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Old 20th March 2010, 19:51   #1
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Default Blow Off Valve For Swift Diesel

Hi Guys,

I am new here and although Ive come across your forum countless number of times for ideas and tips ..... ive never joined the forum or posted anything before.

So In case I am making a wrong posted in a place where I should not be doing it .... moderators pls dont ban meor remove this post. I need some help and wanted some advice. I did not find a similiar post in the forum, so I thot ill make one.

My Question :-
----------------

I found a guy who can make a complete Turbo Diesel BOV and fitting kit for the Swift Diesel. But he needs one info. I asked MASS but they dont know and I dont trust local mechs here in hyderabad to do it for me too. I am from kerala but working in Hyderabad.

The question is, " What is the internal diameter of the rubber boost pipe going to the engine from the turbo" ?

If anyone else also wants a BOV for their DDiS Swift, please let me know. The price would approx be a tad under 9K.

The kit includes the following:-
-------------------------------

Parts included
  • Turbo Diesel Engine modified BOV type 2 with detachable horn (in red, blue or silver)
  • electronic valve
  • pedal switch
  • hose
  • spare parts for wiring
  • instruction manual
This BOV can be used on every turbocharged diesel engine. The BOV is triggered by an electronic valve and a switch, which is mounted to your pedal. When leaving your pedal fastly, you will have the same sound as known from a normal forced induction engine with a BOV. This system will change your spool up time and hence reduce turbo lag.

Last edited by Dippy : 22nd March 2010 at 13:45. Reason: Deleting font tags. Please do not copy from an external text editor
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Old 20th March 2010, 21:34   #2
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First tell us why you want a BOV for a diesel engine.

It will just be a dead weight and a potential leak path.

Also if you want the dia, remove the pipe and measure it with a vernier.
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Old 20th March 2010, 23:07   #3
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Default BOV for diesel - does it have any work to do?

AFAIK most diesel engines do not have petrol like throttle body which has a butterfly that flips open and close (almost) - when you leave your foot from throttle. So, a BOV is needed to release the build up of pressure in the system as your turbo is still spinning and building pressure when you leave the throttle. Assuming your diesel engine does not have a petrol type throttle system you do not need a BOV and even if you install one- it wouldnt have any work to do.
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Old 20th March 2010, 23:51   #4
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This BOV is needed for a petrol turbo. Not for a diesel turbo. Anyway I believe the turbo in question already has a internal wastegate. Ofcourse if it's the sound you're after then you can get a horn kit hooked up to your exhaust.

Last edited by deutscheafrikar : 21st March 2010 at 00:04.
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Old 21st March 2010, 03:37   #5
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So basically .... this wont be any improvement to performance ???


I thought diesel turbos would build more pressure and boost as compared to petrol turbos, So would it not help in reducing the spool up time if there was a pressure release ?

Most diesel performance shops whoz websites Ive visited do sell diesel BOVs and this is what they claim ---> This device has to be connected not only to the turbo boost pipe with the correct dimensions, but also to the Throttle control that goes to the ECU. That solenoid connector electrically realises that the throttle is cut off and so it releases the pressure from turbo and hence keeps the turbo fans spinning, so when u throttle again, your turbo spooling is reduced (in some cases) by almost 700 rpm.. Atleast thats what I understood from what that guy told me.

And he said that the pressure release would be more when you are shifting at close to 3500 - 4000 rpm from 1st to 2nd or from 2nd - 3rd ..... basically as revs increase and so I assume that the sound wont increase if it were just a vocal chord !!!
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Old 21st March 2010, 03:44   #6
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Thumbs up I dont know If you guys have already seen this or not, But check it out !





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Old 21st March 2010, 08:07   #7
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Diesel engines do not have a throttle body, therefore do not require a BOV.

I also do not buy the marketing speak because there is nothing to stop the turbo from spooling in the first place. Nothing is closed on the engine's intake side other than the normal valve action, so...
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Old 21st March 2010, 09:31   #8
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Talking

Quote:
Originally Posted by ImmortalZ View Post
Diesel engines do not have a throttle body, therefore do not require a BOV.

I also do not buy the marketing speak because there is nothing to stop the turbo from spooling in the first place. Nothing is closed on the engine's intake side other than the normal valve action, so...
I too wouldn't buy if it were just a marketing stunt, but major diesel performance companies are selling these BOVs not just for cars, but also for 4x4 and trucks. I dont think its just a cosmetic upgrade that purely makes a noise to simulate the effect.

