unheated inlet manifold - practical option?

[GreenV8S]

Anyone got experience (good or bad) of running an an injection setup with an unheated inlet manifold? This would be for normal use all year round. I expect it could be a problem with carbs, but would an injection setup be OK?

[GreenV8S]

The injection manifold has a hot water chamber built into the base on all models. The throttle body also has a small separate hot water chamber which is fed by external hoses - this is left disconnected on some models. As I understand it, the heating is there to ensure the fuel evaporates to give a uniform mixture even in very cold weather. Which makes sense if you're running carbs, but does it matter for an injection setup? Enquiring minds need to know!

[GreenV8S]

Was that using an injection manifold Steve?

[GreenV8S]

Makes sense to me that a carb manifold has to be heated, but I don't understand why the standard injection manifolds are also heated. Any ideas?

[GreenV8S]

The manifold has a joining chamber that forms the back of the stat housing. The chamber has one outlet at the front, and one at the back. The one at the front is the bypass and should be connected directly to the water pump inlet. The one at the back normally feeds the heater, and the pipe bringing the return from the heater is normally routed back under the manifold so that the bypass and heater return hoses both appear out the front of the manifold under the stat housing. You should have an SD1/EFI water pump which has two inlets to take these two hoses.

The bypass pipe is absolutely essential and must go straight from the manifold to the water pump inlet. Heater feed and return are optional and can come from anywhere you fancy, and don't have to be routed under the manifold (I've seen cars with these two pipes running on top of one of the rocker covers.)

The other pipes you may seen in the area are a pair of small bore pipes from bosses on the front/top of the manifold to the throttle body, these supply the dreaded throttle body heater. Worth disconnecting and blanking these off unless you live in Siberia.

[GreenV8S]

ssc1 said:

would it not be better if they were connected to each other or one removed and the other connected to the stub on the inlet manifold

Doesn't make enough difference to the engine to worry about, but they are connected together on mine and I agree it does look tidier.