Ebv mod

Exhaust Bypass
Valve Mod

Warning: This
mod can cause problems with your second turbo. Besides putting more stress on your first
turbo, it dampens the normal prespool associated with proper ebv operation. This can lead
to the #2 being “slam started” from a stationary position. Please use caution
when doing this mod. Reducing the flow between the T’s is a smart idea if your dead set on
more low end boost.


The EBV (Exhaust
Bypass Valve
) mod is pretty basic. Doing the mod simply gets more PSI from
turbo #1 before the cut-over to turbo #2. What you are doing is slowing the opening of the
exhaust bypass valve (ebv)by diverting some of the turbo pressure away from the VSV. The
ebv really acts as a wastegate for the #1 turbo and the ebv mod is essentially the same
thing as the bleeder T mod(or hose pull mod) for the #2 turbo.

You need to use your discretion when doing this mod,
because it may be harmful to the #2 turbo. This mod somewhat eliminates the #2 turbo
prespool. Without prespool, when the exhaust gas control valve opens, the #2 turbo isn’t
moving so it gets “kick-started” pretty fast by a big rush of pressure.

First step is to remove the A and B hoses(Fig.
1), save all your stock hoses!, and use regular 1/4″ vacuum hose in it’s place. Now
cut A and B in half (new A and B hoses). Insert a vacuum T(Fig.2) or Y(Y is used in the
photo) in line with hose A and B . Each vacuum T will have an open end bleeding pressure
into the atmosphere. Now take another piece of hose (about 5″ long) and connect the
tops of the 2 T’s. That’s it!.

As you will notice in Fig. 4, there is an
adjustable valve in the bypass line so you can enable or disable the modification. With
this mod you should notice an immediate improvement in low end response.


ebv11.jpg (71783 bytes)

Fig. 1


vacuumt.jpg (8316 bytes)

Fig. 2


ebv22.jpg (84572 bytes)

Fig. 3


ebvxxx.jpg (54653 bytes)

Fig. 4

Ebv mod with adjustable valve


supra_su.gif (5342 bytes)


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