High Performance LS Radiator Fan Motors

[2ndGenCrazy]

I have a tuning tip to check for "optimum" initial advance.

If you have a hand held or laptop to view IACV commanded steps, this might be helpful:

While watching the commanded IACV position, add idle spark in 2 degree increments and observe what the IACV steps are.

If the IACV steps go down, add spark until it stops lowering the idle bypass air rate (lower steps from closed).

If the steps go all the way to zero, close the throttle blade using the idle screw until the desired warm IACV steps are achieved. 30 to 35ish?

In the process of doing this, you may need to reset the zero TPS calibration if you did indeed move the idle screw.

This is a method to determine what YOUR ENGINE likes for initial timing. It's not that your current setting is bad per say, but optimizing it to achieve what your engine likes best. You may also notice a slightly lower idle MAP is also achieved after doing this.

 

[2ndGenCrazy]

Another thing to investigate using a thermal heat gun:

With the car at full temp and idling at your 220 mark.

Using the heat gun, measure the hoses at the inlet and outlet of the radiator.

See what the temp drop is across the radiator.

I typically see 20 degrees or more.

 

[CorkyE]

Thanks for the input 2nd Gen. With the PF4, there's no way to command IAC position, just on/off. According to the tuners manual, you adjust throttle blades to give a value of 0 - 15% at idle when engine is warm. I have mine around 5% now.

Timing curve is 20 initial, 1250rmp start, 35.5 total, 3000rpm all in, 7 v/a.
AFR set points are 13.3 idle, 14.0 cruise, 12.6 accel.
Idle rpm is 875.
Thermostat is the recommended 180°, #1 fan on at 185, #2 at 190.

I've hit the top of the radiator with an IR gun, but haven't measured drop and the bottom. I'll do that next time I'm out. Supposed to have rain in the Chattanooga area the weekend, so might be a while.

 

[ULTM8Z]

What water pump are you running?

 

[CorkyE]

Sorry, been gone - Edelbrock Victor, reverse rotation on serpentine setup.

 

[ULTM8Z]

Hmmmm... you might try getting a stock replacement pump.

Frostbite radiator vs "stock replacement"

Had a bit of a heat wave over in SoCal here this weekend... so my mind wandered back to my Frostbite (FB) radiator that I had bought the other year during my "running hot" investigation (that ultimately eneded up in me discovering the thermostat was bottoming out on the Miniram coolant passage...

nastyz28.com

Starting at post #10... I describe my bad experience with a "high-flow" Stewart pump. Personally I don't think these types of pumps are particularly efficient at low rpms...

 

[CorkyE]

I still have the pump that came with the kit. Just have to get to my storage unit and dig it out. I haven't heard this about the Victor pump but it worth a try.

Your right about long time to drain. Petcock on ECP radiator is close to radiator support and water drains onto it. Perfect opportunity for a big mess in the garage.

 

[ULTM8Z]

I dont know how the Victor compares with the Stewart so its something you'll just have to try and see. But the good news is the pump is extremely easy to change on a serpentine setup.

BTW...Since i use silicone sealant, One trick I do is get two really long bolts and use those to initially align the pump. I then slide the pump forward and mate it to the block. I then install two of the actual bolts, pull the two long ones out and then install the remaining two bolts.

It's hard to see what you're doing in there between the two main serpentine brackets so it can get a little messy with the wet silicone. This way I can do it "blind" but still be super accurate in initial placement.

 

[75Maro]

I dont know how the Victor compares with the Stewart so its something you'll just have to try and see. But the good news is the pump is extremely easy to change on a serpentine setup.

BTW...Since i use silicone sealant, One trick I do is get two really long bolts and use those to initially align the pump. I then slide the pump forward and mate it to the block. I then install two of the actual bolts, pull the two long ones out and then install the remaining two bolts.

It's hard to see what you're doing in there between the two main serpentine brackets so it can get a little messy with the wet silicone. This way I can do it "blind" but still be super accurate in initial placement.

Spoken like a true Jedi master

 

[ULTM8Z]

That's not the water pump you're looking for...