I have an 88 Iroc-Z 350 TPI. First, i don't think my thermostat is operating as my car sat for years. What is the recommended thermostat (temperature wise)? Second, I have the dual fan setup. The one on the driver side comes on, but I haven't seen the one on the passenger side come on. Does it only come on when the A/C is on, cuz my A/C doesn't work (compressor doesn't operate)?

do not cut the wire just piggy back the 2 fans.. i did this to my 92 Z28 5.7. so when the main Fan Kicks on the 2 Fans Kick on at the same time..(i want to add i did add a bigger relay) for the 2 fans

you can stand at the back of the car 30 feet away.. and feel the AIR they MOVE..!! 11.1 383 runs about 195 on a Hot day track temp can get up to the same.. but sits most of the time at 190...

How do you piggy back the two fans?

use a splice knuckl from the Hot wire side of the Main Fan. and run it to the hot wire on the 2nd fan....all this dose is power the 2nd fan when the main fan Kicks on.. use the stock wire wrap to cover it all back up..looks stock and runs way cooler..

i do not have AC any more.. and wanted to run the 2nd fan at the same time..
if you dont have AC you can go the the parts yard and Cut the Plug that fits your fan. and use this to piggy back to your 2nd fan from your main fan.. if your fan fuse is a 20 now. go to a 25... or if it's a 15 go to a 20..this is just needed at the start up when the 2 kick on..this is 100% safe...

at night mine runs abot 180.. in the hot days about 190...

Stock thermostat is 195°. A 180 is a good medium for all year use.

Stock secondary fan turns on at 238° via the fan switch in the passenger head.
Replace it with AC Delco D1855B (or equivalent) fan switch. 215°F turn on. 5° cooler then the ECM switched primary. No splicing or, putting those horrid scoth locks on the wiring.

Even with that, it would be wiser to tie the ground from the ECM switched fan relay to the secondary. That way, each fan has it own seperate relay and both fans will turn on at the exact same time. Simple, safe and effective. Plus, all the parts/wiring are already present.

A single stock relay isn't really rated for the amperage of powering two fans. That about the same theory as putting a bigger amp fuse in a circuit that keeps blowing fuses. Sure, it will work for awhile...

But, that's just my opinion.

sorry i was calling it a fuse..it's a relay used for the 2 fans. it's been 15 years ago.
i did this.. and i remember doing the wiring.. have to look at my Note book i made. when i did the car..still have the car.. wanted to move more CFM and with the 2 fans running at the same time works fantastic.. this car's best time was 10.34 @ 124 MPH
would drive it every weekend. (NO RAIN) that is so it was not for a stock set up..
i liked the car to stay cool ..under 200 on the temp..but thats just me.. would make 400 mile road trips and never had a heat prob...
even in stop and go trafic..of the Big citys..

Factory calls for 195 degree thermostat but 180 is good all around keep car cooler in summer heated in winter. Since it has been sitting for awhile I would flush system and refill 50/50 antifreeze to water.