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5KCSTQ Wastegate Springs

 - More Wastegate Springs & Fuel Pump Cutoff stuff ...

I posted this about three weeks ago, and I'm getting ready to get to the
spring manufacturer and have the second batch produced.  If you are 
interested in one or more, let me know before Friday.

This batch is going to be targeted for 1.8 bar without the shim, and 
I'm going to figure $20 including postage.  Again, this isn't a firm
commitment on your part, I just need a ballpark headcount to have
the springs made up.  I'll email you directly and ask for your address
when I've got the springs in hand.

I also told some of the folks offline, that I've figured how to make
an adjustable overboost protection control box - although I've not
got the time to do it right now.  I'll post more on this later.

    - Charlie Smith

    copy of previous post
 - Wastegate Springs & Fuel Pump Cutoff stuff ...

I'm going to have some more wastegate springs wound at the local spring
shop.  All of the first batch are gone, and I've had several people
ask recently if I've got any left.

The reason for this message is to ask who wants one from the next batch.
If you want one (or more), email me and let me know; I won't consider
this a firm commitment on your part, I'm just trying to get an estimate.

The springs I had wound last time gave you about 1.6 bar without any
extra shims, it took an extra 4mm shim on my '86 5k CSTQ to get
to 1.7 bar boost.  This time, I'm going to try for 1.7 bar without
any shims, so these will be just a tad stronger than the last batch
of springs.

I will ask somewhere in the neighborhood of $15 per spring - this time
I'm going to add the cost of shipping onto the price since last time
I ended up a little bit in the hole after I paid for the boxes and
for shipping.  Probably will end up around $20 including postage for
this batch.  Last time the boxes were just over $1 each, and shipping
averaged about $3.50 depending on distance shipped.

I'll include the detailed instructions on how to bypass the overboost 
shutoff of the fuel pump.  I know Ti and one other person haven't wired
up this bypass, but I highly recommend doing it.  First, you won't see
more than 1.5 bar boost without it, and as somebody said - it's a gross 
pain in the *** to have to feather the throttle to avoid the off/on/off/on
action of the overboost circuit killing the fuel pump.

When you set this up like this, the boost is controlled by the wastegate
spring, and there's no automatic overboost protection.  But, I believe 
the only way you are going to get overboost is if the wastegate sticks
shut.  From what we've seen reported here, the major thing this will
cause is to split the ends open on the intercooler.  A protection on this
is to run some large hose clamps around the intercooler - around the
outside edges - to strengthen the end caps that are just crimped on.

I'll try to locate some adjustable pressure switch units that can be 
used along with the bypass circuit to maintain an overboost protection 
capability.  The overboost bypass circuit is just an extra ground wire 
to one of the wires in the ECU plug.  If this added wire grounds through 
an adjustable pressure switch, that opens up when the set pressure 
is reached - then you still have overboost protection.

I'll let you know what I can come up with on this.  It will probably be
three weeks or so before I get to the spring shop, so let me know by
email if you are interested so I have a rough count.

    - Charlie

Charlie Smith   charlie@elektro.cmhnet.org  
Columbus, Ohio USA            614-471-1418  
Cincinnati daytime -          513-381-3885  x423

 4 wheeled fleet:			 2 wheeled fleet:
_________________________               _________________________
86 5kCSTQ      				92 Ducati 851SP     851cc
69 Porsche 911S   3,200cc		95 BMW R100-RT    1,000cc
81 VW Diesel Pickup  			62 BMW R27          250cc