Jump to content
SAU Community

Piston Type Bov's

Get EPIC

By Get EPIC,
in Engines & Forced Induction

 Share

Recommended Posts

Get EPIC Rising Star

Get EPIC

Posted
Posted

Hi all.Just had a few mods done to my r33 and decided to change Bov as it was causing strange lag issues on full boost on gear changes.Have tried 3 different piston type BOV's and have had bad compressor surge with Both the turbosmart v-port and the blitz supersound and a tiny little bit of flutter with a cheapo chinese unit i picked up from rolin imports on the gold coast which has performed the best out of the three.Do piston type bov release as quickly as the stock units or has my mechanic not hooked up the vacuum fitting to the manifold correctly or is it maybe something else?

Link to comment
Share on other sites
rob82 Mentor

rob82

Posted
Posted
Have adjusted all of them as loose as they can go.Thanks.

Stop wasting your money on turbosmart crap and alot of the popular wanker brands - none of them work. If you are still running a MAF based system and you dont care about the wanker sound than get a steel top EVO9 BOV - it is a proper valve style BOV that actually opens under around 10" of vacuum as a BOV is meant to. It has to plumb back tho.

I remember testing a turbo smart item that didn't budged at all with 26" of vacuum with it loose as it will go.

I couldn't believe the difference an EVO9 BOV made on my car - no MAF reversion issues and so much quicker onto boost after a gear change.

Link to comment
Share on other sites
Beer Baron Grand Master

Beer Baron

Posted
Posted

a valve type type BOV (ie a proper one like a trust type R etc) will always be better than the cheap ones that just have a piston inside a tube. better reaction and generally better flow/bypass capability.

Link to comment
Share on other sites
juggernaut1 Proficient

juggernaut1

Posted
Posted (edited)

I agree with all of your comments. I have a Turbosmart raceport bov on my car and its crap.

Firstly there is no spring tension adjustment on the BOV (which I found out after buying it)....so the only way to adjust them is with a spring kit......so I bought a spring kit and tried different springs...basically its still useless as I either get surge on a stiff spring or it won't close on idle with a weaker spring.

Having done a bit of reasearch in the past I decided I was going to get a Trust Type R bov becuase of its valve design......and now the Evo 9 Bov sounds promissing too.

Edited by juggernaut1
Link to comment
Share on other sites
Beer Baron Grand Master

Beer Baron

Posted
Posted

type R is good for plumb back too. :D and it's easily adjustable (and can be ordered from the factory with a stiffer spring kit too) and it will flow as much as you will ever need (well pretty much). It's pretty much the only decent properly made BOV out there. there are some good mega drag 1200hp type ones but they are not really suitable for most of us. just looking at the trust one should tell you it's the one you want, it looks like a wastegate in it's design which is what you want. fast response, good sealing under boost and at idle, and able to quickly bypass large amounts of air. :P

Link to comment
Share on other sites
R31Nismoid Grand Master

R31Nismoid

Posted
Posted

How the trust one is any better than a GTR one i'll never know.

I mean yeah if you are into nice shiny stuff i can understand... but otherwise the GTR BOV does the same job as anything else, and is half the price.

If you use a single one, it's cheaper again!

Link to comment
Share on other sites
rob82 Mentor

rob82

Posted
Posted
type R is good for plumb back too. :D and it's easily adjustable (and can be ordered from the factory with a stiffer spring kit too) and it will flow as much as you will ever need (well pretty much). It's pretty much the only decent properly made BOV out there. there are some good mega drag 1200hp type ones but they are not really suitable for most of us. just looking at the trust one should tell you it's the one you want, it looks like a wastegate in it's design which is what you want. fast response, good sealing under boost and at idle, and able to quickly bypass large amounts of air. :(

You do realise that a good BOV will be open below 10" of vacuum - so it will be open at idle unless you have big cams, thats why you need to plumb them back in a MAF based system. A well designed valve style BOV will have a larger diaphram area than valve area so that the spring force is unnecessary as there is more pressure force on top of the valve than below.

Link to comment
Share on other sites
R31Nismoid Grand Master

R31Nismoid

Posted
Posted

They are good at making annoying noises?

Other than that, nothing beats stock.

If anyone has a GTR BOV for sale iwould like to buy one.I put this in the WTB section last week and it seems they are a bit hard to come by. :(

I've got one i think in my back seat, PM me if you want it.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Lithium
      Boost level and torque curve

      By Lithium · Posted

      There is a LOT of stuff that can be done, it all depends on how much time and money you want to spend on doing in.  Not all ECUs will be able to do it, and the more control you need the more time and knowledge needs to be put into making it work.  If you're willing to spend the time and money and have the right hardware and skills involved there's a lot that can be done. 
    • thx78
      Boost level and torque curve

      By thx78 · Posted

      I am impressed with all this level of adjustment. I didn't expect all this possibility
    • Lithium
      Boost level and torque curve

      By Lithium · Posted

      Correct.  In the case of the 500kw dyno plot I showed you the car actually runs two boost control solenoids for boost control and a 5psi wastegate spring.  It allows me to control how much boost pressure is applied to both sides of the wastegate valve at any point and fairly accurately control boost target as a result. I've tuned it so that it's able to target anywhere from 5psi to 25psi depending on what's needed.  The target tables I've set up in that car are Gear vs RPM, so every gear has potential for a different boost (and torque) curve.   First and second gear have quite low boost targets, third gear actually has different target boost all the way through the rpm range as it's a stock RB25 gearbox - the boost targets have been chosen to maintain a peak of 600nm (what the owner has set as the maximum torque he's happy with putting through the stock 3rd gear) but it carries that to the rev limiter.   The boost curve to achieve that is something of a ramp up, then hold, then ramp up again and the power curve looks more like a flat line haha.  
    • thx78
      Boost level and torque curve

      By thx78 · Posted

      so you can decrease or increase the boost depending on the diet as you wish?     by acting on the wastegate?
    • Lithium
      Boost level and torque curve

      By Lithium · Posted

      That's torque and power, it's all from a single run.  The boost curve is "held back" from it's peak target in the 3500rpm to 5000rpm range from memory, so it ramps hard to something like 18psi then climbs more progressively to 23psi nearer 5000rpm.   It makes the torque (and power) ramp more "natural" and less hard on parts and traction, it doesn't feel artificially held back.   
×
×
  • Create New...