wastegate springs

[Charlie Smith]

Earlier, GEORGE MILLS wrote:
> 
> Nate Stuart wrote:
> > and pulls like a raped ape all the way through 5g's
> 
> Is that a BTDT kindathing...or just rumor, urban legend kindathing?
> Sorry :) I'm just getting primed for Saturday night!

Not a rumor.  

For what it's worth, I've actually sold the last spring of the batch
of 100 that I had manufactured back in what ... 1995 maybe?  I think
I'll see if they can make up another smaller batch.  If so, I'll post 
something here.

As far as the fuel pump relay ...  here's an excerpt from the instructions
I used to mail out with a spring.  It covers the topic of FP relay.

I'd recommend that you read Scott Mockery's web page information
about the effects of raising the boost through a stronger wastegate
spring.  His web address is:  http://www.sjmautotechnik.com/

    - Charlie


  Charlie Smith   charlie at elektro.cmhnet.org  614-471-1418  
  http://elektro.cmhnet.org/~charlie   Columbus Ohio   USA

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features  
  96 Dodge Ram   -  30 PSI, w/Cummins turbo diesel

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
from spring installation document
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In addition to installing the wastegate spring, you will need to
install a fuel pump relay ground wire to circumvent the Engine
Control Unit (ECU) overboost limit.  In it's stock form when the ECU
sees over 1.5 bar boost, it assumes something is wrong and shuts
off the fuel pump.  And, in stock form something would be wrong
since the stock USA setup only puts out 1.3 bar boost pressure.
Since the new spring raises the boost output to 1.6 or 1.7 bar boost
pressure, this ECU overboost limit must be bypassed.

When the ECU thinks it's seeing overboost, it shuts off the fuel
pump relay.  It does this by ungrounding the fuel pump relay,
normally the fuel pump relay ground is through the ECU.  The ECU
also monitors engine RPM, and provides an RPM limiting function by 
ungrounding the fuel pump relay to shut off the engine when
excessive RPM's are detected.

When you bypass the overboost limit with the fuel pump ground wire,
you are also doing away with the rev-limiter function of the ECU.

There's a description below of a good safe way to construct
the fuel pump ground wire circuit.
_________________________________________________________________


After you hook up this fuel pump ground wire, you ideally should
make another modification in the future ... this wire really
**SHOULDN'T** stay grounded if the engine quits.  For safety
reasons, the fuel pump should be OFF when the engine is stopped!
This ground wire will keep the fuel pump running whenever the key is
turned on - this has obvious dangerous implications if you had an
engine fire and the engine quit !!  

To do this so that the fuel pump shuts off when the engine dies, 
do it this way.  Add a "T" fitting under the oil pressure sending 
unit, and then add an oil pressure idiot light switch into the "T".

When oil pressure builds up, the Idiot Light Switch (ILS) will open up
it's contact.   So ...  get a SPST Normally Closed (N.C.) 12V relay 
from Radio Shack, and wire it up so that when the engine has no oil 
pressure (it's stopped) then the ILS is closed - and the closed ILS 
will 'open' the N.C. relay.  Now, use this relay to ground the fuel
pump relay.

Thus, when the engine is running, the ILS is open and the N.C. relay 
provides a ground for the fuel pump relay ... and the computer can't 
shut the engine off by ungrounding the fuel pump relay.

Likewise, if the engine stops, the ILS closes and opens the N.C. relay
which UN-grounds the fuel pump relay ... shutting off the fuel pump.

Follow all that?  Right!

Now, where is the fuel pump relay ground wire?  Try terminal 47 on the
relay board under the hood (left side by firewall), which is connected
to terminal 21 on the Engine Control Unit (ECU) plug.  This should
be a brown wire with a greenish yellow stripe, 3rd connector from the
end of the ECU plug.