From what I understand, the Diesel cars do not have a throttle body, but thats why you have to use the electrical solenoid which is provided with the BOV and fit it to the throttle wire that goes to the ECU .... so that the system realises when the throttle is cut off and releases the pressure.

Apart from this one difference between petrol and diesel, the rest of the functionality of the device called BOV I believe is the same in petrol and diesel... right ????


Also, when the throttle is cut off, the pressure release would surge back into the turbo and make the fans/rotors inside the turbo spin in oppo direction/or make them stop spinning. This can be avoided by using a BOV.
Hence the turbo fins keep spinning freely and dont have to spool up from dead stop when u throttle again. So this reduces spooling right ???

In a blow-through system, sudden throttle closure when the engine is under boost could cause the turbo to surge or choke, this could then damage the turbo. On a drag, drift, race, rally or street car, this can slow response time if you need to quickly get back on the throttle. A blow-off or bypass valve quickly relieves the pressure when you back off the throttle.

I thank all the responses. More suggestions and opinions are always welcome.
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Old 21st March 2010, 09:56   #9
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naaaa ..... nvm !!! I got the answer to this one on another forum. Its just a waste of money and infact reduces throttle response.

In case you wanna read what someone wrote on another forum for the same topic .... here it is and its funny I guess


Quote:
Diesel dump valves part 1:

Petrol engines have a throttle mechanism which controls the flow of air between inlet (turbo-compressor) and the engine combustion chamber, so as to keep the air-fuel mixture in the ignitable range while throttling the engine's power output. The mass of air taken in and fuel added must both be carefully controlled.

When you close the throttle on such an engine the compressor is still pushing air into the inlet and it suddenly has nowhere to go. The back pressure will inevitably slow the turbo down, and cause turbo lag when the throttle is opened again. The solution is to provide a pressure-actuated valve, which reacts to a difference in pressure between the two sides of the throttle, opening to dump the excess pressure to the ambient (dump valve) or back into the inlet (recirculating blowoff, which does a much better job by equalising the pressure on both sides of the turbo). Without this, throttles and turbos would have to be much more heavily engineered and throttle response would suffer.

So dump valves are about throttle response at gearchange and other sudden transient events, not about performance in the leadfoot top-speed way of thinking.

The need for a dump valve is a weakness of turbocharged petrol engines, putting another contraption in the inlet side which disturbs the gas flow and is a point of failure. I find it mildly astonishing that anyone should be proud of their car farting on the overrun. But then I have a diesel so I'm probably disqualified from having an opinion.

Diesel engines have no throttle. Power output is controlled by the fuel quantity injected at each stroke. Mass flow around the compressor-combustion chamber-turbo impeller loop is always uniform. This makes diesels much better candidates for forced induction.

A dump valve can only do harm to the performance of a diesel.

Turbo wastegates are not dump valves, they limit the pressure on the impeller (exhaust) side of the turbine to prevent the turbine from overspeeding when the engine's gas flow becomes too high i.e. at high rev's. The higher-performing VAG turbos use variable-geometry inlet vanes and have no wastegate.

There are "dump valves" for TDi's that are activated by the ECU, such as the Forge one. If fitted and adjusted properly they do not affect performance, they just make a noise. So you can fit them anywhere you like, wherever you want the noise to be heard best - say on the dashboard, or maybe on the roof.

Here endeth the first lesson



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Last edited by aah78 : 21st March 2010 at 22:27. Reason: Additional smileys removed. Please limit smileys to 2/post. Thanks.
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Old 21st March 2010, 13:52   #10
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If you want the turbo to spool up quicker, revise the air intake to a short and none restrictive one.
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Old 21st March 2010, 23:48   #11
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Question To The Mods

This post was taken from the forum for Seat Cupra, www.seatcupra.net

It came as a search result in google when I searched for Diesel BOV. But now when I search it again, the results are different and if I searched for this post again on Seat Cupra forum itself, then its asking me to register myself. So If I get the same post again, I shall definitely post the link here.

There is much discussion abt Diesel BOV in other car forums. I was a little suprised to see no one here actually discussed about this before.

Last edited by Jaggu : 22nd March 2010 at 01:16. Reason: Removing [Font] tags, please avoid copy paste from external font editors, also do a preview before submit. Thanks
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