I spent some time to install the Synaptic diverter valve on my evo IX today. I set it up as a "push" type and used the included hose tee to connect both A and B ports to the manifold vacuum source...basically the same way the stock valve was installed, except that the stock valve on mine seem to be installed in "pull" mode.

My car is tuned for 24 PSI. Initially I feel the boost come on "harder" but the valve does flutter easily when lifting off the throttle. There is also some surging at partial throttle...I haven't played around with the preload yet, and maybe messing around with that will allow it to be smoother. The stock valve did flutter sometimes, but not nearly as easily as this one does. Hopefully I can get it to the point where it's smooth while cruising or I'm going to have to go back to the stock part.

The sound is noticeable even though it's a DV and therefore recirculated...though it's nowhere near as loud as some ricer with a BOV that's VTA.

Anyone else using this DV find a way to make it act nicely when cruising?

 

i suggest putting it in pull mode, a port (closest to the adjusting screw) @ ZERO preload.

 

The ports on mine are equally spaced from the adjusting screw and I did not change the adjusting screw so I assume it was set on zero from the factory.

This is the manual that I found after I installed it:
http://www.synapseengineering.com/su...ual_webres.pdf

Are you suggesting I open one of the ports so it is VTA?

 

^ They are very close, but they are not the same distance from the adjusting screw.... take another / closer look.

1 port pressurizes the center portion, while the other port pressurizes the outter portion of the dv.

 

Yeah I noticed that the ports are spaced differently. I did the switch and plugged in port A, leaving port B VTA and it really smoothed things out. The only thing is that it flutters when I let off under partial acceleration...but I don't think that is a big problem.

 

Are you certain that you are in push mode and not pull? The only reason I'm asking is because the stock DV is installed in push but you mentioned yours was in pull. The Push mode is when the boost pressure from the UICP is helping to open the valve.

In pull mode, I would expect more chance for surge during part throttle accelerations or lift-off. But, I don't have this DV yet, so I'm trying to read up on various people's experiences so far. I would personally run it in push mode though.

 

I haven't had a chance to drive extensively because my clutch is shot and I'm waiting to get that replaced. Hopefully next week I can get that done and then drive the car harder.

One thing I can say is that pull mode works a lot better for me (same setup as stock DV). I initially set it in push mode because I was going by the youtube video that synapse put up. I think for most cars with basic mods pull mode is the way to go, it's night-and-day in terms of smoothness...and with pull mode this one feels as smooth as or better than stock. IT's easy to test out different configurations. Some people say using A+B ports with the T connector is even better than having port B vent to atmosphere.

Another big plus is this thing does not leak at all. People keep saying the stock IX DV can hold up to 30 PSI without a problem but I beg to differ. After putting in this DV I feel the boost coming on a lot stronger and it does not fade away at the peak like it does with the stock. The fact that I merely swapping this valve resulted in my clutch being unable to hold at WOT suggest that I recuperated some power I was losing due to a leaky stock DV (previously I could go WOT and the clutch wouldn't slip much).

 

OK, that's what I thought...you're confusing the two modes. The stock DV is push mode (the UICP pressure help open the valve) and that is the mode that you are saying works better. I would agree 100% even though I don't have the DV yet. Pull mode should cause surge on part-throttle applications.

 

Right...my bad. I was mixing it up. Push mode is the way to go...I had it in pull mode at first, based on the youtube video. I was forgetting that the side connected to the IC pipe is the "inlet" side for boost and not the side sitting on the turbo intake pipe. Just to clarify - using the stock config = best performance for me.