, 2011, 12:45 AM
#206
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i have my dv going up to sale tomorrow.. a little fyi. reason why is because i got tuned on a crushed stock 9 dv and i dont want to play with it. it pulls good as is.
Jun 2, 2011, 10:12 PM
#207
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I just installed mine in Push mode with A+B ports hooked up and didn't run into any problems in my initial testing. It opens fast, closes fast and I could not get it to flutter at all. Tomorrow when I get more time, I'll try B port only (push) and then also Pull mode A+B and B only to see if I can find any noticeable differences.
I will say though, it does come quite close to the strut bar in Push mode and has even rubbed a tiny bit due to engine movement.
I will say though, it does come quite close to the strut bar in Push mode and has even rubbed a tiny bit due to engine movement.
Jun 2, 2011, 11:16 PM
#208
The only thing I haven't tried is A&B together. I think I've figured out my flutter problem though. It does seem to be related to my Grimmspeed 3 port BCS. Whenever the BCS tries to make small changes the valve flutters. I know Synapse said that this will happen when the BCS and DV are hooked up to the same line but the only thing I have hooked up to the line with the DV is my boost gauge so I'm a little confused as to why the BCS is causing the flutter. I basically fixed it by just running the same WGDC from 4000 rpms and up. I don't have as much control over taper now but since I have gear based boost control that doesn't bother me as much.
Jun 3, 2011, 10:54 PM
#210
Yeah I thought they said that it was just the BCS that you shouldn't hook it up with. I tried asking them about the boodt gauge but I never got a reply back. I may try rerouting the lines next week so the DV has it's own designated line but I'm not sure where else I can tap into for the boost gauge.