So I understand that dumpvalves are generally a bad idea as they stall the turbos etc etc (or something along those lines)

Someone told me that if I fitted hard boost pipes I may gate a more pronounced wastegate chatter type sound ? or is this nonsense :)

I do need to get rid of my honking

 

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the cars honking :)

Im running twin bailey dump valves on mine, they work just fine, car boost hard and runs very well generally

Im running twin bailey dump valves on mine, they work just fine, car boost hard and runs very well generally

 

so do you still have your recircs ?

No, recircs replaced by dump valves

can I fit screamer pipes ?

keymeister - do a search :tt2: and stop drinking and posting :pint:

So I understand that dumpvalves are generally a bad idea as they stall the turbos etc etc (or something along those lines)

Someone told me that if I fitted hard boost pipes I may gate a more pronounced wastegate chatter type sound ? or is this nonsense :)

I do need to get rid of my honking

 

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the cars honking :)

 

I would steer clear of dump-valves personally. They are a waste of time and money. They do absolutely ZERO for performance and screw up the metering of air. Some might not notice it, but it does happen. To me, they are completely nonsensical and only sound like the air-brakes from an articulated lorry.

 

Hard pipes will not really pronounce the wastegate chatter. Fitting a cone filter will have more of an effect than anything else. When I fitted my A'pexi, I could really notice a difference. The noise from the wastegate on standard intakes is muffled, whereas in a cone filter, the noise can project outward as it's not sat in a plastic box with a restrictive filter in front of it.

 

If you have honking, then the diaphragm inside the recirc valve is leaking and giving you a croaky quack sound when you come off the throttle. You can either fit another set of known good recircs, get the BDE goose honk killer kit for your existing ones or get yourself some aftermarket recirculating valves. Forge and Bailey both do aftermarket recircs IIRC

Edited May 23, 201411 yr by Funkysi

I would steer clear of dump-valves personally. They are a waste of time and money. They do absolutely ZERO for performance and screw up the metering of air. Some might not notice it, but it does happen. To me, they are completely nonsensical and only sound like the air-brakes from an articulated lorry.

 

Hard pipes will not really pronounce the wastegate chatter. Fitting a cone filter will have more of an effect than anything else. When I fitted my A'pexi, I could really notice a difference. The noise from the wastegate on standard intakes is muffled, whereas in a cone filter, the noise can project outward as it's not sat in a plastic box with a restrictive filter in front of it.

 

If you have honking, then the diaphragm inside the wastegate is leaking and giving you a croaky quack sound when you come off the throttle. You can either fit another set of known good recircs, get the BDE goose honk killer kit for your existing ones or get yourself some aftermarket recirculating valves. Forge and Bailey both do aftermarket recircs IIRC

 

 

I wasn't aware you could get aftermarket recircs , I will kill the goose honk ! cheers

Confusing thread this especially for nubies, to be clear the wastegate is part of the turbo and not what your all discussing, either stock re-circ valve after market blow off valve or dump valves not wastegate.

 

 

Jeff TT

That was my fault. Not sure why I said wastegate in the latter part of my post. Will edit.

Si is right, I have had most of the above issues.

 

My car came with dump valves over the top of the recircs and they made it run really badly due to the metering issue.

 

It was when I fitted hard pipes that I started hearing my goose honk, to me it sounds like the noise you get when you blow over a milk bottle top.

 

To solve that I am having BDE killers fitted. But you can still hear a "K-ssssshhhhhc" noise with recircs if you have the roof open and are near a wall or something.

Confusing thread this especially for nubies, to be clear the wastegate is part of the turbo and not what your all discussing, either stock re-circ valve after market blow off valve or dump valves not wastegate.

 

 

Jeff TT

 

From the general line up of replies I think it's more aiming at the noise commonly referred to as "wastegate chatter" and the relationship with bov or recircs.

Here is my simplified understanding of the noise and the best ways to pronounce it: Blank off the recirc valves and have no atmospheric bov creating a closed system. When coming off boost this now means the pressurised air can only exit the way it came in. In turn this stalls/surges the turbo and the pressure changes confuse the wastegate, a combination of which creates the noise you're after.

