AlligatorMan

Just thought I would post this review for those interested. These BOV's were run as bypass valves (recirculated) on my KA-T S13.

SSQV Experiences:
- Would surge at anything less that 3psi
- I tried everything to resolve this including larger signal line, shorter line, dedicated line, loosening spring, softer springs from sprinkler heads etc)..
- Would not open on light load shifts causing surging and MAF overfueling from surge.
- I would assume all this compressor surge is not good for the turbo...

Synapse Synchronic Experiences:
- Bypass valve design allows air to bypass turbo during light load cruising for increased mileage (less load on engine)
- Opens while reving when stationary which SSQV would not do for me. This thing flows a TON of air!
- Cool sound on full throttle shifts..like a laser beam from Star Treck or something, even recirculated
- Light load shifts is whisper quite (*sleeper style*)
- No surge at all, not even during light shifting.

Overall I'm very pleased with the Synapse BOV. While I would cringe when shifting with the SSQV, the Synapse is a relief! It actuates fast like a pneumatic piston even during vacuum, has a push pull design to increase mileage, does not leak (tried to 10psi) and is easy to install.

I have yet to adjust it so there may be ways to transient increase response as well.

Synapse is the real deal!

patrick4588

iTrader: (1)

badass man. i have not installed mine yet, but i will soon. i am expecting very positive results as well. have you changed the pre load yet? i want to play with that. lol. i also got the 40mm wastegate to toy around with. im waiting on a couple things to get in before i can test it all out. but these are quality pieces for sure.

Mykizism

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlligatorMan &raquo;</TD></TR><TR><TD CLASS="quote">Just thought I would post this review for those interested. These BOV's were run as bypass valves (recirculated) on my KA-T S13.

SSQV Experiences:
- Would not open on light load shifts causing surging and MAF overfueling from surge.

[</TD></TR></TABLE>

how would, the bov not opening would cause a MAF system from overfueling ?

alex_s817

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlligatorMan &raquo;</TD></TR><TR><TD CLASS="quote">
- Bypass valve design allows air to bypass turbo during light load cruising for increased mileage (less load on engine) </TD></TR></TABLE>

im just wondering but doesn't this mean that unfiltered air is entering the engine?

AlligatorMan

Yes if you are venting to atmosphere (VTA) but mine is recirculated as mentioned in my first post.

alex_s817

oh i see, thanks

AlligatorMan

THe BOV not opening causes compressor surge and backflow through the MAF. The N62 (300zx Z32) MAFS in a draw-through setup reads both ways and it counts some of the metered air twice when compressor surge occurs, causing a rich mixture.

Some MAFS only read one way, such as the S13 DOHC KA MAFS.

I noticed that with this BOV recirculated it has less of an overfueling problem on throttle application after a gear shift.

No I have not played with the pre=load yet but I'm waiting for the instructions from Synapse just so I dont screw anything up

Flashmn

MAF has to recirculate, if you let it out into the atmosphere the mixture goes way rich.

As for having air bypass the turbo, I'm not all so hot about that, during cruising your turbo doesnt really give boost, so you wouldnt use additional fuel even if it went though the turbo.

LeGeND4LiFe

Can you post some video clips?

Synapse

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlligatorMan &raquo;</TD></TR><TR><TD CLASS="quote">This thing flows a TON of air!

It actuates fast like a pneumatic piston even during vacuum, has a push pull design to increase mileage, does not leak (tried to 10psi) and is easy to install.

Synapse is the real deal!
</TD></TR></TABLE>

I want to add that most people are far too concerned with flow when it comes to a blow-off valve, bypass valve or DV. High flow is an easy band-aid for eliminating compressor surge. But high flow doesn't do you any good if it actuates late, and you get surge and then the big dump of air. What happens when speed shifting is that by the time you get into the next gear, all you get is surge and no time to dump.

Eliminating compressor surge is all about fast actuation, and accurately following the change in pressure that happens in the intake manifold.

We've tested it to hold pressure to 60 psi with compressed air and no pressure on the actuator side to hold it closed. Just pipe pressure.

HiProfile

I'd be suspect of it actually giving better milage. Unless you have a small motor in a heavy car (like an sr20 in a 240 running 19"s) you won't be drawing all that much air through the fmic. The pressure drop is related to how much flow & pressure is moving through it, and at ~10 Hg" while cruising at 80mph, there would still be minimal restriction. Maybe if you had a small name-brand core that has very dense fins you may see a restriction at low load, but if you aren't making 400+ whp on a $500 fmic, why run it at all, right?

