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· Registered
99 Posts
Discussion Starter · #1 ·
I have done a fair amount of searching on this topic, but I havent been able to come to a concluision about whether I need to fit a BOV or not. So looking for some advice.

My M-Tec installed TD04 conversion has been sweet at a nut since install. Been on the car (1991 1.6 Eunos now for about 18 months).

The Car does about 2k miles a year, Its very well looked after, and I want to keep it that way for many years to come.

Right now, there is no BOV on the car. So when im on boost, and I take my foot off the throttle, I get a flutter from the turbo. I think (please correct me if Im` wrong) this is becuase remaining pressure in the system is hitting the turbo impellers becuase it doesnt have anywhere else to go.

So, questions::

Do I need a BOV?
Without one, am I artifically restricing the life of the Turbo (only 2k miles a year)?
How will a BOV affect the noises coming from the Turbo?
How much will professional fitment cost if I do chose to fit a BOV?
Does the fitment of a BOV mean the car will require a re-maping on a rolling road?
Is it sensible to ask my my local garage to fit it (i`m not mechianical)?

Any help appreciated.

· Hiding from the Ayatollah or making Full Metal Jac
1,830 Posts
Need ? No.

Doesn't require a remap. Doesn't give you more power.

Can, if you shift really really fast, give you slightly faster spool. But you probably won't be able to measure it.

Can probably extend the turbo lifespan a tiny bit. But you probably won't be able to measure it.

· Registered
1,134 Posts
You can add a recirculating valve to reduce the noise below what you currently get or a vent to atmosphere valve to get a "whoosh/tssh" instead of your current noise. In my experience a car without a BOV is louder than either VTA or recirculating BOVs (almost all of the recirculating valves fitted by OEMs are for noise suppression).

Whether your local garage can fit one or not completely depends on the garage. A local "tuner" garage should definitely be able to fit one. If it's just a VTA valve you want it is probably just the valve, a silicon joiner (to replace one in your existing intercooler routing) and then a T-piece silicone vacuum hose from the valve to post throttle that you need (i.e. very simple).
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