As Simon mentioned, a less restrictive filter would make the noise more audible, as would more boost. The noise is generally more apparent on single turbos cars due to running high psi. In theory it's not good practice for turbo longevity but I've also heard of people doing many miles with no issues like this. I wouldn't recommend it.

I'm not an expert on the subject and stand to be corrected if any info is inaccurate.

Edited May 23, 201411 yr by Joely P

Like this: http://youtu.be/Si8VR7aAXnQ

I quite like that noise.

 

I had the goose honk issue, sounded ridiculous. So I got a pair of baileys cost me about £100 I think all in, maybe less to fit them. I call them my angry budgies. At low boost they cheep and higher boost they hiss. I did it because it was fun, I kept a set of working recircs incase I got bored, changed my mind etc but I do enjoy the woosh sound especially down tree or stone lines a roads as it echoes off at full boost.

So I understand that dumpvalves are generally a bad idea as they stall the turbos etc etc (or something along those lines)

Someone told me that if I fitted hard boost pipes I may gate a more pronounced wastegate chatter type sound ? or is this nonsense :)

I do need to get rid of my honking

 

- - - Updated - - -

 

the cars honking :)

 

dump valves are to help stop turbo stall not stall the turbos. from what I have been reading if you making big bhp thay can be a good idea. am going for round 600bhp and will be fitting sequential dump valve to dismiss a dump valve as a waste of time would be a stupid thing to say. yes you don't need one a car making lower power. but if you shooting out big bhp then there is a need for them

The main problem on zeds is that because the dump is after the maf, after each dump it runs rich. If you change the ecu and run a... er... speed density? Setup. Where you don't use a maf it will be fine.

 

A well set up dump or recirc valve will vent the pressure between the turbo and the throttle just enough that you reduce the stress on the butterfly and turbo. But its ready to go again after a gear shift and hasn't got to fully spool again.

 

The audi quattro noise, is air going backwards through the turbo (which is still spinning forwards) which will eventually wear things out a bit quicker.

Yes and no, I think that's an old fashioned thing before recircs were much cop or even fitted in the main. A properly functional recircs will keep the turbo spinning through the gear shift and this in turn reduces lag and lessens the chance of loosing the boost mid change. They are FAR superior hence why you will never see a modern super car hissing down the road.

and also if you going from low boost up to high boost on a engine making big bhp and the change was a big step the stock valve are going to set a given point arnt they that's were sequential dump valve come in. hks made then for a reason

dump valves are to help stop turbo stall not stall the turbos. from what I have been reading if you making big bhp thay can be a good idea. am going for round 600bhp and will be fitting sequential dump valve to dismiss a dump valve as a waste of time would be a stupid thing to say. yes you don't need one a car making lower power. but if you shooting out big bhp then there is a need for them

 

Really? This information fromGreg@SZ may help:

 

http://www.twinturbo.net/nissan/300zx/forums/general/view/2421113/I-do-not-recommend-blow-off-valves-on-the-Z.html

no was talking to a guy who own a tuning shop he tunes jap stuff been doing it for a long time he knows his stuff like

hay don't get me wrong here if I had a stock engine or low bhp I wouldn't bother am only using sequential dump valves for the reason of going from very low boost to very high boost am not saying every one else should do this its just what am doing each to there own 100%

Did you read the post Andrew put up from Greg?

yes I have seen it i know what hes saying

Atmospheric dumps are bad for engine health and are an old fashioned way to do the job, especially when combined with a map sensor system such as ours. A recirc is always better.

 

I know the dumps I've got are a bad idea, I recon my engine will die of abuse first though lol. Once I've had a rebuild il switch them out.

this is not just the 300 isn't any maf car isn't it running bovs. am going sequential dump valves for reason of toggling for very low to very high boost the sequential dump valve would be great for this reason not a stock bov, but yes i know the car will run rich for a very short time when lifting off

can I fit screamer pipes ?

 

Just to highlight this as well, screamer pipes are different althogether. They vent the air from the Wastegate to astmosphere bypassing the exhaust. So that air is unsilenced and unmuffled etc, ie attracts Johnny law.

 

Doing it on a zed is also slightly odd as they have turbos with internal wastegates, meaning it's part of the turbo not a seperate device. So whilst you can do it, it's a bodge and air will exscape before boost is built.

 

The noise is subjective too.