Temperature-based trigger?

[rao]

Would it be advisable to use a temperature-dependent trigger for WI? I am interested in a system that is completely automatic and does not need any adjustment once set-up.

I am concerned that WI is not necessary (and may be disadvantageous) in cooler temps and I don't want to be consulting the weather every time I hop into t he car to decide if WI is needed or not.

Nordskog sells a temp gauge that can be used to tigger a reelay abvove a user-selectable tempartarue. It seems to me taht it would be advisable to put this in-line with the pressure switch so that WI would not be triggered unless the temp in the intake tract was above, say 150 AND the pressue was above the set point.

Does this sound like a good idea, a bad idea, a silly idea?

TIA

[hotrod]

I manually disable my WI system when temps drop below about 50 - 60 deg F, depending on humidity. I can notice the car does not run as well in cool temps if the WI is on --- too much of a good thing I believe.

I have also considered exactly the same approach but have not gotten around to making the necessary changes. I just have an "WI arm" switch that controls power to the pump and relays and do the same thing you are suggesting.

Larry

[keithmac]

problem with using an IAT switch is when the WI activates the teps drop and the switch opens again do to the WI cooling.

MegaSquirt ecu can be used to turn on the WI at a set IAT, boost pressure and rmp, can also fire the HSV off a map so you have full control over waster delivery.

I`m using Megasquirt (Squirt`n`SparkExtra) for Fuel and WI control, maybe a bit overkill for what you want though.

[Shaker666]

problem with using an IAT switch is when the WI activates the teps drop and the switch opens again do to the WI cooling.

MegaSquirt ecu can be used to turn on the WI at a set IAT, boost pressure and rmp, can also fire the HSV off a map so you have full control over waster delivery.

I`m using Megasquirt (Squirt`n`SparkExtra) for Fuel and WI control, maybe a bit overkill for what you want though.

Is the fact that the WI activates/deactives a real problem? It seems like it's simply behaving in a thermostatic manner, ie. maintaining an IAT of 200* F or whatever it's set to. That seems to be fairly ideal to me.

[keithmac]

Good point, although if you`re around the set temperature then the triggers may be too frequent, you`d need some sort of buffer? I think one of the reasons MS only uses the IAT sensor at the point of triggering is because the IAT could see a lower temperature due to water evapouration off the actual sensor, would depend on the individual setup though? Also the MS resets after each water injection, so if you`ve come off throttle and back on it`ll re-evaluate the situation and only fire again if the charge temp is too high.

[Shaker666]

I think the operating frequency of the system is high enough to properly deal with the cycling temps, I wouldn't be too worried about it, although I'd datalog it to be 100% sure. It also depends on the placement of the ACT sensor. Mine is located in the lower intake manifold, after the supercharger, and a about 4-5 inches from the intake valve. The WI would inject into the blower discharge, approximately 6" above and before the ACT sensor. It would definitely cycle, as you say, but I've yet to install a WI system to datalog and verify that it's a problem.

[ride5000]

just put your temp sensor before the injection point and there will be no cycling. hot charge = injection.