MX5 Turbo build - BOV or not?

Joined
5 Aug 2006
Posts
11,185
Location
Derbyshire
Hey all.

I am finally getting around to building my turbo mx5. She is a 1992 1.6.
I have had the ECU (ME221) in her for 4y now. Wideband too.

Collected parts include:
G19 Manifold and downpipe
TD04 turbo refurbished from Midland Turbo
Turbo fitting kit
Colder spark plugs
Clutch

I need to buy an intercooler. I want to buy a kit as this uses molded hoses, rather than pratting around with elbows and jubilee clips.
Some kits have a Blow Off Valve (BOV). Some don't bother.
The internet argues back and forth.
I don't care for the blow off valve noise. I am more interested in turbo life, since the turbo cost me over £400.

What would OcUK do - BOV or not?
 
Soldato
Joined
5 Oct 2009
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12,142
Location
Spalding, Lincs
This is one of those age old debates! I've never seen a turbo killed by lack of BOV, I know plenty running without one no issues. I run one but it's wound right up so plenty of turbo chatter at low boost!

I'd say go with your personal preference, if you don't want one don't fit it. It may shorten the life of the turbo but I'm guessing you're not wanting to get 100k miles out of it so I'm sure it'll be absolutely fine.
 
Soldato
Joined
25 May 2008
Posts
3,303
Location
North Wales
I think it usually depends on the turbo's, in my old Subaru STi it was generally considered a bad idea to have no BOV as the VF35 didn't cope with it very well but older cars with TD05's it seemed to be fine.

I think as you've got a TD04 it'd probably be fine without, but if it was me i'd probably want a recirc one in there for piece of mind as i never thought there was a down side to dumping the excess pressure rather than making the turbo stall with the back pressure.
 
Man of Honour
Joined
13 Nov 2009
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11,512
Location
Northampton
I ran essentially that exact setup but on a 1.8 for close to 4 years with no BOV fitted.

I then swapped to a recirculated Bosch/OEM VW style valve because I wanted things to be quieter , there was no measurable difference in either spool or on/off throttle response between either setup
 
Soldato
OP
Joined
5 Aug 2006
Posts
11,185
Location
Derbyshire
I ran essentially that exact setup but on a 1.8 for close to 4 years with no BOV fitted.

I then swapped to a recirculated Bosch/OEM VW style valve because I wanted things to be quieter , there was no measurable difference in either spool or on/off throttle response between either setup
I remember us talking at the RR day in Stoke. Probs 2016 or 2017?
My turbo project is still in progress :p.
 
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