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Re: SVX Engine cooling "Again & Again"
It has been a long time since this thread has been amended, but I have some new and relevant data. The build on my '94 Emerald Green was getting to be 9 years old, so I thought I would have the belts changed (10 year recommended interval). The shop said that while they were at it, they should go ahead and change the water pump. The fact that the thermostat on my car had been removed from the water pump and a remote thermostat had been added slipped my mind. Drove it home after the work and it was bad old days all over again, but worse. Right after the first time I took it over 5000 rpm, the temperature needle very rapidly moved from slightly below horizontal to vertical, past the red zone. Pulled over, let it cool a bit, drove it home, trying to keep it about 3000 rpm. Still, frequent blips into the red, then subsiding. Got home, overflow tank is full of coolant. Called the shop, scheduled a visit to remove the thermostat. (I don't have a lift and I'm getting old). They removed it. Back to being nice. No overheating spikes. Proving the hypothesis that at least part of the spike overheating problem is cavitation at the inlet to the water pump, caused by the flow restriction of the thermostat. I'm a retired mechancial (HVAC) engineer, and our standard for pump installation is 5 diameters of straight pipe at the suction side or the pump or an inlet diffuser to even out flow into the pump and reduced turbulence. Here are teh standards for pump configuration:
The suction pipe should never be smaller than the suction nozzle of the pump and in most cases it should be at least one size larger. Suction pipes should be as short and as straight as possible. Suction pipe velocities should be in the 1.0 – 1.5 metre per second range, unless suction conditions are unusually good. Higher velocities will increase the friction loss and can result in trouble some air and vapour separation. This is further complicated when elbows or tees are located adjacent to the pump suction nozzle. In that case uneven flow patterns or vapour separation keeps the liquid from evenly filling the impeller. This upsets hydraulic balance leading to noise, vibration, possible cavitation and excessive shaft deflection. Cavitation, erosion damage, shaft breakage or premature bearing failure etc. may result.
Note that the guidance is given in Britspell for all our Southern hemisphere friends.
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95 LS-i Red, 31,xxx; bone stock for now; Daily Driver
94 LS-i Emerald Pearl, 106,xxx,; 246 whp; Tomyx snorkus and HKS Cold air intake; PWR aluminum radiator, silicone hoses; Inline thermostat; enhanced coolant routing; external power steering and oil coolers; Phenolic intake manifold spacers; 2004 WRX 5 speed transmission; ACT Clutch Kit, Heavy Duty Pressure Plate, Lightweight flywheel, performance disc; Group N motor mounts; ‘07 WRX 4-pot front calipers, cryo-treated slotted Tribeca rotors; Hawk HPS ferro-carbon pads; Frozenrotor rear slotted rotors; SS brake lines, Axxis Ultimate pads; Rota Torque 17x8 wheels; 245/40-17 Bridgestone RE01-R's; Koni inserts with Ground Control coilovers, Eibach springs; K-Mac camber/caster adjustable strut mounts; Urethane swaybar bushings; Bontrager rear sway bar; Urethane differential bushing; Custom Whiteline adjustable rear lateral links; Outlaw Engineering forged underdrive pulley; custom grind Web intake and exhaust cams (11 mm lift, 250° duration); solid lifters; CP custom aluminum forged 11 to 1 pistons, Brian Crower coated SS intake & exhaust valves; Brian Crower upgraded springs w/ titanium retainers; NGK sparkplugs; RallyBob (Bob Legere) ported and polished cylinder heads; Eagle H-beam rods; ACL Bearings; Cometic Head gaskets; ARP head studs & fasteners; Hydra Nemesis EMS; Wideband O2 sensor; 740cc Injectors; Walbro 255lph fuel pump; Upgraded WRX starter; Equal length SS headers (3 into 1); dual Magnaflow cat converters; 2 into 1 into 2 SS exhaust with Bullet muffler; OT Fiberglass hood; Oil pressure gauge; Programmable shift light,
2017 Subaru Forester XT, metallic dark gray, 29,xxx
2005 Porsche 911 Turbo S Cabrio, 24,xxx
2006 Subaru Outback LL Bean, 166,xxx sold
92 LSL Dark Teal, Smallcar Shift Kit - sold
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