So far it looks like a good BOV, so don't think I'm slamming it. Just trying to keep any user-created hype to a minimum.

Synapse

Guys here's the instruction manual for the SB001 in case you need it.


http://www.synapseengineering....l.pdf

AlligatorMan

Peter,

Just thought I would make a note that I am getting ~10km/Litre of gasoline while putting around town and some highway driving with the Synapse BOV. This is compared to ~9km/Litre with the HKS SSQV under similar conditions. Interesting benefit that I hope I can continue to enjoy on this thirsty KA24DE.

Also, concerning the BOV signal line plumbing..
1- Should I shorten the T'd part of the signal line to the two ports on the BOV as much as possible to get fastest reaction time?
2- Does it matter which port on the BOV gets the straight T'd section of signal line?
3- What happens if I only run the signal line to one of the ports? Does it matter which one?

Thanks,
Nate

Synapse

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlligatorMan &raquo;</TD></TR><TR><TD CLASS="quote">Peter,

Just thought I would make a note that I am getting ~10km/Litre of gasoline while putting around town and some highway driving with the Synapse BOV. This is compared to ~9km/Litre with the HKS SSQV under similar conditions. Interesting benefit that I hope I can continue to enjoy on this thirsty KA24DE.
</TD></TR></TABLE>

Saying that out loud on HT could get us flamed. But thanks for the feedback. On cruising, there's no reason why you wouldn't get the MPG same as NA stock since you are completely bypassing the turbo.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlligatorMan &raquo;</TD></TR><TR><TD CLASS="quote">Also, concerning the BOV signal line plumbing..
1- Should I shorten the T'd part of the signal line to the two ports on the BOV as much as possible to get fastest reaction time?
2- Does it matter which port on the BOV gets the straight T'd section of signal line?
3- What happens if I only run the signal line to one of the ports? Does it matter which one?

Thanks,
Nate </TD></TR></TABLE>

Great questions

1- It shouldn't make a difference
2- For response times, the straight section of the Tee should go to Port B, the one furthest out from the set screw. With a Y tee, it wouldn't matter.
3- Try either one, but it will only really work if you are running vac, higher than 25" between gears. You've got the best configuration right now that follows design intent, recirc'd and open under vac. Only running 1 port will likely not pop the valve open fast enough since it is a pull-type with no boost helping to open it up.

Why we're using both ports is that by design, I wanted to use the Synchronic geometry, so that the valve would be self centeringer under vac and pressure and seat well at high piston velocities. For later purposes, the 2 port, actually 3-port design is there for overboost protection features that aren't fully developed yet. Much more math to do, unfortunately.

AlligatorMan

I see that the diagram in the instructions illustrates the answers to my questions, if you look closely and pay attention to the port discrepancies.

I had the straight portion of the signal line going to the wrong port, so now I can sleep well at night and look forward to driving tomorrow!

Bailhatch

Now blow off valves make better gas mileage?! this is great!

Synapse

The Jackson Racing roots blowers have this same bypass effect built in. So that at cruising, which is also high idle, you are bypassing the blower.

AlligatorMan

HAHAH OEM turbo cars also have this feature built into their Bosch bypass valves for improved mileage. The downside is that some of them leak under high boost (&gt;15psi), which I think is cured by this design. I havent tested it over 10psi yet.

Bailhatch

Yay!

VspecSiR

this BOV uses HKS style BOV flange, will the synapse BOV bit the HKS flange? or is it different all together, where did you guys buy your BOV's from?

carrnut21

what did you pay for the Synapse?

AlligatorMan

It will fit the HKS weld-on flange. Thats what I have.

I got a good deal on it for being an early adopter (aka guinea pig to some).
Retail pricing should be competitive with other popular BOVs on the market.

F20Cteg

All this **** talking on the HKS has got to stop. If the HKS is not working right then:

1- Yours is fake, get a real one.
2- You expletive*d it up somehow.
3- You have a poor vacuum source.

I have an HKS that is almost 5 years old and not once has any of the 4 setups it has been on created any little bit of surging.

I have to try to not let it open under even under slight vacuum.


HKS SSQV

AlligatorMan

Well I'm glad somebody had a good experience with HKS..now hopefully I can still get something for it when I sell mine.

tyrone27

where do you buy it?