From what i have noticed with voltage drops on my truck with the efans the culprit was the harness and having large enough relays and wires to support them. I have upgraded everything but it all came down to the efan harness itself. Big 10g wire is needed throughout.

 

Every dyno tuner I've talked to always shakes there head about 160 degree stats. They always claim best power on their dyno's have been around 210*.

I've never tested this myself since I don't have a dyno but just thought I'd throw that out there.

 

I need to check the gauge of the wiring but im using a full 05+ oem harness and relays. It should be adequate in that regard.

 

I'll sacrifice some minimal extra wear and friction with the lower temps. I feel safer with the lower temps but dont have any data to back it up. Just anecdotal evidence.

 

They are right. The less heat energy that is transferred to the cylinder walls, the more usable cylinder pressure you have for making power. But for our big power turbo setups, ring expansion is an issue...so they have to be kept cooler if you want to make power. You can make more power with a hotter coolant temp, but it is far less forgiving.

 

Yep makes sense. I'll have to watch temps when I get mine on the dyno. The stock gapped 4.8L rings probably won't like 22+ psi

 

Along the same train of thought...preheating the fuel will increase power as well. Good luck controlling detonation though.

 

Well, bad luck I guess. I've been working like crazy but there was a dyno day event at LMR here in Houston I wanted to go to. I got it fired up last Friday night all was well until after about 5 minutes of running I started getting a nasty lifter tick on the driver's side. Ended up with an oil leak on the bottom side, likely due to the crappy pan gasket I had on. Everything sounded perfect at first fire up so I'm guessing the lifter tick was from lower oil level. Pressure was still up, 55-60 psi cold idle. I do wish I would have replaced my lifters back when I had the heads off with the Tooley SLR's. Anyways, new GM oil pan gasket is on the way just had to pull the rivets off the old pan.

Also, I re-did my turbo oil drain at the pan because I originally had it pretty high in location and the line was abutting the starter. I was worried about it rubbing a hole in the line leading to a catastrophic failure. Well, when I got it off I found out the line was in perfect condition. Anyways, I went to a Summit 1/2 NPT to -10 AN fitting and then a 45 degree -10 pushlock swivel fitting from Summit. Damn thing was leaking at the swivel!

I talked with Summit and told them I wanted to switch to Aeroquip fittings and I was charged $5 for a new 45 swivel fitting an 1/2 NPT to -10 AN fitting. Told to throw away the current fittings. Pleased with that.

Only good news to report is that my OEM efans and OEM harness install worked flawlessly. The OEM harness is a super clean install. Only thing I'm not sure of is what controls high speed for the fans. Obviously, the low speed on is controlled in the tune and I'm guessing high speed is based on the A/C pressures. But what controls high speed when the A/C is off?

 

High and low speed are both controled by the tune. Both can be activated with temp and/or ac pressure.

 

Where is the high speed in EFI live? Does 99-02 have high speed control by temp? This is what I'm working with at the moment