Off Boost Compressor Surge

[vorigan]

many things make there designs poor

piston area versus port outlet are no where near the same

piston lift in relation to piston area

all springs arnt equal a soft spring on a aftermarket b/v means it leaks at idle thus car hates it

spring design is very important it has to retain same tension at set as when open or its linear and cant compensate for all vacuum levels

[sultan]

But does surge at low pressure actually do any damage? I know of cars from factory that do it

[vorigan]

its dependent on load extreme surge can induce over 150 lbs of thrust loading on a thrust bearing that has 2mm of contact area to absorb it, mild is is tolerated and at times cant be helped due to situations like granny driving and doesn't know how to use gears to compensate

bottom line if your happy with that gay whooooossssshhh sound and dont mind killing turbos then theres tons out there to pick from red ones always kill turbos faster

[Pappu1]

HKS SSQV??

arent they supposed to be dual stage pull type so prevent surge at low and high loads?

(just going by their blurb on the website)

[vorigan]

 SP00N said:

HKS SSQV??

arent they supposed to be dual stage pull type so prevent surge at low and high loads?

(just going by their blurb on the website)

have you seen the size of the valves? the so-called dual stage comprises of a 25mm valve with 10mm piston inside, the more noise it makes the less its doing same effect as blowing through a straw versus a 4" pipe.

and theyll print whatever they feel will attract a punter ask them what the cfm rating is in fact ring any shop selling a b/v and see what they say, their answer " itll support up to 500hp" bullshit the car will make 500hp whether thats on the car or not its relative to how much air needs to be dissipated to control surge but its shinny or a top brand name so it must be good.......BS

[ADIKT]

 vorigan']

[quote name='SP00N said:

HKS SSQV??

arent they supposed to be dual stage pull type so prevent surge at low and high loads?

(just going by their blurb on the website)

/quote]

have you seen the size of the valves? the so-called dual stage comprises of a 25mm valve with 10mm piston inside, the more noise it makes the less its doing same effect as blowing through a straw versus a 4" pipe.

and theyll print whatever they feel will attract a punter ask them what the cfm rating is in fact ring any shop selling a b/v and see what they say, their answer " itll support up to 500hp" bulls*** the car will make 500hp whether thats on the car or not its relative to how much air needs to be dissipated to control surge but its shinny or a top brand name so it must be good.......BS

Would using 2 of them equal things out?

[vorigan]

get the cfm rating from hks

[titian]

Mr Vorigan..May I : : : for you!

Bottom line:-Match the BOV/System/sequence to your application!/Driving style/Use/Turbo output!!

Maybe that will sort it out

[Guest]

 titian said:

Mr Vorigan..May I : : : for you!

Bottom line:-Match the BOV/System/sequence to your application!/Driving style/Use/Turbo output!!

Maybe that will sort it out

Whats your comment going to sort out? You are obviously as smart or smarter than steve. We arent...hence the questions. Also I like to understand stuff not just follow like blind sheep.

[vorigan]

 titian said:

Mr Vorigan..May I : : : for you!

Bottom line:-Match the BOV/System/sequence to your application!/Driving style/Use/Turbo output!!

Maybe that will sort it out

and like i havent said that?

its actually matched to the cfm required to prevent surge that has nothing to do with driving style or use it either works or it doesnt.

so how do you calculate the cfm needed?

[funkytown]

 vorigan said:

so how do you calculate the cfm needed?

this was going to be my question to you

just thinking / guessing out loud would it be some calculation of the turbo CFM at a given boost level divided by a period of time like 1 /2 seconds? (given CF is in minutes)

[vorigan]

 funkytown']

[quote name='vorigan said:

so how do you calculate the cfm needed?

/quote]

this was going to be my question to you

just thinking / guessing out loud would it be some calculation of the turbo CFM at a given boost level divided by a period of time like 1 /2 seconds? (given CF is in minutes)

great guess but no ill give out some info but it took me years when i was making my own b/v to find the calcs then apply it but i will say you have to work out back pressure on the comp wheel between load points in relation to the comp wheel flow and engine demand, its not a simple thing to do thus why so many manufacturers don't get it right.

for the most you play safe by running a stock valve or two of them

[Guest]

 vorigan']

[quote name='vorigan said:

so how do you calculate the cfm needed?

/quote]

this was going to be my question to you

just thinking / guessing out loud would it be some calculation of the turbo CFM at a given boost level divided by a period of time like 1 /2 seconds? (given CF is in minutes)

great guess but no ill give out some info but it took me years when i was making my own b/v to find the calcs then apply it but i will say you have to work out back pressure on the comp wheel between load points in relation to the comp wheel flow and engine demand, its not a simple thing to do thus why so many manufacturers don't get it right.

for the most you play safe by running a stock valve or two of them

You still make these? Or recommendations on which is best? Im guessing stock wrx bovs would be easy to come by.

