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5KCSTQ Wastegate Springs
- 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
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 Smith email@example.com
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