Turbo lag

zetec452

zetec452

zetec452

Soldato
Joined
15 Sep 2003
Posts
9,454
Hello,

I have a Mazda 6 TDi with 126k on the clock. Is there any way to reduce the ever increasing amount of turbo lag? The car is well serviced and maintained.

TIA.

Jon
 
Dump valve?

Although you say it's ever increasing lag... some sort of loss of pressure (dodgy pipe?) - although I'm a noob so guessing :)
 
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I thought a dump valve was just so you sounded like a tool (I mean cool) changing gear in your 1.1 corsa?
 
Possibly a weak actuator so its not clamping the wastegate shut when its supposed to, or a boost leak thats getting larger ?
 
pc-modd said:
I thought a dump valve was just so you sounded like a tool (I mean cool) changing gear in your 1.1 corsa?
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Aye, because 1.1 corsas have turbos.

Solari said:
I thought this was the whole point of them unless I'm misinformed? :p But as his is getting worse it'd be pointless...
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Yup, misinformed, they don't really reduce lag at all, well, depending on the car/power.

Totally pointless on a TDi.
 
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Johno please? said:
Aye, because 1.1 corsas have turbos.

Yup, misinformed, they don't really reduce lag at all, well, depending on the car/power.

Totally pointless on a TDi.
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Well that's something new I've learned... so the point of them, in essence, is to make you look like a prat :) Would a remap kick the turbo in at lower revs then to achieve the effect of reducing lag?
 
Solari said:
Well that's something new I've learned... so the point of them, in essence, is to make you look like a prat :)
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No, why would that be the reason for a dump valve :confused:

Its to vent un-needed boost pressure (to atmosphere) when the throttle isn't open.
 
paradigm said:
No, why would that be the reason for a dump valve :confused:

Its to vent un-needed boost pressure (to atmosphere) when the throttle isn't open.
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From what I gather there seems to be a mass misconception (at least among people I talk to) that it keeps the turbo spinning and reduces lag. What's the upside of venting the boost pressure? I still don't see what the benefit is (not being mechanically adept myself). Plus the amount of times I've seen chav cars bumping along with the tell tale "psssssshhht" noise thinking they look cool makes me wonder what on earth it achieves if it doesn't reduce lag?

Maybe a stupid question but I'd rather look a **** and know the answers :)
 
a website said:
[FONT=helvetica,arial]Why do manufacturers fit a dump valve?[/FONT]

[FONT=helvetica,arial]It is for a number of reasons. Without a dump valve, when the throttle was closed, the build up of boost pressure would be immense, very similar to closing a quickly flowing water tap. This excess of pressure, (which could be over five times the running boost pressure), would put the components of the system under a great strain. It would try to burst the intercooler and pipework. More significantly, it would put a large strain on the turbocharger itself, firstly stalling the compressor shaft, then trying to force the compressor wheel out of the turbo, against its bearings.[/FONT]
[FONT=helvetica,arial]So, the dump valve prevents mechanical damage to the intercooler & turbo pipework, prolongs turbocharger life, and prevents excessive turbo - lag that would be caused by the compressor shaft stalling.[/FONT]
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a vent to asmosphre dump valve is basically for show, usually the air has been measured by the MAF and the ecu injects the corrosponding amount of fuel to air, but this air is vented to atmos so the rich mixture also causes flaming/popping etc, the best way is to have a recirc dumpvalve
 
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