[titian]

 evowrx']

[quote name='titian said:

Mr Vorigan..May I : : : for you!

Bottom line:-Match the BOV/System/sequence to your application!/Driving style/Use/Turbo output!!

Maybe that will sort it out

/quote]

Whats your comment going to sort out? You are obviously as smart or smarter than steve. We arent...hence the questions. Also I like to understand stuff not just follow like blind sheep.

Evowrx ...Pretty sure i covered it! (page one) as has Mr Vorigan since... : Obviously without giving out finer details learned over many years ;)Hence the sum up for dum***dums

[Guest]

 titian']

[quote name='titian said:

Mr Vorigan..May I : : : for you!

Bottom line:-Match the BOV/System/sequence to your application!/Driving style/Use/Turbo output!!

Maybe that will sort it out

/quote]

Whats your comment going to sort out? You are obviously as smart or smarter than steve. We arent...hence the questions. Also I like to understand stuff not just follow like blind sheep.

Evowrx ...Pretty sure i covered it! (page one) as has Mr Vorigan since... : Obviously without giving out finer details learned over many years ;)Hence the sum up for dum***dums

I might be a dumdum but it is my god given right to not have to take anything you say seriously. ;D Nothing personal I just dont know you or your rep.

He doesnt say use a low pree and high press either and again not to say youre wrong just I trust people I can trust when talking about my car.

[funkytown]

just saying... this is still page 1.. to some of us..

[vorigan]

have no issues with people thinking their asking a dumb question its more a case of no one taking them seriously or even bother trying to answer them without being a drop kick.

i gave up making my b/v many years ago i first did commercial units 20 years ago but with the cheap chinese stuff taking a strong hold no one wanted to pay for anything worth more than 10 bucks so i stopped.

tial and turbosmart make a unit that with a bit more thought could be worth using but supplying multiple springs to compensate for engine vacuum isn't smart and no other way of adjusting kills what could be a good product as for others?

that's it really,

when the LTSA regs come into play and everyone has to do a plumb back think how your going to do that, i see tial do a cap as such that goes over the top of the valve to allow a hose to be connected to plumb back, awesome stuff great idea except for one small detail.

you build a valve using a 50mm piston then reduce it to 25mm to plumb back and the point of fitting it was?

so why do the aftermarket valves cause issue? many reasons and heres one

30mm piston has a area of 706mm there abouts

has 6x 10mm oulet holes 471mm

now im sure most can see the issue here now at part throttle the holes are half open having a smaller area of around 235mm

stock valve 28mm area 615mm and it full opens even on part throttle can everyone see whats going on?

hope that helps

[titian]

Mr V...Pretty easy to understand..Sad to hear that your "kiwi"fix BOV could not be marketed effectively..Guess it needs one of those "reputable" brand names..Our should that be "repukeable"

I'm sure those that know a thing or two will be interested...At least they bloody well should be!!

[Bazza-NZ]

Great Read.. Thanks for all the information

I am about to sort out my intake and manifold and this has provided very useful

[Stoffa]

Maybe I'll try fitting a factory v7/8 one, I can just get an alloy mounting plate water cut and get it tig welded on the underside of my intercooler pipework and just put my plumb back hose back in.

sounds like a cheap fix to me.

[vorigan]

 titian said:

Mr V...Pretty easy to understand..Sad to hear that your "kiwi"fix BOV could not be marketed effectively..Guess it needs one of those "reputable" brand names..Our should that be "repukeable"

I'm sure those that know a thing or two will be interested...At least they bloody well should be!!

ill take that as a compliment as such

people have a mind set when it comes car mods and parts etc so its a hard one to crack bear in mind it was over 20years ago and i had no issue selling them the biggest down fall was the never wore out which isnt smart for business.

i refuse to compete with knock off products and never will they have there place as per the buyers wallet b/v is a market ill keep well clear even on my own setups i dont use them at all but thats another subject on how too.

[vorigan]

 Stoffa said:

Maybe I'll try fitting a factory v7/8 one, I can just get an alloy mounting plate water cut and get it tig welded on the underside of my intercooler pipework and just put my plumb back hose back in.

sounds like a cheap fix to me.

try two chris it wont hurt and cheap

[sultan]

I had one of your bovs on a previous car. Think it had "show off valve" stamped on it?

[vorigan]

 sultan said:

I had one of your bovs on a previous car. Think it had "show off valve" stamped on it?

nope they were billet ally hard anodized with motorsport eng sticker wrapped around them ive seen afew pop on trademe

[Guest]

May have a stock valve coming so will try and post difference. Not plumbing back yet as need to remake a bunch of piping after the new engine goes in.

Your explanation makes a lot of sense I understand the difference now thanks. I always just assumed bov opened as much as required not full as stock as described. Good to see you still lurk.